Physicochemical Characterization of Feces and Pseudofeces Production by Bivalve Marine Mollusks Cultivated in the South Atlantic

Physicochemical Characterization of Feces and Pseudofeces Production by Bivalve Marine Mollusks Cultivated in the South Atlantic | 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 Research Article Physicochemical Characterization of Feces and Pseudofeces Production by Bivalve Marine Mollusks Cultivated in the South Atlantic Eliziane Silva, Carlos Henrique Araújo de Miranda Gomes, Luis Hamilton Pospissil Garbossa, and 2 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-5397899/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract In order to comprehend carrying capacity of environments conducive to mollusk cultivation, investigations into the chemical properties and determination of biodeposit production rates are imperative. The aim of our study was to conduct physicochemical characterizing the biodeposits production from marine bivalve mollusks in the North and South bays of Santa Catarina Island, observing the rate of production of feces and pseudofeces and C, N e P the biodeposits of Perna perna and Crassostrea gigas . Feces and pseudofeces were gathered utilizing an individual chamber system, facilitating controlled seawater flow at a rate of 500 mL.min⁻¹. Organisms were individually accommodated within these chambers, and biodeposits were amassed over a two-hour period. A total of 130 animals were utilized for the study (60 individuals of C. gigas and 70 individuals of P. perna ), across 13 collections, between December 2021 and April 2022. We quantified the production rates of feces, pseudofeces, total phosphorus, total organic carbon, and total nitrogen. The results provide insight into the influence of the physicochemical characteristics of the environment on the production rates of feces and pseudofeces, as well as the concentrations of carbon, phosphorus, and nitrogen in the biodeposits produced by the animals cultivated at each sampling site. The outcomes of this study facilitate the determination of biodeposit production rates and the chemical characterization of feces and pseudofeces from scientific species, thereby advancing research concerning environmental carrying capacity and striving for the sustainability of malacoculture in Santa Catarina. oyster mussel biodeposits physicochemical characterization Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 1. Introduction In 2020, global fisheries and aquaculture production totaled 214 million tons, encompassing both the capture and cultivation of aquatic animals, which comprised 83.17%, and algae, which constituted the remaining 16.83%, as reported by the Food and Agriculture Organization - FAO of the United Nations (FAO, 2022). When focusing solely on world aquaculture production, it constituted approximately 57.29% of the total global fishing and aquaculture production, with an estimated value of 264.8 billion dollars from aquatic animal trade. Marine and coastal aquaculture contributed 68.1 million tons to global aquaculture production (FAO, 2022). In marine and coastal aquaculture, the cultivation of marine mollusks holds significant importance. China stands as the world’s largest producer, with its production volume surpassing the combined total of all other mollusk-producing countries. In the American continent, the production of marine mollusks amounted to 688,077 tons live weight (FAO, 2022). In Brazil, the Brazilian Institute of Geography and Statistics (IBGE) reported a production of approximately 8,739 tons of marine mollusks in 2022, including varieties such as oysters, scallops, and mussels. Notably, Santa Catarina accounts for approximately 95% of Brazil’s total production of marine bivalve mollusks (IBGE, 2023). The farming of marine bivalve mollusks is widely regarded as sustainable due to their ability to filter particles from the water without requiring additional feed (Bayne, 2017 ; Gosling, 2003 ; Sakamaki et al., 2022 ). Despite its significant advantages, particularly in terms of protein production and its direct impact on production costs, mollusk farming can also have negative environmental consequences. These may arise from the release and sedimentation of organic matter generated by these animals. The extent of these impacts is closely tied to the hydrodynamics of the farming locations, which can result in chemical alterations in the sediments, especially in areas with relatively stable hydrodynamic conditions (Sakamaki and Nishimura, 2007 ). Farming at high mussel production densities can have significant impacts on the surrounding environment, particularly