Geological and experimental evidence of bioavailable phosphite during the Great Oxygenation Event

Geological and experimental evidence of bioavailable phosphite during the Great Oxygenation Event | 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 Article Geological and experimental evidence of bioavailable phosphite during the Great Oxygenation Event Abu Baidya, Joanne Boden, Yuhao Li, Albertus Smith, Kurt Konhauser, and 1 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-5118430/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 24 May, 2025 Read the published version in Nature Communications → Version 1 posted You are reading this latest preprint version Abstract Phosphorus (P) availability throughout geologic time has likely impacted the co-evolution of life and Earth’s environments. Phylogenetic data suggest that phosphate was the primary P-source for microbial life during the Archean, but phosphite, a reduced form of P, became relatively more important leading up towards the Great Oxygenation Event (GOE) in the Neoarchean to Paleoproterozoic. However, seawater phosphite concentrations during this time, and the potential processes driving this shift in P utilization, are unknown. Here, we performed laboratory experiments simulating the precipitation of banded iron formations (BIFs) as hydrous ferric oxyhydroxides (HFO) in deionized water, diluted seawater, and seawater containing phosphate and phosphite. We also measured phosphite concentrations in BIF samples from four Neoarchean-Paleoproterozoic formations. Our results indicate a weaker removal of phosphite compared to phosphate by HFO irrespective of solution chemistry. Paired with measurements of phosphite (up to 0.05–250 ppm) in BIFs, we estimate that seawater phosphite concentration at the onset of the GOE could have reached up to 0.01–0.17 µM. We propose that the preferential removal of phosphate relative to phosphite by HFO, coupled with microbial competition for P facilitated by oxygenic photosynthesis, might have created phosphate-depleted environments, prompting life to exploit alternative P sources such as phosphite. Earth and environmental sciences/Biogeochemistry/Element cycles Earth and environmental sciences/Planetary science/Astrobiology Earth and environmental sciences/Planetary science/Geochemistry Figures Figure 1 Figure 2 Figure 3 Figure 4 Introduction Phosphorus is a key element of modern biology, playing a vital role in the formation of phospholipids, cellular energy exchange, and the storage of genomic information in RNA and DNA. Therefore, P must have been crucial to the origin and early diversification of life. However, among the major bioessential elements, P is the least abundant element in nature 1 . Its most common geological form, apatite, has low solubility in water, potentially making it the ultimate limiting nutrient in marine ecosystems 2 . Consequently, its availability throughout geologic time has likely affected the trajectory of biological evolution 3 , 4 . Modern microbial life is heavily dependent on phosphate (P(V)). However, reduced P species, such as phosphonates (molecules with P-C bonds where P is in a 3 + redox state) and inorganic phosphite (P(III)), also serve as important P sources, especially in P(V)-limiting environments 5 , 67 , 8 . They are thus significant in the global P cycle. P(III) is up to 1000 times more soluble than P(V) in the presence of divalent metals 9 , suggesting that it may be more bioavailable in marine environments than P(V). P(III) is particularly important to modern microbial life for two reasons. First, it can be utilized as a P source for cellular uptake, a process known as assimilatory phosphite oxidation (APO) 10 . Second, it serves as an electron donor and energy source via dissimilatory phosphite oxidation (DPO) 11 . Although DPO is speculated to have evolved as early as 3.3 Ga 10 , a subsequent study 6 concluded that P(V) was the main P-source for microbial life at that time. The genes responsible for P(III) metabolism only became more widespread across the tree of life around the Neoarchean-Paleoproterozoic boundary (2.8–2.2 Ga) 6 , i.e., just before and during the GOE at 2.50–2.20 Ga 12 – 14 . Nonetheless, the processes that might have triggered this shift in P-utilization by microbial life during this time remain unclear. Both abiotic and biotic processes can produce P(III) in modern environments 15 , 16 . In the Archean, the proposed abiotic sources of P(III) include; (1) the reduction of P(V) by iron redox chemistry during diagenesis and metamorphism 9 , 17 , (2) serpentinization 18 , (3) lightning-induced reduction of P(V) 19 , 20 , and (4) the dissolution of phosphide minerals, such as schreibersite ((Fe,Ni) 3 P), either delivered by meteorites and/or produced in soils during lightning strikes or in contact metamorphic rocks 21 – 23 . Iron redox-controlled reduction of P(V), in particular, is facilitated by concomitant oxidation of Fe(II) or by molecular hydrogen (H 2 ) under moderate to high-temperature metamorphic conditions 9 , 17 . Such processes may happen during serpentinization and high-grade metamorphism in the Archean 9 , 17 . Indeed, P(III) has been detected in Eoarchean high-grade metamorphosed BIF and carbonate rocks from the Isua Greenstone Belt and in some recent serpentinites 9 , 18 . The P(III) produced by these processes might have accumulated in significant amounts in the Archean ocean 9 , 24 , as it is kinetically stable, with a slow breakdown rate in the absence of biological activity (e.g., via DPO or APO), radical ions (e.g., ·OH), and molecular oxygen (O 2 ), having an estimated half-life of 0.6 Ma. However, data from P(III) in Precambrian sedimentary rocks are limited, and there is also no direct estimation of dissolved inorganic P(III) in Precambrian seawater 6 . Indirect estimates of P(V) concentrations in the Precambrian oceans have been made using P(V) concentrations in rocks including carbonates 25 , terrigenous marine sediments 3 , and BIFs 26 – 28 . Among these methods, the approach based on P(V) in BIFs assumes that the latter precipitated as hydrous ferric oxyhydroxides (HFO) in the photic zone overlying the continental shelf 29 . It integrates experimental data on the fractionation of phosphate between HFO and seawater, along with P(V) and Fe concentration in the BIFs 26 , 28 . The following equation is used to estimate oceanic P(V) concentrations: [P(V) d ] = (1/K ads ) · (P(V) ads /Fe 3 + ads ); where [P(V) d ] is the concentration (in µM) of dissolved P(V); P(V) ads and Fe 3 + ads are the concentrations (µM) of adsorbed and precipitated P(V) and Fe on HFO, respectively; and K ads (µM ‒ 1 ) is the adsorption coefficient. Typically, K ads (µM ‒ 1 ) is experimentally determined, and the P(V) ads /Fe 3 + ads ratio is directly obtained from BIF analyses. However, this method has never been applied to estimate inorganic P(III) concentrations in the Precambrian ocean. By analogy to P(V), if K ads (µM ‒ 1 ) and P(III) ads /Fe 3 + ads values for P(III) are known, it would be possible to reconstruct the inorganic P(III) concentrations of the Archean-Proterozoic ocean. We conducted laboratory experiments to simulate the precipitation of BIFs as HFO in various solutions; including deionized (DI) water, 10-times diluted seawater, and seawater (artificially made containing 0.56 M NaCl, 0.055 M Ca, 0.045 M Mg with an ionic strength of 0.86 mol/L), with or without dissolved silica (Si) and varying concentrations of P(V) and P(III) (see Materials and Methods for details). The initial iron concentration was 0.2 mM Fe(II), and dissolved Si concentrations were 0 mM, 0.22 mM, or 2.2 mM, with the highest concentrations reflecting estimated concentrations of the Archean-Paleoproterozic 28 , 30 . Adsorption tests were performed at a pH of 8 ± 0.2 following previous studies 28 , 30 , and adsorption coefficients (K ads ) were determined. We also measured concentrations of P-species including P(III), P(V), pyrophosphate (PP(V)), and total P and Fe concentrations in Neoarchean and Paleoproterozoic (2.60–2.46 Ga) BIF samples from five rock formations located in Western Australia (Pilbara Craton) and South Africa (Transvaal Supergroup). We then used the P(III) concentrations of these BIF samples and the experimentally determined K ads of P(III) to estimate the phosphite concentrations in the oceans during the GOE. Finally, we explore possible reasons for the shift in microbial P-utilization during the GOE. Results In our experiments, nearly all (~ 99%) of the dissolved Fe(II) precipitated as HFO irrespective of solution chemistry. By contrast, the removal of P-species was variable depending on the specific solution chemistry. When P-species were removed, they were likely incorporated into the crystal lattices of HFO and adsorbed onto its surface (hereafter referred to as “sorption” to describe the total amount of P(V) or P(III) removed), consistent with previous studies 28 , 30 . The extent of sorption is characterized by K ads , with higher values indicating stronger sorption and more effective removal from the solution. The experiments suggest that salinity has some control on P(V) sorption onto HFO (Fig. 1 A). We observed less sorption of P(V) in DI water (K = 0.011) compared to 10-fold diluted artificial seawater (K = 0.039) (0.22 mM Si; hereafter DiluSeaSi) and concentrated artificial seawater (2.2 mM Si; hereafter SeaSi) (Fig. 1 A). Other studies have reported a K ads value of 0.021 for P(V) sorption in artificial seawater having similar compositions as in our experiments 28 . This value is lower than that in DiluSeaSi, suggesting stronger sorption in DiluSeaSi, which may be due to less dissolved Si in this solution. Previous studies have demonstrated that dissolved Si reduces P(V) sorption in natural seawater and in 0.56M NaCl, for example K ads values for P(V) in these solutions are 0.338 and 0.064, respectively, while the addition of 2.2 mM of Si reduces the K ads values to 0.008 and 0.002, respectively 28 , 30 . Importantly, our experiments show that sorption of P(III) onto HFO is very limited, although solution chemistry does have some influence. The K ads values for P(III) adsorption in DI water, DiluSeaSi, and SeaSi are 0.0003, 0.0011, and 0.0008, respectively, indicating the least sorption in DI water and highest sorption in DilSeaSi (Fig. 1 B). This pattern is similar to what is observed for P(V), suggesting that salinity similarly affect P(III) sorption. Notably, a direct comparison between P(V) and P(III) adsorption coefficients suggests that P(V) is adsorbed 36, 35, and 26 times more strongly than P(III) in DI water, DilSeaSi, and SeaSi, respectively (Fig. 1 A-C). These values imply more efficient removal of P(V) from solution by HFO compared to P(III) under all conditions. Key geological, mineralogical, and compositional features of the studied BIF are summarized in Table 1 . These rocks formed between 2.60 to 2.44 Ga and experienced burial metamorphism at temperatures ranging from 110-170 o C for the South African BIF 31 and 160-360 o C for the Western Australian BIF 32 (further details are avail in the Materials and Methods section). XRD data reveals variable proportions of quartz, magnetite, hematite, siderite, ankerite with minor amount of pyrite, riebeckite, and stilponomelane (Figure S2 in Supplementary Material). The Fe contents of the samples range from 27 to > 50%. The Joffre Member has comparatively low total P ranging from 20 to 110 ppm, while the other four formations contain higher total P levels, ranging from 20 to 3720 ppm (Fig. 2). (A) compiled P(V) sorption data from previous studies 28 are compared with new data (black and red). ‘Natural SW’ is the low-nutrient Sargasso seawater whereas ‘Artificial SW’ is artificially prepared containing NaCl, Ca 2+ , and Mg 2+ and representing the Archean calcitic seawater. K ads is the coefficient of sorption. Individual datapoints for artificial Seawater with 2.2 mM Si were not available, therefore the trend line (orange line) is reconstructed from the K ads value 28 . Data for the Natural SW 28 show the effect of Si on sorption while other three datasets show the effect of salinity. (B) P(III) adsorption data generated in this study. P(III) adsorption is very limited compared to P(V) irrespective of solution chemistry. Error bars in A and B represent standard deviations of the means. For a direct comparison with P(V) sorption trend lines in A, those in B are not forced to go through origin. Two datapoints shown by hollow circles in B, are not considered for producing the trendline because of experimental error. (C) K ads values used for P(V) and P(III) estimates in seawater around the Neoarchean-Paleoproterozoic boundary. As we used K ads value to produce the trend line for P(V), it went through the origin. For a direct comparison, the trendline for P(III) is forced to go through the origin. Table 1 Geological and chemical features of the BIF samples Location Age Max. Meta. Temp No. of Samples Mineralogy (XRD) P(III) (ppm)* P(V) (ppm)* Total P (ppm) # Total Fe (wt%) # Extraction yield (%) Kuruman -Gamohaan Iron Formation $ 2.55–2.44 Ga 170 o C 7 qtz, mag, hem, sid, anke, stilp(?), py(?) 0.22–0.37 1.59–28.4 70–950 26.8–44.8 1.96–4.53 Joffre Base Member £ 2.46 Ga 200-360 o C 4 qtz, mag, hem, sid, anke, py, riebe, stilp(?) 0.02–0.05 2.21–15.4 20–110 27.4–34.7 11.3–37.6 Dales Gorge Member £ 2.49–2.46 Ga 200- 360 o C 6 qtz, mag, hem, anke, py, riebe, stilp(?) 0.15–0.56 1.59–60.6 20–3720 29.6 - >50 1.65–12.5 Marra Mamba Formation £ 2.6 Ga 200-360 o C 4 qtz, mag, sid, anke, py, stilp(?) 0.23–0.34 3.32–11.6 160–1090 30.4 - >50 0.95–2.34 * P(III) and P(V) concentration in EDTA-NaOH extracts; # concentration in solid; Minerals with ‘?’ mark are possibly present. $ -South Africa, £-Western Australia; qtz- quartz, mag- magnetite, hem- hematite, sid- siderite, anke- ankerite, stilp- stilpnomelane, py- pyrite, riebe- riebeckite Figure 2 summarizes the P speciation data from the EDTA-NaOH extracts and total P contents. The EDTA-NaOH solution extracted only a small portion (1–38%) of total amount of P present in the solid samples; however, these yields are consistent with those reported in previous studies 9 . The associated uncertainties in seawater P(III) reconstructions are discussed below. All the studied samples contain P(III), with the highest concentrations found in the Kuruman Iron Formation and the lowest in the Joffre Member. The concentration of P(III) is consistently lower than that of P(V) in the extraction solutions. Discussions Estimation of P(III) in seawater around the GOE The K ads values obtained from our sorption experiments, combined with P-speciation data in BIFs, allow us to estimate P(III) and P(V) concentrations in seawater around the Neoarchean-Paleoproterozoic boundary. This estimation relies on several assumptions: First, we presume that the studied BIFs precipitated as HFO. The precipitation of BIF is debated, with proposed precursors including HFO 33 , greenalite 34 , green rust 35 , magnetite 36 , and siderite 37 . Among these, HFO is the most significant globally 33 . If the primary mineral was instead composed of Fe(II) 34 , the observed Fe(III) phases would have to be of secondary origin. However, the complete absence of primary Fe(III) is unlikely, given hydrological constraints 38 , independent evidence of oxic conditions in Neoarchean surface waters 39 , 40 , highly fractionated Fe isotopes in these BIFs indicating depositional and post-depositional redox cycling 41 , and the incontestable fact that a biosphere capable of oxidizing dissolved Fe(II) existed at that time 29 . Hence HFO, as a precursor of preserved Fe(III) minerals in BIFs, likely formed in shallow-water settings 33 , while Fe(II) precipitation was dominant in the deep ocean proximal to hydrothermal Fe-sources 42 and before upwelling onto the continental shelf 43 . Second, the amount of P(III) detected in the EDTA-NaOH extraction cannot be used directly to calculate the total sorbed P(III) during BIF precipitation without considering two issues: (1) the preferential extraction of P(III) over P(V) by the EDTA-NaOH solution, due to the former’s higher solubility 9 , and (2) the post-depositional transformation of P(V) into P(III) facilitated by iron redox chemistry 9 , 17 . Previous studies have reported low extraction yields (< 3%) of P species in EDTA-NaOH solutions from solid rocks 9 . To the best of our knowledge, no study to date has specifically examined whether P(III) can be preferentially leached. Therefore, we have considered two extreme possibilities: (1) the ratio of P species in BIF is the same as in the EDTA-NaOH extract, and (2) complete extraction of BIF-hosted P(III) into EDTA-NaOH solution. These scenarios help bracket the potential P(III) concentrations in the BIF. To address the post-depositional transformation of P(V) into P(III), we considered three possible cases: (1) no metamorphic P(III), meaning that all measured P(III) represents primary sorbed inorganic P(III) during BIF precipitation; (2) a mixture of sorbed and metamorphic phosphite; and (3) all the P(III) is metamorphic in origin. In case (3), it is impossible to estimate the original P(III) concentration from BIF precipitation, as it implies that none of the detected P(III) was originally sorbed to BIF. Table 2 Estimates of ocean phosphite and phosphate concentrations (µM) Scenario 1 Scenario 2a/2b Scenario 3 Scenario 4a/4b Locations 1. P species ratio in BIF is same as in EDTA-NaOH extract 2. Metamorphic phosphite is none 1. P species ratio in BIF is same as in EDTA-NaOH extract 2. Metamorphic phosphite using exp. yield 1. 100% phosphite is extracted from BIF 2. Metamorphic phosphite is none 1. 100% phosphite is extracted from BIF 2. Metamorphic phosphite using exp. yield P(III) P(V) P(III) P(V) P(III) P(V) P(III) P(V) Kuruman-Gamohaan 0.024–0.075 0.013–0.352 0.000*-0.054 a 0.014-0.354 a 0.001–0.002 0.016–0.354 ENP a 0.016-0.354 a 0.024-0.075 b 0.013-0.352 b 0.001-0.002 b 0.016-0.354 b Joffre 0.000*-0.002 0.005–0.029 0.000 a * 0.005-0.029 a 0.000* 0.005–0.012 ENP a 0.005-0.012 a 0.000*-0.001 b 0.005-0.029 b 0.000* b 0.005-0.029 b Dales Gorge 0.017–0.142 0.002–0.921 0.000*-0.020 a 0.003-0.927 a 0.001–0.002 0.004–0.927 ENP a 0.003-0.927 a 0.017-0.142 b 0.002-0.921 b 0.001*-0.002 b 0.003-0.927 b Marra Mamba 0.058–0.165 0.024-0.300 0.000*-0.033 a 0.025-0.307 a 0.001–0.002 0.027–0.307 ENP a 0.027-0.307 a 0.058-0.165 b 0.024-0.300 b 0.001-0.002 b 0.027-0.307 b a: Scenario 2a/4a- Experimental yield of Herschy et al. 9 ; b: Scenario 2b/4b - Experimental yield of Baidya et al. 17 ; ENP: estimation not possible (all phosphite are metamorphic like Scenario 5); *: values 0.000 means the concentration is less than 0.5 nM. Together, these permutations lead to five scenarios to translate the measured P(III) and P(V) in the BIFs into seawater P(III) and P(V) concentrations (Table 2 ). We note that Scenario 5, where all P(III) is metamorphic in origin, is excluded from the compilation as here the calculated seawater value would be zero. Scenarios 2 and 4 are further subdivided, depending on the metamorphic constraint on P(V) reduction into P(III) in ferruginous diagenetic and metamorphic environments 9 , 17 . The highest estimated values for P(V) range from 0.01 to 0.93 µM with minor variations across the different scenarios (Table 2 , Fig. 3 ). These estimates are lower than estimates based on carbonates 25 , hydrothermal vent precipitates 42 , 44 , as well as experiments and modelling 45 but similar to predictions from several other geochemical estimates based on BIF samples 26 , 28 and genomic estimates 6 (Fig. 3 ). To estimate post-depositional metamorphic P(III), we used published experimental yields of metamorphic and diagenetic P(V) reduction in ferruginous conditions 9 , 17 . Baidya et al. 17 conducted several experiments at 350 o C, which is close to the highest metamorphic temperature experienced by the studied BIF 32 , and reported a yield of 0.075%. They also demonstrated that magnetite inhibits the reduction of P(V) to P(III) even in the presence of H 2 at 350 o C 17 . Given that magnetite is consistently present in the BIF samples (Table 1 ), metamorphic P(III) may be limited, making Scenario 4a and Scenario (5) - where all BIF-bound P(III) is metamorphic - less plausible. Among the remaining scenarios, number (1), which assumes the same ratio of P-species in BIF samples as in the EDTA-NaOH extract and no additional P(III) formation during diagenesis and metamorphism, provides the highest possible concentrations of P(III) in seawater, ranging from 1 to 165 nM (Table 2 ). Importantly, the estimated P(III) and P(V) concentrations in Scenario 1 suggest that P(III) could have constituted 5–88% of total dissolved inorganic P (P(V) + P(III)) in seawater at the onset of the GOE (Fig. 3 ). Shift in microbial P-utilization around the GOE Phylogenetic studies suggest that microbial communities began utilizing P(III) between 2.6–2.2 Ga 6 . If this is the case, there must have been sufficient P(III) in seawater to facilitate this evolutionary shift. So far, there are limited data on P(III) concentration in modern environments and its relation to microbial growth. P(III) was not detected in the tropical Atlantic Ocean 15 but has been reported in geothermal pools (0.06 ± 0.02 µM) 16 , lakes (0.01–0.71 µM) 48 , 49 , rivers (0.08–0.9 µM) 50 , and ponds (0.14–2.90 µM) 50 . In Taihu Lake, concentrations of 10 µM P(III) may support phytoplankton growth, while 30–100 µM may lead to algal blooms 51 . Furthermore, experimental studies suggest that P(III)-dependent microbial growth is possible at 50 µM P(III) 7 . These concentrations are higher than our estimated concentration of P(III) in seawater at the onset of the GOE, suggesting either local enrichment of P(III) above those calculated averages or lower thresholds of P(III) for the growth of microbial life during the GOE. Understanding whether P(III) was used for APO or DPO at the onset of GOE is crucial. Experimental studies have found that higher P(III) (0.1–10 µM) are required for DPO compared to APO (10 µM P(III)) 7 , 10 , 11 , 52 . We analysed a previously published phylogenetic tree of ptxD 6 , which emerged between 2.3–2.2 Ga 6 , and is used in both APO and DPO (see Materials and Method section for further details). The tree reveals that homologs from bacteria performing DPO formed a monophyletic group with a posterior probability of 100, suggesting that DPO evolved once and subsequently radiated into different species. When rooted with minimal ancestor deviation from Tria et al. 53 , the most parsimonious explanation for the evolution of ptxD s is that the earliest ptxD s from 2.3–2.2 Ga were associated with APO, and DPO-associated homologs evolved later (see Figure S1 in Supplementary Material). In the alternative scenario where the first ptxD s were used for DPO, two switches from DPO-associated ptxD to APO-associated ptxD would be required, which is less parsimonious – and therefore less likely – than the one switch required if the first ptxD was associated with APO. Furthermore, a different gene, ptxB , which imports P(III) for APO, evolved between ~ 2.6 and 2.3 Ga, pre-dating the ptxD s. Hence, we suggest that microbes were utilizing P(III) for APO by the onset of the GOE. The low estimated P(III) concentration in seawater at that time (Fig. 3 ) supports this explanation. We posit that increased primary productivity and the preferential removal of P(V) compared to P(III) due to BIF precipitation created P(V)-depleted environments in the surface ocean, which in turn facilitated the evolution of genes responsible for microbial P(III) utilization at the onset of the GOE. Major BIFs were precipitated between 2.65–2.40 Ga 33 , just prior to, and concomitant with, the GOE. Dissolved Si is known to reduce the effect of P(V) sorption onto HFO during BIF precipitation, while dissolved Ca and Mg may mitigate the effect of Si 28 , 30 , leading to variable removal of P(V) from seawater during BIF precipitation depending on Si, Ca 2+ , and Mg 2+ concentrations. Nevertheless, the presence of P in BIF samples worldwide 26 suggests that BIF precipitation indeed removed a portion of the dissolved P(V) from the ocean at the onset of GOE, particularly if biomass-induced accumulation of P(V) was limited 54 . This aligns with higher estimated concentration of dissolved P(V) (1-4000 µM) in the early Archean oceans, as evidenced by several geochemical estimates 25 , 42 , 45 and sub-micromolar concentrations at the onset of the GOE based on genomic 6 and geochemical estimates 26 , 28 , 47 . In contrast, our data show that BIF precipitation had a limited impact on dissolved P(III) due to its minimal sorption onto HFO. Furthermore, it is generally believed that primary productivity was limited in the Archean due to a range of factors, including limited availability of electron donors (e.g., Fe 2+ and H 2 ) necessary for anoxygenic photosynthesis 47 , 55 , less emergent continental landmass and thus less habitable space for microbial mats 56 , and higher UV radiation due to the absence of an ozone layer 57 . With the expansion of oxygenic photosynthesis, which utilizes water as electron donor, primary productivity might have increased ten-fold compared to early Archean times 55 . Such an extreme increase in biological productivity likely depleted the oceans in nutrient elements, particularly P(V). If so, during the GOE, there might have been environments with very limited P(V), akin to modern P(V)-depleted environments where microbial life uses alternative P species such as P(III) 6 , 7 . We therefore suggest that microbial competition for P(V) may have triggered the biological production and utilization of reduced P at the onset of the GOE. In summary, our results provide the first estimate of maximum dissolved P(III) concentrations (1-165 nM) around the time of the GOE, which could have constituted 5–88% of the total dissolved inorganic P (P(V) + P(III)) at that time. The stark contrast between P(V) and P(III) sorption on HFO identified by our experiments, as well as the observed prevalence of P(III) compounds in P(V)-depleted settings in the modern ocean, uncovers a potential linkage between the expansion of oxygenated surface waters, the accumulation of iron oxide minerals on continental shelves, and the radiation of novel P-metabolisms across the tree of life. Our findings thus reveal a previously unknown factor contributing to the co-evolution of Earth and early life. Materials and Methods Adsorption experiments The laboratory experiments simulated the co-precipitation of banded iron formations (BIFs) as hydrous ferric oxyhydroxides (HFO) and inorganic phosphate or phosphite in deionized water, 10-times diluted seawater, and seawater. Acid-washed (1–2 M HCl) and baked (500°C) glass containers, acid- and hot water-washed centrifuge tubes, syringe, and pipette tips were used during all stages of the experiments, subsequent sampling, and analysis. FeCl 2 .4H 2 O (Sigma Aldrich), NaH 2 PO 4 (Thermo Fisher), NaH 2 PO 3 ·5H 2 O (Thermo Fisher), and Na 2 SiO 3 (Thermo Fisher) were dissolved in deionized water for preparing stock solutions of 20 mM Fe 2+ , 1 mM phosphate and phosphite, and 22 mM Si. The Fe 2+ solution was freshly prepared before each set of experiments to avoid significant oxidation under the present atmosphere. Artificial seawater containing 0.56 M NaCl (Sigma Aldrich), 55 mM Ca 2+ (CaCl 2 , Thermo Fisher), and 45 mM Mg 2+ (MgCl 2 .6H 2 O, Thermo Fisher) with an ionic strength of 0.86 mol/L was prepared by dissolving the salts in deionized water. This composition represents Precambrian Si-bearing calcitic sea 28 . Stock solutions were diluted to produce 10 ml experimental solutions containing 0.2 mM Fe 2+ and 0–28 µM phosphate or phosphite with or without Si of 0.22 mM (10x-diluted seawater) or 2.2 mM (seawater). As an example, to prepare a 2 µM phosphite-bearing artificial sweater solution, we mixed 200 µL of 100 µM phosphite, 100 µL of 20 mM Fe 2+ , and 9.7 mL artificial seawater. The experimental solutions were then mixed with dilute dissolved NaOH (variable combinations of 0.01 M, 0.025 M, and 0.05 M) to oxidize Fe 2+ and precipitate HFO. A constant pH of 8 ± 0.2 was maintained for half an hour and adjusted with dilute NaOH and HCl (variable combinations of 0.0.01 M, 0.025 M, and 0.05 M). We kept track of the total amount of NaOH and HCl added to each solution to accurately determine the dilution factors at the end of the experiments. The pH was monitored using a pH probe (Hanna Instruments), which was calibrated before every set of experiments. All experiments were performed as doublets or triplets. After the experiments, the solutions were filtered with previously washed (10 ml deionized water) 0.2 µm PTFE hydrophilic (Fisher) filters. We discarded the first 3ml of the solution after filtering to avoid any contamination from the filter and collected 1ml, which was immediately acidified with 2% ultrapure HNO 3 . All the experimental solutions were diluted 10–100 times with 2% HNO 3 , and the concentrations of 31 P and 56 Fe were measured with a Thermo Scientific Element 2 high resolution inductively coupled plasma mass spectrometer (ICP-MS) equipped with an auto sampler (Elemental Scientific Inc.), a 0.1 ml/min nebulizer, and a Scott spray chamber. Standards containing 0.01 µM to 2.5 µM of Fe and phosphate or phosphite were prepared by dissolving FeCl 3 and NaH 2 PO 4 or NaH 2 PO 3 ·5H 2 O (Thermo Fisher, same salt used for experiments) in the same saline matrix as that of the samples. The ICP-MS was operated at a sample gas flow rate of 1 ml/min, cool gas flowrate of 16 ml/min, and RF power of 1250. The 31 P and 56 Fe intensities of the sample solutions were measured in medium resolution mode, and concentrations were calculated offline with respect to the standards. Each sample and standard were measured twice, and the average intensities were used for assessment. A few standards were measured at the beginning of the ICP-MS sequence as well as in the middle and at the end to quantify the drift of the ICP-MS and corrections were made when it was required. Banded Iron Formation rock analysis Sample location and geology The Marra Mamba Iron Formation samples were collected from drill core WRL-1, while the Dales Gorge Member were collected from drill core DGM-1. Both were provided by the Perth Core Library of the Geological Survey of Western Australia. The Joffre Member were obtained from core sample DD98SGP001 via the Rio Tinto core library in Perth. The Gamohaan and Kuruman Formation samples were recovered from drill core DI1, originally drilled and stored by a mining company (Gefco) at Derby, approximately half way between the towns of Kuruman and Danielskuil in the Northern Cape Province of South Africa 60 .The sample from the Gamohaan Formation was taken