Ocean temperatures and ITCZ migrations triggered cyclone-frequency variations during the Holocene

Ocean temperatures and ITCZ migrations triggered cyclone-frequency variations during the Holocene | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Physical Sciences - Article Ocean temperatures and ITCZ migrations triggered cyclone-frequency variations during the Holocene Dominik Schmitt, Eberhard Gischler, Martin Melles, Volker Wennrich, and 6 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-3758003/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract Blue holes (marine sinkholes) are remarkable archives for past cyclone-frequency reconstructions, as they work as formidable natural sediment traps over periods of several millennia. Tropical cyclones (TC) mobilize allochthonous particles from adjacent areas during their passages. In the Belizean “Great Blue Hole”, these particles become repeatedly redeposited under anoxic bottom-water conditions as coarse-grained event-layers within annually-layered bottom sediments. Chronological counts of these event deposits allow to develop long-term statistics of TC-frequency, exceeding the short range of instrumental TC-monitoring (73-years). In view of an intensifying modern global climate change, it is crucial to understand processes of climate forcing, that naturally alter TC-frequency on centennial to millennial time scales. Here we show, that a mid-Holocene (6.0-4.8 ka BP) climate restructuring entailed substantial changes for south-western Caribbean TC-frequency. We applied a multi-proxy-approach to the 30-m-long sediment core BH8, in order to identify 694 tempestites and developed a 12500-years-long history of storm activity. These data, for the first time, allow to compare frequency statistics with ocean temperatures and Intertropical Convergence Zone (ITCZ) migrations for the entire Holocene interglacial. Our results demonstrate, that an insolation-controlled relocation of Atlantic warm-pools and a subsequent southward displacement of the ITCZ triggered a 6500-years-lasting rise of south-western Caribbean cyclone-frequency. Earth and environmental sciences/Natural hazards Earth and environmental sciences/Climate sciences/Palaeoclimate Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Introduction Tropical cyclones (TCs) are among the most spectacular and dangerous weather phenomena on planet Earth. In view of the ongoing global climate change, TCs should be subject of palaeotempestology studies, addressing climatically-controlled frequency changes over longer pre-industrial time-scales. In the Atlantic Ocean, TCs primarily form along the northern edge of the Intertropical Convergence Zone(ITCZ) 1 , in four clearly defined sub-clusters 2 between 9°N and 20°N, described as the Hurricane Main Development Region (MDR) 3 . During the annual hurricane-season, gradually better self-organizing and progressively intensifying storm cells begin to move (north)-westward in synchrony with the Northern Hemisphere trade-wind circulation. On their way to the west, they pass the tropical Western Atlantic, the Caribbean Sea, and/or the Gulf of Mexico, before they finally deviate northeasterly at about 30°N. Seasonally recurring TCs are hence imminent threats for several countries located within the Atlantic Hurricane Belt. Their landfalls are accompanied by devastating winds, torrential rain, high storm surges, and flooding. Such extreme weather events cause massive economic damage to vulnerable infrastructure in coastal cities and endanger thousands of human lives each year. In modern days, thermodynamic and kinematic boundary conditions, in particular sea-surface temperatures (SST) above 26°C and low vertical wind-shear stress are found to be particularly favourable for a frequent TC-genesis 4,5 . The current hazard potential of TC-strikes could become even more exacerbated in response to a projected global warming of 2°C, constant SSTs above 26°C, and an expected ~1 m global sea-level rise by the end of the 21 st century 6,7,8 . While most studies predict a relative increase in the probability of storm cells reaching higher intensities faster and more frequently 9-16 , other studies rather suggest that the frequency remains at the current high state, although with a northern shift of a maximum activity zone 17 , or even propose decreases 18 . All these forecasts should be, however, treated with caution, as the underlying data originate solely from 173-years-long historical documentations and 73-years-long instrumental measurements. In addition, both records suffer from stochastic 19 , observational 20 and technical biases 21 , the latter two steadily increasing with time and new technical advances. The short instrumental and historical records are regardless highly suitable to decipher high-frequency oscillations of storminess and their underlying causes on multi-annual time scales. But it is already very challenging to appropriately asses multi-decadal climate forcing in TC-frequency prediction models, because all usually considered instrumental records only cover one or two complete cycles of climate phenomena´s modes of actions. All climate boundary conditions that alter TC-frequency on centennial to millennial time-scales cannot be taken into account, without a solid data basis that covers the Holocene interglacial and its different climate stages in its entirety. This requires new and much longer sedimentary records characterized by a high temporal resolution and sensitivity to track several hundred TC event-layers. Such extended statistics will not only help to further update the state-of-the-art information about past and present TC-frequency variability, but also significantly improve the accuracy of future prediction models. A growing number of event-based frequency reconstructions has already contributed to extend our understanding of multi-decadal to centennial-scaled climate drivers, such as the Atlantic Multidecadal Oscillation (AMO) 22 , the North Atlantic Oscillation (NAO) 2 and the El-Niño-Southern-Oscillation (ENSO) 23 , however only up to a 2000-years-long perspective. Appropriate archives were recovered from different sub-aerial sinkholes 1,24-27 and fully inundated marine blue holes 19,28-34 , located in coastal karst basins or on carbonate platforms within the tropical Atlantic Hurricane Belt. Proximal passing storms produce easily identifiable and countable indicator layers (coarse-grained over-wash deposits) in these formidable naturalsediment traps 35 , applicable to reconstruct extended TC-frequency statistics. Chronological studies of these sedimentary archives revealed alternating periods of stronger and calmer storm activity, that are linked for the past 2000-years to inter-annual 36 and multi-decadal 37 , up to centennial-scaled 31 shifts of the summer ITCZ latitude. Elevated local SST in the southern and eastern sub-clusters (2, 3 and 4) of the Atlantic MDR coincided with a generally more southern position of the summer ITCZ, concomitant with increased low-level vorticity and decreasing vertical wind-shear stress, as well as lower sea-level pressure 38 . Thus, we hypothesize that a Holocene-scaled mean annual and seasonal southward displacement of the ITCZ 39 , associated with a mid-Holocene restructuring of Atlantic Ocean warm-pools, would likely exert a strong impact on long-term frequency patterns in the Caribbean region by a commutated migration of the MDR sub-clusters 40 . To prove the hypothesis of a coupled ITCZ- and SST-triggered increase of regional TC-frequency, indicated by a shift of major storm trajectories from once higher (>30°) to lower latitudes (9°-20°), a complete and undisturbed succession of Holocene sediments, deposited in an anoxic south-western Caribbean blue hole site, very sensitive for storm-controlled event-layer deposition, would be required. In this study, we investigated the 30-m-long sediment core BH8 (17°18′57.2′′ N, 87°32′0.60′′ W), successfully recovered from the south-western Caribbean “Great Blue Hole”, which is located in the shallow eastern lagoon of the Lighthouse Reef Atoll, 80 km offshore the mainland coast of Belize (Figs. 1a, b, c). Core BH8 with its outstandingly well preserved event-layer record (n = 694) allowed us to reconstruct a 12500-years-long history of multi-decadal to centennially-scaled TC-frequency variation. These data, for the first time, enable a comparison of frequency statistics with the superimposed trend of a southward ITCZ displacement for the entirety of the Holocene. For that purpose, event-beds, related to a proximal TC passage (Fig. 1d), have been counted in 100-, 50-, and 20-years observational windows 24 . Their identification relied on a tested multi-proxy-identification approach 32 , combining several optical, textural, and geochemical criteria (Fig. S1). Passing cyclones cause a high grade of associated storm-wave erosion at windward marginal reef sites of Lighthouse Reef Atoll (Fig. 1e) and also induce strong hydrodynamic currents towards the atoll lagoon, which enables a re-suspensional transport (over-wash) of eroded reef materials ( Halimeda -chips and other sand- and gravel-sized skeletal debris). The carried sediment load is subsequently transported and redeposited in the sinkhole sediment trap as an event-layer (Fig. 1e) by means of density currents and gradual settling of suspension, respectively. Sedimentology and chronology of core BH8 Our sedimentological and palynological analyses revealed that the sediment succession of the Great Blue Hole can be separated into three major units (Fig. 2) representing (A) fully marine (24.6-0 m), (B) restricted marine (28.6-24.6 m) and (C) cenote-like (30.0-28.6 m) sedimentation. The sedimentary unit C marks an initial terrestrial sinkhole phase. In accordance with a sea-level rise from 60 m to 5 m below modern level 41 , the Great Blue Hole formed a subaerially exposed cenote on a limestone island covered by a Myrtaceae -dominated neotropical forest, during the latest Pleistocene and the early Holocene (12.5-7.2 ka BP). The continued sea-level rise close to the modern level induced a transition of the island to an initially flooded carbonate platform rich in mangrove swamps ( Rhizophora ), and a restricted marine inflow (7.2-5.7 ka BP) into the sinkhole. Since about 5.7 ka BP, the sinkhole is located in an open and well circulated atoll lagoon, resulting in fully marine conditions in the blue hole. Mangrove pollen completely disappeared and only wind-carried pollen of oaks ( Quercus ) and pines ( Pinus ) could be detected in higher abundances (Fig. 2). In the uppermost unit A (Fig. S2), over-washed particles form easily distinguishable white to pale brown event-layers that stand out from a light greyish to greyish green-coloured succession of annually-laminated fair-weather carbonate sediments. Similarly coloured event-layers appear in the slightly darker, greyish green to greyish brown-coloured sediments of the intermediate unit B. Compared to the overlying section, however, these tempestites are sometimes significantly enriched in organic material (wood pieces and leaf material from red mangroves) and thus very dark brown to almost black (Fig. S2). In the lowermost unit C, a grey brown coloured and finely laminated succession of carbonates is repeatedly interrupted by white or reddish and slightly faded event beds of significantly thicker and coarser deposits, which also include fragments of marine organisms, such as Halimeda , bivalves, gastropods and foraminifera tests) as well as organic material (Fig. S2). The chronology of sediment core BH8 is based on a proven combination of varve-counting- and 14 C-AMS-radiocarbon dating models 32 . The primary use of a varve-counting approach allows precise dating of all event-layers identified by optical, textural, and geochemical thresholds. All recovered varves of core BH8 were counted visually in PVC liners and cross-checked with measurements of thickness and colour differences derived from high-resolution images as well as density variations in radiographic recordings. Core parts not recovered in the PVC liners (i.e., core catchers) were texturally analysed and identified either as varved sections with or without an event-layer by means of their textural signatures in comparison with undisturbed core parts. For the age model, the time contained in these sections was estimated by extrapolating the mean sedimentation rates of the bracketing core unit. This proceeding yielded an varve age of 12091 ± 605 a BP at the core base. Eleven calibrated radiocarbon ages (cal. a BP) were used as a secondary age control (Fig. S3). Radiocarbon dating of bulk organic matter from 3000.6 cm depth revealed an overlapping age of 12583 ± 101 cal. a BP at the core base (Suppl. 1). This way, a robust age-depth framework without any core hiatus, was created (Fig. 2). At the core top, two independent chronological markers helped to additionally confirm the accuracy of the varve-counting- and radiocarbon-dating approaches. Increased pollen abundances of corn ( Zea mays ), pine ( Pinus ) and palm ( Arecaceae ) at 2.5 cm depth (Fig. 2), which do not appear elsewhere in the core, provide evidence of known anthropogenic cultivation in the past decade. Higher abundances of volcanic glass shards, likely from the 1982 CE El Chichón eruption, occurred at 32.4 cm depth, which is dated to 1979 ± 2 CE (Fig. 2). Historical storm record calibration The Great Blue Hole is positioned in the trackways of many historic TCs that formed in the Caribbean Sea (cluster 2) and in the western tropical Atlantic (cluster 4), east of the Lesser Antilles 2,42 . Following the described varve-counting-approach, we attributed event-layers identified in the modern sediment facies of the sediment core BH8 (upper 61.8 cm) to historical TCs documented in the International Best Track Archive for Climate Stewardship-IBTrACS 43 . This way, we were able to evaluate the sensitivity of the Great Blue Hole archive for a reconstruction of the Holocene storm activity. Since 1950 CE, 19 storm systems of varying strength passed directly over or adjacent to Lighthouse Reef Atoll in north-western direction (Fig. 1d). Eight of these were categorized as tropical storms and 11 achieved hurricane strength upon the closest passage. We were finally able to allocate 16 coarse-grained event-beds (Suppl. 2) to the 19 historically documented TCs (Fig. 1f). The susceptibility of the Great Blue Hole for event-layer preservation consequently amounts to 84%. Based on the existing calibration of the historical record, we have to concede an underestimation of about 16% for the following reconstruction of prehistoric TC-frequency in the southwestern Caribbean. The textural data (event-layer thickness, amount of coarse fraction >63 μm and mean grain size) of 32 event-layers from an observational record back to 1850 CE (Suppl. 2) were compared with instrumental TC data, such as wind speed at the location (km/h), storm duration (days/hours) and the distance between storm tracks and study site (km). All textural parameters were found to correlate best (p<0,05) with the wind speed at the study site (TC-intensity). The correlations (r = 0.53; r = 0.40; r = 0.45) are only moderate, and, there are not enough data available to create a valid proxy for reconstructing past TC-intensity based on sediment texture (Suppl. 2). In the modern part of the Great Blue Hole record, only two event-layers can be correlated with TC category H2 and just one event-layer with category H3. We therefore focus in this article only on the variability of the Holocene storm frequency. Holocene TC-frequency variability Our Holocene reconstruction of the southwestern Caribbean TC-frequency (Fig. 3) indicates a clear dichotomy with only very few event-layers have been found during the cenote-phase (12.5-7.2 ka BP), whereas considerably more were identified during the restricted marine (7.2-5.7 ka BP) and fully marine (5.7-0 ka BP) stages. The bold black line overlaying both bar graphs (Figs. 3a, b) is a LOWESS-smoothed frequency curve (see methods chapter), visually highlighting a first conspicuous excursion of event-layer frequency at 7.2-6.5 ka BP that is coincident both with a gradual 5 m sea-level rise to the present level 41 and an important mid-Holocene climate restructuring. Since 6.5 ka, the southwestern Caribbean experienced a gradual long-term rise in regional TC-frequency, as indicated by a steady increase of event-bed counts in sediment core BH8. Within this 6500-years-long course, several multi-decadal to centennially-scaled periods of changing TC-activity have been identified. In order to separate active and calm phases, we determined a site-specific threshold (horizontal grey line) for this period at values of 9.3 TCs and 4.7 TCs per 100- and 50-years counting intervals of event-layers, respectively. For most of the Common Era, the Great Blue Hole was exposed to an almost continuous interval of outstanding high TC-activity (Figs. 3a, b). The storm regime was very active in the south-western Caribbean realm from 1.5-0 ka BP (A1) and still moderately active from 1.9-1.6 ka BP (A2), according to the data from the 100-years counting window. Two periods of rather calm conditions occurred from 1.6-1.5 ka BP (C1) and from 2.0-1.9 ka BP (C2). A closer look at the 50-years reconstruction supports the presence of a continuous interval of high activity from 1.6-0 ka BP, however with an incisive drop of storm frequency from 172-122 a BP. In our 50-years counting data, we recognized a more pronounced multi-decadal fluctuation between active and calm phases from 2.0-1.6 ka BP, leading to an obliteration of the active A2 interval. According to our Belizean (Great Blue Hole) compilation (Fig. 4) using three records (Fig. S4), storm activity gradually increased in the south-western Caribbean during the Dark Ages Cold (DAC: 2.0-1.35 ka BP), culminated at a level of very high activity during most parts of the Medieval Warm Period (MWP: 1.35-0.6 ka BP), and then returned to the early DAC level during the progressing Little Ice Age (LIA: 0.6-0.17 ka BP). After the onset of the anthropogenically-caused Industrial Warming (IW: <0.17 ka BP), TC-frequency again strongly rose to and even above the MWP state. In stages older than 2.0 ka BP, a more frequent oscillation between active and quiescent stages occurred. Ten more intervals of increased storm activity (A3-A12) were identified in the 100-years counting window. The individual periods of high activity are exemplary shown in a simplified timeline (Fig. 3c). Rather calm conditions (C3-C12) were reconstructed for the intervening intervals. Likewise, all active and calm intervals of the 100-years graph (Fig. 3a) can be found in the 50-years frequency plot (Fig. 3b). Only a few multi-decadal deviations are apparent, which are not visible in the longer 100-years counting window, likely due to a higher subordinate variability as a result of the shorter counting interval. Interestingly, the identified periods of high and low activity (Fig. 3c) overlap only in parts with those for a Belizean coastal wetland site, reconstructed back to the mid-Holocene 44 . The fairly poor correspondence between the two records is probably caused by the lower temporal resolution and TC preservation potential of the wetland site and the application of different proxies for TC identification in both sites. Effects of a mid-Holocene climate changes During the early Holocene, and also in particular while the Holocene Climate Optimum (HCO), orbital parameters, climate modes, basin-wide SST patterns and the position of the ITCZ significantly differed relative to stages in the Late Holocene (Figs. 5a, c). A more northern tropical band with elevated SSTs and a related ITCZ position at 25-30°N were reconstructed for the Atlantic Ocean at the beginning of the Holocene interglacial 39 . With such a different oceanographic and atmospheric setting, storm systems probably developed not only in MDR sub-clusters further to the north (Fig. 5a), but also recurved, considering modern circumstances, generally away from the southern Caribbean realm 45 . In those days, east-west moving storm cells consequently tended to landfall at locations higher than 30°N along the East Coast of North America. Hence, only few rarely occurring storms belonging to the MDR sub-cluster 2 (Caribbean Sea and Gulf of Mexico), had their landfalls in the wider study area. During the same time, the Great Blue Hole was subaerially exposed as a cenote on a limestone island, as a consequence of a 60 m to 5 m lower sea level 41 . The combination of unfavourable climatic and oceanographic conditions and a different geomorphological setup including a dense vegetation cover around the cenote provides a plausible explanation for a hampered event-bed formation between 12.5-7.2 ka BP. The continuous sea-level rise, inundating the Lighthouse Reef platform between 7.2-5.7 ka BP, may explain the superimposed bipartite pattern and the first significant excursions in storm frequency up to 6.5 ka BP by significantly increasing the formation potential of tempestites in the Great Blue Hole. However, both the observation that the platform interior was already flooded at least several hundred years earlier than 6.5 ka (oldest peat date Lighthouse Reef lagoon 7.8 ka) 46 , and the subsequent long-term trend of increasing event-layer frequency provide strong evidence for a climatic forcing that induced a gradual shift towards a progressively more active storm regime in the south-western Caribbean after 6.5 ka BP. An orbitally-forced (21-ka precession and 41-ka obliquity cycles) reorganisation of global solar insolation 47,48 , starting during the Mid-Holocene Transition (MHT; 6.0-4.8 ka BP) is suspected to have caused hemispheric-scaled reversals 49 of oceanic warm- and cold-pools (Figs. 3b, 5b). These modifications in orbital parameters evoked pronounced changes in seasonal temperature gradients between high and low latitudes. Solar insolation in the tropics generally changed from a lower to a higher level, likely resulting in a southern repositioning of a tropical SST band, that was located far to the north during the early Holocene (Fig. 3b). In polar regions, the situation was exactly the opposite. The same changes in global solar irradiation also significantly increased the prevalence of El-Niño-like conditions in the Pacific Ocean 50 . A progressive southward migration of the mean annual and summer season Atlantic ITCZ is accompanied with these significant changes in high and low latitude insolation, associated with a commutated relocation of Atlantic Ocean warm-pools. An intensified ENSO activity suddenly appearing subsequent to the MHT (5.0-3.5 ka BP) may have amplified the southern ITCZ migration in the Atlantic Ocean, through a simultaneous northward shift of the ITCZ in the Pacific Ocean 51 . After these impactful reorganisations had started, a repositioning of MDR sub-clusters may have commenced (Fig. 5b), finally resulting in the present expansion between 9°-20°N during the Late Holocene (Fig. 5c). In this way, a new oceanic (SST) and atmospheric (ITCZ) configuration was set up, which steadily established a