through the accumulation of biodeposits such as faeces and pseudofeces (Chamberlain, 2002 ). The release of nitrogen and phosphorus from mollusk excretion and biodeposition at the seafloor directly affects nutrient cycling in the vicinity of farming areas (Cranford et al., 2009 ). Furthermore, in addition to altered nitrogen and phosphorus loads resulting from biodeposit accumulation, there may be an increase in oxygen consumption due to bacterial growth associated with the oxidation of organic matter in the environment. Consequently, this can lead to oxygen depletion in the sediment and in the layers close to the seafloor (Filgueira et al., 2015; Grant et al., 2012 ; Weise et al., 2009 ). The production of feces and pseudofeces is closely related to the presence of particles in the water, which directly affects the physiological rates in animals, thus influencing the duration of physiological processes. Assessing the rates of clarification, filtration, and production of feces and pseudofeces aids in comprehending the environmental conditions in which mollusks are cultivated. In addition to the challenge of biodeposition, high-density mollusk farming can lead to a reduction in planktonic biomass around the farming area and alter its composition. This reduction in the biomass directly impacts the mollusks’ diet, potentially resulting in lower growth rates (Cranford et al., 2009 ; Lima et al., 2023 ). Moreover, aside from environmental concerns, conflicts arise over the utilization of marine areas. There is ongoing debate on how to manage coastal zones to foster global development while balancing economic, societal, and environmental needs. This entails the pursuit of efficient resource utilization and ensuring accessibility for various marine activities (Buck and Langan, 2017 ; O’Shea et al., 2022 ). Understanding the physical and chemical interactions within the environment where mollusk farms are established is pivotal in assessing the impact of mollusk farming on the environment (Sakamaki et al., 2022 ; Silva et al., 2019 ; Suplicy, 2004 ). In this context, research focusing on characterizing compounds present in both water and biodeposits is essential for extrapolating results and generating data regarding the carrying capacity of the environment (Chamberlain, 2002 ; Locher et al., 2021 ; Newell, 2006 , 2004 ; Walker et al., 2014 ; Weise et al., 2009 ). In the state of Santa Catarina, mollusk farming predominantly takes place in the North and South Bays of Santa Catarina Island. However, few studies have assessed the production of biodeposits by farmed bivalve mollusks in these areas. As a result, both the general population and the scientific community have raised concerns regarding the carrying capacity of these environments (Nascimento et al., 2022 ; Silva et al., 2019 ; Suplicy, 2004 ). Studies aimed at determining parameters related to farming are essential for developing policies that promote the activity, provide income for those involved, and mitigate irreversible environmental impacts (O’Shea et al., 2022 ; Sakamaki et al., 2022 ; Souza et al., 2022 ). To promote sustainable shellfish farming, it is crucial to investigate the environmental dynamics related to mollusk farming (Sakamaki et al., 2022 ; Vasechkina, 2023 ). Our study aimed to assess the physiological rates linked to biodeposit production and to chemically characterize these biodeposits in terms of total organic carbon, total nitrogen, and total phosphorus. This was conducted for the species Crassostrea gigas (Thunberg, 1793) and Perna perna (Linnaeus, 1758) in both the North Bay and South Bay of Santa Catarina Island. 2. material and methods 2.1 Study area The study was conducted at two sites within Santa Catarina Island Bay: one in the North compartment, Sambaqui (SBQ, 27°29′22.6″S 48°32′16.9″W), and the other in the South compartment, Caieira da Barra do Sul (CBS, 27°48′58.3″S 48°33′50.0″W) (Fig. 1 ). 2.2 Biodeposit collection system and animals studied Biodeposits were collected using a system (Fig. 2 ) similar to that used by Hawkins et al. ( 1996 ) and adapted by Nascimento et al. ( 2022 ), in which the animals were placed in individual chambers (Fig. 3 ). The system was installed at the collection sites (SBQ and CBS), and seawater was pumped in close proximity to the system’s attachment using a submersible pump. The system had 12 chambers with a maximum volume of 4 L. Each of the 10 chambers was assigned an individual mollusk for the collection of feces and pseudofeces (Fig. 4 ). The flow rate of the chambers was controlled at 500 mL.min − 1 . A total of 130 animals were used in the study (60 of the C. gigas species and 70 of the P. perna species). The mollusks used were cultivated at their respective collection sites and were harvested on the same day the data was collected. Adult animals with the following height measurements were selected for the study: mean height of 92.6 ± 7.5 mm for C. gigas and 76.5 ± 4.1 mm for P. perna in SBQ and 83.6 ± 6.9 mm for C. gigas and 81.9 ± 4.1 mm for P. perna in CBS. Biometrics were carried out according to the method outlined by Galtsoff ( 1964 ). Thirteen collections were made at the end of the experiment, on different days between December 2021 and April 2022, including four trials of P. perna biodeposit production and three of C. gigas at the CBS site. For the SBQ site, we conducted three biodeposit production trials with P. perna and three with C. gigas . The sampling days were non-consecutive; therefore, water quality parameters were analyzed to detect potential differences between the collection sites. 2.3 Physicochemical characterization of biodeposits The acclimatization period for the animals in the chambers was defined as the time taken until each animal initially produced biodeposits (approximately 30 min for P. perna and ranged from 1 to 2 h for C. gigas ). Following the acclimatization period, the animals’ feces and pseudofeces were collected over a 2-h period. Out of the system’s 12 chambers, four received one individual each, and the collected material (both feces and pseudofeces) was analyzed for its chemical composition, specifically total organic carbon (TOC), total nitrogen (TN), and total phosphorus (TP) concentrations. Another six chambers each received one individual randomly, and the samples from these chambers were used to measure the rate of biodeposit production. The remaining two chambers did not receive any individuals. Figure 5 outlines the procedure for each test conducted. The feces and pseudofeces samples, generated for the analysis of TOC, TN, and TP in each test, were collected and stored in plastic containers with a capacity of 200 mL. After adding the collected biodeposits, the container was topped up to 200 mL with distilled water and refrigerated until the samples were processed the following day. The TOC, TN, and TP values for biodeposit production from one animal over 2 h, using seawater in the system described in Section 2.2, were established. These values were then standardized to production per hour to simplify data comparison with other analyzed parameters. TOC was analyzed according to the method described by Strickland and Parsons ( 1972 ), with a detection limit of 0.2 mg.L − 1 ; TN was analyzed according to APHA 4500 N C, with a detection limit of 2.0 mg.L − 1 ; and TP was analyzed according to APHA 4500-P E, with detection limits of 0.014 and 0.025 mg.L − 1 . The biodeposit samples, collected for evaluating the biodeposit production rate, underwent filtration through a GF/C glass fiber microfilter, which typically retains particles of 1.2 µm in liquid. Prior to filtration, the filters were pre-washed, then burned, and finally weighed. After filtration, the samples were washed with 20 mL of ammonium formate (0.5 M) to remove the salt (Lysiak-Pastuszak and Andersens, 2004 ). The sample underwent an analysis, followed by a study in which the filters were dried at 60°C for 24 h and then weighed to determine the total particulate matter in both the feces and pseudofeces. Subsequently, the filters with the matter were burned in a muffle furnace at 450°C for 4 h. After cooling, they were weighed again; this resulted in only the inorganic matter remaining. By calculating the difference between total particulate matter (TPM) and particulate inorganic matter (PIM), we were able to determine the particulate organic matter (POM) in the feces and pseudofeces samples. This process enabled calculating the individual feces production rate (FPR) and pseudofeces production rate (PPR) for the animals. Furthermore, we computed the arithmetic mean and standard deviation for the analyzed parameters by species and collection site. Using the production rates of feces and pseudofeces as a basis, we calculated the total filtration rate (FR), clearance rate (CR), and ingestion rate (IR), using the methods described by Iglesias et al. ( 1998 ). Calculating the physiological rates enabled the determination of the load of TOC, TN, and TP ingested and released into the environment as biodeposits. 