from the uppermost Tsineng Member 61 , whereas the samples from the Kuruman Formation were taken from four different members throughout its stratigraphy. The Hamersley Group comprises about 2.5 Km of consecutive sedimentary and volcanic rocks located within the ca. 80,000 km 2 Hamersley Province of the Pilbara craton in Western Australia. It comprises five IF units, in ascending order the 2.60 Ga Marra Mamba Iron Formation, the 2.48 Ga Dales Gorge Member of the Bockman Iron Formation, the 2.46 Ga Joffre Member of the Brockman Iron Formation, the 2.45 Ga Weeli Wolli Formation and the uppermost Bolgeeda Iron Formation which is approximated at 2.44 Ga 62 . Metamorphic grade for the Hamersley Basin units have been interpreted from the widespread presence of the minerals prehenite, pumpellyite, epidote and actinolite, which corresponds to a maximum temperature range between 200-360 o C 32 , 63 . The Gamohaan Formation is approximately 110 m thick and is the uppermost formation of the approximately 1600 m thick Campbellrand Subgroup of the lower Ghaap Group of the Griqualand West region of the Transvaal Supergroup of southern Africa 61 . Although the Campbellrand Subgroup is dominated by stromatolitic dolostone and limestone, the Gamohaan Formation contains a BIF (originally described as an Fe-rich banded chert), called the Tsineng Member, at its top 61 that was sampled for this study. The depositional age range for the upper Campbellr and Subgroup is approximately 2.55 to 2.52 Ga 64 . The Kuruman Formation is the lower formation of the Asbesheuwels Subgroup, which directly overlies the Campbellrand Subgroup 60 , 65 . Together with the overlying Griquatown Formation, the Asbesheuwels Subgroup comprises 385 to 1000 m of continuous micritic and granular iron formation 60 . The depositional age range for the Kuruman Formation is approximately 2.48 to 2.44 Ga 64 . Together with the correlative Penge Formation in the Transvaal region 64 , it is the oldest iron formation of the Transvaal Supergroup. Other than the Griquatown Formation, the Transvaal Supergroup in the Griqualand West region contains two more iron formations in the approximately 2.43 Ga Koegas Subgroup 66 (Schröder et al., 2011) and four iron formations interbedded with manganese beds in the approximately 2.41 Ga Hotazel Formation 67 , 68 .Estimated burial temperatures of the Kuruman Formation is 100-150 o C 69 . A similar burial temperature is inferred for the Gamohaan Formation as it directly underlies the Kuruman Formation. Solid characterization using powder X-ray diffraction (PXRD) The powdered rock samples were loaded into 0.5 mm or 0.7 mm capillary tubes and sealed for XRD analysis. The PXRD patterns were recorded on a STOE STADIP diffractometer using Mo Kα1 radiation at room temperature from 2.5 o to 37° (2θ) with a scan rate of 2.5-3.0 o (2θ)/step in capillary Debye-Scherrer mode. The PXRD data were compared to solids in the Inorganic Crystal Structure Database (ICSD) for phase identification using the Crystal Diffract software (version 6.9.3). Whole rock analysis Approximately 0.30–0.60 g of powder from each of the samples was sent to Australian Laboratory Services (ALS) in Dublin, Ireland, for whole-rock geochemical characterisation using their method ME-MS-61r of four-acid digestion (HCl, HNO 3 , HF, HClO 4 ) followed by ICP-MS and -AES analyses. Reproducibility was assessed with rock standards OREAS-45d, OREAS-905 and MRGeo-08, and with sample replicates. It was found to be 5% or better for P and Fe. Quantification of P species in the extraction solution and in the BIFs An aliquot (ca. 0.2–0.25 gm) of the powdered samples was treated with an Ethylenediaminetetraacetic acid-sodium hydroxide (0.05M EDTA and 0.25M NaOH) solution 18 maintaining a solid:solution ratio of 1:10 for 14–15 hours. Na 2 EDTA (Sigma Aldrich) salt and 10M NaOH solution (Thermo Scientific) were dissolved in deionized water to make the EDTA-NaOH solution mixture. Acid- and hot-water washed 10 ml Falcon tubes were used during the extraction procedure. The solutions were then centrifuged at 3000 rpm for 15–20 minutes. In most cases, the solution was transparent after centrifuging, suggesting the precipitation of all the extracted Fe. In a few cases, the solution was yellow to orange, which suggested the presence of dissolved Fe. Such solutions were further treated with 1M NaOH to precipitate all the Fe, which is essential for the P speciation measurements using the subsequent Ion Chromatograph (IC)-ICPMS analysis 70 . This is because excess dissolved iron may precipitate as oxides in the anion separation column of the IC and bind phosphate by adsorption within the column, thereby impacting analytical quality. Four phosphorus species, namely hypophosphite, phosphite, phosphate, and pyrophosphate were analyzed using the IC-ICPMS set-up of Baidya and Stüeken 70 . In this IC-ICPMS set-up, a Thermo Scientific Dionex ICS-6000 IC equipped with a Dionex AS-AP autosampler, a 25 mm Dionex IonPac AS17-C separation column (2 mm bore), a 25mm Dionex IonPac AG17-G guard column (2 mm bore), and a Dionex ADRS-600 (2 mm) suppressor were used to separate the P species in the solution. The flow rate in the IC was held constant at 0.5 ml/min while the concentration of the KOH eluent solution was ramped up from 1 mM to 40 mM over 20 minutes. This maximum KOH concentration was held constant for another 22 minutes followed by a ramp down to 1 mM over 8 minutes. The suppressor outlet of the IC was physically connected to a 1 ml/min nebulizer attached to the spray chamber (Scott model; quartz glass) of the Element 2 ICP-MS. The IC-PMS was operated at a sample gas flow rate of 1.1 ml/min, cool gas flowrate of 16 ml/min, and RF power of 1183 in medium resolution mode. Data were collected in the ICP-MS as chromatographs of 3 minutes duration (one minute for monitoring the pre-peak background, one minute for the peak, and one minute for monitoring post-peak background) for each P-species. The chromatographic data were smoothened with the OriginLab software, using the fast furrier transform filter with a points-of-window value of 5, and the peak area under the curve was used for quantification of phosphorus. Standards of the four P species (prepared from NaH 2 PO 2 .H 2 O (Thermo Fisher), Na 2 HPO 3 ·5H 2 O (Thermo Fisher), NaH 2 PO 4 (Thermo Fisher), and Na 4 P 2 O 7 (Sigma Aldrich)) with the similar matrix as used for the samples and ranging in concentrations from 0.2 ppb to 100 ppb were analyzed in the same way as the samples. The peak integrals of the standards were used to generate calibration curves, which were then used to quantify concentrations of the four P species in the solution. The detection limits of the IC-ICPMS were < 0.1 ppb for phosphite and phosphate, 0.1 ppb for hypophosphite, and 0.2 ppb for pyrophosphate. Phylogenetic tree Phosphite dehydrogenase genes were obtained from Boden et al. 6 . Briefly, this involved searching for homologs of experimentally-characterised PtxD enzymes in a sample of 865 genomes representing all major orders of the tree of life in GTDB release 95 71 . These sequences were aligned with MAFFT v. 7.4 72 , trimmed to remove gaps present in more than 70% of sequences at a given column with trimAl v1.2rev59 73 and the phylogeny reconstructed in MrBayes v3.2.7a 74 using default parameters plus a mixed amino acid model prior, a proportion of invariant sites and gamma-distributed site rates. Once converged, the resulting tree was rooted with the minimal ancestor deviation method 53 . To differentiate between phosphite dehydrogenases associated with dissimilatory phosphite oxidation which uses phosphite to produce energy and assimilatory phosphite oxidation which uses phosphite as a source of phosphorus (both to support microbial growth), each genome found to harbour a ptxD gene was interrogated for homologs of ptxE, ptdC, ptdG, ptdH, ptdI and ptdF using HMMER3 75 with the scoring thresholds of Ewens et al. 10 . Genomes found to harbour one or more of these homologs are assumed to use their ptxD genes for DPO based on the premise all organisms known to perform DPO harbour one or more of these genes 10 , 52 , 76 . Declarations Acknowledgements This work was financially supported by a Natural Environment Research Council (NERC < UKRI) Frontiers grant to EES (NE/V010824/1) and Marie Skłodowska-Curie Actions grant to ASB (EP/Y026497/1). We acknowledge Annabel Long and Oxana Magdysyuk for their help during IC-ICPMS and XRD analyses, respectively. For XRD analyses, we acknowledge the Engineering and Physical Science Research Council (EPSRC) Core Equipment Grant (EP/V034138/1). We greatly appreciate the Geological Survey of Western Australia and Perth Core Library for providing samples from the Dales Gorge Member and Marra Mamba Iron Formation. We are also grateful to the Rio Tinto core library in Perth for providing Joffre member core samples. The complete data for this study is available through the National Geoscience Data Centre of the British Geological Survey under https://doi.org/10.5285/dc1d80f5-db1e-42ef-9e07-b3980e43cd43 . In order to meet institutional and research funder open access requirements, any accepted manuscript arising shall be open access under a Creative Commons Attribution (CC BY) reuse licence with zero embargo. References Anders E, Ebihara M (1982) Solar-system abundances of the elements. 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PLOS Comput Biol 7:e1002195 Figueroa IA et al (2018) Metagenomics-guided analysis of microbial chemolithoautotrophic phosphite oxidation yields evidence of a seventh natural CO2 fixation pathway. Proc. Natl. Acad. Sci. 115, E92–E101 Additional Declarations There is NO Competing Interest. Supplementary Files Dataforadsorptiontest.xlsx Dataset 1 DataforPspeciationinBIF.xlsx Dataset 2 SupplementaryMaterials.docx Cite Share Download PDF Status: Published Journal Publication published 24 May, 2025 Read the published version in Nature Communications → 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. 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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-5118430","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Article","associatedPublications":[],"authors":[{"id":387131677,"identity":"4bc9a539-66a7-4e97-94d2-a54c1a4e6bb6","order_by":0,"name":"Abu Baidya","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA80lEQVRIie2RsWrDMBCGLwiSRUXreUlfQaZQyKRXsTFkMp49GCMvXvMCJo/hWUbgLjZZXbykBDp56N7S1sZDhxAl3TLom47jPv47DsBiuUvo4vQVzyX+dZVRIZw28/TNyhIf8v8obNcqdPZpCqu26uNYC1jpIxlzL4Jd5HG31Ag0CjZNo31Jt5zQzrBXR7nnlwqFCp+dLO89gBAI/bhsPB4arqoiRWDDqHz3YizMClehm2WSIOCUIvuFxCnFsJjbRQGBWjsSh6eNrH/8HN95VRjOXx/al09IUgYsdF9lshWMBW/HoTacf8YSrjzSYrFYLNf5BV+HTrndNoj2AAAAAElFTkSuQmCC","orcid":"https://orcid.org/0000-0001-8894-8813","institution":"University of St. Andrews","correspondingAuthor":true,"prefix":"","firstName":"Abu","middleName":"","lastName":"Baidya","suffix":""},{"id":387131678,"identity":"cd096b3f-e2a0-4481-b0f5-9d63793063bd","order_by":1,"name":"Joanne Boden","email":"","orcid":"https://orcid.org/0000-0003-0412-3668","institution":"University of St.Andrews","correspondingAuthor":false,"prefix":"","firstName":"Joanne","middleName":"","lastName":"Boden","suffix":""},{"id":387131679,"identity":"adc277f4-2311-426f-a57b-efa666b94c27","order_by":2,"name":"Yuhao Li","email":"","orcid":"","institution":"University of Alberta","correspondingAuthor":false,"prefix":"","firstName":"Yuhao","middleName":"","lastName":"Li","suffix":""},{"id":387131680,"identity":"585458c8-0fa4-4aed-9cfc-04fd7a84e254","order_by":3,"name":"Albertus Smith","email":"","orcid":"https://orcid.org/0000-0002-7918-5313","institution":"University of Johannesburg","correspondingAuthor":false,"prefix":"","firstName":"Albertus","middleName":"","lastName":"Smith","suffix":""},{"id":387131681,"identity":"230b1b31-42ad-4b5d-a947-bef496b394a3","order_by":4,"name":"Kurt Konhauser","email":"","orcid":"https://orcid.org/0000-0001-7722-7068","institution":"University of Alberta","correspondingAuthor":false,"prefix":"","firstName":"Kurt","middleName":"","lastName":"Konhauser","suffix":""},{"id":387131682,"identity":"001a0640-2369-4b98-acbc-740b8ded6556","order_by":5,"name":"Eva Stüeken","email":"","orcid":"https://orcid.org/0000-0001-6861-2490","institution":"University of St Andrews","correspondingAuthor":false,"prefix":"","firstName":"Eva","middleName":"","lastName":"Stüeken","suffix":""}],"badges":[],"createdAt":"2024-09-19 16:20:20","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-5118430/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-5118430/v1","draftVersion":[],"editorialEvents":[{"content":"https://doi.org/10.1038/s41467-025-59963-0","type":"published","date":"2025-05-24T04:00:00+00:00"}],"editorialNote":"","failedWorkflow":false,"files":[{"id":70902448,"identity":"7c5093c4-cfd2-4b8c-ad88-e21f59a1597f","added_by":"auto","created_at":"2024-12-09 06:06:13","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":201926,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eP(V) and P(III) sorption patterns from co-precipitation experiments.\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e(A) compiled P(V) sorption data from previous studies\u003csup\u003e28\u003c/sup\u003e are compared with new data (black and red). ‘Natural SW’ is the low-nutrient Sargasso seawater whereas ‘Artificial SW’ \u0026nbsp;is artificially prepared containing NaCl, Ca\u003csup\u003e2+\u003c/sup\u003e, and Mg\u003csup\u003e2+\u003c/sup\u003e and representing the Archean calcitic seawater. K\u003csub\u003eads\u003c/sub\u003e is the coefficient of sorption. Individual datapoints for artificial Seawater with 2.2 mM Si were not available, therefore the trend line (orange line) is reconstructed from the K\u003csub\u003eads\u003c/sub\u003e value\u003csup\u003e28\u003c/sup\u003e. Data for the Natural SW\u003csup\u003e28\u003c/sup\u003e show the effect of Si on sorption while other three datasets show the effect of salinity. (B) P(III) adsorption data generated in this study. P(III) adsorption is very limited compared to P(V) irrespective of solution chemistry. Error bars in A and B represent standard deviations of the means. For a direct comparison with P(V) sorption trend lines in A, those in B are not forced to go through origin. Two datapoints shown by hollow circles in B, are not considered for producing the trendline because of experimental error. (C) K\u003csub\u003eads\u003c/sub\u003e values used for P(V) and P(III) estimates in seawater around the Neoarchean-Paleoproterozoic boundary. As we used K\u003csub\u003eads\u003c/sub\u003e value to produce the trend line for P(V), it went through the origin. For a direct comparison, the trendline for P(III) is forced to go through the origin.\u003c/p\u003e","description":"","filename":"1.png","url":"https://assets-eu.researchsquare.com/files/rs-5118430/v1/3a7b921b9a113afe684446d4.png"},{"id":70901144,"identity":"885146cc-0106-4625-a145-a4a8e5f86242","added_by":"auto","created_at":"2024-12-09 05:42:13","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":106452,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eBox plots show the P speciation and total P contents in the BIF rocks.\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eDetectable amounts of P(III) are present in all the EDTA-NaOH extracts of the BIF samples and its concentration is lower than P(V). Total extracted amount of P-species (P(III), P(V), and pyrophosphate (PP(V)) are lower than total P in the solid samples.