shift of major storm trajectories from once higher (>30°) to now lower latitudes (9°-20°). The new configuration likely promoted storm systems developing in more southern sub-clusters two and four, to migrated straight westwards through the Caribbean Sea, where they henceforth commonly made their landfalls along the coasts of Central America and the Gulf of Mexico. The centennial-scaled variability within this 6500-years-long trend is best explained by solar activity cycles 52 and solar insolation fluctuations, in particular the latter one causing climatic responses and multi-centennial SST variations in the Atlantic storm formation zones, as seen for example during the MWP and the LIA 53 . The multi-decadal variability in our storm frequency data originates from rather shorter-term modulations aligned to climate phenomena modes, which includes especially AMO phase changes and variations of ENSO amplitudes 32 . Comparison with Atlantic TC-frequency reconstructions A comparison with other TC-frequency reconstructions yields coherent TC-frequency patterns in the wider Atlantic region. As virtually all other blue hole and palaeotempestology studies with sufficient temporal resolution cover at best the past 2000 years of Holocene storm history, we have deliberately limited the comparison to the Common Era. Preliminary studies highlighted already a higher storm activity in the western North Atlantic 54 , in particular during the first half of the Common Era (1150-250 CE). A similar high-activity interval until 1500-1400 CE is also reconstructed for the south-western Caribbean 27-29 , the Gulf of Mexico 24 and parts of the Bahamas archipelago 31,33,55 . These phases of high TC-activity are consistent with the results gained from our smoothed Belizean (Great Blue Hole) compilation (Fig. 4). During the Dark Ages Cold (DAC: 650-0 CE), we found a trend of progressive increase of already high storminess. Furthermore, two periods of outstanding high TC-frequency (1050-800 CE and 1350-1200 CE) have been reconstructed for the MWP (1400-650 CE). This pattern of a basin-wide homogenously elevated TC-frequency during the first millennium was likely the consequence of a relative tropical Atlantic warming, due to high, near-equatorial insolation, and reinforcing effects of more La-Niña-like climate conditions 56 , both favouring cyclogenesis due to outstanding high ocean temperatures in all four tropical Atlantic storm-formation sub-clusters 31 . Within the second half of the MWP (1400-1150 CE), the lack of intense TC-activity along the East Coast of the United States and some islands of the Bahamas archipelago might indicate temporal changes on a more regional scale. Cooler SSTs along the East Coast of the United States 54 could have regionally hampered cyclogenesis in the northwestern sub-cluster one. A sudden southward relocation of the ITCZ (1200-1000 CE) 39 , a dampened African Easterly Jet 30 and a simultaneous phase of intense volcanic activity 57 might have additionally altered the trajectories of TCs on a more regional level. While sediment cores from the Bahamas 19,30,33,34 and New England 54 recorded again more active storm landfalls since the onset of the LIA (1700-1400 CE), various archives 24,27-29 located further south conversely indicate an abrupt change to calmer conditions. Our southwestern Caribbean TC-frequency compilation (Fig. 4) supplies additional evidence for an antiphase north-south variability by revealing a similar decrease of storminess at the Great Blue Hole during the LIA. The re-establishment of a warm SST anomaly along the East Coast of the United States 54 probably favoured stronger storm formation in the north-western part of the MDR (sub-cluster one), reminiscent of the prevailing climatic and oceanographic conditions in the Early Holocene (Figs. 5a, c). A strongly negative NAO gradient 29 , a particularly active African Easterly Jet 58 and/or latitudinal shifts of the North Atlantic Subtropical High (NASH) 2 are discussed as additional drivers for this heterogeneity. Between 1400-1150 CE, straight westwards moving cyclones frequently made landfall in the southwestern Caribbean realm and around the Gulf Coast, probably in response to a southern NASH displacement. These straight moving cyclones temporarily transformed into north-east recurving storms that preferably impacted the Bahamas and the East Coast of the United States, after the NASH moved back to the north subsequent to 1400 CE 59 . All these results support the hypothesis that the present spatial heterogeneity, which is well-known from observational data, persisted across the Atlantic Basin over the last 700 years 19 . Conclusions and Outlook The sediment core BH8, recovered from the bottom of the Great Blue Hole (Belize), indicates an obvious bipartite TC pattern. Event-layers have been found only sporadically during the cenote-phase (12.5-7.2 ka BP), whereas they were considerably more frequent during the restricted marine (7.2-5.7 ka BP) and fully marine (5.7-0 ka BP) stages. The superimposed bipartition and the first excursions of event-layer frequency between 7.2-6.5 ka BP is best explained by a persistent Holocene sea-level rise, which increased the chance of event-layer formation in the Great Blue Hole after the modern level was reached. Since then, a long-term gradual increase in event-layer counts and thus TC-frequency was accompanied in response to an orbitally-forced restructuring of global climate- and ocean dynamics at the MHT, including in particular a reorganisation of Atlantic warm and cold pools and a persistent southward ITCZ migration, as well as a general ENSO intensification in the Pacific Ocean. These changing circumstances resulted in a latitudinal shift of MDR sub-clusters to the south and increased thereby the preferences for a higher number of storm systems migrating westwards at lower latitudes. This in turn entailed step-wise more landfalls in Central America and in the Gulf of Mexico region, sufficient to create the gradually increasing amount of event-layers in the Great Blue Hole. Twelve alternating periods of increased (A1-A12) and decreased (C1-C12) activity were identified within this 6500-years-long pattern of gradually increasing storm activity. The centennial and multidecadal variations in our record are interpreted to be the result of solar insolation changes and climate phenomena modulations (e.g., AMO phase changes and ENSO amplitudes), respectively. The short-term variability within a continuous interval of high-stand storm activity (A1), lasting the past 1500 years, is similar to patterns observed from other TC archives in the Atlantic Basin. Based on our record and the forecast that the northern Atlantic will considerably heat up until the end of the 21 st century 17 , a scenario similar to that of the early Holocene could gradually emerge again. In the future, regional TC-frequency could probably decrease in the south-western Caribbean, but in contrast increase in the more northern Atlantic regions due to a northward ITCZ relocation in response to a northwards shifting Atlantic warm pool. Declarations Acknowledgements We would like to thank the Belize Audubon Society, the Geology and Petroleum Department, and the Belize Fisheries Department for site access, issuing of research permit and sample export permissions. We feel obliged to our German and Austrian colleagues Gabriela Meyer (Frankfurt), Martin Niederreiter and Richard Niederreiter (Mondsee), who assisted us in many operative and technical ways before and during the fieldwork. We would also like to thank captain Norlan Lamb and first mate Ashbert Miranda for the fieldwork campaign in Lighthouse Reef and their efforts to realise a successful project. In this context, we would also like to thank the employees of LPL-Projects + Logistic GmbH (Hamburg), who worked tirelessly to ensure that the sea freight finally arrived in Belize, despite major pandemic-related delays caused by the shipping company. Broker Bert Bradley and his crew of Belize City dealt with Belize Customs and worked hard to mobilize our equipment. Ms. Colette Grimshaw of Old Belize Marina helped us in many ways. The assistance of student helpers Andreas Buchheim, Annika Wiegand (Frankfurt) and Elija Nolte (Cologne) during preparation, sampling and measuring is gratefully acknowledged. We also owe a great debt of gratitude to Doris Bergmann-Dörr and Jenniffer Markwirth (Frankfurt) for access and assistance in Laser-Optical-Particle-Analyser measurements and Nicole Mantke and Jacob Feller (Cologne) for assistance in running the XRF-analyses. Author Contributions E.G. and M.M. did the field-work in Belize. V.W. and D.S. made the photo documentation, XRF-measurements, radiographic images and core correlations. D.S. performed the sampling processes, core description and the TC-frequency reconstruction. D.S wrote large parts of the original manuscript draft. All co-authors discussed the results and provided resources and equally input to the manuscript. Competing Interests The authors declare no competing interests. Data-Availability All data generated or analysed during this study are included in this published article (and its extended data figures and supplementary information files). Funding The authors acknowledge the financial support from the DFG in project Gi 222/31-2. References van Hengstum, P. J., et al. The intertropical convergence zone modulates intense hurricane strikes on the western North Atlantic margin. Sci. Rep. 6 , 21728 (2016). 10.1038/srep21728 Kossin, J. P., Camargo, S. J. & Sitkowski M. Climate modulation of North Atlantic hurricane tracks. J. Clim. 23(11) , 3057-3076 (2010). Gray, W. M. Global view of the origin of tropical disturbances and storms. Month. Weath. Rev . 96, 669-700 (1968). Webster, P .J., Holland, G. J., Curry, J. A. & Chang, H.-R. Changes in tropical cyclone number, duration, and intensity in a warming environment. Science 1844 , 1844-1846 (2005). Rios-Berrios, R. & Torn, R. D. Climatological analysis of tropical cyclone intensity changes under moderate vertical wind shear. Mon. Weath. Rev. 145 , 1717-1738 (2017). https://doi.org/10.1175/MWR-D-16-0350.1 Knutson, T. R., et al. Tropical cyclone and climate changes. Nat. Geosci. 3, 157-163 (2010). Oppenheimer, M. & Hinkel, J. Sea Level Rise and Implications for Low Lying Islands, Coasts and Communities Supplementary Material. IPCC Special Report on the Ocean and Cryosphere in a Changing Climate (2019). Knutson, T., et al. Tropical Cyclones and Climate Change Assessment Part II: Projected Response to Anthropogenic Warming. Bull. Am. Meteorol. Soc. 303-322 (2020). https://doi.org/10.1175/BAMS-D-18-0194.1 Emanuel, K., Sundararajan, R. & Williams, J. Hurricanes and global warming: results from downscaling IPCC AR4 simulations. Bull. Am. Meterorol. Soc. 89 , 347-367. (2008). Bender, M. A., et al. Modeled impact of anthropogenic warming on the frequency of intense Atlantic hurricanes, Science 327(5964) , 454-458 (2010). Emanuel, K.A. Downscaling CMIP5 climate models shows increased tropical cyclone activity over the 21st century. Proc. Natl. Acad. Sci. USA 110 , 12219-12224 (2013). Villarini, G. & Vecchi G. A. Projected increases in North Atlantic tropical cyclone intensity from CMIP5 models. J. Clim. 26(10), 3231-3240 (2013). Walsh, K. J. E., et al. Tropical cyclones and climate change. Wiley Interdiscip. Rev. Clim. Change 7(1) . (2016): https://doi.org/10.1002/wcc.371 Korty, R. L., Emanuel, K. A., Huber, M. & Zamora, R. A. Tropical cyclones downscaled from simulations with very high carbon dioxide levels. J. Clim. 30(2) , 649-667 (2017). https://doi.org/10.1175/JCLI-D-16-0256.1 Bhatia, K., Vecchi, G., Murakami, H., Underwood, S. & Kossin, J. Projected response of tropical cyclone intensity and intensification in a global climate model. J. Clim . 31(20) , 8281-8303 (2018). https://doi.org/10.1175/JCLI-D-17-0898.1 Kossin, J. P., Knapp, K. R., Olander, T. L. & Velden, C.S. Global increase in major tropical cyclone exceedance probability over the past four decades. Proc. Nat. Acad. Sci. 117(22) , 11975-11980 (2020). https://doi.org/10.1073/pnas.1920849117 Ting, M., Kossin, J. P., Camargo, S. J. & Li, C. Past and future hurricane intensity change along the U.S. East Coast. Sci. Rep . 9 , 1-8. (2019) https://doi.org/10.1038/s41598-019-44252-w Sugi , M., Yoshida, K. & Murakami, H. More tropical cyclones in a cooler climate?. Geophys. Res. Lett. 42 , 6780-6784 (2015). Winkler, T. S., et al. Revising evidence of hurricane strikes on Abaco Island (The Bahamas) over the last 680 years. Sci. Rep. 10 , 16556 (2020). https://doi.org/10.1038/s41598-020-73132-x Landsea , C. W., et al. The Atlantic hurricane data­base re-analysis project: Documentation for 1851-1910 alterations and additions to the HURDAT database. in : Murnane, R.J. & Liu, K-b. ( eds ) Hurricanes and Typhoons: Past, Present and Future. New York: Colum­bia University Press, pp. 177-221 (2004). Landsea, C. W. & Franklin, J. L. Atlantic Hurricane Database Uncertainty and Presentation of a New Database Format. Mon. Weath. Rev. 141(10) , 3576-3592 (2013). https://doi.org/10.1175/MWR-D-12-00254.1 Wang, C., Lee, S.-K. & Enfield, D. B. Atlantic warm pool acting as a link between Atlantic multidecadal oscillation and Atlantic tropical cyclone activity. Geochemistry Geophys. Geosystems 9 , Q05V03 (2008). Goldenberg,S. B. & Shapiro, L. J. Physical mechanisms for the Association of El Niño and West African rainfall with Atlantic major hurricane activity. J. Clim. 9 , 1169-1187 (1996). Lane, P., Donnelly, J. P., Woodruff, J. D. & Hawkes, A. D. A decadally-resolved paleohurricane record archived in the late Holocene sediments of a Florida sinkhole, Mar. Geol. 287(1) , 14-30 (2011). Brandon, C. M., Woodruff, J. D., Lane, D. P. & Donnelly, J. P. Tropical cyclone wind speed constraints from resultant storm surge deposition: A 2500-year reconstruction of hurricane activity from St. Marks, FL. Geochemistry, Geophys., Geosystems 14(8) , 2993-3008 (2013). https://doi.org/10.1002/ggge.20217 Brown , L. A., Reinhard, E. G., van Hengstum, P. J. & Pilarczyk, J. E. A coastal Yucatan sinkhole records intense Hurricane events. J. Coast. Res. 30-2 , 418-428 (2014). Sullivan , R. M., et al. Northeast Yucatan hurricane activity during the Maya Classic and Postclassic periods. Sci. Rep. 12, 20107 (2022). https://doi.org/10.1038/s41598-022-22756-2 Gischler, E., Shinn, E. A., Oschmann, W., Fiebig, J. & Buster, N. A. A 1500-year Holocene Caribbean climate archive from the Blue Hole, Lighthouse Reef, Belize, J. Coast. Res. 24(6), 1495-1505 (2008). Denommee,K., Bentley, S. & Droxler A. Climatic controls on hurricane patterns: A 1200-y near-annual record from Lighthouse Reef, Belize, Sci. Rep. 4, 3876 (2014). https://doi.org/10.1038/srep03876 van Hengstum, P. J., et al. Heightened hurricane activity on the Little Bahama Bank from 1350 to 1650 AD. Cont. Shelf. Res. 86, 103-115 (2014). https://doi.org/10.1016/j.csr.2013.04.032 Wallace, E. J., et al. Intense hurricane activity over the past 1500 years at south Andros Island, the Bahamas. Paleoceanogr. Paleocl. 34-11 ,1761-1783 (2019). Schmitt, D., Gischler, E. Anselmetti, F.S. & Vogel H. Caribbean cyclone activity: an annually-resolved Common Era record . Sci. Rep, 10(1):11780 (2020). https://doi.org/10.1038/s41598-020-68633-8 Wallace, E. J., et al. Regional shifts in paleohurricane activity over the last 1500 years derived from blue hole sediments offshore of Middle Caicos Island. Quat. Sci. Rev. 268 , 1-18 (2021). https://doi.org/10.1016/j.quascirev.2021.107126 Winkler, T. S., et al. Oceanic passage of hurricanes across Cay Sal Bank in The Bahamas over the last 530 years. Mar. Geol. 443 (2022). https://doi.org/10.1016/j.margeo.2021.106653 Shinn,E. A., Reich, C. D., Locker, S. D. & Hine, A. C. A Giant Sediment Trap in the Florida Keys. J. Coast. Res. 12(4) , 953-959 (1996). Liao, X., et al. Observed interannual relationship between ITCZ position and tropical cyclone frequency. J. Clim. 1-37 (2023). https://doi.org/10.1175/JCLI-D-22-0865.1 Goldenberg,S. B., Landsea, C. W., Mestas-Nuñez, A. M. & Gray W. M. The recent increase in Atlantic hurricane activity: Causes and implications. Science 293(5529) , 474-479 (2001). Kossin, J. P. & Vimont, D. J. A more general framework for understanding Atlantic hurricane variability and trends. Bull. Am. Meteorol. Soc. 88(11) , 1767-1781 (2007). Haug, G. H., Hughen, K. A., Sigman, D. M., Peterson, L. C. & Röhl, U. Southward migration of the intertropical convergence zone through the Holocene. Science 293 , 1304-1308 (2001). Merlis, T. M., Zhao, M. & Held I. M. The sensitivity of hurricane frequency to ITCZ changes and radiatively forced warming in aquaplanet simulations. Geophys. Res. Lett. 40(15) , 4109-4114 (2013). https://doi.org/10.1002/grl.50680 Peltier, W. R. & Fairbanks, R. G. Global glacial ice volume and last glacial maximum duration from an extended Barbados sea level record. Quat. Sci. Rev. 25 , 3322-3337 (2006). Wallace, E. J., Dee, S. G. & Emanuel, K. A. Resolving long-term variations in North Atlantic tropical cyclone activity using a pseudo proxy paleotempestology network approach. Geophys. Res. Lett. 48 , e2021GL094891 (2021) https://doi.org/10.1029/2021GL094891 Knapp, K. R., Diamond, H. J., Kossin, J. P., Kruk, M. C. & Schreck III, C. J. International Best Track Archive for Climate Stewardship (IBTrACS) Project, Version 4. [Atlantic Basin US_SSHS subset]. NOAA National Centers for Environmental Information (2018). https://data.nodc.noaa.gov/cgi-bin/iso?id=gov.noaa.ncdc:C01552 McCloskey, T. A. & Liu, K.-B. A 7000 year record of paleohurricane activity from a coastal wetland in Belize. Holocene 23(2) , 278-291 (2012). https://doi.org/10.1177/0959683612460782 Elsner,J. B. Tracking hurricanes. Bulletin of the American Meteorological Society , 84(3) , 353-356(2003). https://doi.org/10.1175/BAMS-84-3-353 Gischler, E., Hudson, J. H., Eisenhauer, A., Parang, S. & Deveaux, M. 9000 years of change in coral community structure and accretion in Belize reefs, western Atlantic, Sci. Rep . 13 , 11349 (2023). https://doi.org/10.1038/s41598-023-38118-5 Björck, S., et al. High-resolution analyses of an early Holocene climate event may imply decreased solar forcing as an important climate trigger. Geology 29(12) , 1107-1110 (2001). Wanner, H., Solomina, O., Grosjean, M., Ritz, S. P. & Jetel, M. Structure and origin of Holocene cold events. Quat. Sci. Rev. 30(21-22) , 3109-3123 (2011). https://doi.org/10.1016/j.quascirev.2011.07.010 Lorenz, S. J., Kim, J. H., Rimbu, N., Schneider, R.R. & Lohmann, G. Orbitally driven insolation forcing on Holocene climate trends: Evidence from alkenone data and climate modelling. Paleoceanography 21(1) (2006).https://doi.org/10.1029/2005PA001152 Clement, A. C., Seager, R. & Cane, M.A. Orbital controls on the El-Niño/Southern Oscillation and the tropical climate. Paleoceanography 14(4) , 441-456 (1999). Wahl, R., Byrne, R. & Anderson, L. An 8700 year paleoclimate reconstruction from the southern Maya lowlands. Quat. Sci. Rev. 103 , 19-25 (2014). https://doi.org/10.1016/j.quascirev.2014.08.004 Elsner, J. B. & Jagger, T.H. United States and Caribbean tropical cyclone activity related to the solar cycle. Geophys. Res. Lett. 35 , L18705 (2008). https://doi.org/10.1029/2008GL034431 Mann, M. E., Woodruff, J. D., Donnelly, J. P. & Zhang Z. Atlantic hurricanes and climate over the past 1,500 years. Nature 460(7257) , 880-883 (2009). https://doi.org/10.1038/nature08219 Donnelly, J. P., et al. Climate forcing of unprecedented intense-hurricane activity in the last 2000 years. Earth’s Future 3 , 49-65 (2015). https://doi.org/10.1002/2014EF000274 Wallace, E. J., et al. 1,050 years of hurricane strikes on Long Island in The Bahamas. Paleoceanogr. Paleoclimatol. 36(3) , (2021). https://doi.org/10.1029/2020PA004156 Mann, M. E., et al. Global signatures and dynamical origins of the Little Ice Age and Medieval climate anomaly. Science 326 , 1256-1260 (2009). Gao, C., Robock, A. & Ammann, C. Volcanic forcing of climate over the past 1500 years: An improved ice core‐based index for climate models. J. Geophys. Res. 113 , D16112(2008). https://doi.org/10.1029/2008JD010239 Nguetsop, V. F., Servant-Vildary, S. & Servant, M. Late Holocene climate changes in west Africa, a high resolution diatom record from equatorial Cameroon. Quat. Sci. Rev. 23 , 591-609(2004). Ortegren, J. T. & Maxwell, J.T. Spatiotemporal patterns of drought/tropical cyclone Co-occurrence in the southeastern USA: linkages to north Atlantic climate variability. Geogr. Compass 8 , 540-559 (2014). Schmitt, D., Gischler, E. & Walkenfort, D. Holocene sediments of an inundated sinkhole: facies analysis of the “Great Blue Hole”, Lighthouse Reef, Belize. Facies 67 , 10 (2021).https://doi.org/10.1007/s10347-020-00615-8 Marcott , S., Shakun, J., Clark, P. & Mix, A. A Reconstruction of Regional and Global Temperature for the Past 11,300 Years. Science 339 , 1198-1201 (2013). DOI: 10.1126/science.1228026 Liu, Z., et al. The Holocene temperature conundrum. Proc. Natl. Acad. Sci. USA 111(34) , E3501-3505 (2014). https://doi.org/10.1073/pnas.1407229111 Cionco, R., Soon, W. & Quaranta, N. On the calculation of latitudinal insolation gradients throughout the Holocene. Adv. Space Res. 66(3) (2020). https://doi.org/10.1016/j.asr.2020.04.030 Cleveland, W. S. Robust locally weighted fitting and smoothing scatterplots. J. Am. Stat. Assoc. 