2.4 Physicochemical parameters of water quality In each trial, measurements were taken for temperature (T), salinity (SAL), turbidity (TURB), TPM, PIM, POM, organic content of seston, chlorophyll (CP), TOC, TP, and TN in the seawater samples collected at the CBS and SBQ sites. TOC, TN, and TP analyses were conducted in accordance with the methods described in Section 2.3. For each trial, a composite sample of seawater was prepared for subsequent analysis of the parameters evaluated. To create the composite sample, an initial volume of 3 L of seawater was collected at the beginning of the biodeposit collection period and transferred into a container. Subsequently, every 30 min, an additional 3 L of seawater was collected and added to this container, resulting in a total of 15 L from five samples. Duplicate samples were taken from this composite sample to analyze the following parameters: TOC, TP, and TN (200 mL for each sample); CP (1 L for each sample); and TPM (1 L for each sample). The seawater samples were refrigerated and stored, then analyzed in the laboratory the following day. The results for these parameters were determined using the simple arithmetic average from duplicate analyses of a sample comprising five seawater aliquots collected over a 2-h trial period. The T, SAL, and TURB parameters were measured at the collection point; they were evaluated both at the beginning and at the end of the experiment. Turbidity was measured using a benchtop digital turbidimeter (model TB-2000), salinity was measured using a portable refractometer (model RHS-10), and temperature was measured using a portable thermometer. The methodology used to determine TPM, PIM, and POM followed the same protocol as that for the biodeposit samples mentioned in Fig. 5 . The variables TPM, PIM, POM, and the PIM/POM ratio were determined according to the method described by Hawkins et al. ( 1996 ). 3. Results 3.1 Physicochemical parameters of water quality Table 1 presents the physicochemical parameters analyzed in the seawater samples. Water salinity remained at 35 g.kg − 1 in all trials at both collection points. CP ranged from 0.25 to 4.74 µg.L − 1 , while TURB ranged from 6.99 to 27.50 NTU. The T observed was similar across the sampling points (SBQ and CBS). TPM ranged from 5.72 to 44.87 mg.L − 1 , PIM ranged from 4.68 to 40.36 mg.L − 1 , POM ranged from 1.05 to 4.52 mg.L − 1 , and the ratio of PIM/POM ranged from 3.34 to 8.94. Table 1 Mean values of physicochemical parameters analyzed in seawater samples by species and collection point on trial days. CP, chlorophyll (detection limit: 0.25 µg/L); TURB, turbidity; T, temperature; TPM, total particulate matter; PIM, particulate inorganic matter; POM, particulate organic matter; PIM/POM, ratio of PIM to POM. CBS represents Caieira da Barra do Sul and SBQ represents Sambaqui. Point/ Specie CP (µg.L − 1 ) TURB (NTU) T (°C) TPM (mg.L − 1 ) PIM (mg.L − 1 ) POM (mg.L − 1 ) PIM/POM SBQ C. gigas 0.25 ± 0.00 9.43 ± 14.63 25.90 ± 1.39 21.23 ± 10.00 18.46 ± 18.46 2.78 ± 1.14 6.64 P. perna 4.74 ± 4.46 27.50 ± 6.54 27.63 ± 0.71 44.87 ± 7.15 40.36 ± 8.03 4.52 ± 0.93 8.94 CBS C. gigas 0.87 ± 0.81 6.99 ± 5.04 22.77 ± 1.17 5.72 ± 0.39 4.68 ± 0.39 1.05 ± 0.05 4.45 P. perna 1.54 ± 0.92 7.24 ± 7.63 24.90 ± 2.00 7.81 ± 1.80 6.01 ± 1.80 1.80 ± 0.43 3.34 3.2 Physiological rates and physicochemical characterization of biodeposits Table 2 presents Chemical characterization of the biodeposits and water, and the calculated physiological rates of molluks. Table 2 Mean TOC and TP values of the seawater samples, mean values and standard deviation of the production rates of feces (FPR), pseudofeces (PPR), filtration (FR), clarification (CR), ingestion (IR), and Total Organic Carbon (TOC), as well as Total Nitrogen (TN), and Total Phosphorus (TP) of the biodeposits. Samples that fell below the detection limit of the analysis method are denoted by --. TOC, total organic carbon; TP, total phosphorus; TN, total nitrogen. FPR represents the production rate of feces produced by the individuals analyzed; PPR represents the production rate of pseudofeces; FR the total filtration rate; CR, the clearing rate; IR the total ingestion rate; SBQ represents Sambaqui, and CBS represents Caieira da Barra do Sul. Note: *Out of 12 samples, only four showed values above the detection limit of the analysis method (2.0 mg/L). **Out of 12 samples, only one sample exceeded the detection limit of the analysis method (2.0 mg/L). For the chemical composition of the water, composite sampling was used. The results were presented as the simple average of analyses performed in duplicate on five aliquots of water collected over 2 h. In SBQ, six water samples were analyzed for P. perna and another six for C. gigas . In CBS, eight samples were analyzed for P. perna and six for C. gigas . For FPR and PPR in SBQ, 18 samples