\u003c/p\u003e","description":"","filename":"2.png","url":"https://assets-eu.researchsquare.com/files/rs-5118430/v1/ed942feaa9fe82e6b7a2ad63.png"},{"id":70902054,"identity":"2341f420-e71d-44e9-93a0-46b0b3b0a681","added_by":"auto","created_at":"2024-12-09 05:58:13","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":223013,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eEstimated P(III) and P(V) concentrations in ocean at the onset of the GOE. \u003c/strong\u003eThe boxplots show the estimated concentrations of P(III) and P(V) in two extreme scenarios, (1) and (5), which provide the highest and lowest possible concentrations of P(III), respectively. In scenario 5, all the P(III) assumed to be metamorphic implying P(III) estimation in Precambrian seawater is not possible. The inset box plot shows the P(III) proportions of total dissolved inorganic P (P(III)+P(V)) in scenario 1. The green lines and arrows show the estimated P(V) concentrations in the Archean and around the Neoarchean-Paleoproterozoic boundary by previous geochemical\u003csup\u003e3,25,44–47\u003c/sup\u003e and genomic approaches\u003csup\u003e6\u003c/sup\u003e. The grey arrow is the estimation of P(III) in this study.\u003c/p\u003e","description":"","filename":"3.png","url":"https://assets-eu.researchsquare.com/files/rs-5118430/v1/c5459e838d95a85f5ae6426e.png"},{"id":70902059,"identity":"5c102b28-9022-4ad4-81e0-79c437588468","added_by":"auto","created_at":"2024-12-09 05:58:14","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":104458,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eTemporal evolution of key parameters related to microbial P-utilization in deep time.\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003ePanels (A) and (B) show the temporal evolution of O\u003csub\u003e2\u003c/sub\u003e in the atmosphere and primary productivity in the ocean, respectively\u003csup\u003e58,59\u003c/sup\u003e. Primary productivity increased around the GOE. (C) shows the amount of precipitated BIF, reaching a maximum between 2.65-2.40 Ga\u003csup\u003e33\u003c/sup\u003e. (D) shows the timing of microbial P utilization along with known estimates of P(V) in the Archean and Paleoproterozoic\u003csup\u003e6\u003c/sup\u003e.\u003c/p\u003e","description":"","filename":"4.png","url":"https://assets-eu.researchsquare.com/files/rs-5118430/v1/ab6ee9eca86fb26481c25d2b.png"},{"id":83376346,"identity":"e2f259af-dd56-46b0-8b99-c13f44d953b6","added_by":"auto","created_at":"2025-05-24 07:06:23","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":1493207,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-5118430/v1/c68ce8a5-5a93-4b52-9db2-081ac766e699.pdf"},{"id":70902052,"identity":"5f52e918-4689-4960-bbd3-1e8358834a38","added_by":"auto","created_at":"2024-12-09 05:58:13","extension":"xlsx","order_by":1,"title":"","display":"","copyAsset":false,"role":"supplement","size":34764,"visible":true,"origin":"","legend":"Dataset 1","description":"","filename":"Dataforadsorptiontest.xlsx","url":"https://assets-eu.researchsquare.com/files/rs-5118430/v1/e82594e04a01d9f5164a4725.xlsx"},{"id":70902057,"identity":"c40775e9-cc5d-47b2-a8c8-98f66f5301e9","added_by":"auto","created_at":"2024-12-09 05:58:14","extension":"xlsx","order_by":2,"title":"","display":"","copyAsset":false,"role":"supplement","size":13471,"visible":true,"origin":"","legend":"Dataset 2","description":"","filename":"DataforPspeciationinBIF.xlsx","url":"https://assets-eu.researchsquare.com/files/rs-5118430/v1/63d01c62b4fa3722f6b9fc38.xlsx"},{"id":70901157,"identity":"82e01779-1ffa-4dcc-8e3d-bbd841f7b26b","added_by":"auto","created_at":"2024-12-09 05:42:14","extension":"docx","order_by":3,"title":"","display":"","copyAsset":false,"role":"supplement","size":508535,"visible":true,"origin":"","legend":"","description":"","filename":"SupplementaryMaterials.docx","url":"https://assets-eu.researchsquare.com/files/rs-5118430/v1/2cdc47e74e48e1a1fdecc324.docx"}],"financialInterests":"There is \u003cb\u003eNO\u003c/b\u003e Competing Interest.","formattedTitle":"Geological and experimental evidence of bioavailable phosphite during the Great Oxygenation Event","fulltext":[{"header":"Introduction","content":"\u003cp\u003ePhosphorus is a key element of modern biology, playing a vital role in the formation of phospholipids, cellular energy exchange, and the storage of genomic information in RNA and DNA. Therefore, P must have been crucial to the origin and early diversification of life. However, among the major bioessential elements, P is the least abundant element in nature\u003csup\u003e\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e\u003c/sup\u003e. Its most common geological form, apatite, has low solubility in water, potentially making it the ultimate limiting nutrient in marine ecosystems\u003csup\u003e\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e\u003c/sup\u003e. Consequently, its availability throughout geologic time has likely affected the trajectory of biological evolution\u003csup\u003e\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e,\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e\u003c/sup\u003e.\u003c/p\u003e \u003cp\u003eModern microbial life is heavily dependent on phosphate (P(V)). However, reduced P species, such as phosphonates (molecules with P-C bonds where P is in a 3\u0026thinsp;+\u0026thinsp;redox state) and inorganic phosphite (P(III)), also serve as important P sources, especially in P(V)-limiting environments\u003csup\u003e\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e,\u003cspan citationid=\"CR67\" class=\"CitationRef\"\u003e67\u003c/span\u003e,\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e\u003c/sup\u003e. They are thus significant in the global P cycle. P(III) is up to 1000 times more soluble than P(V) in the presence of divalent metals\u003csup\u003e\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e\u003c/sup\u003e, suggesting that it may be more bioavailable in marine environments than P(V). P(III) is particularly important to modern microbial life for two reasons. First, it can be utilized as a P source for cellular uptake, a process known as assimilatory phosphite oxidation (APO)\u003csup\u003e\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e\u003c/sup\u003e. Second, it serves as an electron donor and energy source via dissimilatory phosphite oxidation (DPO)\u003csup\u003e\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e\u003c/sup\u003e. Although DPO is speculated to have evolved as early as 3.3 Ga\u003csup\u003e\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e\u003c/sup\u003e, a subsequent study\u003csup\u003e\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e\u003c/sup\u003e concluded that P(V) was the main P-source for microbial life at that time. The genes responsible for P(III) metabolism only became more widespread across the tree of life around the Neoarchean-Paleoproterozoic boundary (2.8\u0026ndash;2.2 Ga)\u003csup\u003e\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e\u003c/sup\u003e, i.e., just before and during the GOE at 2.50\u0026ndash;2.20 Ga\u003csup\u003e\u003cspan additionalcitationids=\"CR13\" citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e\u003c/sup\u003e. Nonetheless, the processes that might have triggered this shift in P-utilization by microbial life during this time remain unclear.\u003c/p\u003e \u003cp\u003eBoth abiotic and biotic processes can produce P(III) in modern environments\u003csup\u003e\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e,\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e\u003c/sup\u003e. In the Archean, the proposed abiotic sources of P(III) include; (1) the reduction of P(V) by iron redox chemistry during diagenesis and metamorphism\u003csup\u003e\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e,\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e\u003c/sup\u003e, (2) serpentinization\u003csup\u003e\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e\u003c/sup\u003e, (3) lightning-induced reduction of P(V)\u003csup\u003e\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e,\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e\u003c/sup\u003e, and (4) the dissolution of phosphide minerals, such as schreibersite ((Fe,Ni)\u003csub\u003e3\u003c/sub\u003eP), either delivered by meteorites and/or produced in soils during lightning strikes or in contact metamorphic rocks\u003csup\u003e\u003cspan additionalcitationids=\"CR22\" citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e\u003c/sup\u003e. Iron redox-controlled reduction of P(V), in particular, is facilitated by concomitant oxidation of Fe(II) or by molecular hydrogen (H\u003csub\u003e2\u003c/sub\u003e) under moderate to high-temperature metamorphic conditions\u003csup\u003e\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e,\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e\u003c/sup\u003e. Such processes may happen during serpentinization and high-grade metamorphism in the Archean\u003csup\u003e\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e,\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e\u003c/sup\u003e. Indeed, P(III) has been detected in Eoarchean high-grade metamorphosed BIF and carbonate rocks from the Isua Greenstone Belt and in some recent serpentinites\u003csup\u003e\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e,\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e\u003c/sup\u003e. The P(III) produced by these processes might have accumulated in significant amounts in the Archean ocean\u003csup\u003e\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e,\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e\u003c/sup\u003e, as it is kinetically stable, with a slow breakdown rate in the absence of biological activity (e.g., via DPO or APO), radical ions (e.g., \u0026middot;OH), and molecular oxygen (O\u003csub\u003e2\u003c/sub\u003e), having an estimated half-life of 0.6 Ma. However, data from P(III) in Precambrian sedimentary rocks are limited, and there is also no direct estimation of dissolved inorganic P(III) in Precambrian seawater\u003csup\u003e\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e\u003c/sup\u003e.\u003c/p\u003e \u003cp\u003eIndirect estimates of P(V) concentrations in the Precambrian oceans have been made using P(V) concentrations in rocks including carbonates\u003csup\u003e\u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e\u003c/sup\u003e, terrigenous marine sediments\u003csup\u003e\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e\u003c/sup\u003e, and BIFs\u003csup\u003e\u003cspan additionalcitationids=\"CR27\" citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e\u003c/sup\u003e. Among these methods, the approach based on P(V) in BIFs assumes that the latter precipitated as hydrous ferric oxyhydroxides (HFO) in the photic zone overlying the continental shelf\u003csup\u003e\u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e\u003c/sup\u003e. It integrates experimental data on the fractionation of phosphate between HFO and seawater, along with P(V) and Fe concentration in the BIFs\u003csup\u003e\u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e,\u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e\u003c/sup\u003e. The following equation is used to estimate oceanic P(V) concentrations: [P(V)\u003csub\u003ed\u003c/sub\u003e] = (1/K\u003csub\u003eads\u003c/sub\u003e) \u0026middot; (P(V)\u003csub\u003eads\u003c/sub\u003e/Fe\u003csup\u003e3\u0026thinsp;+\u003c/sup\u003e\u0026thinsp;\u003csub\u003eads\u003c/sub\u003e); where [P(V)\u003csub\u003ed\u003c/sub\u003e] is the concentration (in \u0026micro;M) of dissolved P(V); P(V)\u003csub\u003eads\u003c/sub\u003e and Fe\u003csup\u003e3\u0026thinsp;+\u003c/sup\u003e\u0026thinsp;\u003csub\u003eads\u003c/sub\u003e are the concentrations (\u0026micro;M) of adsorbed and precipitated P(V) and Fe on HFO, respectively; and K\u003csub\u003eads\u003c/sub\u003e (\u0026micro;M\u003csup\u003e‒\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e\u003c/sup\u003e) is the adsorption coefficient. Typically, K\u003csub\u003eads\u003c/sub\u003e (\u0026micro;M\u003csup\u003e‒\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e\u003c/sup\u003e) is experimentally determined, and the P(V)\u003csub\u003eads\u003c/sub\u003e/Fe\u003csup\u003e3\u0026thinsp;+\u003c/sup\u003e\u0026thinsp;\u003csub\u003eads\u003c/sub\u003e ratio is directly obtained from BIF analyses. However, this method has never been applied to estimate inorganic P(III) concentrations in the Precambrian ocean. By analogy to P(V), if K\u003csub\u003eads\u003c/sub\u003e (\u0026micro;M\u003csup\u003e‒\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e\u003c/sup\u003e) and P(III)\u003csub\u003eads\u003c/sub\u003e/Fe\u003csup\u003e3\u0026thinsp;+\u003c/sup\u003e\u0026thinsp;\u003csub\u003eads\u003c/sub\u003e values for P(III) are known, it would be possible to reconstruct the inorganic P(III) concentrations of the Archean-Proterozoic ocean.\u003c/p\u003e \u003cp\u003eWe conducted laboratory experiments to simulate the precipitation of BIFs as HFO in various solutions; including deionized (DI) water, 10-times diluted seawater, and seawater (artificially made containing 0.56 M NaCl, 0.055 M Ca, 0.045 M Mg with an ionic strength of 0.86 mol/L), with or without dissolved silica (Si) and varying concentrations of P(V) and P(III) (see Materials and Methods for details). The initial iron concentration was 0.2 mM Fe(II), and dissolved Si concentrations were 0 mM, 0.22 mM, or 2.2 mM, with the highest concentrations reflecting estimated concentrations of the Archean-Paleoproterozic\u003csup\u003e\u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e,\u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e30\u003c/span\u003e\u003c/sup\u003e. Adsorption tests were performed at a pH of 8\u0026thinsp;\u0026plusmn;\u0026thinsp;0.2 following previous studies\u003csup\u003e\u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e,\u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e30\u003c/span\u003e\u003c/sup\u003e, and adsorption coefficients (K\u003csub\u003eads\u003c/sub\u003e) were determined. We also measured concentrations of P-species including P(III), P(V), pyrophosphate (PP(V)), and total P and Fe concentrations in Neoarchean and Paleoproterozoic (2.60\u0026ndash;2.46 Ga) BIF samples from five rock formations located in Western Australia (Pilbara Craton) and South Africa (Transvaal Supergroup). We then used the P(III) concentrations of these BIF samples and the experimentally determined K\u003csub\u003eads\u003c/sub\u003e of P(III) to estimate the phosphite concentrations in the oceans during the GOE. Finally, we explore possible reasons for the shift in microbial P-utilization during the GOE.\u003c/p\u003e"},{"header":"Results","content":"\u003cp\u003eIn our experiments, nearly all (~\u0026thinsp;99%) of the dissolved Fe(II) precipitated as HFO irrespective of solution chemistry. By contrast, the removal of P-species was variable depending on the specific solution chemistry. When P-species were removed, they were likely incorporated into the crystal lattices of HFO and adsorbed onto its surface (hereafter referred to as \u0026ldquo;sorption\u0026rdquo; to describe the total amount of P(V) or P(III) removed), consistent with previous studies\u003csup\u003e\u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e,\u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e30\u003c/span\u003e\u003c/sup\u003e. The extent of sorption is characterized by K\u003csub\u003eads\u003c/sub\u003e, with higher values indicating stronger sorption and more effective removal from the solution.