74 , 829-836(1979). Cleveland, W. S. A program for smoothing scatterplots by robust locally weighted fitting. Am Stat. 35 , 54 (1981). Methods Anoxic blue holes have some noteworthy advantages, in contrast to coastal lake sites 66 , back barrier lagoons 67,68 , coastal wetland sites 44,69,70 and salt marsh ponds 71-73 . They are largely independent to sea-level changes, not affected by bioturbation and permanent wave action, and marked by a high fair-weather sediment supply, as well as an ample accommodation space 35 . Fieldwork at Lighthouse Reef: coring the anoxic Great Blue Hole The coring equipment operated on the Great Blue Hole was shipped in a 20-foot shipping-container from Cologne (Germany) to Belize City (Belize). It consisted of an UWITEC Hybrid Platform, equipped with UWITEC gravity and percussion piston corers. The coring platform was assembled in the Old Belize Marina and towed to Lighthouse Reef (Belize) by a 9-m-long charter boat with outboard engines. The Belize Fisheries Department and the Belize Audubon Society helped to organize the use of existing mooring buoys and finding arrangements with dive boats that visit the Great Blue Hole on a daily basis, as the anchored platform was a potential obstacle for other boats. The coring platform was moored in the sinkhole centre (17°18′57.2′′ N, 87°32′0.60′′ W) at four fixed positions during a 6-days-long coring operation in June 2022, using ropes attached to two mooring buoys at the NE and NW margins of the Great Blue Hole and two special marine reef anchors that were temporarily added at the SE and SW margins. The gravity corer was employed twice to sample the sediment-water interface and the uppermost 14 cm of the sediment succession. Deeper sediments were recovered with successive deployments of the piston corer, which was guided into the borehole by a metal funnel that was placed on the sinkhole floor. The piston corer consists of a 2-m-long steel barrel with an inner PVC liner and a core catcher at the bottom. The sediments in the core catchers (in average 13 cm) were not sampled in the PVC liners, but as bulk samples. Such gaps were closed down to 2.5 m by two additional piston cores (BH8-18; BH8-19), which were taken from a new hole close by and correlated with the uppermost gravity (BH8-CO412-1; BH8-CO412-2) and piston cores (BH8-4). A UAV (unmanned aerial vehicle/drone) was used to take aerial photos from both the location and the operational coring set-up. After equipment break-down, up to 1-m-long core segments (PVC-tubes) were transported in thermo-boxes by air cargo from Belize City to Cologne (Germany). Following initial processing in Cologne, the cores were shipped further to Frankfurt (Germany) for subsequent analyses. Core opening and photo documentation The PVC-tubes were opened lengthwise by cutting them in halves, one for subsampling and one for archive, with a semi-automatic core opening system with cranks and blades. The surface area was smoothed with an ultra-thin copper sheet (0.7 mm). All 36 core segments were remeasured to precisely determine the actual core depth (cm). A photo documentation was subsequently carried out using a line-scan camera attached to a non-destructive X-ray fluorescence core scanner (XRF; COX-ITRAX). X‑ray fluorescence analyses To determine the element composition of the sediment (in counts per second, cps), the archive-halves were scanned at 2 mm resolution (~13400 measurements) with an ITRAX-XRF scanner that was equipped with a Cr-anode-X-ray-tube set to 30 kV and 55 mA with 60s integration time. Special attention was given to the Strontium content and its ratio over Calcium. The Sr/Ca ratio (Suppl. 3) is a sensitive tool for tempestite identification in carbonate sinkhole environments 32 , as it records minor differences between over-washed event layers (mean Sr/Ca-ratio: 0.0329 ± 0.0222) and fair-weather sediments (mean Sr/Ca ratio: 0.0289 ± 0.0083). Materials from the marginal reef (e.g., aragonitic coral skeletons and Halimeda chips) are typically enriched in Sr, while lagoonal particles (e.g., mollusc shells and foraminiferal tests) are depleted 75 . With a second, high-energetic XRF-scanning run, radiographic images were created, reflecting minor density variations in the sediment cores. Areas with lighter colours (lower density) overlap with event-layers and darker areas (higher density) agree with varved core sections, representing the annual fair-weather sedimentation. Grey-scale values were automatically recorded at 0.20-0.40 mm intervals through the sediment core BH8 and processed in a profile by using the open source image processing software ImageJ v.1.53t. Tempestites are accompanied with visible peaks in the grey-scale values, while the varved-sections tend to lie around an average value of 383.54 ± 88.59 (Suppl. 4). The radiographic grey-scale analysis, presented for the first time in this context, is thus applicable as a new, grain-size-independent, optical proxy for storm-layer identification in carbonate-dominated blue hole environments. After completing both XRF-runs, the archive-halves were packed in vacuum, transported to Frankfurt and stored in a cold room at 4°C for archive purpose. Stratigraphic description and correlation with existing cores A visual core description was done by using both the working-halves and the high-resolution core images (Fig. S1). The stratigraphic recording includes an optical differentiation of fair-weather sections and cyclone event deposits, a description of different unconsolidated lithologies, measurements of varve- and event layer thickness, characterization of sedimentary contacts and registration of macrofossils. The sediment core BH8 was stratigraphically and chronologically correlated with an 8.55-m-long core (BH6) from a previous project 32 by complementary using the open-source application Corelyzer (version 2.2.1) for optical core images visualization. It became qualitatively apparent, that there is a high degree of visual and sedimentological compliance of coarse sediment anomalies between BH8 and BH6. In the overlapping depth interval (8.3 m), 162 out of 212 event layers (76 %) were replicated by both cores. 50 tempestites occurred only in BH8 and another 31 only in core BH6 (Suppl. 5). Adapted sampling strategy Texture and sedimentological parameters of both event-layers and fair-weather sediments have been readily established in two previous projects 28,32 . For this reason, we will not repeat such detailed measurements and focus mainly on the textural analysis of event-layers. All samples were again taken in 2.5 mm slabs, approximately equalling an annual sampling resolution, with ultra-thin metal cut-out plates, according to the tested methodology 32 . For radiocarbon dating, 9 bulk samples were first cut out of undisturbed sections of varved fair-weather sediments that show clear signs of a changing sedimentology, particularly with regard to different sedimentological units. Afterwards, 694 samples were discretely taken from optically determined event-layers (Suppl. 6). We finally decided to randomly extract 125 more samples from undisturbed fair-weather sections at different sampling intervals with a maximum spacing of 50 cm, mainly for comparative purposes (Suppl. 6). Thirty-eight samples were investigated for pollen analysis following a proven methodology 76 . A total of 5 g bulk material was needed either way for quantitative textural analysis, pollen investigation and radiocarbon dating. Age dating: radiocarbon- and varve-counting models For age dating, we used a combination of varve counting- and radiocarbon age models. Both applications show very similar progressions, with a noteworthy age offset appearing only in the middle core part (Fig. 2). To gain an age model for event-layer timing on annual resolution, undisturbed varves were counted visually in the PVC lines and cross-checked with the high-resolution images using optical colour differences. Grey-scale/density variations, visible in the radiographic images 77 were supportively used, besides varve thickness measurements, for creating a varve-counting-based age model. We excluded geologically instantaneous event sedimentation and determined event-free rates downcore by considering only laminae thickness measurements of fair-weather deposits. This proceeding resulted in a three-part division of core BH8 (units A, B, C). A near linear mean sedimentation rate of 2.41 ± 0.04 mm/a was computed down to a depth of 24.6 m. This confirms the sedimentation rate of 2.55 ± 0.05 mm/a, known from two shorter Great Blue Hole cores 28,32 . In unit B (24.6-28.6 m), sedimentation rates are slightly higher (3.18 ± 0.03 mm). Unit C (28.6-30.0 m) is characterized by a much lower mean annual sedimentation rate of 0.20 ± 0.00 mm/a. All core catchers samples, not included in the PVC liners, were texturally analysed and identified either as an undisturbed varved deposition or a varved section, that includes an event-layer, by means of their textural signatures in relation to both sections from the PVC liners. The time contained in these bulk core catcher samples was estimated in an approximation approach, following the calculated event-free sedimentation rates of the respective core unit. In a depth between 16-24 m, the varve counting approach is more difficult to apply as in younger core sections, because of blurry varves and a few core catcher segments up to 40 cm thickness, completely lacking intact sedimentology. For these intervals, we also had to extrapolate on the assumption of a constant sedimentation rate of 2.41 ± 0.04 mm/a, resulting in an estimated final varve-counting error of 5%. We used a total of 15 radiocarbon dates at 79.8 cm, 161.3 cm, 410.5 cm, 622.3 cm, 660.5 cm, 839.3 cm, 926.0 cm, 1019.2 cm, 1613.1 cm, 2011.2 cm, 2409.2 cm, 2609.2 cm, 2814.0 cm, 2874.0 cm and 3000.6 cm as age-control points (Suppl. 1), in order to establish a secondary age control for the varve age model. Nine of those samples were extracted from the core BH8, but we also considered six depth-corrected radiocarbon-dates from the uppermost 9 m, measured on the previously dated sediment core BH6 32 . A radiocarbon-based age model (Fig. S3) with 95% confidence intervals was developed with Bayesian statistical approaches using the R library package BACON v 2.2 78 . The 14 C-radiocarbon dating has been undertaken by Beta Analytic Inc., Miami, Florida with Accelerator Mass Spectrometry (AMS). The organic material was separated from the bulk sediment samples by dissolving the carbonate material with HCl, washing the sample with NaOH, and repeating until no more carbonate remained. For the samples down to a depth of 2814.0 cm, Beta Analytic Inc., Miami, Florida, provided average δ 13 C values of -16.8 ‰. Such a δ 13 C value is typically associated with a marine carbon origin, attributable to aquatic macrophytes and algae 79 . The two samples at 2874.0 cm and 3000.6 cm have more negative δ 13 C values ranging from -17.7 ‰ to -27.2 ‰. This is indicative of a different organic matter source, such as terrestrial C3-plants (-20‰ to -30 ‰) 80 . For reservoir correction, the global marine reservoir effect of 405 years (residence time of carbon cycled in the ocean prior to bio-assimilation) was considered and applied by Beta Analytic Inc., Miami, Florida. The conventional radiocarbon ages from both the marine and terrestrial organic residues were converted to calibrated years before present using either the BetaCal4.20 MARINE20 81 or INTCAL20 82 calibration curves (High Probability Density Range Method) 83 . All calibrated ages are presented with a 2-σ error in a 95% confidence interval. Quantitative textural analyses: the classic proxy for event-layer identification In the Great Blue Hole sedimentation system, a quantitative textural analysis constitutes a successfully tested tool 32 to safely differentiate between coarser storm-induced event-layers and the finer background sedimentation (Suppl. 6). For quantitative textural analysis, a total of 819 samples have been first wet sieved through a 63 μm standard grain-size sieve to separate the coarse fraction (>63 μm) from the fine fraction (<63 μm). The coarse grain-size fraction was dried at 50°C for 12 hours with a ThermoScientific HERATHERMA-OVEN OMS-180, sieved through standard grain-size sieves of 2 mm, 1 mm, 500 μm, 250 μm, and 125 μm and then weighed to determine dry masses, respectively. The fine fraction was left to rest for 48 hours in a sedimentation vessel (settling out of suspension), subsequently decanted, dried at 50°C for 24 hours and dry-weighed to equally define the amount of fine material. From these data, a grain-size distribution was created with absolute (g) and relative (%) values for each sieving interval. For mean grain-size determination, a more detailed analysis of the fine fraction is needed, including a further separation of the fine fraction into 63 μm, 50 μm, 40 μm, 20 μm, 10 μm, 2 μm, 1 μm and 0.05 μm intervals. Fine material analyses were performed by using a laser-optical particle analyser (HORIBA Laser Particle Analyser-950), which runs with 1 g fine material, suspended in 0.4 N Na 4 P 2 O 7 and demineralized water. All visible event layers (n = 32) from the historical record were analysed down to a depth of 103 cm, using the HORIBA Laser Particle Analyser-950 (Suppl. 7). In addition, the fine materials of 32 more samples (n = 28 fair-weather and n = 4 event-layers) were measured for fine material abundances across the core at ~1 m intervals (Suppl. 7). All of these samples were categorized by determination of classical sedimentary parameters (mean grain size, sorting, skewness and kurtosis), following the “Geometric and Logarithmic Folk & Ward method” using the software package gradistat v. 9.1 84 . A linear calibration was made between mean grain-size values, obtained from these 64 samples and their amounts of coarse fraction, received from the initial sieving test (Suppl. 8). The correlation between both parameters is statistically significant (r = 0.81; p < 0.05). The mean grain-size values of all other event-layers of core BH8 can be inferred in a sufficiently accurate approximation by using the linear equation from this calibration step: y = 2.6664 x amount of coarse fraction (%). Workflow of TC-event-layer identification We used an already established 32 and complemented (grey-scale values) multi-proxy-approach to ensure a reliable identification of TC event-layers in the sediment core BH8. 694 tempestites have been preliminary identified on a visual core and optical images inspection. The light greyish (Munsell colour: 5GY 6/2) to greyish green (Munsell colour: 5GY 5/2) fair-weather deposits are clearly distinguishable from white (Munsell colour: 2.5Y 8/1) to pale brown (Munsell colour: 2.5Y 8/2) coloured event beds in the full marine unit A. Similarly coloured, however slightly darker, greyish green (Munsell colour: 5GY 5/2) to greyish brown (Munsell colour: 2.5Y 5/2) fair-weather deposits appear in the restricted marine unit B. In this core section, event-beds are still clearly defined as white (Munsell colour: 2.5Y 8/1) and very dark brown (Munsell colour: 10YR 2/2), up to almost black (Munsell colour: 10YR 2/1) layers. In the cenote-like unit C, the background sedimentation is first characterized by a fine lamination of grey brown (Munsell colour: 2.5Y 3/2) deposits, followed by a structureless black (Munsell colour: 2.5Y 2.5/1) section at the core base. White (Munsell colour: 2.5Y 8/1) coloured and slightly faded event-layers are again visible in this core part. In addition to the conspicuous differences in colour, there are some more visual sedimentary characteristics that allow an optical separation: (1) sharp sedimentary contacts, (2) presence of coarse grains (e.g., mollusc shells, coral fragments and/or Halimeda -platelets), (3) lack of lamination, (4) signs of coarsening/fining upwards and (5) increased content of organic material. Another helpful parameter to identify event-layers is the thickness of the storm deposit, as the sedimentation rate should be significantly increased during an instantaneous high-energy event. In years without a storm landfall, varve thickness was determined to average values of 2.4 mm (unit A), 3.2 mm (unit B) and 0.2 mm (unit C). The thickness of the 694 event-layers ranges from a minimum of 2.5 mm up to maximum of 37.6 cm. The average thickness of all tempestites is 1.7 cm and thus much thicker than a common annual varve. In the process, we confirmed the optical identification of storm indicator layers by cross-checking them with quantitative coarse fraction data (%) and measured/calculated mean grain size values (μm), received from the classic textural analysis. The fair-weather sediments are characterized by a very low average coarse fraction content (>63 μm) of 4.3 % (unit A), 2.3 % (unit B) and 4.5 % (unit C). For the event-layers, coarse-fraction abundances were calculated on average at 20.8 %, with a range appearing from 2.1 % to 96.5 %. The mean grain sizes of fair-weather sediments were computed to 16.4 μm (coarse silt) in unit A, 8.4 μm (medium silt) in unit B and 15.9 μm (medium silt) in unit C. The average grain size of the event-layers is very coarse silt (54.9 μm), but encompasses a range from fine silt (5.7 μm) to coarse sand (625.9 μm). On this basis, we established event bed cutoffs for units A (6.6 % and 24.9 μm), B (3.8 % and 14.5 μm) and C (6.5 % and 21.0 μm), respectively. 91-96 % of all visible event beds correspond to peaks above the unit cutoffs in the coarse fraction (>63 μm) data. The grade of agreement with the mean grain size is significantly lower at 74-80%, which is probably a result of the linear approximation approach. In the same manner, we have determined the geochemical thresholds (Suppl. 3) for Sr-abundances between fair-weather and storm deposits of units A (0.0293 ± 0.081), B (0.0254 ± 0.061) and C (0.0334 ± 00122). In units A and B 70.5% and 66.7% of the visible event-layers correspond to Sr/Ca peaks above the respective units cutoff. In the sedimentary unit C, the accuracy of the Sr/Ca proxy comparably decreases sharply (38.2%), which might be the result of an increasing terrestrial influence and a lack of coral fragments as important Sr sources. A new quantitative method for tempestite identification was also conducted, by developing an optical cutoff using grey-scale values from radiographic images (Suppl. 4). We calculated optical thresholds of density variation between fair-weather and storm deposits of units A (395.91 ± 93.84), B (355.71 ± 66.08) and C (347.75 ± 62.59). In units A, B and C 63.9%, 74.1% and 76.5% of the visible event-layers correspond to grey-value excursion below the respective units cutoff. For a final TC-identification, the optical, sedimentary, and geochemical cutoffs had to be overstepped at best in all the different criteria, but at least in several of those, resulting in the highest available degree of accuracy. Our multi-proxy analyses support the results of two studies, 85,86 indicating that the amount of the grain-size fraction (>63 μm) is sufficient to accurately identify tempestite layers in reef lagoon sediments of carbonate environments. Computing TC-frequency After all event-layers had been reliably identified, we computed TC-frequency changes by simply counting the number of storm deposits in the undisturbed PVC liners 24 and added event-layers found in the core catcher samples after textural analysis and the described extrapolation. The use of a 100-year observational window is not only appropriate to picture centennial-scaled shifts of storm frequency, but also to facilitate basin-wide comparisons with other records using the same time window 33 . A 50-years observational window was also used, in order to map multi-decadal shifts of TC-frequency in the record. Active and quiescent phases of storm activity were identified in 100- and 50-years windows, by using regionally-derived thresholds 19 of 9.3 ± 5.7 TCs/100a and 4.6 ± 3.2 TCs/50a. We repeated the procedure for a 20-years observational window, in order to compare the new data with previous TC-frequency reconstructions from the Great Blue Hole 28,29,32 . The 100-, 50-, and 20-years frequency data were smoothed (Suppl. 9) using the software package PAST.v.4.08 and the LOWESS (LOcally WEighted Scatterplot Smoothing) algorithm with recommended default parameters 64,65 and user specified smoothing parameters (q). With a bootstrap option, a 95% confidence band is displayable for the smoothed curve fit, based on 999 random replicates. This kind of data smoothing was applied, in order to create a Belizean compilation (Fig. 4) out of different single Common Era frequency plots (Fig. S4), finally usable for a more meaningful characterisation of regional TC-frequency and its climatic drivers 87 . We excluded the core LOCO2 28 from the compilation, because a systematic sedimentological investigation was not applied in that study with regard to a quantitative identification of tempestites. Historical record calibration In the uppermost 100 cm´s of the core, 36 event-layers were compared with the historical record of TCs (International Best Track Archive for Climate Stewardship-IBTrACS) 43,80 passing the study site within a 100 km radius, in order to assess the sensitivity of the record for event bed formation. In the past two centuries, 32 storms of different strengths left their traces in the unconsolidated sediments of the Great Blue Hole (Suppl. 2). Their strength ranged from tropical depressions (rare) to tropical storms (moderate) and hurricanes (frequent) up to occasional passing major hurricanes of categories 4 and 5 (Saffir-Simpson scale). 19 of these storm deposits are located in a core depth, attributable to times younger than 1950 CE. From this point on, airplane reconnaissance 89 and satellite monitoring 90 supplied very reliable data for storm track distance, maximum wind speed/intensity and residence time. We confine our instrumental record calibration thus only to historically documented TCs (intensity: tropical storms-major hurricanes), that migrated over the study site between 2022-1950 CE (n = 19). We were able to assign 16 recent event-layers to passing storm systems with very small age offsets to the recorded strike year (Suppl. 2). Among these are tropical storms like HARVEY (2011 CE), ALEX (2010 CE), ARTHUR (2008 CE), KYLE (1996 CE) and GERT (1993 CE), and stronger hurricanes, such as H1 NANA (2020 CE), H1 EARL (2016 CE), H4 IRIS (2001), H4 KEITH (2000 CE), H3 GRETA (1978 CE), H1 EDITH (1971 CE) and H1 ABBY (1960 CE). A 14.4 cm thick event-layer (EL20) at 45 cm core depth is furthermore very likely attributable to H5 HATTIE (1961 CE), that struck Lighthouse Reef as one of the most powerful storms ever 91 . Besides these, three more distal crossing storm systems likely left also clearly distinguishable event beds in the sedimentary record. Although H5 DEAN (2005 CE; 176 km), H5 MITCH (1998 CE; 217 km) and H2 FRANCELIA (1969 CE; 122 km) passed outside of the initially used 100 km observational radius, they are due to their high intensity still in range to produce an event-layer 42 . With a matching rate of 84.2%, the Great Blue Hole site has, like all other proxy-based TC-frequency archives, a bias for underrating past storm activity (here: 15.8%). The remnants of three cyclones from the Instrumental Era could not been found in core BH8 at or near the expected depth and age. Among these are exclusively weaker tropical storms (HERMINE 1980 CE, LAURA 1971 CE and GILDA 1954 CE). The reasons why a nearby passing cyclone does not induce the formation of an event-bed can be naturally manifold. Prerequisite for an event-bed formation is that the intensity of a proximal passing storm system is high enough to generate storm waves and surges at the study site. In this context, the evaluation of the instrumental data yielded in an interesting result. At the Great Blue Hole, it makes a huge difference, weather a storm system passes in the north, central or in the south. With a success rate of 90.9%, nearly all south-traversing storm systems were recovered in the sedimentary record. The centrally- or northerly-crossing storm systems were obtained much less often with only 75% respectively. We are convinced that this is related to the morphology of the sinkhole (eastern and northern channels in the surrounding coral reef) and the rotational direction of storm systems on the northern hemisphere. For south-trending storm systems with counter-clockwise rotation, it is much easier to produce an event-layer at the sinkhole floor. In such a case, the storms' strongest northeasterly winds and the attributed storm waves are oriented straight in direction to the location. With a northerly migration path, the strongest winds and highest waves tend to be directed away from the Great Blue Hole. Both HERMINE 1980 CE as well as LAURA 1971 CE passed Lighthouse Reef at or from a northern position. GILDA 1954 CE, however crossed the region, unlike the two other storms, further south. Tropical storm GILDA 1954 CE was probably just too weak and distant to leave a visible event bed, despite its generally favourable pathway. An alternative explanation for these missing event-layers is that we were simply not able to core the corresponding event-layers. The geometry of such deposits is, due to a spatially-limited density-surge deposition, very often lobe-shaped in the spacious Great Blue Hole. Tempestites do thus not cover the entire bottom of the sinkhole 60 . Two identified event-layers (EL17: 1965 CE and EL19: 1962 CE) did not match any known historical TC-events. Single coarse-grained anomalies may have been caused by strong seismic activity at the active strike-slip zone along the Caribbean and North American plate boundary, leading to tsunami-wave controlled redepositions of allochthonous particles and/or sinkhole slope destabilisations. EL19 was probably the result of higher waves originating from a strong nearby earthquake with a magnitude of 6.1 (United States Geological Survey), located 55 km south of Bodden Town, Cayman Islands. Far-field tsunamis were completely absent in the historical record and occurred in the Caribbean realm only very rarely in prehistoric times 92,93 . Only two major tsunami events were identified in the Caribbean realm during the past 1600 years 94 , however with only very small wave runups compared to the storm waves of intensive storms. Given the large number of 694 event-layers in sediment core BH8, recurring passages of TCs are by far the most likely origin for all the coarse-grained event-layers in the Great Blue Hole, considering the low number of tsunami events and the excellent historical record match of TCs. References (methods only) Liu, K.