were used for each species analyzed. In CBS, 18 samples of C. gigas and 24 samples of P. perna were used. For the analysis of TOC, TN, and TP in SBQ, 12 samples from each species were analyzed. In CBS, 12 samples of C. gigas and 16 samples of P. perna were used. The TOC, TN, and TP results of the biodeposits were standardized to a duration of 1 h. WATER Biodeposits Chemical characterization Chemical characterization Rates Point/ Specie TOC (mg.L − 1 ) TP (mg.L − 1 ) TOC (mg.L − 1 .ind − 1 ) TN (mg.L − 1 .ind − 1 ) TP (mg.L − 1 .ind − 1 ) FPR (mg.h − 1 .ind − 1 ) PPR (mg.h − 1 .ind − 1 ) FR (mg.h − 1 .ind − 1 ) CR (L.h − 1 .ind − 1 ) IR (mg.h − 1 .ind − 1 ) SBQ C. gigas 0.69 ± 0.30 0.03 ± 0.00 75.17 ± 35.39 124.60 ± 18.64* 11.77 ± 9.51 22.0 ± 13.0 57.0 ± 29.0 84.68 ± 33.61 3.99 ± 1.58 15.15 ± 6.82 P. perna 0.63 ± 0.16 0.04 ± 0.01 41.43 ± 17.21 77.31** 10.18 ± 7.58 13.0 ± 6.0 98.0 ± 56.0 113.64 ± 61.88 2.53 ± 1.38 -30.30 ± 30.10 CBS C. gigas 0.72 ± 0.12 0.03 ± 0.01 229.85 ± 62.63 -- 10.52 ± 2.83 16.0 ± 4.0 67.0 ± 20.0 78.34 ± 35.23 13.68 ± 6.15 2.35 ± 9.00 P. perna 0.97 ± 0.70 0.03 ± 0.00 365.56 ± 204.02 144.44** 24.03 ± 11.65 7.0 ± 3.0 37.0 ± 19.0 39.54 ± 23.16 6.03 ± 3.53 11.57 ± 31.76 TOC ranged from 0.63 to 0.97 mg.L − 1 for water between SBQ and CBS, and 75. 17 and 365.56 mg.L − 1 .ind − 1 for biodeposits between SBQ and CBS; TP presents low variation for water and ranged from 10.18 to 24.03 mg.L − 1 . ind − 1 for biodeposits between SBQ and CBS.; TN varied between 77.31 and 144.44 mg.L − 1 . ind − 1 between SBQ and CBS, and only five samples reached the detection limit for biodeposits characterization. All seawater TN samples had values below the detection limit; therefore, their results are not presented. Biodeposits rates ranged for 7.0 (CBS) to 13.0 (SBQ) mg.h − 1 . ind − 1 for P. perna and 16.0 (CBS) to 22.0 (SBQ) mg.h − 1 . ind − 1 for C. gigas for FPR; 37.0 (CBS) to 98.0 (SBQ) mg.h − 1 . ind − 1 for P. perna and 57.0 (SBQ) to 67.0 (CBS) mg.h − 1 . ind − 1 for C. gigas for PPR; 39.54 (CBS) to 113.64 (SBQ) mg.h − 1 . ind − 1 for P. perna and 78.34 (CBS) to 84.68 (SBQ) mg.h − 1 . ind − 1 for C. gigas for FR; 2.53 (SBQ) to 6.03 (CBS) L.h − 1 . ind − 1 for P. perna and 3.99 (SBQ) to 13.68 (CBS) L.h − 1 . ind − 1 for C. gigas for CR, and; -30.30 (SBQ) to 11.57 (CBS) mg.h − 1 . ind − 1 for P. perna and 2.35 (CBS) to 15.15 (SBQ) mg.h − 1 . ind − 1 for C. gigas for IR. The analysis of biodeposit particles allowed us to determine the percentages of organic and inorganic matter in the feces and pseudofeces, across species at the two collection points (SBQ and CBS) (Fig. 6 ). By analyzing the filtration rates, ingestion, and production of feces and pseudofeces, we determined the concentrations of TOC, TN, and TP in the particles ingested by the animals and the concentrations eliminated as feces and pseudofeces for each species analyzed, X and Y, and according to the data observed and calculated for each location (Figs. 7 and 8 ). 4. Discussion In our study, we conducted the chemical characterization of mollusk feces and pseudofeces and quantified their production rates. Descriptive analyses of the obtained results were performed, enabling a comprehensive evaluation of the analyzed parameters. The results of this study allowed us to observe how the particles present in the North and South Bays of Santa Catarina Island influenced those ingested and excreted as feces and pseudo-feces by the oyster C. gigas and the mussel P. perna at the study site. Our findings align with those of Lima et al. ( 2023 ), Nascimento et al. ( 2022 ), and Ferreira et al. ( 2006 ) regarding the disparities between the SBQ and CBS collection points for PIM, indicating that SBQ exhibits higher PIM values than CBS. The variation in PIM values between SBQ and CBS could be linked to differences in physical characteristics and chemical composition across the North and South regions of the Bay of Santa Catarina Island. The South section of the Bay, where the CBS collection point is situated, experiences significant tidal fluctuations, unlike the North section, and factors such as wind and ocean current velocities directly impact suspended particles in the water (Ferreira et al., 2006 ; Garbossa et al., 2014 ; Silva et al., 2019 ). Lima et al. ( 2023 ) reported significant variations between SBQ and CBS as we observed in our study. This discrepancy could be attributed to the number of samples collected and the experiment duration conducted by these authors. Specifically, they collected 120 samples to evaluate water quality parameters. In contrast, our samples were collected at specific points in time. Therefore, in