\u003c/p\u003e \u003cp\u003eThe experiments suggest that salinity has some control on P(V) sorption onto HFO (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003eA). We observed less sorption of P(V) in DI water (K\u0026thinsp;=\u0026thinsp;0.011) compared to 10-fold diluted artificial seawater (K\u0026thinsp;=\u0026thinsp;0.039) (0.22 mM Si; hereafter DiluSeaSi) and concentrated artificial seawater (2.2 mM Si; hereafter SeaSi) (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003eA). Other studies have reported a K\u003csub\u003eads\u003c/sub\u003e value of 0.021 for P(V) sorption in artificial seawater having similar compositions as in our experiments\u003csup\u003e\u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e\u003c/sup\u003e. This value is lower than that in DiluSeaSi, suggesting stronger sorption in DiluSeaSi, which may be due to less dissolved Si in this solution. Previous studies have demonstrated that dissolved Si reduces P(V) sorption in natural seawater and in 0.56M NaCl, for example K\u003csub\u003eads\u003c/sub\u003e values for P(V) in these solutions are 0.338 and 0.064, respectively, while the addition of 2.2 mM of Si reduces the K\u003csub\u003eads\u003c/sub\u003e values to 0.008 and 0.002, respectively\u003csup\u003e\u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e,\u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e30\u003c/span\u003e\u003c/sup\u003e.\u003c/p\u003e \u003cp\u003eImportantly, our experiments show that sorption of P(III) onto HFO is very limited, although solution chemistry does have some influence. The K\u003csub\u003eads\u003c/sub\u003e values for P(III) adsorption in DI water, DiluSeaSi, and SeaSi are 0.0003, 0.0011, and 0.0008, respectively, indicating the least sorption in DI water and highest sorption in DilSeaSi (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003eB). This pattern is similar to what is observed for P(V), suggesting that salinity similarly affect P(III) sorption. Notably, a direct comparison between P(V) and P(III) adsorption coefficients suggests that P(V) is adsorbed 36, 35, and 26 times more strongly than P(III) in DI water, DilSeaSi, and SeaSi, respectively (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003eA-C). These values imply more efficient removal of P(V) from solution by HFO compared to P(III) under all conditions.\u003c/p\u003e \u003cp\u003eKey geological, mineralogical, and compositional features of the studied BIF are summarized in Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e. These rocks formed between 2.60 to 2.44 Ga and experienced burial metamorphism at temperatures ranging from 110-170\u003csup\u003eo\u003c/sup\u003eC for the South African BIF\u003csup\u003e\u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e31\u003c/span\u003e\u003c/sup\u003e and 160-360\u003csup\u003eo\u003c/sup\u003eC for the Western Australian BIF\u003csup\u003e\u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e32\u003c/span\u003e\u003c/sup\u003e (further details are avail in the \u003cspan refid=\"Sec4\" class=\"InternalRef\"\u003eMaterials and Methods\u003c/span\u003e section). XRD data reveals variable proportions of quartz, magnetite, hematite, siderite, ankerite with minor amount of pyrite, riebeckite, and stilponomelane (Figure S2 in Supplementary Material). The Fe contents of the samples range from 27 to \u0026gt;\u0026thinsp;50%. The Joffre Member has comparatively low total P ranging from 20 to 110 ppm, while the other four formations contain higher total P levels, ranging from 20 to 3720 ppm (Fig.\u0026nbsp;2).\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003e \u003cem\u003e(A) compiled P(V) sorption data from previous studies\u003c/em\u003e \u003csup\u003e \u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e \u003c/sup\u003e \u003cem\u003eare compared with new data (black and red). \u0026lsquo;Natural SW\u0026rsquo; is the low-nutrient Sargasso seawater whereas \u0026lsquo;Artificial SW\u0026rsquo; is artificially prepared containing NaCl, Ca\u003c/em\u003e\u003csup\u003e\u003cem\u003e2+\u003c/em\u003e\u003c/sup\u003e, \u003cem\u003eand Mg\u003c/em\u003e\u003csup\u003e\u003cem\u003e2+\u003c/em\u003e\u003c/sup\u003e \u003cem\u003eand representing the Archean calcitic seawater. K\u003c/em\u003e\u003csub\u003e\u003cem\u003eads\u003c/em\u003e\u003c/sub\u003e \u003cem\u003eis the coefficient of sorption. Individual datapoints for artificial Seawater with 2.2 mM Si were not available, therefore the trend line (orange line) is reconstructed from the K\u003c/em\u003e\u003csub\u003e\u003cem\u003eads\u003c/em\u003e\u003c/sub\u003e \u003cem\u003evalue\u003c/em\u003e\u003csup\u003e\u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e\u003c/sup\u003e. \u003cem\u003eData for the Natural SW\u003c/em\u003e\u003csup\u003e\u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e\u003c/sup\u003e \u003cem\u003eshow the effect of Si on sorption while other three datasets show the effect of salinity. (B) P(III) adsorption data generated in this study. P(III) adsorption is very limited compared to P(V) irrespective of solution chemistry. Error bars in A and B represent standard deviations of the means. For a direct comparison with P(V) sorption trend lines in A, those in B are not forced to go through origin. Two datapoints shown by hollow circles in B, are not considered for producing the trendline because of experimental error. (C) K\u003c/em\u003e\u003csub\u003e\u003cem\u003eads\u003c/em\u003e\u003c/sub\u003e \u003cem\u003evalues used for P(V) and P(III) estimates in seawater around the Neoarchean-Paleoproterozoic boundary. As we used K\u003c/em\u003e\u003csub\u003e\u003cem\u003eads\u003c/em\u003e\u003c/sub\u003e \u003cem\u003evalue to produce the trend line for P(V), it went through the origin. For a direct comparison, the trendline for P(III) is forced to go through the origin.\u003c/em\u003e\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab1\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eGeological and chemical features of the BIF samples\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"11\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c7\" colnum=\"7\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c8\" colnum=\"8\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c9\" colnum=\"9\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c10\" colnum=\"10\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c11\" colnum=\"11\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eLocation\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eAge\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eMax. Meta. Temp\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eNo. of Samples\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003eMineralogy (XRD)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c6\"\u003e \u003cp\u003eP(III) (ppm)*\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c7\"\u003e \u003cp\u003eP(V) (ppm)*\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c8\"\u003e \u003cp\u003eTotal P (ppm)\u003csup\u003e#\u003c/sup\u003e\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c9\"\u003e \u003cp\u003eTotal Fe (wt%)\u003csup\u003e#\u003c/sup\u003e\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c10\"\u003e \u003cp\u003eExtraction yield (%)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"1\" nameend=\"c11\" namest=\"c11\"\u003e\u0026nbsp;\u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eKuruman -Gamohaan Iron Formation\u003csup\u003e$\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e2.55\u0026ndash;2.44 Ga\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e170\u003csup\u003eo\u003c/sup\u003eC\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eqtz, mag, hem, sid, anke, stilp(?), py(?)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.22\u0026ndash;0.37\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e1.59\u0026ndash;28.4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e70\u0026ndash;950\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e26.8\u0026ndash;44.8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003e1.96\u0026ndash;4.53\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"1\" nameend=\"c11\" namest=\"c11\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eJoffre Base Member\u003csup\u003e\u0026pound;\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e2.46 Ga\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e200-360\u003csup\u003eo\u003c/sup\u003eC\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eqtz, mag, hem, sid, anke, py, riebe, stilp(?)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.02\u0026ndash;0.05\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e2.21\u0026ndash;15.4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e20\u0026ndash;110\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e27.4\u0026ndash;34.7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003e11.3\u0026ndash;37.6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"1\" nameend=\"c11\" namest=\"c11\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eDales Gorge Member\u003csup\u003e\u0026pound;\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e2.49\u0026ndash;2.46 Ga\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e200- 360\u003csup\u003eo\u003c/sup\u003eC\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eqtz, mag, hem, anke, py, riebe, stilp(?)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.15\u0026ndash;0.56\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e1.59\u0026ndash;60.6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e20\u0026ndash;3720\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e29.6 - \u0026gt;50\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003e1.65\u0026ndash;12.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"1\" nameend=\"c11\" namest=\"c11\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eMarra Mamba Formation\u003csup\u003e\u0026pound;\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e2.6 Ga\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e200-360\u003csup\u003eo\u003c/sup\u003eC\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eqtz, mag, sid, anke, py, stilp(?)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.23\u0026ndash;0.34\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e3.32\u0026ndash;11.6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e160\u0026ndash;1090\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e30.4 - \u0026gt;50\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003e0.95\u0026ndash;2.34\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"1\" nameend=\"c11\" namest=\"c11\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"11\" nameend=\"c11\" namest=\"c1\"\u003e \u003cp\u003e* P(III) and P(V) concentration in EDTA-NaOH extracts; # concentration in solid; Minerals with \u0026lsquo;?\u0026rsquo; mark are possibly present. \u003cspan\u003e$\u003c/span\u003e-South Africa, \u0026pound;-Western Australia; qtz- quartz, mag- magnetite, hem- hematite, sid- siderite, anke- ankerite, stilp- stilpnomelane, py- pyrite, riebe- riebeckite\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003eFigure 2 summarizes the P speciation data from the EDTA-NaOH extracts and total P contents. The EDTA-NaOH solution extracted only a small portion (1\u0026ndash;38%) of total amount of P present in the solid samples; however, these yields are consistent with those reported in previous studies\u003csup\u003e\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e\u003c/sup\u003e. The associated uncertainties in seawater P(III) reconstructions are discussed below. All the studied samples contain P(III), with the highest concentrations found in the Kuruman Iron Formation and the lowest in the Joffre Member. The concentration of P(III) is consistently lower than that of P(V) in the extraction solutions.\u003c/p\u003e"},{"header":"Discussions","content":"\u003cp\u003eEstimation of P(III) in seawater around the GOE\u003c/p\u003e \u003cp\u003eThe K\u003csub\u003eads\u003c/sub\u003e values obtained from our sorption experiments, combined with P-speciation data in BIFs, allow us to estimate P(III) and P(V) concentrations in seawater around the Neoarchean-Paleoproterozoic boundary. This estimation relies on several assumptions: First, we presume that the studied BIFs precipitated as HFO. The precipitation of BIF is debated, with proposed precursors including HFO\u003csup\u003e\u003cspan citationid=\"CR33\" class=\"CitationRef\"\u003e33\u003c/span\u003e\u003c/sup\u003e, greenalite\u003csup\u003e\u003cspan citationid=\"CR34\" class=\"CitationRef\"\u003e34\u003c/span\u003e\u003c/sup\u003e, green rust\u003csup\u003e\u003cspan citationid=\"CR35\" class=\"CitationRef\"\u003e35\u003c/span\u003e\u003c/sup\u003e, magnetite\u003csup\u003e\u003cspan citationid=\"CR36\" class=\"CitationRef\"\u003e36\u003c/span\u003e\u003c/sup\u003e, and siderite\u003csup\u003e\u003cspan citationid=\"CR37\" class=\"CitationRef\"\u003e37\u003c/span\u003e\u003c/sup\u003e. Among these, HFO is the most significant globally\u003csup\u003e\u003cspan citationid=\"CR33\" class=\"CitationRef\"\u003e33\u003c/span\u003e\u003c/sup\u003e. If the primary mineral was instead composed of Fe(II)\u003csup\u003e\u003cspan citationid=\"CR34\" class=\"CitationRef\"\u003e34\u003c/span\u003e\u003c/sup\u003e, the observed Fe(III) phases would have to be of secondary origin. However, the complete absence of primary Fe(III) is unlikely, given hydrological constraints\u003csup\u003e\u003cspan citationid=\"CR38\" class=\"CitationRef\"\u003e38\u003c/span\u003e\u003c/sup\u003e, independent evidence of oxic conditions in Neoarchean surface waters\u003csup\u003e\u003cspan citationid=\"CR39\" class=\"CitationRef\"\u003e39\u003c/span\u003e,\u003cspan citationid=\"CR40\" class=\"CitationRef\"\u003e40\u003c/span\u003e\u003c/sup\u003e, highly fractionated Fe isotopes in these BIFs indicating depositional and post-depositional redox cycling\u003csup\u003e\u003cspan citationid=\"CR41\" class=\"CitationRef\"\u003e41\u003c/span\u003e\u003c/sup\u003e, and the incontestable fact that a biosphere capable of oxidizing dissolved Fe(II) existed at that time\u003csup\u003e\u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e\u003c/sup\u003e. Hence HFO, as a precursor of preserved Fe(III) minerals in BIFs, likely formed in shallow-water settings\u003csup\u003e\u003cspan citationid=\"CR33\" class=\"CitationRef\"\u003e33\u003c/span\u003e\u003c/sup\u003e, while Fe(II) precipitation was dominant in the deep ocean proximal to hydrothermal Fe-sources\u003csup\u003e\u003cspan citationid=\"CR42\" class=\"CitationRef\"\u003e42\u003c/span\u003e\u003c/sup\u003e and before upwelling onto the continental shelf\u003csup\u003e\u003cspan citationid=\"CR43\" class=\"CitationRef\"\u003e43\u003c/span\u003e\u003c/sup\u003e. Second, the amount of P(III) detected in the EDTA-NaOH extraction cannot be used directly to calculate the total sorbed P(III) during BIF precipitation without considering two issues: (1) the preferential extraction of P(III) over P(V) by the EDTA-NaOH solution, due to the former\u0026rsquo;s higher solubility\u003csup\u003e\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e\u003c/sup\u003e, and (2) the post-depositional transformation of P(V) into P(III) facilitated by iron redox chemistry\u003csup\u003e\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e,\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e\u003c/sup\u003e.