-B. & Fearn, M.L. Reconstruction of prehistoric landfall frequen­cies of catastrophic hurricanes in northwestern Florida from lake sediment records. Quat. Res. 54 , 238-24 5(2000). Donnelly,J. P. & Woodruff, J.D. Intense hurricane activity over the past 5,000 years controlled by El Nino and the West African monsoon. Nature 447 , 465-468 (2007). Park, L.E. Comparing two long-term hurricane frequency and intensity records from San Salvador Island, Bahamas, J. Coast. Res. 28 , 891-902 (2012). Donnelly, J. P., et al. A backbarrier overwash record of intense storms from Brigantine, New Jersey. Mar. Geol. 210 , 107-121 (2004). McCloskey, T. A. & Keller, G. 5000 year sedimentary record of hurri­cane strikes on the central coast of Belize. Quat. Int. 195, 53-68 (2009). Scileppi, E. & Donnelly, J. P. Sedimentary evidence of hurricane strikes in western Long Island, New York. Geochem. Geophys. Geosystems 8 (2007). https://doi.org/10.1029/2006GC001463 Boldt, K. V., Lane, P., Woodruff, J. D. & Donnelly, J. P. Calibrating a sedimentary record of overwash from Southeastern New England using modeled historic hurricane surges. Mar. Geol. 275(1-4) , 127-139 (2010). https://doi.org/10.1016/j.margeo.2010.05.002 Kiage, L. M., et al. A 1900-year paleohur­ricane record from Wassaw Island, Georgia, USA. J. Quat. Sci. 26 , 714-722 (2011). Bregy, J. C., Wallace, D. J., Minzoni, R. T. & Cruz, V. J. 2500-year paleotempestological record of intense storms for the northern Gulf of Mexico, United States. Mar. Geol. 396 , 26-42 (2018). https://doi.org/10.1016/j.margeo.2017.09.009 Gischler, E. & Lomando, A. J. Recent sedimentary facies of isolated carbonate platforms, Belize-Yucatan system, Central America. J. Sediment. Res. 69 , 747-763 (1999). Wooller, M. J., Behling, H., Guerrero, J. L., Jantz, N. & Zweigert, M. E. Late Holocene hydrologic and vegetation changes at Turneffe atoll, Belize, compared with records from mainland central America and Mexico. Palaios 24 , 650-656 (2009). Cooper, M. C. The use of digital image analysis in the study of laminated sediments. J. Paleolimnol. 19 , 33-40 (1998). https://doi.org/10.1023/A:1007912417389 Blaauw, M. & Christen, J. A. Flexible paleoclimate age‐depth models using an autoregressive gamma process. Bayesian Analysis , 6(3) , 457-474 (2011). DOI:10.1214/11-BA618 Wefer, G. & Killingley, J.S. Carbon isotopes in organic matter from a benthic alga Halimeda incrassata (Bermuda): effects of light intensity. Chem. Geol. 59 , 321-326 (1986). Kohn, M. J. Carbon isotope compositions of terrestrial C3 plants as indicators of (paleo) ecology and (paleo) climate. Proc. Natl. Acad. Sci. Unit. States Am. 107 , 19691-19695 (2010). https://doi.org/10.1073/pnas.1004933107 Heaton, T. J., et al. Marine20-The Marine Radiocarbon Age Calibration Curve (0–55,000 cal BP). Radiocarbon 62(4) , 779-820 (2020). Reimer, P.J., et al. The IntCal20 Northern Hemisphere Radiocarbon Age Calibration Curve (0–55 cal kBP). Radiocarbon 62(4) , 725-757(2020). Ramsey, B. C. Bayesian analysis of radiocarbon dates . Radiocarbon 51(1) , 337-360 (2009). Blott, S. J. & Pye, K. Gradistat: A grain size distribution and statistics package for the analysis of unconsolidated sediments. Earth Surf. Proc. Lan, 26 , 1237-1248 (2001). Toomey, M. R., Donnelly, J. P. & Woodruff, J. D. Reconstructing mid-late Holocene cyclone variability in the Central Pacific using sedimentary records from Tahaa, French Polynesia. Quat. Sci. Rev. 77 , 181-189 (2013). Isaack, A., et al. A new model evaluating sediment dynamics throughout the Holocene: insights from a mixed carbonate-siliciclastic lagoon (Bora Bora, Society Islands, French Polynesia, South Pacific). Sediment. Geol. 343 , 99-118 (2016). Wallace, E. J., Coats, S., Emanuel, K. A. & Donnelly, J. P. Centennial-scale shifts in storm frequency captured in paleohurricane records from The Bahamas arise predominantly from random variability. Geophys. Res. Lett. 47 , e2020GL091145 (2020). https://doi.org/10.1029/2020GL091145 Knapp , K., Kruk, M. C., Levinson, D. H., Diamond, H. J. & Neumann, C. J. The International Best Track Archive for Climate Stewardship (IBTrACS). Bull. Am. Meteorol. Soc. 91(3) , 363-376 (2010). https://doi.org/10.1175/2009BAMS2755.1 McAdie, C., Landsea, C., Neumann, C. J., David, J. E. & Blake, E. S. (2009): Tropical Cyclones of the North Atlantic Ocean, 1851–2006: With 2007 and 2008 Track Maps Included Vol. 6 (US Department of Commerce, National Oceanic and Atmospheric Administration). Vecchi, G. A. & Knutson, T. R. Estimating annual numbers of Atlantic hurricanes missing from the HURDAT database (1878-1965) using ship track density. J. Clim. 24 , 1736-1746 (2011). Stoddart, D. R. Effects of Hurricane Hattie on the British Honduras reefs and cays, October 30-31. Atoll Res. Bull. 95 , 1-142 (1963). Kelletat, D., et al. Holocene tsunami deposits on the Bahaman islands of Long Island and Eleuthera. Zeitschrift für Geo­morphologie, 48 , 519-540 (2004). Scheffers, A. & Kelletat, D. New evidence and dating of Holocene paleo-tsunami events in the Caribbean (Barbados, St. Martin and Anguilla). In : Mercado-Irizarry, A. & Liu, P. ( eds ) Caribbean Tsunami Hazard . New Jer­sey: World Scientific Press, pp. 178-202 (2006). Biguenet, M., et al. 1600 year-long sedimentary record of tsunamis and hurricanes in the Lesser Antilles (Scrub Island, Anguilla). Sediment. Geol. 412 , 105806 (2021). https://doi.org/10.1016/j.sedgeo.2020.105806 Barkan, R., Uri, S. & Lin, J. Far field tsunami simulations of the 1755 Lisbon earthquake: Implications for tsunami hazard to the US East Coast and the Caribbean. Mar. Geol. 264 , 109-122 (2009). Additional Declarations There is NO Competing Interest. Supplementary Files Suppl.1.xlsx Dataset 1 Suppl.2.xlsx Dataset 2 Suppl.3.xlsx Dataset 3 Suppl.4.xlsx Dataset 4 Suppl.5.xlsx Dataset 5 Suppl.6.xlsx Dataset 6 Suppl.7.xlsx Dataset 7 Suppl.8.xlsx Dataset 8 Suppl.9.xlsx Dataset 9 Fig.S1.pdf Extended Data 1 Fig.S2.pdf Extended Data 2 Fig.S3.pdf Extended Data 3 Fig.S4.pdf Extended Data 4 Cite Share Download PDF Status: Posted Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-3758003","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Physical Sciences - Article","associatedPublications":[],"authors":[{"id":261454624,"identity":"d0b2b85f-55f2-4834-b721-357790a29dd0","order_by":0,"name":"Dominik Schmitt","email":"data:image/png;base64,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","orcid":"","institution":"Institut für Geowissenschaften, Johann Wolfgang Goethe-Universität","correspondingAuthor":true,"submittingAuthor":false,"prefix":"","firstName":"Dominik","middleName":"","lastName":"Schmitt","suffix":""},{"id":261454625,"identity":"c0e8f55c-ba3a-4d32-a9d5-193661c5c985","order_by":1,"name":"Eberhard Gischler","email":"","orcid":"","institution":"Goethe-Universitaet - Institut fuer Geowissenschaften - Facheinheit Paläontologie","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Eberhard","middleName":"","lastName":"Gischler","suffix":""},{"id":261454626,"identity":"db16d92f-acd2-44b4-9d09-22fb9dcfc6b5","order_by":2,"name":"Martin Melles","email":"","orcid":"https://orcid.org/0000-0003-0977-9463","institution":"University of Cologne","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Martin","middleName":"","lastName":"Melles","suffix":""},{"id":261454627,"identity":"0ab2c706-0152-46a7-b68d-b5b6cb90bb2f","order_by":3,"name":"Volker Wennrich","email":"","orcid":"","institution":"University of Cologne","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Volker","middleName":"","lastName":"Wennrich","suffix":""},{"id":261454628,"identity":"35d65294-3e99-4dab-a190-7ac031c70e2f","order_by":4,"name":"Hermann Behling","email":"","orcid":"","institution":"Dept. Palynology and Climate Dynamics, University of Goettingen","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Hermann","middleName":"","lastName":"Behling","suffix":""},{"id":261454629,"identity":"5083964d-2187-43ab-b914-2285d1e57a30","order_by":5,"name":"Lyudmila Shumilovskikh","email":"","orcid":"","institution":"University of Goettingen","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Lyudmila","middleName":"","lastName":"Shumilovskikh","suffix":""},{"id":261454630,"identity":"4586aeb4-9852-4ca9-b7fe-803626ec7a4e","order_by":6,"name":"Flavio Anselmetti","email":"","orcid":"","institution":"University of Bern","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Flavio","middleName":"","lastName":"Anselmetti","suffix":""},{"id":261454631,"identity":"055bcc97-6084-4920-a2e0-4ec7b6b97de6","order_by":7,"name":"Hendrik Vogel","email":"","orcid":"https://orcid.org/0000-0002-9902-8120","institution":"University of Bern","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Hendrik","middleName":"","lastName":"Vogel","suffix":""},{"id":261454632,"identity":"b469d255-26da-447b-a5bd-c36b1ccc1957","order_by":8,"name":"Jörn Peckmann","email":"","orcid":"https://orcid.org/0000-0002-8572-0060","institution":"Universität Hamburg","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Jörn","middleName":"","lastName":"Peckmann","suffix":""},{"id":261454633,"identity":"a2986c8d-56cd-42bf-8b4a-242d9a5886f7","order_by":9,"name":"Daniel Birgel","email":"","orcid":"","institution":"","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Daniel","middleName":"","lastName":"Birgel","suffix":""}],"badges":[],"createdAt":"2023-12-15 10:02:03","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-3758003/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-3758003/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":48682622,"identity":"4c709916-11eb-4f04-aa16-765b8d74e9ba","added_by":"auto","created_at":"2023-12-22 14:56:39","extension":"jpg","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":637968,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eStudy area, mechanisms of event sedimentation and historical storm record\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e(a)\u003c/strong\u003e This map of the circum-Caribbean region\u003csup\u003e60\u003c/sup\u003e (latitude 0-30° N; longitude 55-100° W) was created by digitizing satellite imagery from the open access NASA Worldview application (https://worldview.earthdata.nasa.gov), part of the NASA Earth Observing System Data and Information System\u003cstrong\u003e \u003c/strong\u003e(EOSDIS) using the vector graphic software\u003cstrong\u003e \u003c/strong\u003eAdobe Illustrator CS4 V.14.0. The red pin points to the study site. \u003cstrong\u003e(b)\u003c/strong\u003e Position of the Great Blue Hole (encircled) on an open access ASTER satellite image of Lighthouse Reef (https://asterweb.jpl.nasa.gov) supplied by Japan Space Systems, and U.S/Japan ASTER Science TEAM (NASA/METI/AIST/). \u003cstrong\u003e(c)\u003c/strong\u003e Aerial view taken from an UAV (unmanned aerial vehicle/drone) indicating\u003cstrong\u003e \u003c/strong\u003ethe position of the sediment core BH8 (17° 18.572′ N, 87° 32.060′ W) within the sinkhole structure. Photo: E. Gischler. \u003cstrong\u003e(d)\u003c/strong\u003e Selected tropical cyclones (TC) from the historical record (2022-1950 CE) passing over the study site within a 100 km diameter circle. The storm track maps were downloaded from https://coast.noaa.gov/hurricanes/ and compared with the International Best Track Archive for Climate Stewardship-IBTrACS\u003csup\u003e43\u003c/sup\u003e. \u003cstrong\u003e(e)\u003c/strong\u003e Mechanisms and processes of cyclone-induced event-layer formation in carbonate sinkhole environments. \u003cstrong\u003e(f)\u003c/strong\u003e Comparison of modern event-layers (EL1-EL23) visible on a high-resolution core image and historically documented TCs (2022-1950 CE), including max. intensity (Saffir-Simpson scale), wind speed at the study-site (km/h), distance to the core position (km) and duration time (days).\u003c/p\u003e","description":"","filename":"1.jpg","url":"https://assets-eu.researchsquare.com/files/rs-3758003/v1/25bf407d30ab3fa737bddee1.jpg"},{"id":48682626,"identity":"8d565e70-0909-4213-8907-fa37a681f271","added_by":"auto","created_at":"2023-12-22 14:56:39","extension":"jpg","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":300835,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eAge-depth framework of sediment core BH8\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe provided age model is a combination of tested varve-counting and \u003csup\u003e14\u003c/sup\u003eC-AMS-radiocarbon approaches\u003csup\u003e32\u003c/sup\u003e. The Great Blue Hole succession is separated into three major units, characterized by different sedimentation rates and pollen appearances.\u003c/p\u003e","description":"","filename":"2.jpg","url":"https://assets-eu.researchsquare.com/files/rs-3758003/v1/ba1793bbcf2abc586e4c607a.jpg"},{"id":48682621,"identity":"9bf5fe97-f879-4b2a-ad26-1e725f8fdb5e","added_by":"auto","created_at":"2023-12-22 14:56:39","extension":"jpg","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":707198,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eHolocene reconstruction of south-western Caribbean TC-frequency\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e(a)\u003c/strong\u003e 100-years-counting-window; \u003cstrong\u003e(b)\u003c/strong\u003e 50-years-counting-window. Both bar graphs indicate a bipartite Holocene pattern of event-layer frequency with a long-term increasing trend, visible since the Mid-Holocene (6.5 ka BP) and alternating periods of increased (active = red) and decreased (calm = blue) activity. In panel \u003cstrong\u003e(a)\u003c/strong\u003e, latitudinal shifts of the ITCZ, reconstructed by titanium amounts\u003csup\u003e39\u003c/sup\u003e, proxy-based global mean surface temperatures\u003csup\u003e61\u003c/sup\u003e and a CO\u003csub\u003e2\u003c/sub\u003e-based Holocene temperature simulation\u003csup\u003e62\u003c/sup\u003e are shown top down in grey, orange and green, respectively. Several prominent Holocene climate changes are listed in the upper part: HCO = Holocene Climate Optimum; MHT = Mid-Holocene Transition; PCP = Piora Cold Period, SWP = Sumerian Warm Period; BAC = Bronce Age Cold; MIWP = Minoan Warm Period; IAC = Iron Age Cold; RWP = Roman Warm Period; DAC = Dark Ages Cold; MWP = Medieval Warm Period; LIA = Little Ice Age and IW = Industrial Warmth. In panel \u003cstrong\u003e(b),\u003c/strong\u003e obliquity and precession changes are presented in fuchsia and brown, respectively\u003csup\u003e63\u003c/sup\u003e. The onset of increasing ENSO activity\u003csup\u003e51\u003c/sup\u003e subsequent to the MHT is highlighted by a black arrow on the right side. The onset of the marine inundation is visualized by a yellow star\u003csup\u003e46\u003c/sup\u003e. In the upper part of this sub-section, a Mesoamerican subdivision of Holocene times, related to the Maya Civilization, is shown. In panel \u003cstrong\u003e(c)\u003c/strong\u003e, intervals of active and calm storm conditions are listed. For colouring please consider the online version of the manuscript.\u003c/p\u003e","description":"","filename":"3.jpg","url":"https://assets-eu.researchsquare.com/files/rs-3758003/v1/4045a06da238b43499a98f86.jpg"},{"id":48682630,"identity":"701e6416-5d98-4024-a20b-7fa94c3dd71a","added_by":"auto","created_at":"2023-12-22 14:56:39","extension":"jpg","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":604882,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eCompilation of Belizean TC-frequency reconstructions\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e(a)\u003c/strong\u003e 100-, \u003cstrong\u003e(b)\u003c/strong\u003e 50-, and \u003cstrong\u003e(c)\u003c/strong\u003e 20-years-counting-windows, encompassing the past recent 2000-years, i.e., the Common Era. Sediment cores BZE-BH-SVC4\u003csup\u003e29\u003c/sup\u003e, BH6/7\u003csup\u003e32 \u003c/sup\u003eand BH8 (this study) were considered. The sediment core BH6/7\u003csup\u003e32\u003c/sup\u003e was re-correlated with the new core BH8 and age-depth corrected by means of overlapping event-layers. Individual frequency data were smoothed using the LOWESS algorithms\u003csup\u003e64,65\u003c/sup\u003e. The grey band is the 95% confidence interval, displayable for the smoothed curve fit, based on 999 random replicates.\u003c/p\u003e","description":"","filename":"4.jpg","url":"https://assets-eu.researchsquare.com/files/rs-3758003/v1/aa94ab065e870288b128dde6.jpg"},{"id":48682628,"identity":"78a3f1ab-e972-4563-864d-aca1c5b74573","added_by":"auto","created_at":"2023-12-22 14:56:39","extension":"jpg","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":292891,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eConceptual model of cyclone formation during three Holocene stages\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e(a)\u003c/strong\u003e Oceanic (SST) and atmospheric (ITCZ) configuration during the early Holocene, with frequent westwards moving cyclones in higher latitudes. (b) An orbitally-forced mid-Holocene insolation change caused restructurings of Atlantic warm and cold pools as well as latitudinal ITCZ migrations,\u003csup\u003e39 \u003c/sup\u003eboth together triggering a shift of major storm trajectories through positioning changes of the Hurricane Main Development Region (MDR) and its four cyclone formation sub-clusters (ellipsoids numbered: 1, 2, 3, 4)\u003csup\u003e2,42\u003c/sup\u003e. (c) These still ongoing reorganisations are sufficient to explain a gradual long-term rise of Holocene storm activity since 6.5 ka BP by an establishment of gradually more westwards moving storm systems landfalling in lower latitudes.\u003c/p\u003e","description":"","filename":"5.jpg","url":"https://assets-eu.researchsquare.com/files/rs-3758003/v1/073a14e2fc33c95734fc4f97.jpg"},{"id":49771758,"identity":"e5bd7411-99f3-4ef3-81ae-f829ea39aac1","added_by":"auto","created_at":"2024-01-17 18:19:10","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":1430906,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-3758003/v1/f5bf7d8d-3ba6-49cd-885c-802a5fd37963.pdf"},{"id":48683693,"identity":"b506b18d-bc06-4a31-a9ce-f875babc109c","added_by":"auto","created_at":"2023-12-22 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2","description":"","filename":"Fig.S2.pdf","url":"https://assets-eu.researchsquare.com/files/rs-3758003/v1/1694d45178274323f08576b6.pdf"},{"id":48682638,"identity":"bb52d87c-71c8-4e79-8b1f-eca9fe83d612","added_by":"auto","created_at":"2023-12-22 14:56:40","extension":"pdf","order_by":12,"title":"","display":"","copyAsset":false,"role":"supplement","size":9370928,"visible":true,"origin":"","legend":"\u003cp\u003eExtended Data 3\u003c/p\u003e","description":"","filename":"Fig.S3.pdf","url":"https://assets-eu.researchsquare.com/files/rs-3758003/v1/e40191d6d1fcdbfd7e7aca5a.pdf"},{"id":48682633,"identity":"4ed54e7c-3772-4756-be71-3d61b0cf01a0","added_by":"auto","created_at":"2023-12-22 14:56:39","extension":"pdf","order_by":13,"title":"","display":"","copyAsset":false,"role":"supplement","size":1222599,"visible":true,"origin":"","legend":"\u003cp\u003eExtended Data 4\u003c/p\u003e","description":"","filename":"Fig.S4.pdf","url":"https://assets-eu.researchsquare.com/files/rs-3758003/v1/9b9c661f4d3e014a0d81c33e.pdf"}],"financialInterests":"There is \u003cb\u003eNO\u003c/b\u003e Competing Interest.","formattedTitle":"Ocean temperatures and ITCZ migrations triggered cyclone-frequency variations during the Holocene","fulltext":[{"header":"Introduction","content":"\u003cp\u003eTropical cyclones (TCs) are among the most spectacular and dangerous weather phenomena on planet Earth. In view of the ongoing global climate change, TCs should be subject of palaeotempestology studies, addressing climatically-controlled frequency changes over longer pre-industrial time-scales. In the Atlantic Ocean, TCs primarily form along the northern edge of the Intertropical Convergence Zone(ITCZ)\u003csup\u003e1\u003c/sup\u003e, in four clearly defined sub-clusters\u003csup\u003e2\u003c/sup\u003e between 9\u0026deg;N and 20\u0026deg;N, described as the Hurricane Main Development Region (MDR)\u003csup\u003e3\u003c/sup\u003e. During the annual hurricane-season, gradually better self-organizing and progressively intensifying storm cells begin to move (north)-westward in synchrony with the Northern Hemisphere trade-wind circulation. On their way to the west, they pass the tropical Western Atlantic, the Caribbean Sea, and/or the Gulf of Mexico, before they finally deviate northeasterly at about 30\u0026deg;N. Seasonally recurring TCs are hence imminent threats for several countries located within the Atlantic Hurricane Belt. Their landfalls are accompanied by devastating winds, torrential rain, high storm surges, and flooding. Such extreme weather events cause massive economic damage to vulnerable infrastructure in coastal cities and endanger thousands of human lives each year. \u003c/p\u003e\n\u003cp\u003eIn modern days, thermodynamic and kinematic boundary conditions, in particular sea-surface temperatures (SST) above 26\u0026deg;C and low vertical wind-shear stress are found to be particularly favourable for a frequent TC-genesis\u003csup\u003e4,5\u003c/sup\u003e. The current hazard potential of TC-strikes could become even more exacerbated in response to a projected global warming of 2\u0026deg;C, constant SSTs above 26\u0026deg;C, and an expected ~1 m global sea-level rise by the end of the 21\u003csup\u003est\u003c/sup\u003e century\u003csup\u003e6,7,8\u003c/sup\u003e. While most studies predict a relative increase in the probability of storm cells reaching higher intensities faster and more frequently\u003csup\u003e9-16\u003c/sup\u003e, other studies rather suggest that the frequency remains at the current high state, although with a northern shift of a maximum activity zone\u003csup\u003e17\u003c/sup\u003e, or even propose decreases\u003csup\u003e18\u003c/sup\u003e. All these forecasts should be, however, treated with caution, as the underlying data originate solely from 173-years-long historical documentations and 73-years-long instrumental measurements. In addition, both records suffer from stochastic\u003csup\u003e19\u003c/sup\u003e, observational\u003csup\u003e20\u003c/sup\u003e and technical biases\u003csup\u003e21\u003c/sup\u003e, the latter two steadily increasing with time and new technical advances.