future studies, a larger number of water samples should be collected to more effectively demonstrate the differences between the analyzed collection sites. The SAL, T, and CP parameters at both sites are consistent with the findings reported by Nascimento et al. ( 2022 ) for the same collection sites. However, Ferreira et al. ( 2006 ) identified a higher concentration of CP in the North Bay than in the South Bay. This variation seems to be associated with the extended duration of their study, during which data was collected bi-weekly over 14 years. In contrast, our study conducted weekly collections, which might have been more immediately impacted by variable factors such as wind and tide. According to Ferreira et al. ( 2006 ), water quality monitoring, including measurements of CP and TPM, suggested that the northern Bay provides a richer food source for bivalve mollusks compared to the South Bay. However, this food source may be less accessible due to the increased energy expenditure required by bivalves to select and metabolize the particles. The feeding behavior and metabolism of the fauna surrounding marine animal cultivation areas are directly influenced by the properties and composition of POM in seawater. This matter is selectively consumed by filter-feeding organisms, such as mollusks, which alters its composition, consequently impacting the feeding habits and biodeposition of marine bivalve mollusks (Sakamaki et al., 2020 ). The literature reports a wide range of production rates of biodeposits. These variations are attributed to different methodologies, model species, and the physical and chemical parameters of the water where the bivalve mollusks reside, as well as the physiological rates specific to each species and age (Callier et al., 2006 ; Dame, 1993 ; Lin et al., 2016 ; Nascimento et al., 2022 ). Rates are measured both individually (Callier et al., 2006 ; Chamberlain, 2002 ; Haven and Morales-Alamo, 1966 ; Nascimento et al., 2022 ; Navarro and Thompson, 1997 ; Schmitt, 2002 ) and collectively, as is the case with studies conducted directly in the environment (Boucher-Rodoni and Boucher, 1990 ; Hayakawa et al., 2001 ; Jaramillo et al., 1992 ; Mallet et al., 2006 ; Mitchell, 2006 ). Taking into account the cultivation areas allocated to the bays of Santa Catarina Island, this analysis centers on the daily production of feces and pseudofeces in a marine mollusk farm. A farm may encompass an area of one hectare, for instance, comprising 10 longlines, each with 50 units of ropes (for mussels) or lantern nets (for oysters), with each unit housing 180 animals. Assuming an equal division of production between mussels and oysters, the total production of feces and pseudofeces for the entire farming area is approximately 171.18 kg per day, which equates to a density of about 17.12 g.m − 2 in a single day. Understanding these values is crucial for building scenarios with physically-based numerical models, which help us grasp how particles behave in the environment, including how the generated material spreads and settles, as well as how it interacts and reacts with the seabed and water column. The Figure of 17.12 g.m − 2 refers to the daily production of feces and pseudofeces, representing raw data on biodeposit generation. It is important to note that mollusks’ feces and pseudofeces are consumed by free-swimming animals, decompose before reaching the seabed, and are transported by sea currents (affect horizontal velocities and dispersion radius). Therefore, by integrating this data into hydrodynamic models and accounting for the various factors influencing biodeposits, we can enhance the accuracy of determining the load and dispersion plume of feces and pseudofeces produced by mollusk farms in specific locations. Furthermore, the role of mollusks in providing ecosystem services is significant, as they are filter-feeding organisms that utilize suspended particles in the water for growth. Through this process, they contribute to critical environmental functions such as coastal stabilization, habitat provision for other species, nutrient cycling (phosphorus and nitrogen), and water purification via their filtration mechanisms (Catherine et al., 2024 ). A study conducted in Mosquito Lagoon, Florida (USA), evaluated the chemical composition of biodeposits from juvenile Crassostrea virginica in a laboratory setting. The study found that juveniles of this species exhibited higher rates of chlorophyll-α removal and ammonium release than their older counterparts. Moreover, their biodeposits contained higher concentrations of dissolved organic carbon, nitrate, and ammonium