\u003c/p\u003e \u003cp\u003ePrevious studies have reported low extraction yields (\u0026lt;\u0026thinsp;3%) of P species in EDTA-NaOH solutions from solid rocks\u003csup\u003e\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e\u003c/sup\u003e. To the best of our knowledge, no study to date has specifically examined whether P(III) can be preferentially leached. Therefore, we have considered two extreme possibilities: (1) the ratio of P species in BIF is the same as in the EDTA-NaOH extract, and (2) complete extraction of BIF-hosted P(III) into EDTA-NaOH solution. These scenarios help bracket the potential P(III) concentrations in the BIF. To address the post-depositional transformation of P(V) into P(III), we considered three possible cases: (1) no metamorphic P(III), meaning that all measured P(III) represents primary sorbed inorganic P(III) during BIF precipitation; (2) a mixture of sorbed and metamorphic phosphite; and (3) all the P(III) is metamorphic in origin. In case (3), it is impossible to estimate the original P(III) concentration from BIF precipitation, as it implies that none of the detected P(III) was originally sorbed to BIF.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab2\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 2\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eEstimates of ocean phosphite and phosphate concentrations (\u0026micro;M)\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"9\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c7\" colnum=\"7\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c8\" colnum=\"8\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c9\" colnum=\"9\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/th\u003e \u003cth align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e \u003cp\u003eScenario 1\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"2\" nameend=\"c5\" namest=\"c4\"\u003e \u003cp\u003eScenario 2a/2b\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"2\" nameend=\"c7\" namest=\"c6\"\u003e \u003cp\u003eScenario 3\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"2\" nameend=\"c9\" namest=\"c8\"\u003e \u003cp\u003eScenario 4a/4b\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003eLocations\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e \u003cp\u003e1. P species ratio in BIF is same as in EDTA-NaOH extract \u003c/p\u003e \u003cp\u003e2. Metamorphic phosphite is none\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c5\" namest=\"c4\"\u003e \u003cp\u003e1. P species ratio in BIF is same as in EDTA-NaOH extract \u003c/p\u003e \u003cp\u003e2. Metamorphic phosphite using exp. yield\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c7\" namest=\"c6\"\u003e \u003cp\u003e1. 100% phosphite is extracted from BIF\u003c/p\u003e \u003cp\u003e2. Metamorphic phosphite is none\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c9\" namest=\"c8\"\u003e \u003cp\u003e1. 100% phosphite is extracted from BIF\u003c/p\u003e \u003cp\u003e2. Metamorphic phosphite using exp. yield\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eP(III)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eP(V)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eP(III)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eP(V)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eP(III)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003eP(V)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003eP(III)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003eP(V)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003eKuruman-Gamohaan\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003e0.024\u0026ndash;0.075\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003e0.013\u0026ndash;0.352\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.000*-0.054\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.014-0.354\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003e0.001\u0026ndash;0.002\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003e0.016\u0026ndash;0.354\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003eENP\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e0.016-0.354\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.024-0.075\u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.013-0.352\u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e0.001-0.002\u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e0.016-0.354\u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003eJoffre\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003e0.000*-0.002\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003e0.005\u0026ndash;0.029\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.000\u003csup\u003ea\u003c/sup\u003e*\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.005-0.029\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003e0.000*\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003e0.005\u0026ndash;0.012\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003eENP\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e0.005-0.012\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.000*-0.001\u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.005-0.029\u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e0.000*\u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e0.005-0.029\u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003eDales Gorge\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003e0.017\u0026ndash;0.142\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003e0.002\u0026ndash;0.921\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.000*-0.020\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.003-0.927\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003e0.001\u0026ndash;0.002\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003e0.004\u0026ndash;0.927\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003eENP\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e0.003-0.927\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.017-0.142\u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.002-0.921\u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e0.001*-0.002\u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e0.003-0.927\u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003eMarra Mamba\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003e0.058\u0026ndash;0.165\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003e0.024-0.300\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.000*-0.033\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.025-0.307\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003e0.001\u0026ndash;0.002\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003e0.027\u0026ndash;0.307\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003eENP\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e0.027-0.307\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.058-0.165\u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.024-0.300\u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e0.001-0.002\u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e0.027-0.307\u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"9\" nameend=\"c9\" namest=\"c1\"\u003e \u003cp\u003ea: Scenario 2a/4a- Experimental yield of Herschy et al.\u003csup\u003e\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e\u003c/sup\u003e; b: Scenario 2b/4b - Experimental yield of Baidya et al.\u003csup\u003e\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e\u003c/sup\u003e; ENP: estimation not possible (all phosphite are metamorphic like Scenario 5); *: values 0.000 means the concentration is less than 0.5 nM.\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003eTogether, these permutations lead to five scenarios to translate the measured P(III) and P(V) in the BIFs into seawater P(III) and P(V) concentrations (Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e). We note that Scenario 5, where all P(III) is metamorphic in origin, is excluded from the compilation as here the calculated seawater value would be zero. Scenarios 2 and 4 are further subdivided, depending on the metamorphic constraint on P(V) reduction into P(III) in ferruginous diagenetic and metamorphic environments\u003csup\u003e\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e,\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e\u003c/sup\u003e. The highest estimated values for P(V) range from 0.01 to 0.93 \u0026micro;M with minor variations across the different scenarios (Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e, Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e3\u003c/span\u003e). These estimates are lower than estimates based on carbonates\u003csup\u003e\u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e\u003c/sup\u003e, hydrothermal vent precipitates\u003csup\u003e\u003cspan citationid=\"CR42\" class=\"CitationRef\"\u003e42\u003c/span\u003e,\u003cspan citationid=\"CR44\" class=\"CitationRef\"\u003e44\u003c/span\u003e\u003c/sup\u003e, as well as experiments and modelling\u003csup\u003e\u003cspan citationid=\"CR45\" class=\"CitationRef\"\u003e45\u003c/span\u003e\u003c/sup\u003e but similar to predictions from several other geochemical estimates based on BIF samples\u003csup\u003e\u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e,\u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e\u003c/sup\u003e and genomic estimates\u003csup\u003e\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e\u003c/sup\u003e (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e3\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eTo estimate post-depositional metamorphic P(III), we used published experimental yields of metamorphic and diagenetic P(V) reduction in ferruginous conditions\u003csup\u003e\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e,\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e\u003c/sup\u003e. Baidya et al.\u003csup\u003e\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e\u003c/sup\u003e conducted several experiments at 350\u003csup\u003eo\u003c/sup\u003eC, which is close to the highest metamorphic temperature experienced by the studied BIF\u003csup\u003e\u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e32\u003c/span\u003e\u003c/sup\u003e, and reported a yield of 0.075%. They also demonstrated that magnetite inhibits the reduction of P(V) to P(III) even in the presence of H\u003csub\u003e2\u003c/sub\u003e at 350 \u003csup\u003eo\u003c/sup\u003eC\u003csup\u003e\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e\u003c/sup\u003e. Given that magnetite is consistently present in the BIF samples (Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e), metamorphic P(III) may be limited, making Scenario 4a and Scenario (5) - where all BIF-bound P(III) is metamorphic - less plausible. Among the remaining scenarios, number (1), which assumes the same ratio of P-species in BIF samples as in the EDTA-NaOH extract and no additional P(III) formation during diagenesis and metamorphism, provides the highest possible concentrations of P(III) in seawater, ranging from 1 to 165 nM (Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e). Importantly, the estimated P(III) and P(V) concentrations in Scenario 1 suggest that P(III) could have constituted 5\u0026ndash;88% of total dissolved inorganic P (P(V)\u0026thinsp;+\u0026thinsp;P(III)) in seawater at the onset of the GOE (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e3\u003c/span\u003e).\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eShift in microbial P-utilization around the GOE\u003c/p\u003e \u003cp\u003ePhylogenetic studies suggest that microbial communities began utilizing P(III) between 2.6\u0026ndash;2.2 Ga\u003csup\u003e\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e\u003c/sup\u003e. If this is the case, there must have been sufficient P(III) in seawater to facilitate this evolutionary shift. So far, there are limited data on P(III) concentration in modern environments and its relation to microbial growth. P(III) was not detected in the tropical Atlantic Ocean\u003csup\u003e\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e\u003c/sup\u003e but has been reported in geothermal pools (0.06\u0026thinsp;\u0026plusmn;\u0026thinsp;0.02 \u0026micro;M)\u003csup\u003e\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e\u003c/sup\u003e, lakes (0.01\u0026ndash;0.71 \u0026micro;M)\u003csup\u003e\u003cspan citationid=\"CR48\" class=\"CitationRef\"\u003e48\u003c/span\u003e,\u003cspan citationid=\"CR49\" class=\"CitationRef\"\u003e49\u003c/span\u003e\u003c/sup\u003e, rivers (0.08\u0026ndash;0.9 \u0026micro;M)\u003csup\u003e\u003cspan citationid=\"CR50\" class=\"CitationRef\"\u003e50\u003c/span\u003e\u003c/sup\u003e, and ponds (0.14\u0026ndash;2.90 \u0026micro;M)\u003csup\u003e\u003cspan citationid=\"CR50\" class=\"CitationRef\"\u003e50\u003c/span\u003e\u003c/sup\u003e. In Taihu Lake, concentrations of 10 \u0026micro;M P(III) may support phytoplankton growth, while 30\u0026ndash;100 \u0026micro;M may lead to algal blooms\u003csup\u003e\u003cspan citationid=\"CR51\" class=\"CitationRef\"\u003e51\u003c/span\u003e\u003c/sup\u003e. Furthermore, experimental studies suggest that P(III)-dependent microbial growth is possible at 50 \u0026micro;M P(III)\u003csup\u003e\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e\u003c/sup\u003e. These concentrations are higher than our estimated concentration of P(III) in seawater at the onset of the GOE, suggesting either local enrichment of P(III) above those calculated averages or lower thresholds of P(III) for the growth of microbial life during the GOE.\u003c/p\u003e \u003cp\u003eUnderstanding whether P(III) was used for APO or DPO at the onset of GOE is crucial. Experimental studies have found that higher P(III) (0.1\u0026ndash;10 \u0026micro;M) are required for DPO compared to APO (10 \u0026micro;M P(III))\u003csup\u003e\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e,\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e,\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e,\u003cspan citationid=\"CR52\" class=\"CitationRef\"\u003e52\u003c/span\u003e\u003c/sup\u003e. We analysed a previously published phylogenetic tree of \u003cem\u003eptxD\u003c/em\u003e\u003csup\u003e\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e\u003c/sup\u003e, which emerged between 2.3\u0026ndash;2.2 Ga\u003csup\u003e\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e\u003c/sup\u003e, and is used in both APO and DPO (see Materials and Method section for further details). The tree reveals that homologs from bacteria performing DPO formed a monophyletic group with a posterior probability of 100, suggesting that DPO evolved once and subsequently radiated into different species. When rooted with minimal ancestor deviation from Tria et al.