\u003c/p\u003e\n\u003cp\u003eThe short instrumental and historical records are regardless highly suitable to decipher high-frequency oscillations of storminess and their underlying causes on multi-annual time scales. But it is already very challenging to appropriately asses multi-decadal climate forcing in TC-frequency prediction models, because all usually considered instrumental records only cover one or two complete cycles of climate phenomena\u0026acute;s modes of actions. All climate boundary conditions that alter TC-frequency on centennial to millennial time-scales cannot be taken into account, without a solid data basis that covers the Holocene interglacial and its different climate stages in its entirety. This requires new and much longer sedimentary records characterized by a high temporal resolution and sensitivity to track several hundred TC event-layers. Such extended statistics will not only help to further update the state-of-the-art information about past and present TC-frequency variability, but also significantly improve the accuracy of future prediction models. \u003c/p\u003e\n\u003cp\u003eA growing number of event-based frequency reconstructions has already contributed to extend our understanding of multi-decadal to centennial-scaled climate drivers, such as the Atlantic Multidecadal Oscillation (AMO)\u003csup\u003e22\u003c/sup\u003e, the North Atlantic Oscillation (NAO)\u003csup\u003e2\u003c/sup\u003e and the El-Ni\u0026ntilde;o-Southern-Oscillation (ENSO)\u003csup\u003e23\u003c/sup\u003e, however only up to a 2000-years-long perspective. Appropriate archives were recovered from different sub-aerial sinkholes\u003csup\u003e1,24-27 \u003c/sup\u003eand fully inundated marine blue holes\u003csup\u003e19,28-34\u003c/sup\u003e, located in coastal karst basins or on carbonate platforms within the tropical Atlantic Hurricane Belt. Proximal passing storms produce easily identifiable and countable indicator layers (coarse-grained over-wash deposits) in these formidable naturalsediment traps\u003csup\u003e35\u003c/sup\u003e, applicable to reconstruct extended TC-frequency statistics. \u003c/p\u003e\n\u003cp\u003eChronological studies of these sedimentary archives revealed alternating periods of stronger and calmer storm activity, that are linked for the past 2000-years to inter-annual\u003csup\u003e36\u003c/sup\u003e and multi-decadal\u003csup\u003e37\u003c/sup\u003e, up to centennial-scaled\u003csup\u003e31\u003c/sup\u003e shifts of the summer ITCZ latitude. Elevated local SST in the southern and eastern sub-clusters (2, 3 and 4) of the Atlantic MDR coincided with a generally more southern position of the summer ITCZ, concomitant with increased low-level vorticity and decreasing vertical wind-shear stress, as well as lower sea-level pressure\u003csup\u003e38\u003c/sup\u003e. Thus, we hypothesize that a Holocene-scaled mean annual and seasonal southward displacement of the ITCZ\u003csup\u003e39\u003c/sup\u003e, associated with a mid-Holocene restructuring of Atlantic Ocean warm-pools, would likely exert a strong impact on long-term frequency patterns in the Caribbean region by a commutated migration of the MDR sub-clusters\u003csup\u003e40\u003c/sup\u003e. To prove the hypothesis of a coupled ITCZ- and SST-triggered increase of regional TC-frequency, indicated by a shift of major storm trajectories from once higher (\u0026gt;30\u0026deg;) to lower latitudes (9\u0026deg;-20\u0026deg;), a complete and undisturbed succession of Holocene sediments, deposited in an anoxic south-western Caribbean blue hole site, very sensitive for storm-controlled event-layer deposition, would be required. \u003c/p\u003e\n\u003cp\u003eIn this study, we investigated the 30-m-long sediment core BH8 (17\u0026deg;18\u0026prime;57.2\u0026prime;\u0026prime; N, 87\u0026deg;32\u0026prime;0.60\u0026prime;\u0026prime; W), successfully recovered from the south-western Caribbean \u0026ldquo;Great Blue Hole\u0026rdquo;, which is located in the shallow eastern lagoon of the Lighthouse Reef Atoll, 80 km offshore the mainland coast of Belize (Figs. 1a, b, c). Core BH8 with its outstandingly well preserved event-layer record (n = 694) allowed us to reconstruct a 12500-years-long history of multi-decadal to centennially-scaled TC-frequency variation. These data, for the first time, enable a comparison of frequency statistics with the superimposed trend of a southward ITCZ displacement for the entirety of the Holocene. For that purpose, event-beds, related to a proximal TC passage (Fig. 1d), have been counted in 100-, 50-, and 20-years observational windows\u003csup\u003e24\u003c/sup\u003e. Their identification relied on a tested multi-proxy-identification approach\u003csup\u003e32\u003c/sup\u003e, combining several optical, textural, and geochemical criteria (Fig. S1). Passing cyclones cause a high grade of associated storm-wave erosion at windward marginal reef sites of Lighthouse Reef Atoll (Fig. 1e) and also induce strong hydrodynamic currents towards the atoll lagoon, which enables a re-suspensional transport (over-wash) of eroded reef materials (\u003cem\u003eHalimeda\u003c/em\u003e-chips and other sand- and gravel-sized skeletal debris). The carried sediment load is subsequently transported and redeposited in the sinkhole sediment trap as an event-layer (Fig. 1e) by means of density currents and gradual settling of suspension, respectively. \u003c/p\u003e"},{"header":"Sedimentology and chronology of core BH8","content":"\u003cp\u003eOur sedimentological and palynological analyses revealed that the sediment succession of the Great Blue Hole can be separated into three major units (Fig. 2) representing (A) fully marine (24.6-0 m), (B) restricted marine (28.6-24.6 m) and (C) cenote-like (30.0-28.6 m) sedimentation. The sedimentary unit C marks an initial terrestrial sinkhole phase. In accordance with a sea-level rise from 60 m to 5 m below modern level\u003csup\u003e41\u003c/sup\u003e, the Great Blue Hole formed a subaerially exposed cenote on a limestone island covered by a \u003cem\u003eMyrtaceae\u003c/em\u003e-dominated neotropical forest, during the latest Pleistocene and the early Holocene (12.5-7.2 ka BP). The continued sea-level rise close to the modern level induced a transition of the island to an initially flooded carbonate platform rich in mangrove swamps (\u003cem\u003eRhizophora\u003c/em\u003e), and a restricted marine inflow (7.2-5.7 ka BP) into the sinkhole. Since about 5.7 ka BP, the sinkhole is located in an open and well circulated atoll lagoon, resulting in fully marine conditions in the blue hole. Mangrove pollen completely disappeared and only wind-carried pollen of oaks (\u003cem\u003eQuercus\u003c/em\u003e) and pines (\u003cem\u003ePinus\u003c/em\u003e) could be detected in higher abundances (Fig. 2). \u003c/p\u003e\n\u003cp\u003eIn the uppermost unit A (Fig. S2), over-washed particles form easily distinguishable white to pale brown event-layers that stand out from a light greyish to greyish green-coloured succession of annually-laminated fair-weather carbonate sediments. Similarly coloured event-layers appear in the slightly darker, greyish green to greyish brown-coloured sediments of the intermediate unit B. Compared to the overlying section, however, these tempestites are sometimes significantly enriched in organic material (wood pieces and leaf material from red mangroves) and thus very dark brown to almost black (Fig. S2). In the lowermost unit C, a grey brown coloured and finely laminated succession of carbonates is repeatedly interrupted by white or reddish and slightly faded event beds of significantly thicker and coarser deposits, which also include fragments of marine organisms, such as \u003cem\u003eHalimeda\u003c/em\u003e, bivalves, gastropods and foraminifera tests) as well as organic material (Fig. S2).\u003c/p\u003e\n\u003cp\u003eThe chronology of sediment core BH8 is based on a proven combination of varve-counting- and \u003csup\u003e14\u003c/sup\u003eC-AMS-radiocarbon dating models\u003csup\u003e32\u003c/sup\u003e. The primary use of a varve-counting approach allows precise dating of all event-layers identified by optical, textural, and geochemical thresholds. All recovered varves of core BH8 were counted visually in PVC liners and cross-checked with measurements of thickness and colour differences derived from high-resolution images as well as density variations in radiographic recordings. Core parts not recovered in the PVC liners (i.e., core catchers) were texturally analysed and identified either as varved sections with or without an event-layer by means of their textural signatures in comparison with undisturbed core parts. For the age model, the time contained in these sections was estimated by extrapolating the mean sedimentation rates of the bracketing core unit. \u003c/p\u003e\n\u003cp\u003eThis proceeding yielded an varve age of 12091 \u0026plusmn; 605 a BP at the core base. Eleven calibrated radiocarbon ages (cal. a BP) were used as a secondary age control (Fig. S3). Radiocarbon dating of bulk organic matter from 3000.6 cm depth revealed an overlapping age of 12583 \u0026plusmn; 101 cal. a BP at the core base (Suppl. 1). This way, a robust age-depth framework without any core hiatus, was created (Fig. 2). At the core top, two independent chronological markers helped to additionally confirm the accuracy of the varve-counting- and radiocarbon-dating approaches. Increased pollen abundances of corn (\u003cem\u003eZea mays\u003c/em\u003e), pine (\u003cem\u003ePinus\u003c/em\u003e) and palm (\u003cem\u003eArecaceae\u003c/em\u003e) at 2.5 cm depth (Fig. 2), which do not appear elsewhere in the core, provide evidence of known anthropogenic cultivation in the past decade. Higher abundances of volcanic glass shards, likely from the 1982 CE El Chich\u0026oacute;n eruption, occurred at 32.4 cm depth, which is dated to 1979 \u0026plusmn; 2 CE (Fig. 2). \u003c/p\u003e"},{"header":"Historical storm record calibration","content":"\u003cp\u003eThe Great Blue Hole is positioned in the trackways of many historic TCs that formed in the Caribbean Sea (cluster 2) and in the western tropical Atlantic (cluster 4), east of the Lesser Antilles\u003csup\u003e2,42\u003c/sup\u003e. Following the described varve-counting-approach, we attributed event-layers identified in the modern sediment facies of the sediment core BH8 (upper 61.8 cm) to historical TCs documented in the International Best Track Archive for Climate Stewardship-IBTrACS\u003csup\u003e43\u003c/sup\u003e. This way, we were able to evaluate the sensitivity of the Great Blue Hole archive for a reconstruction of the Holocene storm activity. Since 1950 CE, 19 storm systems of varying strength passed directly over or adjacent to Lighthouse Reef Atoll in north-western direction (Fig. 1d). Eight of these were categorized as tropical storms and 11 achieved hurricane strength upon the closest passage. We were finally able to allocate 16 coarse-grained event-beds (Suppl. 2) to the 19 historically documented TCs (Fig. 1f). The susceptibility of the Great Blue Hole for event-layer preservation consequently amounts to 84%. Based on the existing calibration of the historical record, we have to concede an underestimation of about 16% for the following reconstruction of prehistoric TC-frequency in the southwestern Caribbean.\u003c/p\u003e\n\u003cp\u003eThe textural data (event-layer thickness, amount of coarse fraction \u0026gt;63 \u0026mu;m and mean grain size) of 32 event-layers from an observational record back to 1850 CE (Suppl. 2) were compared with instrumental TC data, such as wind speed at the location (km/h), storm duration (days/hours) and the distance between storm tracks and study site (km). All textural parameters were found to correlate best (p\u0026lt;0,05) with the wind speed at the study site (TC-intensity). The correlations (r = 0.53; r = 0.40; r = 0.45) are only moderate, and, there are not enough data available to create a valid proxy for reconstructing past TC-intensity based on sediment texture (Suppl. 2). In the modern part of the Great Blue Hole record, only two event-layers can be correlated with TC category H2 and just one event-layer with category H3. We therefore focus in this article only on the variability of the Holocene storm frequency.\u003c/p\u003e"},{"header":"Holocene TC-frequency variability ","content":"\u003cp\u003eOur Holocene reconstruction of the southwestern Caribbean TC-frequency (Fig. 3) indicates a clear dichotomy with only very few event-layers have been found during the cenote-phase (12.5-7.2 ka BP), whereas considerably more were identified during the restricted marine (7.2-5.7 ka BP) and fully marine (5.7-0 ka BP) stages. The bold black line overlaying both bar graphs (Figs. 3a, b) is a LOWESS-smoothed frequency curve (see methods chapter), visually highlighting a first conspicuous excursion of event-layer frequency at 7.2-6.5 ka BP that is coincident both with a gradual 5 m sea-level rise to the present level\u003csup\u003e41\u003c/sup\u003e and an important mid-Holocene climate restructuring. Since 6.5 ka, the southwestern Caribbean experienced a gradual long-term rise in regional TC-frequency, as indicated by a steady increase of event-bed counts in sediment core BH8. Within this 6500-years-long course, several multi-decadal to centennially-scaled periods of changing TC-activity have been identified. In order to separate active and calm phases, we determined a site-specific threshold (horizontal grey line) for this period at values of 9.3 TCs and 4.7 TCs per 100- and 50-years counting intervals of event-layers, respectively.\u003c/p\u003e\n\u003cp\u003eFor most of the Common Era, the Great Blue Hole was exposed to an almost continuous interval of outstanding high TC-activity (Figs. 3a, b). The storm regime was very active in the south-western Caribbean realm from 1.5-0 ka BP (A1) and still moderately active from 1.9-1.6 ka BP (A2), according to the data from the 100-years counting window. Two periods of rather calm conditions occurred from 1.6-1.5 ka BP (C1) and from 2.0-1.9 ka BP (C2). A closer look at the 50-years reconstruction supports the presence of a continuous interval of high activity from 1.6-0 ka BP, however with an incisive drop of storm frequency from 172-122 a BP. In our 50-years counting data, we recognized a more pronounced multi-decadal fluctuation between active and calm phases from 2.0-1.6 ka BP, leading to an obliteration of the active A2 interval. According to our Belizean (Great Blue Hole) compilation (Fig. 4) using three records (Fig. S4), storm activity gradually increased in the south-western Caribbean during the Dark Ages Cold (DAC: 2.0-1.35 ka BP), culminated at a level of very high activity during most parts of the Medieval Warm Period (MWP: 1.35-0.6 ka BP), and then returned to the early DAC level during the progressing Little Ice Age (LIA: 0.6-0.17 ka BP). After the onset of the anthropogenically-caused Industrial Warming (IW: \u0026lt;0.17 ka BP), TC-frequency again strongly rose to and even above the MWP state. In stages older than 2.0 ka BP, a more frequent oscillation between active and quiescent stages occurred. \u003c/p\u003e\n\u003cp\u003eTen more intervals of increased storm activity (A3-A12) were identified in the 100-years counting window. The individual periods of high activity are exemplary shown in a simplified timeline (Fig. 3c). Rather calm conditions (C3-C12) were reconstructed for the intervening intervals. Likewise, all active and calm intervals of the 100-years graph (Fig. 3a) can be found in the 50-years frequency plot (Fig. 3b). Only a few multi-decadal deviations are apparent, which are not visible in the longer 100-years counting window, likely due to a higher subordinate variability as a result of the shorter counting interval. Interestingly, the identified periods of high and low activity (Fig. 3c) overlap only in parts with those for a Belizean coastal wetland site, reconstructed back to the mid-Holocene\u003csup\u003e44\u003c/sup\u003e. The fairly poor correspondence between the two records is probably caused by the lower temporal resolution and TC preservation potential of the wetland site and the application of different proxies for TC identification in both sites. \u003c/p\u003e"},{"header":"Effects of a mid-Holocene climate changes","content":"\u003cp\u003eDuring the early Holocene, and also in particular while the Holocene Climate Optimum (HCO), orbital parameters, climate modes, basin-wide SST patterns and the position of the ITCZ significantly differed relative to stages in the Late Holocene (Figs. 5a, c). A more northern tropical band with elevated SSTs and a related ITCZ position at 25-30\u0026deg;N were reconstructed for the Atlantic Ocean at the beginning of the Holocene interglacial\u003csup\u003e39\u003c/sup\u003e. With such a different oceanographic and atmospheric setting, storm systems probably developed not only in MDR sub-clusters further to the north (Fig. 5a), but also recurved, considering modern circumstances, generally away from the southern Caribbean realm\u003csup\u003e45\u003c/sup\u003e. In those days, east-west moving storm cells consequently tended to landfall at locations higher than 30\u0026deg;N along the East Coast of North America. Hence, only few rarely occurring storms belonging to the MDR sub-cluster 2 (Caribbean Sea and Gulf of Mexico), had their landfalls in the wider study area. \u003c/p\u003e\n\u003cp\u003eDuring the same time, the Great Blue Hole was subaerially exposed as a cenote on a limestone island, as a consequence of a 60 m to 5 m lower sea level\u003csup\u003e41\u003c/sup\u003e. The combination of unfavourable climatic and oceanographic conditions and a different geomorphological setup including a dense vegetation cover around the cenote provides a plausible explanation for a hampered event-bed formation between 12.5-7.2 ka BP. The continuous sea-level rise, inundating the Lighthouse Reef platform between 7.2-5.7 ka BP, may explain the superimposed bipartite pattern and the first significant excursions in storm frequency up to 6.5 ka BP by significantly increasing the formation potential of tempestites in the Great Blue Hole. However, both the observation that the platform interior was already flooded at least several hundred years earlier than 6.5 ka (oldest peat date Lighthouse Reef lagoon 7.8 ka)\u003csup\u003e46\u003c/sup\u003e, and the subsequent long-term trend of increasing event-layer frequency provide strong evidence for a climatic forcing that induced a gradual shift towards a progressively more active storm regime in the south-western Caribbean after 6.5 ka BP. \u003c/p\u003e\n\u003cp\u003eAn orbitally-forced (21-ka precession and 41-ka obliquity cycles) reorganisation of global solar insolation\u003csup\u003e47,48 \u003c/sup\u003e, starting during the Mid-Holocene Transition (MHT; 6.0-4.8 ka BP) is suspected to have caused hemispheric-scaled reversals\u003csup\u003e49\u003c/sup\u003e of oceanic warm- and cold-pools (Figs. 3b, 5b). These modifications in orbital parameters evoked pronounced changes in seasonal temperature gradients between high and low latitudes. Solar insolation in the tropics generally changed from a lower to a higher level, likely resulting in a southern repositioning of a tropical SST band, that was located far to the north during the early Holocene (Fig. 3b). In polar regions, the situation was exactly the opposite. The same changes in global solar irradiation also significantly increased the prevalence of El-Ni\u0026ntilde;o-like conditions in the Pacific Ocean\u003csup\u003e50\u003c/sup\u003e. A progressive southward migration of the mean annual and summer season Atlantic ITCZ is accompanied with these significant changes in high and low latitude insolation, associated with a commutated relocation of Atlantic Ocean warm-pools. An intensified ENSO activity suddenly appearing subsequent to the MHT (5.0-3.5 ka BP) may have amplified the southern ITCZ migration in the Atlantic Ocean, through a simultaneous northward shift of the ITCZ in the Pacific Ocean\u003csup\u003e51\u003c/sup\u003e. \u003c/p\u003e\n\u003cp\u003eAfter these impactful reorganisations had started, a repositioning of MDR sub-clusters may have commenced (Fig. 5b), finally resulting in the present expansion between 9\u0026deg;-20\u0026deg;N during the Late Holocene (Fig. 5c). In this way, a new oceanic (SST) and atmospheric (ITCZ) configuration was set up, which steadily established a shift of major storm trajectories from once higher (\u0026gt;30\u0026deg;) to now lower latitudes (9\u0026deg;-20\u0026deg;). The new configuration likely promoted storm systems developing in more southern sub-clusters two and four, to migrated straight westwards through the Caribbean Sea, where they henceforth commonly made their landfalls along the coasts of Central America and the Gulf of Mexico. The centennial-scaled variability within this 6500-years-long trend is best explained by solar activity cycles\u003csup\u003e52\u003c/sup\u003e and solar insolation fluctuations, in particular the latter one causing climatic responses and multi-centennial SST variations in the Atlantic storm formation zones, as seen for example during the MWP and the LIA\u003csup\u003e53\u003c/sup\u003e. The multi-decadal variability in our storm frequency data originates from rather shorter-term modulations aligned to climate phenomena modes, which includes especially AMO phase changes and variations of ENSO amplitudes\u003csup\u003e32\u003c/sup\u003e.\u003c/p\u003e"},{"header":"Comparison with Atlantic TC-frequency reconstructions","content":"\u003cp\u003eA comparison with other TC-frequency reconstructions yields coherent TC-frequency patterns in the wider Atlantic region. As virtually all other blue hole and palaeotempestology studies with sufficient temporal resolution cover at best the past 2000 years of Holocene storm history, we have deliberately limited the comparison to the Common Era. Preliminary studies highlighted already a higher storm activity in the western North Atlantic\u003csup\u003e54\u003c/sup\u003e, in particular during the first half of the Common Era (1150-250 CE). A similar high-activity interval until 1500-1400 CE is also reconstructed for the south-western Caribbean\u003csup\u003e27-29\u003c/sup\u003e, the Gulf of Mexico\u003csup\u003e24\u003c/sup\u003e and parts of the Bahamas archipelago\u003csup\u003e31,33,55\u003c/sup\u003e. These phases of high TC-activity are consistent with the results gained from our smoothed Belizean (Great Blue Hole) compilation (Fig. 4). During the Dark Ages Cold (DAC: 650-0 CE), we found a trend of progressive increase of already high storminess. Furthermore, two periods of outstanding high TC-frequency (1050-800 CE and 1350-1200 CE) have been reconstructed for the MWP (1400-650 CE). This pattern of a basin-wide homogenously elevated TC-frequency during the first millennium was likely the consequence of a relative tropical Atlantic warming, due to high, near-equatorial insolation, and reinforcing effects of more La-Ni\u0026ntilde;a-like climate conditions\u003csup\u003e56\u003c/sup\u003e, both favouring cyclogenesis due to outstanding high ocean temperatures in all four tropical Atlantic storm-formation sub-clusters\u003csup\u003e31\u003c/sup\u003e.