ion than the older oysters (Locher et al., 2021 ). The age of mollusks also directly affects their metabolism and, as a result, influences the production of biodeposits (Bayne, 2017 ). A higher concentration of TOC was found in the biodeposits produced by the mollusks in CBS than those produced by the mollusks in SBQ. This difference may be due to the greater amount of particles being rejected as pseudofeces (Locher et al., 2021 ), which enriches the concentration of total biodeposits due to the increased load of inorganic particles, as also described by Newell and Jordan ( 1983 ). The TOC data collected from the water were similar across the sampling sites (SBQ – CBS), however, significant variation was observed in relation to the biodeposits., potentially attributable to the composition of particulate matter in the environment. These findings support those of Nascimento et al. ( 2022 ), who observed significant differences in particulate matter levels between the North Bay and the South Bay, consequently affecting the feeding rates of mollusks. The low concentration of TOC found in the biodeposits of the bivalve mollusks evaluated in the SBQ region appears to have an inverse relationship with the high PIM values found in the seawater of SBQ. In other words, when there is less organic matter in the water, the biodeposits produced by animals have lower concentrations of TOC than those produced by animals in environments with less inorganic matter, such as CBS. This factor might be associated with the animals’ energy physiology. Among these aspects, the clearing rate stands out, showing significant differences between the species and sites analyzed. The rates were higher in CBS compared to SBQ, suggesting that the mollusks had to filter a larger volume of water in CBS to obtain the same particle load as in SBQ. Furthermore, the variation in clearance rates may be linked to the energy physiology of the animals, particularly their ability to filter and select suitable particles for their diet and metabolism. Nascimento et al. ( 2022 ) observed a relationship between the clearance rate and the weight of the animal, TPM, and the PIM/POM ratio, for the same collection sites that we analyzed. The filtration and ingestion rates did not show any significant differences, which we believe can be attributed to the occasional collections. The variation in these rates is related to the presence of organic and inorganic particles in the water, and we can link these rate results to the observed PIM/POM ratio. Ratio values higher than 6 can lead oysters or mussels to produce more pseudofeces than feces. According to (Adams et al., 2019), there is an inverse relationship between IR and the PIM/POM ratio, which can indicate the resuspension of sediments in the environment, which directly affects the physiological processes undertaken by mollusks. We observed that the lower rates of whitening in SBQ are indicative of higher PIM/POM ratio results when compared to those in CBS. Our data corroborates the results obtained by Galimany et al. (2017), who observed when studying C. virginica that this mollusk can reject inorganic matter and increase its CR when the content of organic matter decreases. The concentrations of TOC, TN, and TP in the water are crucial for understanding nutrient cycling and are essential in determining the amounts ingested by mollusks, as well as those expelled and returned to the environment. This information highlights the importance of understanding the effects of marine aquaculture farm installations on the benthic environment. Dan et al. ( 2021 ), in a study conducted in Daya Bay, China, found that biodeposits - specifically feces, pseudofeces, and uneaten fish feed - constitute over 40% of the organic matter found in the sediment beneath aquaculture systems. Studies that examine the concentration of nitrogen in both water and biodeposits, with appropriate detection limits for the samples, are essential for comprehending the processes subsequent to the release of biodeposits into the water. Dalrymple and Carmichael ( 2015 ) affirm the significance of conducting such studies. They demonstrated that the quantity of nitrogen released in biodeposits did not differ between age groups. However, they noted variances in metabolism and assimilation between juvenile and adult age groups. Concentrations of TP play a crucial role as they are closely associated with the growth of marine organisms, particularly phytoplankton (Newell et al., 2005 ). Despite its significant influence on various environmental processes, there are limited studies focusing on phosphorus concentrations, particularly