\u003csup\u003e\u003cspan citationid=\"CR53\" class=\"CitationRef\"\u003e53\u003c/span\u003e\u003c/sup\u003e, the most parsimonious explanation for the evolution of \u003cem\u003eptxD\u003c/em\u003es is that the earliest \u003cem\u003eptxD\u003c/em\u003es from 2.3\u0026ndash;2.2 Ga were associated with APO, and DPO-associated homologs evolved later (see Figure S1 in Supplementary Material). In the alternative scenario where the first \u003cem\u003eptxD\u003c/em\u003es were used for DPO, two switches from DPO-associated \u003cem\u003eptxD\u003c/em\u003e to APO-associated \u003cem\u003eptxD\u003c/em\u003e would be required, which is less parsimonious \u0026ndash; and therefore less likely \u0026ndash; than the one switch required if the first \u003cem\u003eptxD\u003c/em\u003e was associated with APO. Furthermore, a different gene, \u003cem\u003eptxB\u003c/em\u003e, which imports P(III) for APO, evolved between ~\u0026thinsp;2.6 and 2.3 Ga, pre-dating the \u003cem\u003eptxD\u003c/em\u003es. Hence, we suggest that microbes were utilizing P(III) for APO by the onset of the GOE. The low estimated P(III) concentration in seawater at that time (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e3\u003c/span\u003e) supports this explanation.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eWe posit that increased primary productivity and the preferential removal of P(V) compared to P(III) due to BIF precipitation created P(V)-depleted environments in the surface ocean, which in turn facilitated the evolution of genes responsible for microbial P(III) utilization at the onset of the GOE. Major BIFs were precipitated between 2.65\u0026ndash;2.40 Ga\u003csup\u003e\u003cspan citationid=\"CR33\" class=\"CitationRef\"\u003e33\u003c/span\u003e\u003c/sup\u003e, just prior to, and concomitant with, the GOE. Dissolved Si is known to reduce the effect of P(V) sorption onto HFO during BIF precipitation, while dissolved Ca and Mg may mitigate the effect of Si\u003csup\u003e\u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e,\u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e30\u003c/span\u003e\u003c/sup\u003e, leading to variable removal of P(V) from seawater during BIF precipitation depending on Si, Ca\u003csup\u003e2+\u003c/sup\u003e, and Mg\u003csup\u003e2+\u003c/sup\u003e concentrations. Nevertheless, the presence of P in BIF samples worldwide\u003csup\u003e\u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e\u003c/sup\u003e suggests that BIF precipitation indeed removed a portion of the dissolved P(V) from the ocean at the onset of GOE, particularly if biomass-induced accumulation of P(V) was limited\u003csup\u003e\u003cspan citationid=\"CR54\" class=\"CitationRef\"\u003e54\u003c/span\u003e\u003c/sup\u003e. This aligns with higher estimated concentration of dissolved P(V) (1-4000 \u0026micro;M) in the early Archean oceans, as evidenced by several geochemical estimates\u003csup\u003e\u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e,\u003cspan citationid=\"CR42\" class=\"CitationRef\"\u003e42\u003c/span\u003e,\u003cspan citationid=\"CR45\" class=\"CitationRef\"\u003e45\u003c/span\u003e\u003c/sup\u003e and sub-micromolar concentrations at the onset of the GOE based on genomic\u003csup\u003e\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e\u003c/sup\u003e and geochemical estimates\u003csup\u003e\u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e,\u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e,\u003cspan citationid=\"CR47\" class=\"CitationRef\"\u003e47\u003c/span\u003e\u003c/sup\u003e. In contrast, our data show that BIF precipitation had a limited impact on dissolved P(III) due to its minimal sorption onto HFO. Furthermore, it is generally believed that primary productivity was limited in the Archean due to a range of factors, including limited availability of electron donors (e.g., Fe\u003csup\u003e2+\u003c/sup\u003e and H\u003csub\u003e2\u003c/sub\u003e) necessary for anoxygenic photosynthesis\u003csup\u003e\u003cspan citationid=\"CR47\" class=\"CitationRef\"\u003e47\u003c/span\u003e,\u003cspan citationid=\"CR55\" class=\"CitationRef\"\u003e55\u003c/span\u003e\u003c/sup\u003e, less emergent continental landmass and thus less habitable space for microbial mats\u003csup\u003e\u003cspan citationid=\"CR56\" class=\"CitationRef\"\u003e56\u003c/span\u003e\u003c/sup\u003e, and higher UV radiation due to the absence of an ozone layer\u003csup\u003e\u003cspan citationid=\"CR57\" class=\"CitationRef\"\u003e57\u003c/span\u003e\u003c/sup\u003e. With the expansion of oxygenic photosynthesis, which utilizes water as electron donor, primary productivity might have increased ten-fold compared to early Archean times\u003csup\u003e\u003cspan citationid=\"CR55\" class=\"CitationRef\"\u003e55\u003c/span\u003e\u003c/sup\u003e. Such an extreme increase in biological productivity likely depleted the oceans in nutrient elements, particularly P(V). If so, during the GOE, there might have been environments with very limited P(V), akin to modern P(V)-depleted environments where microbial life uses alternative P species such as P(III)\u003csup\u003e\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e,\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e\u003c/sup\u003e. We therefore suggest that microbial competition for P(V) may have triggered the biological production and utilization of reduced P at the onset of the GOE.\u003c/p\u003e \u003cp\u003eIn summary, our results provide the first estimate of maximum dissolved P(III) concentrations (1-165 nM) around the time of the GOE, which could have constituted 5\u0026ndash;88% of the total dissolved inorganic P (P(V)\u0026thinsp;+\u0026thinsp;P(III)) at that time. The stark contrast between P(V) and P(III) sorption on HFO identified by our experiments, as well as the observed prevalence of P(III) compounds in P(V)-depleted settings in the modern ocean, uncovers a potential linkage between the expansion of oxygenated surface waters, the accumulation of iron oxide minerals on continental shelves, and the radiation of novel P-metabolisms across the tree of life. Our findings thus reveal a previously unknown factor contributing to the co-evolution of Earth and early life.\u003c/p\u003e"},{"header":"Materials and Methods","content":"\u003cp\u003eAdsorption experiments\u003c/p\u003e \u003cp\u003eThe laboratory experiments simulated the co-precipitation of banded iron formations (BIFs) as hydrous ferric oxyhydroxides (HFO) and inorganic phosphate or phosphite in deionized water, 10-times diluted seawater, and seawater. Acid-washed (1\u0026ndash;2 M HCl) and baked (500\u0026deg;C) glass containers, acid- and hot water-washed centrifuge tubes, syringe, and pipette tips were used during all stages of the experiments, subsequent sampling, and analysis. FeCl\u003csub\u003e2\u003c/sub\u003e.4H\u003csub\u003e2\u003c/sub\u003eO (Sigma Aldrich), NaH\u003csub\u003e2\u003c/sub\u003ePO\u003csub\u003e4\u003c/sub\u003e (Thermo Fisher), NaH\u003csub\u003e2\u003c/sub\u003ePO\u003csub\u003e3\u003c/sub\u003e\u0026middot;5H\u003csub\u003e2\u003c/sub\u003eO (Thermo Fisher), and Na\u003csub\u003e2\u003c/sub\u003eSiO\u003csub\u003e3\u003c/sub\u003e (Thermo Fisher) were dissolved in deionized water for preparing stock solutions of 20 mM Fe\u003csup\u003e2+\u003c/sup\u003e, 1 mM phosphate and phosphite, and 22 mM Si. The Fe\u003csup\u003e2+\u003c/sup\u003e solution was freshly prepared before each set of experiments to avoid significant oxidation under the present atmosphere. Artificial seawater containing 0.56 M NaCl (Sigma Aldrich), 55 mM Ca\u003csup\u003e2+\u003c/sup\u003e (CaCl\u003csub\u003e2\u003c/sub\u003e, Thermo Fisher), and 45 mM Mg\u003csup\u003e2+\u003c/sup\u003e (MgCl\u003csub\u003e2\u003c/sub\u003e.6H\u003csub\u003e2\u003c/sub\u003eO, Thermo Fisher) with an ionic strength of 0.86 mol/L was prepared by dissolving the salts in deionized water. This composition represents Precambrian Si-bearing calcitic sea\u003csup\u003e\u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e\u003c/sup\u003e. Stock solutions were diluted to produce 10 ml experimental solutions containing 0.2 mM Fe\u003csup\u003e2+\u003c/sup\u003e and 0\u0026ndash;28 \u0026micro;M phosphate or phosphite with or without Si of 0.22 mM (10x-diluted seawater) or 2.2 mM (seawater). As an example, to prepare a 2 \u0026micro;M phosphite-bearing artificial sweater solution, we mixed 200 \u0026micro;L of 100 \u0026micro;M phosphite, 100 \u0026micro;L of 20 mM Fe\u003csup\u003e2+\u003c/sup\u003e, and 9.7 mL artificial seawater. The experimental solutions were then mixed with dilute dissolved NaOH (variable combinations of 0.01 M, 0.025 M, and 0.05 M) to oxidize Fe\u003csup\u003e2+\u003c/sup\u003e and precipitate HFO. A constant pH of 8\u0026thinsp;\u0026plusmn;\u0026thinsp;0.2 was maintained for half an hour and adjusted with dilute NaOH and HCl (variable combinations of 0.0.01 M, 0.025 M, and 0.05 M). We kept track of the total amount of NaOH and HCl added to each solution to accurately determine the dilution factors at the end of the experiments. The pH was monitored using a pH probe (Hanna Instruments), which was calibrated before every set of experiments. All experiments were performed as doublets or triplets. After the experiments, the solutions were filtered with previously washed (10 ml deionized water) 0.2 \u0026micro;m PTFE hydrophilic (Fisher) filters. We discarded the first 3ml of the solution after filtering to avoid any contamination from the filter and collected 1ml, which was immediately acidified with 2% ultrapure HNO\u003csub\u003e3\u003c/sub\u003e.\u003c/p\u003e \u003cp\u003eAll the experimental solutions were diluted 10\u0026ndash;100 times with 2% HNO\u003csub\u003e3\u003c/sub\u003e, and the concentrations of \u003csup\u003e\u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e31\u003c/span\u003e\u003c/sup\u003eP and \u003csup\u003e\u003cspan citationid=\"CR56\" class=\"CitationRef\"\u003e56\u003c/span\u003e\u003c/sup\u003eFe were measured with a Thermo Scientific Element 2 high resolution inductively coupled plasma mass spectrometer (ICP-MS) equipped with an auto sampler (Elemental Scientific Inc.), a 0.1 ml/min nebulizer, and a Scott spray chamber. Standards containing 0.01 \u0026micro;M to 2.5 \u0026micro;M of Fe and phosphate or phosphite were prepared by dissolving FeCl\u003csub\u003e3\u003c/sub\u003e and NaH\u003csub\u003e2\u003c/sub\u003ePO\u003csub\u003e4\u003c/sub\u003e or NaH\u003csub\u003e2\u003c/sub\u003ePO\u003csub\u003e3\u003c/sub\u003e\u0026middot;5H\u003csub\u003e2\u003c/sub\u003eO (Thermo Fisher, same salt used for experiments) in the same saline matrix as that of the samples. The ICP-MS was operated at a sample gas flow rate of 1 ml/min, cool gas flowrate of 16 ml/min, and RF power of 1250. The \u003csup\u003e\u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e31\u003c/span\u003e\u003c/sup\u003eP and \u003csup\u003e\u003cspan citationid=\"CR56\" class=\"CitationRef\"\u003e56\u003c/span\u003e\u003c/sup\u003eFe intensities of the sample solutions were measured in medium resolution mode, and concentrations were calculated offline with respect to the standards. Each sample and standard were measured twice, and the average intensities were used for assessment. A few standards were measured at the beginning of the ICP-MS sequence as well as in the middle and at the end to quantify the drift of the ICP-MS and corrections were made when it was required.\u003c/p\u003e \u003cp\u003eBanded Iron Formation rock analysis\u003c/p\u003e\n\u003ch3\u003eSample location and geology\u003c/h3\u003e\n\u003cp\u003eThe Marra Mamba Iron Formation samples were collected from drill core WRL-1, while the Dales Gorge Member were collected from drill core DGM-1. Both were provided by the Perth Core Library of the Geological Survey of Western Australia. The Joffre Member were obtained from core sample DD98SGP001 via the Rio Tinto core library in Perth. The Gamohaan and Kuruman Formation samples were recovered from drill core DI1, originally drilled and stored by a mining company (Gefco) at Derby, approximately half way between the towns of Kuruman and Danielskuil in the Northern Cape Province of South Africa\u003csup\u003e\u003cspan citationid=\"CR60\" class=\"CitationRef\"\u003e60\u003c/span\u003e\u003c/sup\u003e.The sample from the Gamohaan Formation was taken from the uppermost Tsineng Member\u003csup\u003e\u003cspan citationid=\"CR61\" class=\"CitationRef\"\u003e61\u003c/span\u003e\u003c/sup\u003e, whereas the samples from the Kuruman Formation were taken from four different members throughout its stratigraphy.\u003c/p\u003e \u003cp\u003eThe Hamersley Group comprises about 2.5 Km of consecutive sedimentary and volcanic rocks located within the ca. 80,000 km\u003csup\u003e\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e\u003c/sup\u003e Hamersley Province of the Pilbara craton in Western Australia. It comprises five IF units, in ascending order the 2.60 Ga Marra Mamba Iron Formation, the 2.48 Ga Dales Gorge Member of the Bockman Iron Formation, the 2.46 Ga Joffre Member of the Brockman Iron Formation, the 2.45 Ga Weeli Wolli Formation and the uppermost Bolgeeda Iron Formation which is approximated at 2.44 Ga\u003csup\u003e\u003cspan citationid=\"CR62\" class=\"CitationRef\"\u003e62\u003c/span\u003e\u003c/sup\u003e. Metamorphic grade for the Hamersley Basin units have been interpreted from the widespread presence of the minerals prehenite, pumpellyite, epidote and actinolite, which corresponds to a maximum temperature range between 200-360\u003csup\u003eo\u003c/sup\u003eC\u003csup\u003e\u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e32\u003c/span\u003e,\u003cspan citationid=\"CR63\" class=\"CitationRef\"\u003e63\u003c/span\u003e\u003c/sup\u003e.\u003c/p\u003e \u003cp\u003eThe Gamohaan Formation is approximately 110 m thick and is the uppermost formation of the approximately 1600 m thick Campbellrand Subgroup of the lower Ghaap Group of the Griqualand West region of the Transvaal Supergroup of southern Africa\u003csup\u003e\u003cspan citationid=\"CR61\" class=\"CitationRef\"\u003e61\u003c/span\u003e\u003c/sup\u003e. Although the Campbellrand Subgroup is dominated by stromatolitic dolostone and limestone, the Gamohaan Formation contains a BIF (originally described as an Fe-rich banded chert), called the Tsineng Member, at its top\u003csup\u003e\u003cspan citationid=\"CR61\" class=\"CitationRef\"\u003e61\u003c/span\u003e\u003c/sup\u003e that was sampled for this study. The depositional age range for the upper Campbellr and Subgroup is approximately 2.55 to 2.52 Ga\u003csup\u003e\u003cspan citationid=\"CR64\" class=\"CitationRef\"\u003e64\u003c/span\u003e\u003c/sup\u003e. The Kuruman Formation is the lower formation of the Asbesheuwels Subgroup, which directly overlies the Campbellrand Subgroup\u003csup\u003e\u003cspan citationid=\"CR60\" class=\"CitationRef\"\u003e60\u003c/span\u003e,\u003cspan citationid=\"CR65\" class=\"CitationRef\"\u003e65\u003c/span\u003e\u003c/sup\u003e. Together with the overlying Griquatown Formation, the Asbesheuwels Subgroup comprises 385 to 1000 m of continuous micritic and granular iron formation\u003csup\u003e\u003cspan citationid=\"CR60\" class=\"CitationRef\"\u003e60\u003c/span\u003e\u003c/sup\u003e. The depositional age range for the Kuruman Formation is approximately 2.48 to 2.44 Ga\u003csup\u003e\u003cspan citationid=\"CR64\" class=\"CitationRef\"\u003e64\u003c/span\u003e\u003c/sup\u003e. Together with the correlative Penge Formation in the Transvaal region\u003csup\u003e\u003cspan citationid=\"CR64\" class=\"CitationRef\"\u003e64\u003c/span\u003e\u003c/sup\u003e, it is the oldest iron formation of the Transvaal Supergroup. Other than the Griquatown Formation, the Transvaal Supergroup in the Griqualand West region contains two more iron formations in the approximately 2.43 Ga Koegas Subgroup\u003csup\u003e\u003cspan citationid=\"CR66\" class=\"CitationRef\"\u003e66\u003c/span\u003e\u003c/sup\u003e (Schr\u0026ouml;der et al., 2011) and four iron formations interbedded with manganese beds in the approximately 2.41 Ga Hotazel Formation\u003csup\u003e\u003cspan citationid=\"CR67\" class=\"CitationRef\"\u003e67\u003c/span\u003e,\u003cspan citationid=\"CR68\" class=\"CitationRef\"\u003e68\u003c/span\u003e\u003c/sup\u003e .Estimated burial temperatures of the Kuruman Formation is 100-150\u003csup\u003eo\u003c/sup\u003eC\u003csup\u003e\u003cspan citationid=\"CR69\" class=\"CitationRef\"\u003e69\u003c/span\u003e\u003c/sup\u003e. A similar burial temperature is inferred for the Gamohaan Formation as it directly underlies the Kuruman Formation.