\u003c/p\u003e\n\u003cp\u003eWithin the second half of the MWP (1400-1150 CE), the lack of intense TC-activity along the East Coast of the United States and some islands of the Bahamas archipelago might indicate temporal changes on a more regional scale. Cooler SSTs along the East Coast of the United States\u003csup\u003e54\u003c/sup\u003e could have regionally hampered cyclogenesis in the northwestern sub-cluster one. A sudden southward relocation of the ITCZ (1200-1000 CE)\u003csup\u003e39\u003c/sup\u003e, a dampened African Easterly Jet\u003csup\u003e30\u003c/sup\u003e and a simultaneous phase of intense volcanic activity\u003csup\u003e57\u003c/sup\u003e might have additionally altered the trajectories of TCs on a more regional level. \u003c/p\u003e\n\u003cp\u003eWhile sediment cores from the Bahamas\u003csup\u003e19,30,33,34 \u003c/sup\u003eand New England\u003csup\u003e54\u003c/sup\u003e recorded again more active storm landfalls since the onset of the LIA (1700-1400 CE), various archives\u003csup\u003e24,27-29 \u003c/sup\u003elocated further south conversely indicate an abrupt change to calmer conditions. Our southwestern Caribbean TC-frequency compilation (Fig. 4) supplies additional evidence for an antiphase north-south variability by revealing a similar decrease of storminess at the Great Blue Hole during the LIA. The re-establishment of a warm SST anomaly along the East Coast of the United States\u003csup\u003e54\u003c/sup\u003e probably favoured stronger storm formation in the north-western part of the MDR (sub-cluster one), reminiscent of the prevailing climatic and oceanographic conditions in the Early Holocene (Figs. 5a, c). A strongly negative NAO gradient\u003csup\u003e29\u003c/sup\u003e, a particularly active African Easterly Jet\u003csup\u003e58\u003c/sup\u003e and/or latitudinal shifts of the North Atlantic Subtropical High (NASH)\u003csup\u003e2\u003c/sup\u003e are discussed as additional drivers for this heterogeneity. Between 1400-1150 CE, straight westwards moving cyclones frequently made landfall in the southwestern Caribbean realm and around the Gulf Coast, probably in response to a southern NASH displacement. These straight moving cyclones temporarily transformed into north-east recurving storms that preferably impacted the Bahamas and the East Coast of the United States, after the NASH moved back to the north subsequent to 1400 CE\u003csup\u003e59\u003c/sup\u003e. All these results support the hypothesis that the present spatial heterogeneity, which is well-known from observational data, persisted across the Atlantic Basin over the last 700 years\u003csup\u003e19\u003c/sup\u003e.\u003c/p\u003e"},{"header":"Conclusions and Outlook","content":"\u003cp\u003eThe sediment core BH8, recovered from the bottom of the Great Blue Hole (Belize), indicates an obvious bipartite TC pattern. Event-layers have been found only sporadically during the cenote-phase (12.5-7.2 ka BP), whereas they were considerably more frequent during the restricted marine (7.2-5.7 ka BP) and fully marine (5.7-0 ka BP) stages. The superimposed bipartition and the first excursions of event-layer frequency between 7.2-6.5 ka BP is best explained by a persistent Holocene sea-level rise, which increased the chance of event-layer formation in the Great Blue Hole after the modern level was reached.\u003c/p\u003e\n\u003cp\u003eSince then, a long-term gradual increase in event-layer counts and thus TC-frequency was accompanied in response to an orbitally-forced restructuring of global climate- and ocean dynamics at the MHT, including in particular a reorganisation of Atlantic warm and cold pools and a persistent southward ITCZ migration, as well as a general ENSO intensification in the Pacific Ocean. These changing circumstances resulted in a latitudinal shift of MDR sub-clusters to the south and increased thereby the preferences for a higher number of storm systems migrating westwards at lower latitudes. This in turn entailed step-wise more landfalls in Central America and in the Gulf of Mexico region, sufficient to create the gradually increasing amount of event-layers in the Great Blue Hole.\u003c/p\u003e\n\u003cp\u003eTwelve alternating periods of increased (A1-A12) and decreased (C1-C12) activity were identified within this 6500-years-long pattern of gradually increasing storm activity. The centennial and multidecadal variations in our record are interpreted to be the result of solar insolation changes and climate phenomena modulations (e.g., AMO phase changes and ENSO amplitudes), respectively. The short-term variability within a continuous interval of high-stand storm activity (A1), lasting the past 1500 years, is similar to patterns observed from other TC archives in the Atlantic Basin.\u003c/p\u003e\n\u003cp\u003eBased on our record and the forecast that the northern Atlantic will considerably heat up until the end of the 21\u003csup\u003est\u003c/sup\u003e century\u003csup\u003e17\u003c/sup\u003e, a scenario similar to that of the early Holocene could gradually emerge again. In the future, regional TC-frequency could probably decrease in the south-western Caribbean, but in contrast increase in the more northern Atlantic regions due to a northward ITCZ relocation in response to a northwards shifting Atlantic warm pool.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eAcknowledgements\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eWe would like to thank the Belize Audubon Society, the Geology and Petroleum Department, and the Belize Fisheries Department for site access, issuing of research permit and sample export permissions. We feel obliged to our German and Austrian colleagues Gabriela Meyer (Frankfurt), Martin Niederreiter and Richard Niederreiter (Mondsee), who assisted us in many operative and technical ways before and during the fieldwork. We would also like to thank captain Norlan Lamb and first mate Ashbert Miranda for the fieldwork campaign in Lighthouse Reef and their efforts to realise a successful project. In this context, we would also like to thank the employees of LPL-Projects + Logistic GmbH (Hamburg), who worked tirelessly to ensure that the sea freight finally arrived in Belize, despite major pandemic-related delays caused by the shipping company. Broker Bert Bradley and his crew of Belize City dealt with Belize Customs and worked hard to mobilize our equipment. Ms. Colette Grimshaw of Old Belize Marina helped us in many ways. The assistance of student helpers Andreas Buchheim, Annika Wiegand (Frankfurt) and Elija Nolte (Cologne) during preparation, sampling and measuring is gratefully acknowledged. We also owe a great debt of gratitude to Doris Bergmann-D\u0026ouml;rr and Jenniffer Markwirth (Frankfurt) for access and assistance in Laser-Optical-Particle-Analyser measurements and Nicole Mantke and Jacob Feller (Cologne) for assistance in running the XRF-analyses.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthor Contributions\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eE.G. and M.M. did the field-work in Belize. V.W. and D.S. made the photo documentation, XRF-measurements, radiographic images and core correlations. D.S. performed the sampling processes, core description and the TC-frequency reconstruction. D.S wrote large parts of the original manuscript draft. All co-authors discussed the results and provided resources and equally input to the manuscript.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCompeting Interests\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors declare no competing interests.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eData-Availability\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAll data generated or analysed during this study are included in this published article (and its extended data figures and supplementary information files).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFunding\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors acknowledge the financial support from the DFG in project Gi 222/31-2.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003evan Hengstum, P. J., et al. The intertropical convergence zone modulates intense hurricane strikes on the western North Atlantic margin. \u003cem\u003eSci. Rep.\u003c/em\u003e \u003cstrong\u003e6\u003c/strong\u003e, 21728 (2016). 10.1038/srep21728\u003c/li\u003e\n\u003cli\u003eKossin, J. P., Camargo, S. J. \u0026amp; Sitkowski M. Climate modulation of North Atlantic hurricane tracks. \u003cem\u003eJ. Clim.\u003c/em\u003e \u003cstrong\u003e23(11)\u003c/strong\u003e, 3057-3076 (2010).\u003c/li\u003e\n\u003cli\u003eGray, W. M. Global view of the origin of tropical disturbances and storms. \u003cem\u003eMonth. Weath. Rev\u003c/em\u003e. \u003cstrong\u003e96, \u003c/strong\u003e669-700 (1968).\u003c/li\u003e\n\u003cli\u003eWebster, P .J., Holland, G. J., Curry, J. A. \u0026amp; Chang, H.-R. Changes in tropical cyclone number, duration, and intensity in a warming environment. \u003cem\u003eScience\u003c/em\u003e \u003cstrong\u003e1844\u003c/strong\u003e, 1844-1846 (2005).\u003c/li\u003e\n\u003cli\u003eRios-Berrios, R. \u0026amp; Torn, R. D. Climatological analysis of tropical cyclone intensity changes under moderate vertical wind shear. \u003cem\u003eMon. Weath. Rev.\u003c/em\u003e \u003cstrong\u003e145\u003c/strong\u003e, 1717-1738 (2017). https://doi.org/10.1175/MWR-D-16-0350.1\u003c/li\u003e\n\u003cli\u003eKnutson, T. R., et al. Tropical cyclone and climate changes. \u003cem\u003eNat. Geosci. \u003c/em\u003e\u003cstrong\u003e3,\u003c/strong\u003e 157-163 (2010).\u003c/li\u003e\n\u003cli\u003eOppenheimer, M. \u0026amp; Hinkel, J. Sea Level Rise and Implications for Low Lying Islands, Coasts and Communities Supplementary Material. IPCC Special Report on the Ocean and Cryosphere in a Changing Climate (2019).\u003c/li\u003e\n\u003cli\u003eKnutson, T., et al. Tropical Cyclones and Climate Change Assessment Part II: Projected Response to Anthropogenic Warming. \u003cem\u003eBull. Am. Meteorol. Soc. \u003c/em\u003e303-322 (2020). https://doi.org/10.1175/BAMS-D-18-0194.1\u003c/li\u003e\n\u003cli\u003eEmanuel, K., Sundararajan, R. \u0026amp; Williams, J. Hurricanes and global warming: results from downscaling IPCC AR4 simulations. \u003cem\u003eBull. Am. Meterorol. Soc. \u003c/em\u003e\u003cstrong\u003e89\u003c/strong\u003e, 347-367. (2008).\u003c/li\u003e\n\u003cli\u003eBender, M. A., et al. Modeled impact of anthropogenic warming on the frequency of intense Atlantic hurricanes, \u003cem\u003eScience\u003c/em\u003e \u003cstrong\u003e327(5964)\u003c/strong\u003e, 454-458 (2010).\u003c/li\u003e\n\u003cli\u003eEmanuel, K.A. Downscaling CMIP5 climate models shows increased tropical cyclone activity over the 21st century. \u003cem\u003eProc. Natl. Acad. Sci. USA \u003c/em\u003e\u003cstrong\u003e110\u003c/strong\u003e, 12219-12224 (2013).\u003c/li\u003e\n\u003cli\u003eVillarini, G. \u0026amp; Vecchi G. A. Projected increases in North Atlantic tropical cyclone intensity from CMIP5 models. \u003cem\u003eJ. Clim.\u003c/em\u003e \u003cstrong\u003e26(10),\u003c/strong\u003e 3231-3240 (2013).\u003c/li\u003e\n\u003cli\u003eWalsh, K. J. E., et al. Tropical cyclones and climate change. \u003cem\u003eWiley Interdiscip. Rev. Clim. Change\u003c/em\u003e \u003cstrong\u003e7(1)\u003c/strong\u003e. (2016): https://doi.org/10.1002/wcc.371\u003c/li\u003e\n\u003cli\u003eKorty, R. L., Emanuel, K. A., Huber, M. \u0026amp; Zamora, R. A. Tropical cyclones downscaled from simulations with very high carbon dioxide levels. \u003cem\u003eJ. Clim. \u003c/em\u003e\u003cstrong\u003e30(2)\u003c/strong\u003e, 649-667 (2017). https://doi.org/10.1175/JCLI-D-16-0256.1\u003c/li\u003e\n\u003cli\u003eBhatia, K., Vecchi, G., Murakami, H., Underwood, S. \u0026amp; Kossin, J. Projected response of tropical cyclone intensity and intensification in a global climate model. \u003cem\u003eJ. Clim\u003c/em\u003e. \u003cstrong\u003e31(20)\u003c/strong\u003e, 8281-8303 (2018). https://doi.org/10.1175/JCLI-D-17-0898.1\u003c/li\u003e\n\u003cli\u003eKossin, J. P., Knapp, K. R., Olander, T. L. \u0026amp; Velden, C.S. Global increase in major tropical cyclone exceedance probability over the past four decades. \u003cem\u003eProc. Nat. Acad. Sci.\u003c/em\u003e \u003cstrong\u003e117(22)\u003c/strong\u003e, 11975-11980 (2020). https://doi.org/10.1073/pnas.1920849117\u003c/li\u003e\n\u003cli\u003eTing, M., Kossin, J. P., Camargo, S. J. \u0026amp; Li, C. Past and future hurricane intensity change along the U.S. East Coast. \u003cem\u003eSci. Rep\u003c/em\u003e. \u003cstrong\u003e9\u003c/strong\u003e, 1-8. (2019) https://doi.org/10.1038/s41598-019-44252-w\u003c/li\u003e\n\u003cli\u003eSugi\u003cstrong\u003e,\u003c/strong\u003e M., Yoshida, K. \u0026amp; Murakami, H. More tropical cyclones in a cooler climate?. \u003cem\u003eGeophys. Res. Lett. \u003c/em\u003e\u003cstrong\u003e42\u003c/strong\u003e, 6780-6784 (2015).\u003c/li\u003e\n\u003cli\u003eWinkler, T. S., et al. Revising evidence of hurricane strikes on Abaco Island (The Bahamas) over the last 680 years. \u003cem\u003eSci. Rep.\u003c/em\u003e \u003cstrong\u003e10\u003c/strong\u003e, 16556 (2020). https://doi.org/10.1038/s41598-020-73132-x\u003c/li\u003e\n\u003cli\u003eLandsea\u003cstrong\u003e,\u003c/strong\u003e C. W., et al. The Atlantic hurricane data\u0026shy;base re-analysis project: Documentation for 1851-1910 alterations and additions to the HURDAT database. \u003cem\u003ein\u003c/em\u003e: Murnane, R.J. \u0026amp; Liu, K-b. (\u003cem\u003eeds\u003c/em\u003e) Hurricanes and Typhoons: Past, Present and Future. New York: Colum\u0026shy;bia University Press, pp. 177-221 (2004).\u003c/li\u003e\n\u003cli\u003eLandsea, C. W. \u0026amp; Franklin, J. L. Atlantic Hurricane Database Uncertainty and Presentation of a New Database Format. \u003cem\u003eMon. Weath. Rev.\u003c/em\u003e \u003cstrong\u003e141(10)\u003c/strong\u003e, 3576-3592 (2013). https://doi.org/10.1175/MWR-D-12-00254.1\u003c/li\u003e\n\u003cli\u003eWang, C., Lee, S.-K. \u0026amp; Enfield, D. B. Atlantic warm pool acting as a link between Atlantic multidecadal oscillation and Atlantic tropical cyclone activity. \u003cem\u003eGeochemistry Geophys. Geosystems\u003c/em\u003e \u003cstrong\u003e9\u003c/strong\u003e, Q05V03 (2008).\u003c/li\u003e\n\u003cli\u003eGoldenberg,S. B. \u0026amp; Shapiro, L. J. Physical mechanisms for the Association of El Ni\u0026ntilde;o and West African rainfall with Atlantic major hurricane activity. \u003cem\u003eJ. Clim. \u003c/em\u003e\u003cstrong\u003e9\u003c/strong\u003e, 1169-1187 (1996).\u003c/li\u003e\n\u003cli\u003eLane, P., Donnelly, J. P., Woodruff, J. D. \u0026amp; Hawkes, A. D. A decadally-resolved paleohurricane record archived in the late Holocene sediments of a Florida sinkhole, \u003cem\u003eMar. Geol.\u003c/em\u003e \u003cstrong\u003e287(1)\u003c/strong\u003e, 14-30 (2011).\u003c/li\u003e\n\u003cli\u003eBrandon, C. M., Woodruff, J. D., Lane, D. P. \u0026amp; Donnelly, J. P. Tropical cyclone wind speed constraints from resultant storm surge deposition: A 2500-year reconstruction of hurricane activity from St. Marks, FL. \u003cem\u003eGeochemistry, Geophys., Geosystems\u003c/em\u003e \u003cstrong\u003e14(8)\u003c/strong\u003e, 2993-3008 (2013). https://doi.org/10.1002/ggge.20217\u003c/li\u003e\n\u003cli\u003eBrown\u003cstrong\u003e,\u003c/strong\u003e L. A., Reinhard, E. G., van Hengstum, P. J. \u0026amp; Pilarczyk, J. E. A coastal Yucatan sinkhole records intense Hurricane events. \u003cem\u003eJ. Coast. Res. \u003c/em\u003e\u003cstrong\u003e30-2\u003c/strong\u003e, 418-428 (2014).\u003c/li\u003e\n\u003cli\u003eSullivan\u003cstrong\u003e,\u003c/strong\u003e R. M., et al.\u003cem\u003e \u003c/em\u003eNortheast Yucatan hurricane activity during the Maya Classic and Postclassic periods. \u003cem\u003eSci. Rep.\u003c/em\u003e 12, 20107 (2022). https://doi.org/10.1038/s41598-022-22756-2\u003c/li\u003e\n\u003cli\u003eGischler, E., Shinn, E. A., Oschmann, W., Fiebig, J. \u0026amp; Buster, N. A. A 1500-year Holocene Caribbean climate archive from the Blue Hole, Lighthouse Reef, Belize, \u003cem\u003eJ. Coast. Res. \u003c/em\u003e\u003cstrong\u003e24(6),\u003c/strong\u003e 1495-1505 (2008).\u003c/li\u003e\n\u003cli\u003eDenommee,K., Bentley, S. \u0026amp; Droxler A. Climatic controls on hurricane patterns: A 1200-y near-annual record from Lighthouse Reef, Belize, \u003cem\u003eSci. Rep. \u003c/em\u003e\u003cstrong\u003e4,\u003c/strong\u003e 3876 (2014). https://doi.org/10.1038/srep03876\u003c/li\u003e\n\u003cli\u003evan Hengstum, P. J., et al. Heightened hurricane activity on the Little Bahama Bank from 1350 to 1650 AD. \u003cem\u003eCont. Shelf. Res.\u003c/em\u003e \u003cstrong\u003e86,\u003c/strong\u003e 103-115 (2014). https://doi.org/10.1016/j.csr.2013.04.032\u003c/li\u003e\n\u003cli\u003eWallace, E. J., et al. Intense hurricane activity over the past 1500 years at south Andros Island, the Bahamas. \u003cem\u003ePaleoceanogr. Paleocl. \u003c/em\u003e\u003cstrong\u003e34-11\u003c/strong\u003e,1761-1783 (2019).\u003c/li\u003e\n\u003cli\u003eSchmitt, D., Gischler, E. Anselmetti, F.S. \u0026amp; Vogel H. Caribbean cyclone activity: an annually-resolved Common Era record\u003cem\u003e. Sci. Rep,\u003c/em\u003e \u003cstrong\u003e10(1):11780 \u003c/strong\u003e(2020). https://doi.org/10.1038/s41598-020-68633-8\u003c/li\u003e\n\u003cli\u003eWallace, E. J., et al. Regional shifts in paleohurricane activity over the last 1500 years derived from blue hole sediments offshore of Middle Caicos Island. \u003cem\u003eQuat. Sci. Rev. \u003c/em\u003e\u003cstrong\u003e268\u003c/strong\u003e, 1-18 (2021). https://doi.org/10.1016/j.quascirev.2021.107126\u003c/li\u003e\n\u003cli\u003eWinkler, T. S., et al. Oceanic passage of hurricanes across Cay Sal Bank in The Bahamas over the last 530 years. \u003cem\u003eMar. Geol. \u003c/em\u003e\u003cstrong\u003e443 \u003c/strong\u003e(2022). https://doi.org/10.1016/j.margeo.2021.106653\u003c/li\u003e\n\u003cli\u003eShinn,E. A., Reich, C. D., Locker, S. D. \u0026amp; Hine, A. C. A Giant Sediment Trap in the Florida Keys. \u003cem\u003eJ. Coast. Res. \u003c/em\u003e\u003cstrong\u003e12(4)\u003c/strong\u003e, 953-959 (1996).\u003c/li\u003e\n\u003cli\u003eLiao, X., et al. Observed interannual relationship between ITCZ position and tropical cyclone frequency. \u003cem\u003eJ. Clim. \u003c/em\u003e1-37 (2023). https://doi.org/10.1175/JCLI-D-22-0865.1\u003c/li\u003e\n\u003cli\u003eGoldenberg,S. B., Landsea, C. W., Mestas-Nu\u0026ntilde;ez, A. M. \u0026amp; Gray W. M. The recent increase in Atlantic hurricane activity: Causes and implications. \u003cem\u003eScience\u003c/em\u003e \u003cstrong\u003e293(5529)\u003c/strong\u003e, 474-479 (2001).\u003c/li\u003e\n\u003cli\u003eKossin, J. P. \u0026amp; Vimont, D. J. A more general framework for understanding Atlantic hurricane variability and trends. \u003cem\u003eBull. Am. Meteorol. Soc.\u003c/em\u003e \u003cstrong\u003e88(11)\u003c/strong\u003e, 1767-1781 (2007).\u003c/li\u003e\n\u003cli\u003eHaug, G. H., Hughen, K. A., Sigman, D. M., Peterson, L. C. \u0026amp; R\u0026ouml;hl, U. Southward migration of the intertropical convergence zone through the Holocene. \u003cem\u003eScience \u003c/em\u003e\u003cstrong\u003e293\u003c/strong\u003e, 1304-1308 (2001).\u003c/li\u003e\n\u003cli\u003eMerlis, T. M., Zhao, M. \u0026amp; Held I. M. The sensitivity of hurricane frequency to ITCZ changes and radiatively forced warming in aquaplanet simulations. \u003cem\u003eGeophys. Res. Lett.\u003c/em\u003e \u003cstrong\u003e40(15)\u003c/strong\u003e, 4109-4114 (2013). https://doi.org/10.1002/grl.50680\u003c/li\u003e\n\u003cli\u003ePeltier, W. R. \u0026amp; Fairbanks, R. G. Global glacial ice volume and last glacial maximum duration from an extended Barbados sea level record. \u003cem\u003eQuat. Sci. Rev. \u003c/em\u003e\u003cstrong\u003e25\u003c/strong\u003e, 3322-3337 (2006).\u003c/li\u003e\n\u003cli\u003eWallace, E. J., Dee, S. G. \u0026amp; Emanuel, K. A. Resolving long-term variations in North Atlantic tropical cyclone activity using a pseudo proxy paleotempestology network approach. \u003cem\u003eGeophys. Res. Lett.\u003c/em\u003e \u003cstrong\u003e48\u003c/strong\u003e, e2021GL094891 (2021) https://doi.org/10.1029/2021GL094891\u003c/li\u003e\n\u003cli\u003eKnapp, K. R., Diamond, H. J., Kossin, J. P., Kruk, M. C. \u0026amp; Schreck III, C. J. International Best Track Archive for Climate Stewardship (IBTrACS) Project, Version 4. [Atlantic Basin US_SSHS subset]. NOAA National Centers for Environmental Information (2018). https://data.nodc.noaa.gov/cgi-bin/iso?id=gov.noaa.ncdc:C01552\u003c/li\u003e\n\u003cli\u003eMcCloskey, T. A. \u0026amp; Liu, K.-B. A 7000 year record of paleohurricane activity from a coastal wetland in Belize. \u003cem\u003eHolocene\u003c/em\u003e \u003cstrong\u003e23(2)\u003c/strong\u003e, 278-291 (2012). https://doi.org/10.1177/0959683612460782\u003c/li\u003e\n\u003cli\u003eElsner,J. B. Tracking hurricanes. \u003cem\u003eBulletin of the American Meteorological Society\u003c/em\u003e, \u003cstrong\u003e84(3)\u003c/strong\u003e, 353-356(2003). https://doi.org/10.1175/BAMS-84-3-353\u003c/li\u003e\n\u003cli\u003eGischler, E., Hudson, J. H., Eisenhauer, A., Parang, S. \u0026amp; Deveaux, M. 9000 years of change in coral community structure and accretion in Belize reefs, western Atlantic, \u003cem\u003eSci. Rep .\u003c/em\u003e\u003cstrong\u003e13\u003c/strong\u003e, 11349 (2023). https://doi.org/10.1038/s41598-023-38118-5\u003c/li\u003e\n\u003cli\u003eBj\u0026ouml;rck, S., et al. High-resolution analyses of an early Holocene climate event may imply decreased solar forcing as an important climate trigger. \u003cem\u003eGeology\u003c/em\u003e \u003cstrong\u003e29(12)\u003c/strong\u003e, 1107-1110 (2001).