\u003c/p\u003e\n\u003ch3\u003eSolid characterization using powder X-ray diffraction (PXRD)\u003c/h3\u003e\n\u003cp\u003eThe powdered rock samples were loaded into 0.5 mm or 0.7 mm capillary tubes and sealed for XRD analysis. The PXRD patterns were recorded on a STOE STADIP diffractometer using Mo Kα1 radiation at room temperature from 2.5\u003csup\u003eo\u003c/sup\u003e to 37\u0026deg; (2θ) with a scan rate of 2.5-3.0\u003csup\u003eo\u003c/sup\u003e (2θ)/step in capillary Debye-Scherrer mode. The PXRD data were compared to solids in the Inorganic Crystal Structure Database (ICSD) for phase identification using the Crystal Diffract software (version 6.9.3).\u003c/p\u003e\n\u003ch3\u003eWhole rock analysis\u003c/h3\u003e\n\u003cp\u003eApproximately 0.30\u0026ndash;0.60 g of powder from each of the samples was sent to Australian Laboratory Services (ALS) in Dublin, Ireland, for whole-rock geochemical characterisation using their method ME-MS-61r of four-acid digestion (HCl, HNO\u003csub\u003e3\u003c/sub\u003e, HF, HClO\u003csub\u003e4\u003c/sub\u003e) followed by ICP-MS and -AES analyses. Reproducibility was assessed with rock standards OREAS-45d, OREAS-905 and MRGeo-08, and with sample replicates. It was found to be 5% or better for P and Fe.\u003c/p\u003e \u003cdiv id=\"Sec8\" class=\"Section2\"\u003e \u003ch2\u003eQuantification of P species in the extraction solution and in the BIFs\u003c/h2\u003e \u003cp\u003eAn aliquot (ca. 0.2\u0026ndash;0.25 gm) of the powdered samples was treated with an Ethylenediaminetetraacetic acid-sodium hydroxide (0.05M EDTA and 0.25M NaOH) solution\u003csup\u003e\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e\u003c/sup\u003e maintaining a solid:solution ratio of 1:10 for 14\u0026ndash;15 hours. Na\u003csub\u003e2\u003c/sub\u003eEDTA (Sigma Aldrich) salt and 10M NaOH solution (Thermo Scientific) were dissolved in deionized water to make the EDTA-NaOH solution mixture. Acid- and hot-water washed 10 ml Falcon tubes were used during the extraction procedure. The solutions were then centrifuged at 3000 rpm for 15\u0026ndash;20 minutes. In most cases, the solution was transparent after centrifuging, suggesting the precipitation of all the extracted Fe. In a few cases, the solution was yellow to orange, which suggested the presence of dissolved Fe. Such solutions were further treated with 1M NaOH to precipitate all the Fe, which is essential for the P speciation measurements using the subsequent Ion Chromatograph (IC)-ICPMS analysis\u003csup\u003e\u003cspan citationid=\"CR70\" class=\"CitationRef\"\u003e70\u003c/span\u003e\u003c/sup\u003e. This is because excess dissolved iron may precipitate as oxides in the anion separation column of the IC and bind phosphate by adsorption within the column, thereby impacting analytical quality.\u003c/p\u003e \u003cp\u003eFour phosphorus species, namely hypophosphite, phosphite, phosphate, and pyrophosphate were analyzed using the IC-ICPMS set-up of Baidya and St\u0026uuml;eken\u003csup\u003e\u003cspan citationid=\"CR70\" class=\"CitationRef\"\u003e70\u003c/span\u003e\u003c/sup\u003e. In this IC-ICPMS set-up, a Thermo Scientific Dionex ICS-6000 IC equipped with a Dionex AS-AP autosampler, a 25 mm Dionex IonPac AS17-C separation column (2 mm bore), a 25mm Dionex IonPac AG17-G guard column (2 mm bore), and a Dionex ADRS-600 (2 mm) suppressor were used to separate the P species in the solution. The flow rate in the IC was held constant at 0.5 ml/min while the concentration of the KOH eluent solution was ramped up from 1 mM to 40 mM over 20 minutes. This maximum KOH concentration was held constant for another 22 minutes followed by a ramp down to 1 mM over 8 minutes. The suppressor outlet of the IC was physically connected to a 1 ml/min nebulizer attached to the spray chamber (Scott model; quartz glass) of the Element 2 ICP-MS. The IC-PMS was operated at a sample gas flow rate of 1.1 ml/min, cool gas flowrate of 16 ml/min, and RF power of 1183 in medium resolution mode. Data were collected in the ICP-MS as chromatographs of 3 minutes duration (one minute for monitoring the pre-peak background, one minute for the peak, and one minute for monitoring post-peak background) for each P-species. The chromatographic data were smoothened with the OriginLab software, using the fast furrier transform filter with a points-of-window value of 5, and the peak area under the curve was used for quantification of phosphorus. Standards of the four P species (prepared from NaH\u003csub\u003e2\u003c/sub\u003ePO\u003csub\u003e2\u003c/sub\u003e.H\u003csub\u003e2\u003c/sub\u003eO (Thermo Fisher), Na\u003csub\u003e2\u003c/sub\u003eHPO\u003csub\u003e3\u003c/sub\u003e\u0026middot;5H\u003csub\u003e2\u003c/sub\u003eO (Thermo Fisher), NaH\u003csub\u003e2\u003c/sub\u003ePO\u003csub\u003e4\u003c/sub\u003e (Thermo Fisher), and Na\u003csub\u003e4\u003c/sub\u003eP\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e7\u003c/sub\u003e (Sigma Aldrich)) with the similar matrix as used for the samples and ranging in concentrations from 0.2 ppb to 100 ppb were analyzed in the same way as the samples. The peak integrals of the standards were used to generate calibration curves, which were then used to quantify concentrations of the four P species in the solution. The detection limits of the IC-ICPMS were \u0026lt;\u0026thinsp;0.1 ppb for phosphite and phosphate, 0.1 ppb for hypophosphite, and 0.2 ppb for pyrophosphate.\u003c/p\u003e \u003cp\u003ePhylogenetic tree\u003c/p\u003e \u003cp\u003ePhosphite dehydrogenase genes were obtained from Boden et al.\u003csup\u003e\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e\u003c/sup\u003e. Briefly, this involved searching for homologs of experimentally-characterised PtxD enzymes in a sample of 865 genomes representing all major orders of the tree of life in GTDB release 95\u003csup\u003e71\u003c/sup\u003e. These sequences were aligned with MAFFT v. 7.4\u003csup\u003e72\u003c/sup\u003e, trimmed to remove gaps present in more than 70% of sequences at a given column with trimAl v1.2rev59\u003csup\u003e73\u003c/sup\u003e and the phylogeny reconstructed in MrBayes v3.2.7a\u003csup\u003e\u003cspan citationid=\"CR74\" class=\"CitationRef\"\u003e74\u003c/span\u003e\u003c/sup\u003e using default parameters plus a mixed amino acid model prior, a proportion of invariant sites and gamma-distributed site rates. Once converged, the resulting tree was rooted with the minimal ancestor deviation method\u003csup\u003e\u003cspan citationid=\"CR53\" class=\"CitationRef\"\u003e53\u003c/span\u003e\u003c/sup\u003e. To differentiate between phosphite dehydrogenases associated with dissimilatory phosphite oxidation which uses phosphite to produce energy and assimilatory phosphite oxidation which uses phosphite as a source of phosphorus (both to support microbial growth), each genome found to harbour a ptxD gene was interrogated for homologs of ptxE, ptdC, ptdG, ptdH, ptdI and ptdF using HMMER3\u003csup\u003e75\u003c/sup\u003e with the scoring thresholds of Ewens et al.\u003csup\u003e\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e\u003c/sup\u003e. Genomes found to harbour one or more of these homologs are assumed to use their ptxD genes for DPO based on the premise all organisms known to perform DPO harbour one or more of these genes\u003csup\u003e\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e,\u003cspan citationid=\"CR52\" class=\"CitationRef\"\u003e52\u003c/span\u003e,\u003cspan citationid=\"CR76\" class=\"CitationRef\"\u003e76\u003c/span\u003e\u003c/sup\u003e.\u003c/p\u003e \u003c/div\u003e"},{"header":"Declarations","content":"\u003ch2\u003eAcknowledgements\u003c/h2\u003e \u003cp\u003eThis work was financially supported by a Natural Environment Research Council (NERC\u0026thinsp;\u0026lt;\u0026thinsp;UKRI) Frontiers grant to EES (NE/V010824/1) and Marie Skłodowska-Curie Actions grant to ASB (EP/Y026497/1). We acknowledge Annabel Long and Oxana Magdysyuk for their help during IC-ICPMS and XRD analyses, respectively. For XRD analyses, we acknowledge the Engineering and Physical Science Research Council (EPSRC) Core Equipment Grant (EP/V034138/1). We greatly appreciate the Geological Survey of Western Australia and Perth Core Library for providing samples from the Dales Gorge Member and Marra Mamba Iron Formation. We are also grateful to the Rio Tinto core library in Perth for providing Joffre member core samples. The complete data for this study is available through the National Geoscience Data Centre of the British Geological Survey under \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.5285/dc1d80f5-db1e-42ef-9e07-b3980e43cd43\u003c/span\u003e\u003cspan address=\"10.5285/dc1d80f5-db1e-42ef-9e07-b3980e43cd43\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e. In order to meet institutional and research funder open access requirements, any accepted manuscript arising shall be open access under a Creative Commons Attribution (CC BY) reuse licence with zero embargo.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eAnders E, Ebihara M (1982) Solar-system abundances of the elements. Geochim Cosmochim Acta 46:2363\u0026ndash;2380\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eTyrrell T (1999) The relative influences of nitrogen and phosphorus on oceanic primary production. Nature 400:525\u0026ndash;531\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eReinhard CT et al (2017) Evolution of the global phosphorus cycle. Nature 541:386\u0026ndash;389\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003ePlanavsky NJ et al (2010) The evolution of the marine phosphate reservoir. 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Mol Biol Evol 30:772\u0026ndash;780\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eCapella-Guti\u0026eacute;rrez S, Silla-Mart\u0026iacute;nez JM, Gabald\u0026oacute;n T (2009) trimAl: a tool for automated alignment trimming in large-scale phylogenetic analyses. Bioinformatics 25:1972\u0026ndash;1973\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eRonquist F et al (2012) MrBayes 3.2: Efficient Bayesian phylogenetic inference and model choice across a large model space. Syst Biol 61:539\u0026ndash;542\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eEddy SR (2011) Accelerated profile HMM searches. PLOS Comput Biol 7:e1002195\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eFigueroa IA et al (2018) Metagenomics-guided analysis of microbial chemolithoautotrophic phosphite oxidation yields evidence of a seventh natural CO2 fixation pathway. \u003cem\u003eProc. Natl. Acad. Sci.\u003c/em\u003e 115, E92\u0026ndash;E101\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":true,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":true,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"nature-portfolio","isNatureJournal":true,"hasQc":false,"allowDirectSubmit":false,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"","title":"Nature Portfolio","twitterHandle":"","acdcEnabled":false,"dfaEnabled":false,"editorialSystem":"ejp","reportingPortfolio":"","inReviewEnabled":true,"inReviewRevisionsEnabled":false},"keywords":"","lastPublishedDoi":"10.21203/rs.3.rs-5118430/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-5118430/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003ePhosphorus (P) availability throughout geologic time has likely impacted the co-evolution of life and Earth\u0026rsquo;s environments. Phylogenetic data suggest that phosphate was the primary P-source for microbial life during the Archean, but phosphite, a reduced form of P, became relatively more important leading up towards the Great Oxygenation Event (GOE) in the Neoarchean to Paleoproterozoic. However, seawater phosphite concentrations during this time, and the potential processes driving this shift in P utilization, are unknown. Here, we performed laboratory experiments simulating the precipitation of banded iron formations (BIFs) as hydrous ferric oxyhydroxides (HFO) in deionized water, diluted seawater, and seawater containing phosphate and phosphite. We also measured phosphite concentrations in BIF samples from four Neoarchean-Paleoproterozoic formations. Our results indicate a weaker removal of phosphite compared to phosphate by HFO irrespective of solution chemistry. Paired with measurements of phosphite (up to 0.05\u0026ndash;250 ppm) in BIFs, we estimate that seawater phosphite concentration at the onset of the GOE could have reached up to 0.01\u0026ndash;0.17 \u0026micro;M. We propose that the preferential removal of phosphate relative to phosphite by HFO, coupled with microbial competition for P facilitated by oxygenic photosynthesis, might have created phosphate-depleted environments, prompting life to exploit alternative P sources such as phosphite.\u003c/p\u003e","manuscriptTitle":"Geological and experimental evidence of bioavailable phosphite during the Great Oxygenation Event","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2024-12-09 05:42:08","doi":"10.21203/rs.3.rs-5118430/v1","editorialEvents":[],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"nature-communications","isNatureJournal":true,"hasQc":false,"allowDirectSubmit":false,"externalIdentity":"NCOMMS","sideBox":"Learn more about [Nature Communications](http://www.nature.com/ncomms/)","snPcode":"","submissionUrl":"https://mts-ncomms.nature.com/","title":"Nature Communications","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"ejp","reportingPortfolio":"Nature Communications","inReviewEnabled":true,"inReviewRevisionsEnabled":false}}],"origin":"","ownerIdentity":"dc57fece-5dd6-48a0-8ebe-44cce0ceb1a6","owner":[],"postedDate":"December 9th, 2024","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"published-in-journal","subjectAreas":[{"id":41256980,"name":"Earth and environmental sciences/Biogeochemistry/Element cycles"},{"id":41256981,"name":"Earth and environmental sciences/Planetary science/Astrobiology"},{"id":41256982,"name":"Earth and environmental sciences/Planetary science/Geochemistry"}],"tags":[],"updatedAt":"2025-05-24T07:06:14+00:00","versionOfRecord":{"articleIdentity":"rs-5118430","link":"https://doi.org/10.1038/s41467-025-59963-0","journal":{"identity":"nature-communications","isVorOnly":false,"title":"Nature Communications"},"publishedOn":"2025-05-24 04:00:00","publishedOnDateReadable":"May 24th, 2025"},"versionCreatedAt":"2024-12-09 05:42:08","video":"","vorDoi":"10.1038/s41467-025-59963-0","vorDoiUrl":"https://doi.org/10.1038/s41467-025-59963-0","workflowStages":[]},"version":"v1","identity":"rs-5118430","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-5118430","identity":"rs-5118430","version":["v1"]},"buildId":"qtupq5eGEP_6zYnWcrvyt","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}