\u003c/li\u003e\n\u003cli\u003eWanner, H., Solomina, O., Grosjean, M., Ritz, S. P. \u0026amp; Jetel, M. Structure and origin of Holocene cold events. \u003cem\u003eQuat. Sci. Rev. \u003c/em\u003e\u003cstrong\u003e30(21-22)\u003c/strong\u003e, 3109-3123 (2011). https://doi.org/10.1016/j.quascirev.2011.07.010\u003c/li\u003e\n\u003cli\u003eLorenz, S. J., Kim, J. H., Rimbu, N., Schneider, R.R. \u0026amp; Lohmann, G. Orbitally driven insolation forcing on Holocene climate trends: Evidence from alkenone data and climate modelling. \u003cem\u003ePaleoceanography\u003c/em\u003e \u003cstrong\u003e21(1)\u003c/strong\u003e (2006).https://doi.org/10.1029/2005PA001152\u003c/li\u003e\n\u003cli\u003eClement, A. C., Seager, R. \u0026amp; Cane, M.A. Orbital controls on the El-Ni\u0026ntilde;o/Southern Oscillation and the tropical climate. \u003cem\u003ePaleoceanography\u003c/em\u003e \u003cstrong\u003e14(4)\u003c/strong\u003e, 441-456 (1999). \u003c/li\u003e\n\u003cli\u003eWahl, R., Byrne, R. \u0026amp; Anderson, L. An 8700 year paleoclimate reconstruction from the southern Maya lowlands. \u003cem\u003eQuat. Sci. Rev. \u003c/em\u003e\u003cstrong\u003e103\u003c/strong\u003e, 19-25 (2014). https://doi.org/10.1016/j.quascirev.2014.08.004\u003c/li\u003e\n\u003cli\u003eElsner, J. B. \u0026amp; Jagger, T.H. United States and Caribbean tropical cyclone activity related to the solar cycle. \u003cem\u003eGeophys. Res. Lett.\u003c/em\u003e \u003cstrong\u003e35\u003c/strong\u003e, L18705 (2008). https://doi.org/10.1029/2008GL034431\u003c/li\u003e\n\u003cli\u003eMann, M. E., Woodruff, J. D., Donnelly, J. P. \u0026amp; Zhang Z. Atlantic hurricanes and climate over the past 1,500 years. \u003cem\u003eNature\u003c/em\u003e \u003cstrong\u003e460(7257)\u003c/strong\u003e, 880-883 (2009). https://doi.org/10.1038/nature08219\u003c/li\u003e\n\u003cli\u003eDonnelly, J. P., et al. Climate forcing of unprecedented intense-hurricane activity in the last 2000 years. \u003cem\u003eEarth\u0026rsquo;s\u003c/em\u003e \u003cem\u003eFuture\u003c/em\u003e \u003cstrong\u003e3\u003c/strong\u003e, 49-65 (2015). https://doi.org/10.1002/2014EF000274\u003c/li\u003e\n\u003cli\u003eWallace, E. J., et al. 1,050 years of hurricane strikes on Long Island in The Bahamas. \u003cem\u003ePaleoceanogr. Paleoclimatol. \u003c/em\u003e\u003cstrong\u003e36(3)\u003c/strong\u003e, (2021). https://doi.org/10.1029/2020PA004156\u003c/li\u003e\n\u003cli\u003eMann, M. E., et al. Global signatures and dynamical origins of the Little Ice Age and Medieval climate anomaly. \u003cem\u003eScience\u003c/em\u003e \u003cstrong\u003e326\u003c/strong\u003e, 1256-1260 (2009).\u003c/li\u003e\n\u003cli\u003eGao, C., Robock, A. \u0026amp; Ammann, C. Volcanic forcing of climate over the past 1500 years: An improved ice core‐based index for climate models. \u003cem\u003eJ. Geophys. Res. \u003c/em\u003e\u003cstrong\u003e113\u003c/strong\u003e, D16112(2008). https://doi.org/10.1029/2008JD010239\u003c/li\u003e\n\u003cli\u003eNguetsop, V. F., Servant-Vildary, S. \u0026amp; Servant, M. Late Holocene climate changes in west Africa, a high resolution diatom record from equatorial Cameroon. \u003cem\u003eQuat. Sci. Rev. \u003c/em\u003e\u003cstrong\u003e23\u003c/strong\u003e, 591-609(2004).\u003c/li\u003e\n\u003cli\u003eOrtegren, J. T. \u0026amp; Maxwell, J.T. Spatiotemporal patterns of drought/tropical cyclone Co-occurrence in the southeastern USA: linkages to north Atlantic climate variability. \u003cem\u003eGeogr. Compass\u003c/em\u003e \u003cstrong\u003e8\u003c/strong\u003e, 540-559 (2014).\u003c/li\u003e\n\u003cli\u003eSchmitt, D., Gischler, E. \u0026amp; Walkenfort, D. Holocene sediments of an inundated sinkhole: facies analysis of the \u0026ldquo;Great Blue Hole\u0026rdquo;, Lighthouse Reef, Belize. \u003cem\u003eFacies\u003c/em\u003e \u003cstrong\u003e67\u003c/strong\u003e, 10 (2021).https://doi.org/10.1007/s10347-020-00615-8\u003c/li\u003e\n\u003cli\u003eMarcott\u003cstrong\u003e,\u003c/strong\u003e S., Shakun, J., Clark, P. \u0026amp; Mix, A. A Reconstruction of Regional and Global Temperature for the Past 11,300 Years. \u003cem\u003eScience \u003c/em\u003e\u003cstrong\u003e339\u003c/strong\u003e, 1198-1201 (2013). DOI: 10.1126/science.1228026\u003c/li\u003e\n\u003cli\u003eLiu, Z., et al. The Holocene temperature conundrum. \u003cem\u003eProc. Natl. Acad. Sci. USA\u003c/em\u003e \u003cstrong\u003e111(34)\u003c/strong\u003e, E3501-3505 (2014). https://doi.org/10.1073/pnas.1407229111\u003c/li\u003e\n\u003cli\u003eCionco, R., Soon, W. \u0026amp; Quaranta, N. On the calculation of latitudinal insolation gradients throughout the Holocene. \u003cem\u003eAdv. Space Res. \u003c/em\u003e\u003cstrong\u003e66(3)\u003c/strong\u003e (2020). https://doi.org/10.1016/j.asr.2020.04.030\u003c/li\u003e\n\u003cli\u003eCleveland, W. S. Robust locally weighted fitting and smoothing scatterplots. \u003cem\u003eJ. Am. Stat. Assoc. \u003c/em\u003e\u003cstrong\u003e74\u003c/strong\u003e, 829-836(1979). \u003c/li\u003e\n\u003cli\u003eCleveland, W. S. A program for smoothing scatterplots by robust locally weighted fitting. \u003cem\u003eAm Stat. \u003c/em\u003e\u003cstrong\u003e35\u003c/strong\u003e, 54 (1981).\u003c/li\u003e\n\u003c/ol\u003e"},{"header":"Methods","content":"\u003cp\u003eAnoxic blue holes have some noteworthy advantages, in contrast to coastal lake sites\u003csup\u003e66\u003c/sup\u003e, back barrier lagoons\u003csup\u003e67,68\u003c/sup\u003e, coastal wetland sites\u003csup\u003e44,69,70 \u003c/sup\u003eand salt marsh ponds\u003csup\u003e71-73\u003c/sup\u003e. They are largely independent to sea-level changes, not affected by bioturbation and permanent wave action, and marked by a high fair-weather sediment supply, as well as an ample accommodation space\u003csup\u003e35\u003c/sup\u003e. \u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFieldwork at Lighthouse Reef: coring the anoxic Great Blue Hole\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe coring equipment operated on the Great Blue Hole was shipped in a 20-foot shipping-container from Cologne (Germany) to Belize City (Belize). It consisted of an UWITEC Hybrid Platform, equipped with UWITEC gravity and percussion piston corers. The coring platform was assembled in the Old Belize Marina and towed to Lighthouse Reef (Belize) by a 9-m-long charter boat with outboard engines. The Belize Fisheries Department and the Belize Audubon Society helped to organize the use of existing mooring buoys and finding arrangements with dive boats that visit the Great Blue Hole on a daily basis, as the anchored platform was a potential obstacle for other boats. The coring platform was moored in the sinkhole centre (17\u0026deg;18\u0026prime;57.2\u0026prime;\u0026prime; N, 87\u0026deg;32\u0026prime;0.60\u0026prime;\u0026prime; W) at four fixed positions during a 6-days-long coring operation in June 2022, using ropes attached to two mooring buoys at the NE and NW margins of the Great Blue Hole and two special marine reef anchors that were temporarily added at the SE and SW margins. \u003c/p\u003e\n\u003cp\u003eThe gravity corer was employed twice to sample the sediment-water interface and the uppermost 14 cm of the sediment succession. Deeper sediments were recovered with successive deployments of the piston corer, which was guided into the borehole by a metal funnel that was placed on the sinkhole floor. The piston corer consists of a 2-m-long steel barrel with an inner PVC liner and a core catcher at the bottom. The sediments in the core catchers (in average 13 cm) were not sampled in the PVC liners, but as bulk samples. Such gaps were closed down to 2.5 m by two additional piston cores (BH8-18; BH8-19), which were taken from a new hole close by and correlated with the uppermost gravity (BH8-CO412-1; BH8-CO412-2) and piston cores (BH8-4). A UAV (unmanned aerial vehicle/drone) was used to take aerial photos from both the location and the operational coring set-up. After equipment break-down, up to 1-m-long core segments (PVC-tubes) were transported in thermo-boxes by air cargo from Belize City to Cologne (Germany). Following initial processing in Cologne, the cores were shipped further to Frankfurt (Germany) for subsequent analyses.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCore opening and photo documentation \u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe PVC-tubes were opened lengthwise by cutting them in halves, one for subsampling and one for archive, with a semi-automatic core opening system with cranks and blades. The surface area was smoothed with an ultra-thin copper sheet (0.7 mm). All 36 core segments were remeasured to precisely determine the actual core depth (cm). A photo documentation was subsequently carried out using a line-scan camera attached to a non-destructive X-ray fluorescence core scanner (XRF; COX-ITRAX). \u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eX‑ray fluorescence analyses\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eTo determine the element composition of the sediment (in counts per second, cps), the archive-halves were scanned at 2 mm resolution (~13400 measurements) with an ITRAX-XRF scanner that was equipped with a Cr-anode-X-ray-tube set to 30 kV and 55 mA with 60s integration time. Special attention was given to the Strontium content and its ratio over Calcium. The Sr/Ca ratio (Suppl. 3) is a sensitive tool for tempestite identification in carbonate sinkhole environments\u003csup\u003e32\u003c/sup\u003e, as it records minor differences between over-washed event layers (mean Sr/Ca-ratio: 0.0329 \u0026plusmn; 0.0222) and fair-weather sediments (mean Sr/Ca ratio: 0.0289 \u0026plusmn; 0.0083). Materials from the marginal reef (e.g., aragonitic coral skeletons and \u003cem\u003eHalimeda\u003c/em\u003e chips) are typically enriched in Sr, while lagoonal particles (e.g., mollusc shells and foraminiferal tests) are depleted\u003csup\u003e75\u003c/sup\u003e. \u003c/p\u003e\n\u003cp\u003eWith a second, high-energetic XRF-scanning run, radiographic images were created, reflecting minor density variations in the sediment cores. Areas with lighter colours (lower density) overlap with event-layers and darker areas (higher density) agree with varved core sections, representing the annual fair-weather sedimentation. Grey-scale values were automatically recorded at 0.20-0.40 mm intervals through the sediment core BH8 and processed in a profile by using the open source image processing software \u003cem\u003eImageJ\u003c/em\u003e v.1.53t. Tempestites are accompanied with visible peaks in the grey-scale values, while the varved-sections tend to lie around an average value of 383.54 \u0026plusmn; 88.59 (Suppl. 4). The radiographic grey-scale analysis, presented for the first time in this context, is thus applicable as a new, grain-size-independent, optical proxy for storm-layer identification in carbonate-dominated blue hole environments. After completing both XRF-runs, the archive-halves were packed in vacuum, transported to Frankfurt and stored in a cold room at 4\u0026deg;C for archive purpose.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eStratigraphic description and correlation with existing cores\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eA visual core description was done by using both the working-halves and the high-resolution core images (Fig. S1). The stratigraphic recording includes an optical differentiation of fair-weather sections and cyclone event deposits, a description of different unconsolidated lithologies, measurements of varve- and event layer thickness, characterization of sedimentary contacts and registration of macrofossils. The sediment core BH8 was stratigraphically and chronologically correlated with an 8.55-m-long core (BH6) from a previous project\u003csup\u003e32\u003c/sup\u003e by complementary using the open-source application \u003cem\u003eCorelyzer \u003c/em\u003e(version 2.2.1) for optical core images visualization. It became qualitatively apparent, that there is a high degree of visual and sedimentological compliance of coarse sediment anomalies between BH8 and BH6. In the overlapping depth interval (8.3 m), 162 out of 212 event layers (76 %) were replicated by both cores. 50 tempestites occurred only in BH8 and another 31 only in core BH6 (Suppl. 5). \u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAdapted sampling strategy\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eTexture and sedimentological parameters of both event-layers and fair-weather sediments have been readily established in two previous projects\u003csup\u003e28,32\u003c/sup\u003e. For this reason, we will not repeat such detailed measurements and focus mainly on the textural analysis of event-layers. All samples were again taken in 2.5 mm slabs, approximately equalling an annual sampling resolution, with ultra-thin metal cut-out plates, according to the tested methodology\u003csup\u003e32\u003c/sup\u003e. For radiocarbon dating, 9 bulk samples were first cut out of undisturbed sections of varved fair-weather sediments that show clear signs of a changing sedimentology, particularly with regard to different sedimentological units. Afterwards, 694 samples were discretely taken from optically determined event-layers (Suppl. 6). We finally decided to randomly extract 125 more samples from undisturbed fair-weather sections at different sampling intervals with a maximum spacing of 50 cm, mainly for comparative purposes (Suppl. 6). Thirty-eight samples were investigated for pollen analysis following a proven methodology\u003csup\u003e76\u003c/sup\u003e. A total of 5 g bulk material was needed either way for quantitative textural analysis, pollen investigation and radiocarbon dating.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAge dating: radiocarbon- and varve-counting models\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eFor age dating, we used a combination of varve counting- and radiocarbon age models. Both applications show very similar progressions, with a noteworthy age offset appearing only in the middle core part (Fig. 2). To gain an age model for event-layer timing on annual resolution, undisturbed varves were counted visually in the PVC lines and cross-checked with the high-resolution images using optical colour differences. Grey-scale/density variations, visible in the radiographic images\u003csup\u003e77\u003c/sup\u003e were supportively used, besides varve thickness measurements, for creating a varve-counting-based age model. We excluded geologically instantaneous event sedimentation and determined event-free rates downcore by considering only laminae thickness measurements of fair-weather deposits. This proceeding resulted in a three-part division of core BH8 (units A, B, C). A near linear mean sedimentation rate of 2.41 \u0026plusmn; 0.04 mm/a was computed down to a depth of 24.6 m. This confirms the sedimentation rate of 2.55 \u0026plusmn; 0.05 mm/a, known from two shorter Great Blue Hole cores\u003csup\u003e28,32\u003c/sup\u003e. In unit B (24.6-28.6 m), sedimentation rates are slightly higher (3.18 \u0026plusmn; 0.03 mm). Unit C (28.6-30.0 m) is characterized by a much lower mean annual sedimentation rate of 0.20 \u0026plusmn; 0.00 mm/a. All core catchers samples, not included in the PVC liners, were texturally analysed and identified either as an undisturbed varved deposition or a varved section, that includes an event-layer, by means of their textural signatures in relation to both sections from the PVC liners. The time contained in these bulk core catcher samples was estimated in an approximation approach, following the calculated event-free sedimentation rates of the respective core unit. In a depth between 16-24 m, the varve counting approach is more difficult to apply as in younger core sections, because of blurry varves and a few core catcher segments up to 40 cm thickness, completely lacking intact sedimentology. For these intervals, we also had to extrapolate on the assumption of a constant sedimentation rate of 2.41 \u0026plusmn; 0.04 mm/a, resulting in an estimated final varve-counting error of 5%.\u003c/p\u003e\n\u003cp\u003eWe used a total of 15 radiocarbon dates at 79.8 cm, 161.3 cm, 410.5 cm, 622.3 cm, 660.5 cm, 839.3 cm, 926.0 cm, 1019.2 cm, 1613.1 cm, 2011.2 cm, 2409.2 cm, 2609.2 cm, 2814.0 cm, 2874.0 cm and 3000.6 cm as age-control points (Suppl. 1), in order to establish a secondary age control for the varve age model. Nine of those samples were extracted from the core BH8, but we also considered six depth-corrected radiocarbon-dates from the uppermost 9 m, measured on the previously dated sediment core BH6\u003csup\u003e32\u003c/sup\u003e. A radiocarbon-based age model (Fig. S3) with 95% confidence intervals was developed with Bayesian statistical approaches using the R library package BACON v 2.2\u003csup\u003e78\u003c/sup\u003e. The \u003csup\u003e14\u003c/sup\u003eC-radiocarbon dating has been undertaken by Beta Analytic Inc., Miami, Florida with Accelerator Mass Spectrometry (AMS). The organic material was separated from the bulk sediment samples by dissolving the carbonate material with HCl, washing the sample with NaOH, and repeating until no more carbonate remained. For the samples down to a depth of 2814.0 cm, Beta Analytic Inc., Miami, Florida, provided average \u0026delta;\u003csup\u003e13\u003c/sup\u003eC values of -16.8 \u0026permil;. Such a \u0026delta;\u003csup\u003e13\u003c/sup\u003eC value is typically associated with a marine carbon origin, attributable to aquatic macrophytes and algae\u003csup\u003e79\u003c/sup\u003e. The two samples at 2874.0 cm and 3000.6 cm have more negative \u0026delta;\u003csup\u003e13\u003c/sup\u003eC values ranging from -17.7 \u0026permil; to -27.2 \u0026permil;. This is indicative of a different organic matter source, such as terrestrial C3-plants (-20\u0026permil; to -30 \u0026permil;)\u003csup\u003e80\u003c/sup\u003e. For reservoir correction, the global marine reservoir effect of 405 years (residence time of carbon cycled in the ocean prior to bio-assimilation) was considered and applied by Beta Analytic Inc., Miami, Florida. The conventional radiocarbon ages from both the marine and terrestrial organic residues were converted to calibrated years before present using either the BetaCal4.20 MARINE20\u003csup\u003e81\u003c/sup\u003e or INTCAL20\u003csup\u003e82\u003c/sup\u003e calibration curves (High Probability Density Range Method)\u003csup\u003e83\u003c/sup\u003e. All calibrated ages are presented with a 2-\u0026sigma; error in a 95% confidence interval. \u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eQuantitative textural analyses: the classic proxy for event-layer identification\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eIn the Great Blue Hole sedimentation system, a quantitative textural analysis constitutes a successfully tested tool\u003csup\u003e32\u003c/sup\u003e to safely differentiate between coarser storm-induced event-layers and the finer background sedimentation (Suppl. 6). For quantitative textural analysis, a total of 819 samples have been first wet sieved through a 63 \u0026mu;m standard grain-size sieve to separate the coarse fraction (\u0026gt;63 \u0026mu;m) from the fine fraction (\u0026lt;63 \u0026mu;m). The coarse grain-size fraction was dried at 50\u0026deg;C for 12 hours with a ThermoScientific HERATHERMA-OVEN OMS-180, sieved through standard grain-size sieves of 2 mm, 1 mm, 500 \u0026mu;m, 250 \u0026mu;m, and 125 \u0026mu;m and then weighed to determine dry masses, respectively. The fine fraction was left to rest for 48 hours in a sedimentation vessel (settling out of suspension), subsequently decanted, dried at 50\u0026deg;C for 24 hours and dry-weighed to equally define the amount of fine material. From these data, a grain-size distribution was created with absolute (g) and relative (%) values for each sieving interval. \u003c/p\u003e\n\u003cp\u003eFor mean grain-size determination, a more detailed analysis of the fine fraction is needed, including a further separation of the fine fraction into 63 \u0026mu;m, 50 \u0026mu;m, 40 \u0026mu;m, 20 \u0026mu;m, 10 \u0026mu;m, 2 \u0026mu;m, 1 \u0026mu;m and 0.05 \u0026mu;m intervals. Fine material analyses were performed by using a laser-optical particle analyser (HORIBA Laser Particle Analyser-950), which runs with 1 g fine material, suspended in 0.4 N Na\u003csub\u003e4\u003c/sub\u003eP\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e7\u003c/sub\u003e and demineralized water. All visible event layers (n = 32) from the historical record were analysed down to a depth of 103 cm, using the HORIBA Laser Particle Analyser-950 (Suppl. 7). In addition, the fine materials of 32 more samples (n = 28 fair-weather and n = 4 event-layers) were measured for fine material abundances across the core at ~1 m intervals (Suppl. 7). All of these samples were categorized by determination of classical sedimentary parameters (mean grain size, sorting, skewness and kurtosis), following the \u0026ldquo;Geometric and Logarithmic Folk \u0026amp; Ward method\u0026rdquo; using the software package \u003cem\u003egradistat \u003c/em\u003ev. 9.1\u003csup\u003e84\u003c/sup\u003e. A linear calibration was made between mean grain-size values, obtained from these 64 samples and their amounts of coarse fraction, received from the initial sieving test (Suppl. 8). The correlation between both parameters is statistically significant (r = 0.81; p \u0026lt; 0.05). The mean grain-size values of all other event-layers of core BH8 can be inferred in a sufficiently accurate approximation by using the linear equation from this calibration step: y = 2.6664 x amount of coarse fraction (%).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eWorkflow of TC-event-layer identification\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eWe used an already established\u003csup\u003e32\u003c/sup\u003e and complemented (grey-scale values) multi-proxy-approach to ensure a reliable identification of TC event-layers in the sediment core BH8. 694 tempestites have been preliminary identified on a visual core and optical images inspection. The light greyish (Munsell colour: 5GY 6/2) to greyish green (Munsell colour: 5GY 5/2) fair-weather deposits are clearly distinguishable from white (Munsell colour: 2.5Y 8/1) to pale brown (Munsell colour: 2.5Y 8/2) coloured event beds in the full marine unit A. Similarly coloured, however slightly darker, greyish green (Munsell colour: 5GY 5/2) to greyish brown (Munsell colour: 2.5Y 5/2) fair-weather deposits appear in the restricted marine unit B. In this core section, event-beds are still clearly defined as white (Munsell colour: 2.5Y 8/1) and very dark brown (Munsell colour: 10YR 2/2), up to almost black (Munsell colour: 10YR 2/1) layers. In the cenote-like unit C, the background sedimentation is first characterized by a fine lamination of grey brown (Munsell colour: 2.5Y 3/2) deposits, followed by a structureless black (Munsell colour: 2.5Y 2.5/1) section at the core base. White (Munsell colour: 2.5Y 8/1) coloured and slightly faded event-layers are again visible in this core part. In addition to the conspicuous differences in colour, there are some more visual sedimentary characteristics that allow an optical separation: (1) sharp sedimentary contacts, (2) presence of coarse grains (e.g., mollusc shells, coral fragments and/or \u003cem\u003eHalimeda\u003c/em\u003e-platelets), (3) lack of lamination, (4) signs of coarsening/fining upwards and (5) increased content of organic material. Another helpful parameter to identify event-layers is the thickness of the storm deposit, as the sedimentation rate should be significantly increased during an instantaneous high-energy event. In years without a storm landfall, varve thickness was determined to average values of 2.4 mm (unit A), 3.2 mm (unit B) and 0.2 mm (unit C). The thickness of the 694 event-layers ranges from a minimum of 2.5 mm up to maximum of 37.6 cm. The average thickness of all tempestites is 1.7 cm and thus much thicker than a common annual varve. \u003c/p\u003e\n\u003cp\u003eIn the process, we confirmed the optical identification of storm indicator layers by cross-checking them with quantitative coarse fraction data (%) and measured/calculated mean grain size values (\u0026mu;m), received from the classic textural analysis. The fair-weather sediments are characterized by a very low average coarse fraction content (\u0026gt;63 \u0026mu;m) of 4.3 % (unit A), 2.3 % (unit B) and 4.5 % (unit C). For the event-layers, coarse-fraction abundances were calculated on average at 20.8 %, with a range appearing from 2.1 % to 96.5 %. The mean grain sizes of fair-weather sediments were computed to 16.4 \u0026mu;m (coarse silt) in unit A, 8.4 \u0026mu;m (medium silt) in unit B and 15.9 \u0026mu;m (medium silt) in unit C. The average grain size of the event-layers is very coarse silt (54.9 \u0026mu;m), but encompasses a range from fine silt (5.7 \u0026mu;m) to coarse sand (625.9 \u0026mu;m). On this basis, we established event bed cutoffs for units A (6.6 % and 24.9 \u0026mu;m), B (3.8 % and 14.5 \u0026mu;m) and C (6.5 % and 21.0 \u0026mu;m), respectively. 91-96 % of all visible event beds correspond to peaks above the unit cutoffs in the coarse fraction (\u0026gt;63 \u0026mu;m) data. The grade of agreement with the mean grain size is significantly lower at 74-80%, which is probably a result of the linear approximation approach. \u003c/p\u003e\n\u003cp\u003eIn the same manner, we have determined the geochemical thresholds (Suppl. 3) for Sr-abundances between fair-weather and storm deposits of units A (0.0293 \u0026plusmn; 0.081), B (0.0254 \u0026plusmn; 0.061) and C (0.0334 \u0026plusmn; 00122). In units A and B 70.5% and 66.7% of the visible event-layers correspond to Sr/Ca peaks above the respective units cutoff. In the sedimentary unit C, the accuracy of the Sr/Ca proxy comparably decreases sharply (38.2%), which might be the result of an increasing terrestrial influence and a lack of coral fragments as important Sr sources. A new quantitative method for tempestite identification was also conducted, by developing an optical cutoff using grey-scale values from radiographic images (Suppl. 4). We calculated optical thresholds of density variation between fair-weather and storm deposits of units A (395.91 \u0026plusmn; 93.84), B (355.71 \u0026plusmn; 66.08) and C (347.75 \u0026plusmn; 62.59). In units A, B and C 63.9%, 74.1% and 76.5% of the visible event-layers correspond to grey-value excursion below the respective units cutoff. For a final TC-identification, the optical, sedimentary, and geochemical cutoffs had to be overstepped at best in all the different criteria, but at least in several of those, resulting in the highest available degree of accuracy. Our multi-proxy analyses support the results of two studies,\u003csup\u003e85,86 \u003c/sup\u003eindicating that the amount of the grain-size fraction (\u0026gt;63 \u0026mu;m) is sufficient to accurately identify tempestite layers in reef lagoon sediments of carbonate environments.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eComputing TC-frequency\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAfter all event-layers had been reliably identified, we computed TC-frequency changes by simply counting the number of storm deposits in the undisturbed PVC liners\u003csup\u003e24\u003c/sup\u003e and added event-layers found in the core catcher samples after textural analysis and the described extrapolation. The use of a 100-year observational window is not only appropriate to picture centennial-scaled shifts of storm frequency, but also to facilitate basin-wide comparisons with other records using the same time window\u003csup\u003e33\u003c/sup\u003e. A 50-years observational window was also used, in order to map multi-decadal shifts of TC-frequency in the record. Active and quiescent phases of storm activity were identified in 100- and 50-years windows, by using regionally-derived thresholds\u003csup\u003e19\u003c/sup\u003e of 9.3 \u0026plusmn; 5.7 TCs/100a and 4.6 \u0026plusmn; 3.2 TCs/50a. We repeated the procedure for a 20-years observational window, in order to compare the new data with previous TC-frequency reconstructions from the Great Blue Hole\u003csup\u003e28,29,32\u003c/sup\u003e. The 100-, 50-, and 20-years frequency data were smoothed (Suppl. 9) using the software package PAST.v.4.08 and the LOWESS (LOcally WEighted Scatterplot Smoothing) algorithm with recommended default parameters\u003csup\u003e64,65 \u003c/sup\u003eand user specified smoothing parameters (q). With a bootstrap option, a 95% confidence band is displayable for the smoothed curve fit, based on 999 random replicates. This kind of data smoothing was applied, in order to create a Belizean compilation (Fig. 4) out of different single Common Era frequency plots (Fig. S4), finally usable for a more meaningful characterisation of regional TC-frequency and its climatic drivers\u003csup\u003e87\u003c/sup\u003e. We excluded the core LOCO2\u003csup\u003e28\u003c/sup\u003e from the compilation, because a systematic sedimentological investigation was not applied in that study with regard to a quantitative identification of tempestites. \u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eHistorical record calibration\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eIn the uppermost 100 cm\u0026acute;s of the core, 36 event-layers were compared with the historical record of TCs (International Best Track Archive for Climate Stewardship-IBTrACS)\u003csup\u003e43,80\u003c/sup\u003e passing the study site within a 100 km radius, in order to assess the sensitivity of the record for event bed formation. In the past two centuries, 32 storms of different strengths left their traces in the unconsolidated sediments of the Great Blue Hole (Suppl. 2). Their strength ranged from tropical depressions (rare) to tropical storms (moderate) and hurricanes (frequent) up to occasional passing major hurricanes of categories 4 and 5 (Saffir-Simpson scale). 19 of these storm deposits are located in a core depth, attributable to times younger than 1950 CE. From this point on, airplane reconnaissance\u003csup\u003e89\u003c/sup\u003e and satellite monitoring\u003csup\u003e90\u003c/sup\u003e supplied very reliable data for storm track distance, maximum wind speed/intensity and residence time. We confine our instrumental record calibration thus only to historically documented TCs (intensity: tropical storms-major hurricanes), that migrated over the study site between 2022-1950 CE (n = 19). \u003c/p\u003e\n\u003cp\u003eWe were able to assign 16 recent event-layers to passing storm systems with very small age offsets to the recorded strike year (Suppl. 2). Among these are tropical storms like HARVEY (2011 CE), ALEX (2010 CE), ARTHUR (2008 CE), KYLE (1996 CE) and GERT (1993 CE), and stronger hurricanes, such as H1 NANA (2020 CE), H1 EARL (2016 CE), H4 IRIS (2001), H4 KEITH (2000 CE), H3 GRETA (1978 CE), H1 EDITH (1971 CE) and H1 ABBY (1960 CE). A 14.4 cm thick event-layer (EL20) at 45 cm core depth is furthermore very likely attributable to H5 HATTIE (1961 CE), that struck Lighthouse Reef as one of the most powerful storms ever\u003csup\u003e91\u003c/sup\u003e. Besides these, three more distal crossing storm systems likely left also clearly distinguishable event beds in the sedimentary record. Although H5 DEAN (2005 CE; 176 km), H5 MITCH (1998 CE; 217 km) and H2 FRANCELIA (1969 CE; 122 km) passed outside of the initially used 100 km observational radius, they are due to their high intensity still in range to produce an event-layer\u003csup\u003e42\u003c/sup\u003e. With a matching rate of 84.2%, the Great Blue Hole site has, like all other proxy-based TC-frequency archives, a bias for underrating past storm activity (here: 15.8%). The remnants of three cyclones from the Instrumental Era could not been found in core BH8 at or near the expected depth and age. Among these are exclusively weaker tropical storms (HERMINE 1980 CE, LAURA 1971 CE and GILDA 1954 CE). \u003c/p\u003e\n\u003cp\u003eThe reasons why a nearby passing cyclone does not induce the formation of an event-bed can be naturally manifold. Prerequisite for an event-bed formation is that the intensity of a proximal passing storm system is high enough to generate storm waves and surges at the study site. In this context, the evaluation of the instrumental data yielded in an interesting result. At the Great Blue Hole, it makes a huge difference, weather a storm system passes in the north, central or in the south. With a success rate of 90.9%, nearly all south-traversing storm systems were recovered in the sedimentary record. The centrally- or northerly-crossing storm systems were obtained much less often with only 75% respectively. We are convinced that this is related to the morphology of the sinkhole (eastern and northern channels in the surrounding coral reef) and the rotational direction of storm systems on the northern hemisphere. For south-trending storm systems with counter-clockwise rotation, it is much easier to produce an event-layer at the sinkhole floor. In such a case, the storms\u0026apos; strongest northeasterly winds and the attributed storm waves are oriented straight in direction to the location. With a northerly migration path, the strongest winds and highest waves tend to be directed away from the Great Blue Hole. Both HERMINE 1980 CE as well as LAURA 1971 CE passed Lighthouse Reef at or from a northern position. GILDA 1954 CE, however crossed the region, unlike the two other storms, further south. Tropical storm GILDA 1954 CE was probably just too weak and distant to leave a visible event bed, despite its generally favourable pathway. \u003c/p\u003e\n\u003cp\u003eAn alternative explanation for these missing event-layers is that we were simply not able to core the corresponding event-layers. The geometry of such deposits is, due to a spatially-limited density-surge deposition, very often lobe-shaped in the spacious Great Blue Hole. Tempestites do thus not cover the entire bottom of the sinkhole\u003csup\u003e60\u003c/sup\u003e. Two identified event-layers (EL17: 1965 CE and EL19: 1962 CE) did not match any known historical TC-events. Single coarse-grained anomalies may have been caused by strong seismic activity at the active strike-slip zone along the Caribbean and North American plate boundary, leading to tsunami-wave controlled redepositions of allochthonous particles and/or sinkhole slope destabilisations. EL19 was probably the result of higher waves originating from a strong nearby earthquake with a magnitude of 6.1 (United States Geological Survey), located 55 km south of Bodden Town, Cayman Islands. Far-field tsunamis were completely absent in the historical record and occurred in the Caribbean realm only very rarely in prehistoric times\u003csup\u003e92,93\u003c/sup\u003e. Only two major tsunami events were identified in the Caribbean realm during the past 1600 years\u003csup\u003e94\u003c/sup\u003e, however with only very small wave runups compared to the storm waves of intensive storms. Given the large number of 694 event-layers in sediment core BH8, recurring passages of TCs are by far the most likely origin for all the coarse-grained event-layers in the Great Blue Hole, considering the low number of tsunami events and the excellent historical record match of TCs.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eReferences (methods only)\u003c/strong\u003e\u003c/p\u003e\n\u003col start=\"66\"\u003e\n\u003cli\u003eLiu, K.-B. \u0026amp; Fearn, M.L. Reconstruction of prehistoric landfall frequen\u0026shy;cies of catastrophic hurricanes in northwestern Florida from lake sediment records. \u003cem\u003eQuat. Res. \u003c/em\u003e\u003cstrong\u003e54\u003c/strong\u003e, 238-24 5(2000).\u003c/li\u003e\n\u003cli\u003eDonnelly,J. P. \u0026amp; Woodruff, J.D. Intense hurricane activity over the past 5,000 years controlled by El Nino and the West African monsoon. \u003cem\u003eNature \u003c/em\u003e\u003cstrong\u003e447\u003c/strong\u003e, 465-468 (2007).\u003c/li\u003e\n\u003cli\u003ePark, L.E. Comparing two long-term hurricane frequency and intensity records from San Salvador Island, Bahamas, \u003cem\u003eJ. Coast. Res.\u003c/em\u003e \u003cstrong\u003e28\u003c/strong\u003e, 891-902 (2012).\u003c/li\u003e\n\u003cli\u003eDonnelly, J. P., et al. A backbarrier overwash record of intense storms from Brigantine, New Jersey. \u003cem\u003eMar. Geol. \u003c/em\u003e\u003cstrong\u003e210\u003c/strong\u003e, 107-121 (2004).\u003c/li\u003e\n\u003cli\u003eMcCloskey, T. A. \u0026amp; Keller, G. 5000 year sedimentary record of hurri\u0026shy;cane strikes on the central coast of Belize. \u003cem\u003eQuat. Int. \u003c/em\u003e\u003cstrong\u003e195,\u003c/strong\u003e 53-68 (2009).\u003c/li\u003e\n\u003cli\u003eScileppi, E. \u0026amp; Donnelly, J. P. Sedimentary evidence of hurricane strikes in western Long Island, New York. \u003cem\u003eGeochem. Geophys. Geosystems \u003c/em\u003e\u003cstrong\u003e8 \u003c/strong\u003e(2007). https://doi.org/10.1029/2006GC001463\u003c/li\u003e\n\u003cli\u003eBoldt, K. V., Lane, P., Woodruff, J. D. \u0026amp; Donnelly, J. P. Calibrating a sedimentary record of overwash from Southeastern New England using modeled historic hurricane surges. \u003cem\u003eMar. Geol. \u003c/em\u003e\u003cstrong\u003e275(1-4)\u003c/strong\u003e, 127-139 (2010). https://doi.org/10.1016/j.margeo.2010.05.002\u003c/li\u003e\n\u003cli\u003eKiage, L. M., et al. A 1900-year paleohur\u0026shy;ricane record from Wassaw Island, Georgia, USA. \u003cem\u003eJ. Quat. Sci. \u003c/em\u003e\u003cstrong\u003e26\u003c/strong\u003e, 714-722 (2011).\u003c/li\u003e\n\u003cli\u003eBregy, J. C., Wallace, D. J., Minzoni, R. T. \u0026amp; Cruz, V. J. 2500-year paleotempestological record of intense storms for the northern Gulf of Mexico, United States. \u003cem\u003eMar. Geol. \u003c/em\u003e\u003cstrong\u003e396\u003c/strong\u003e, 26-42 (2018). https://doi.org/10.1016/j.margeo.2017.09.009\u003c/li\u003e\n\u003cli\u003eGischler, E. \u0026amp; Lomando, A. J. Recent sedimentary facies of isolated carbonate platforms, Belize-Yucatan system, Central America. \u003cem\u003eJ. Sediment. Res. \u003c/em\u003e\u003cstrong\u003e69\u003c/strong\u003e, 747-763 (1999).\u003c/li\u003e\n\u003cli\u003eWooller, M. J., Behling, H., Guerrero, J. L., Jantz, N. \u0026amp; Zweigert, M. E. Late Holocene hydrologic and vegetation changes at Turneffe atoll, Belize, compared with records from mainland central America and Mexico. \u003cem\u003ePalaios\u003c/em\u003e \u003cstrong\u003e24\u003c/strong\u003e, 650-656 (2009).\u003c/li\u003e\n\u003cli\u003eCooper, M. C. The use of digital image analysis in the study of laminated sediments. \u003cem\u003eJ. Paleolimnol. \u003c/em\u003e\u003cstrong\u003e19\u003c/strong\u003e, 33-40 (1998). https://doi.org/10.1023/A:1007912417389\u003c/li\u003e\n\u003cli\u003eBlaauw, M. \u0026amp; Christen, J. A. Flexible paleoclimate age‐depth models using an autoregressive gamma process. \u003cem\u003eBayesian Analysis\u003c/em\u003e, \u003cstrong\u003e6(3)\u003c/strong\u003e, 457-474 (2011). DOI:10.1214/11-BA618\u003c/li\u003e\n\u003cli\u003eWefer, G. \u0026amp; Killingley, J.S. Carbon isotopes in organic matter from a benthic alga \u003cem\u003eHalimeda\u003c/em\u003e incrassata (Bermuda): effects of light intensity. \u003cem\u003eChem. Geol.\u003c/em\u003e \u003cstrong\u003e59\u003c/strong\u003e, 321-326 (1986).\u003c/li\u003e\n\u003cli\u003eKohn, M. J. Carbon isotope compositions of terrestrial C3 plants as indicators of (paleo) ecology and (paleo) climate. \u003cem\u003eProc. Natl. Acad. Sci. Unit. States Am.\u003c/em\u003e \u003cstrong\u003e107\u003c/strong\u003e, 19691-19695 (2010). https://doi.org/10.1073/pnas.1004933107\u003c/li\u003e\n\u003cli\u003eHeaton, T. J., et al. Marine20-The Marine Radiocarbon Age Calibration Curve (0\u0026ndash;55,000 cal BP).\u003cem\u003e Radiocarbon\u003c/em\u003e \u003cstrong\u003e62(4)\u003c/strong\u003e, 779-820 (2020).\u003c/li\u003e\n\u003cli\u003eReimer, P.J., et al. The IntCal20 Northern Hemisphere Radiocarbon Age Calibration Curve (0\u0026ndash;55 cal kBP). \u003cem\u003eRadiocarbon\u003c/em\u003e \u003cstrong\u003e62(4)\u003c/strong\u003e, 725-757(2020).\u003c/li\u003e\n\u003cli\u003eRamsey, B. C. Bayesian analysis of radiocarbon dates\u003cem\u003e. Radiocarbon\u003c/em\u003e \u003cstrong\u003e51(1)\u003c/strong\u003e, 337-360 (2009).\u003c/li\u003e\n\u003cli\u003eBlott, S. J. \u0026amp; Pye, K. Gradistat: A grain size distribution and statistics package for the analysis of unconsolidated sediments. \u003cem\u003eEarth Surf. Proc. Lan, \u003c/em\u003e\u003cstrong\u003e26\u003c/strong\u003e, 1237-1248 (2001).\u003c/li\u003e\n\u003cli\u003eToomey, M. R., Donnelly, J. P. \u0026amp; Woodruff, J. D. Reconstructing mid-late Holocene cyclone variability in the Central Pacific using sedimentary records from Tahaa, French Polynesia. \u003cem\u003eQuat. Sci. Rev. \u003c/em\u003e\u003cstrong\u003e77\u003c/strong\u003e, 181-189 (2013).\u003c/li\u003e\n\u003cli\u003eIsaack, A., et al. A new model evaluating sediment dynamics throughout the Holocene: insights from a mixed carbonate-siliciclastic lagoon (Bora Bora, Society Islands, French Polynesia, South Pacific). \u003cem\u003eSediment. Geol. \u003c/em\u003e\u003cstrong\u003e343\u003c/strong\u003e, 99-118 (2016).\u003c/li\u003e\n\u003cli\u003eWallace, E. J., Coats, S., Emanuel, K. A. \u0026amp; Donnelly, J. P. Centennial-scale shifts in storm frequency captured in paleohurricane records from The Bahamas arise predominantly from random variability. \u003cem\u003eGeophys.\u003c/em\u003e \u003cem\u003eRes. Lett. \u003c/em\u003e\u003cstrong\u003e47\u003c/strong\u003e, e2020GL091145 (2020). https://doi.org/10.1029/2020GL091145\u003c/li\u003e\n\u003cli\u003eKnapp\u003cstrong\u003e,\u003c/strong\u003e K., Kruk, M. C., Levinson, D. H., Diamond, H. J. \u0026amp; Neumann, C. J. The International Best Track Archive for Climate Stewardship (IBTrACS). \u003cem\u003eBull. Am. Meteorol. Soc. \u003c/em\u003e\u003cstrong\u003e91(3)\u003c/strong\u003e, 363-376 (2010). https://doi.org/10.1175/2009BAMS2755.1\u003c/li\u003e\n\u003cli\u003eMcAdie, C., Landsea, C., Neumann, C. J., David, J. E. \u0026amp; Blake, E. S. (2009): \u003cem\u003eTropical Cyclones of the North Atlantic Ocean, 1851\u0026ndash;2006: With 2007 and 2008 Track Maps Included \u003c/em\u003eVol. 6 (US Department of Commerce, National Oceanic and Atmospheric Administration).\u003c/li\u003e\n\u003cli\u003eVecchi, G. A. \u0026amp; Knutson, T. R. Estimating annual numbers of Atlantic hurricanes missing from the HURDAT database (1878-1965) using ship track density. \u003cem\u003eJ. Clim. \u003c/em\u003e\u003cstrong\u003e24\u003c/strong\u003e, 1736-1746 (2011).\u003c/li\u003e\n\u003cli\u003eStoddart, D. R. Effects of Hurricane Hattie on the British Honduras reefs and cays, October 30-31. \u003cem\u003eAtoll Res. Bull. \u003c/em\u003e\u003cstrong\u003e95\u003c/strong\u003e, 1-142 (1963).\u003c/li\u003e\n\u003cli\u003eKelletat, D., et al. Holocene tsunami deposits on the Bahaman islands of Long Island and Eleuthera. \u003cem\u003eZeitschrift f\u0026uuml;r Geo\u0026shy;morphologie, \u003c/em\u003e\u003cstrong\u003e48\u003c/strong\u003e, 519-540 (2004).\u003c/li\u003e\n\u003cli\u003eScheffers, A. \u0026amp; Kelletat, D. New evidence and dating of Holocene paleo-tsunami events in the Caribbean (Barbados, St. Martin and Anguilla). \u003cem\u003eIn\u003c/em\u003e: Mercado-Irizarry, A. \u0026amp; Liu, P. (\u003cem\u003eeds\u003c/em\u003e) \u003cem\u003eCaribbean Tsunami Hazard\u003c/em\u003e. New Jer\u0026shy;sey: World Scientific Press, pp. 178-202 (2006).\u003c/li\u003e\n\u003cli\u003eBiguenet, M., et al. 1600 year-long sedimentary record of tsunamis and hurricanes in the Lesser Antilles (Scrub Island, Anguilla). \u003cem\u003eSediment. Geol. \u003c/em\u003e\u003cstrong\u003e412\u003c/strong\u003e, 105806 (2021). https://doi.org/10.1016/j.sedgeo.2020.105806\u003c/li\u003e\n\u003cli\u003eBarkan, R., Uri, S. \u0026amp; Lin, J. Far field tsunami simulations of the 1755 Lisbon earthquake: Implications for tsunami hazard to the US East Coast and the Caribbean. \u003cem\u003eMar. Geol. \u003c/em\u003e\u003cstrong\u003e264\u003c/strong\u003e, 109-122 (2009).\u003c/li\u003e\n\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":true,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"","lastPublishedDoi":"10.21203/rs.3.rs-3758003/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-3758003/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"Blue holes (marine sinkholes) are remarkable archives for past cyclone-frequency reconstructions, as they work as formidable natural sediment traps over periods of several millennia. Tropical cyclones (TC) mobilize allochthonous particles from adjacent areas during their passages. In the Belizean “Great Blue Hole”, these particles become repeatedly redeposited under anoxic bottom-water conditions as coarse-grained event-layers within annually-layered bottom sediments. Chronological counts of these event deposits allow to develop long-term statistics of TC-frequency, exceeding the short range of instrumental TC-monitoring (73-years). In view of an intensifying modern global climate change, it is crucial to understand processes of climate forcing, that naturally alter TC-frequency on centennial to millennial time scales. Here we show, that a mid-Holocene (6.0-4.8 ka BP) climate restructuring entailed substantial changes for south-western Caribbean TC-frequency. We applied a multi-proxy-approach to the 30-m-long sediment core BH8, in order to identify 694 tempestites and developed a 12500-years-long history of storm activity. These data, for the first time, allow to compare frequency statistics with ocean temperatures and Intertropical Convergence Zone (ITCZ) migrations for the entire Holocene interglacial. Our results demonstrate, that an insolation-controlled relocation of Atlantic warm-pools and a subsequent southward displacement of the ITCZ triggered a 6500-years-lasting rise of south-western Caribbean cyclone-frequency.","manuscriptTitle":"Ocean temperatures and ITCZ migrations triggered cyclone-frequency variations during the Holocene","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2023-12-22 14:56:34","doi":"10.21203/rs.3.rs-3758003/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"05518a97-ee9e-4d8a-8a0e-2b088e1393b5","owner":[],"postedDate":"December 22nd, 2023","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[{"id":27599034,"name":"Earth and environmental sciences/Natural hazards"},{"id":27599035,"name":"Earth and environmental sciences/Climate sciences/Palaeoclimate"}],"tags":[],"updatedAt":"2024-01-17T18:11:03+00:00","versionOfRecord":[],"versionCreatedAt":"2023-12-22 14:56:34","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-3758003","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-3758003","identity":"rs-3758003","version":["v1"]},"buildId":"rHA-KDH7Qsr4HCuvH75dn","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}