in biodeposits (Magni et al., 2000 ; Newell et al., 2005 ). The physicochemical characterization of particles in water and biodeposits facilitates the estimation of calculations such as mass balance, which is pivotal for comprehending the chemical reactions occurring in the environment. This data will enable the extrapolation of calculations to determine the environment’s carrying capacity, which in turn, will aid in developing sustainable mariculture and identifying management strategies to preserve the environment (Buck and Langan, 2017 ; Sakamaki et al., 2022 ; Silva et al., 2019 ). Ferreira et al. ( 2006 ) highlighted the necessity of conducting studies to monitor shellfish farming at the sites we investigated, to enable the industry’s growth without causing environmental harm. These data also highlight the ecological significance of mollusks, given the wide range of ecosystem services they provide (Catherine et al., 2024 ). 5. Conclusions The study enabled successful physicochemical characterization of the biodeposits from C. gigas and P. perna cultivated at collection sites in the North and South Bays of Santa Catarina Island. Additionally, it was possible to determine the production rates of feces, pseudofeces, filtration, clarification, and ingestion. The results revealed a noteworthy disparity in particulate inorganic matter between the collection sites, with SBQ exhibiting higher levels than CBS. Moreover, the total organic carbon content of the biodeposits was greater in CBS compared to SBQ for both species. Significant differences in clearance rates were observed among species and collection sites. The chemical characterization of the biodeposits and the observed physiological rates in this study will pave the way for further research aimed at determining the carrying capacity of the North and South Bays for the farming of marine bivalve mollusks. Declarations CRediT authorship contribution statement Eliziane Silva : Performed the research, Collected data, Performed the analysis, Wrote the manuscript with input from all authors, Discussed the results and contributed to the final manuscript. Carlos Henrique Araujo de Miranda Gomes: Carried out the implementation of experiments, Collected the data, Discussed the results and contributed to the final manuscript. Luis Hamilton Pospissil Garbossa: Helped to write manuscript and designed the study, Discussed the results and contributed to the final manuscript. Claudio Manoel Rodrigues de Melo: Responsible for funding acquisition, Supervising the research activities, Discussed the results and contributed to the final manuscript. Katt Regina Lapa: Responsible for funding acquisition, Supervising the research activities, Discussed the results and contributed to the final manuscript. Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper. Data availability Data will be made available on request. Acknowledgments The authors would like to thank Epagri for supporting carrying out the experiments, and Fazenda Marinha Paraíso das Ostras for their availability as a location for collection. Funding This study was financed by the ‘Coordination for the Improvement of Higher Education Personnel – Brazil (CAPES) – Finance Code 001’ and by the Federal University of Santa Catarina (249/2016). The authors also thank the ‘National Council for Scientific and Technological Development (CNPq),’ who provided a scholarship to Claudio De Melo. The present work was supported by FAPESC, call for proposals 53/2022. Ethics approval According to Brazilian law, authorization for the use of invertebrates, including oysters, is not required in the conduct of scientific experiments. References Bayne, B., 2017. Biology of Oysters. Academic Press. https://doi.org/10.1038/150544c0 Boucher-Rodoni, R., Boucher, G., 1990. In situ study of the effect of oyster biomass on benthic metabolic exchange rates. Hydrobiologia 206, 115–123. https://doi.org/10.1007/BF00018637 Buck, B.H., Langan, R., 2017. Aquaculture Perspective of Multi-Use Sites in the Open Ocean: The Untapped Potential for Marine Resources in the Anthropocene. https://doi.org/10.1007/978-3-319-51159-7 Callier, M.D., Weise, A.M., McKindsey, C.W., Desrosiers, G., 2006. 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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-5397899","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":375362810,"identity":"323cb6cc-4c69-43c0-9c58-d086685d2fb5","order_by":0,"name":"Eliziane Silva","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA+UlEQVRIiWNgGAWjYNCCAgkGNhD9AYjZ2InSYgDRwjgDpIWZOC0QipkHTBJQzC/dfoHhg4GFPR/72YOPbX5tk+djZmD88DEHtxbJOWcKGGcYSDCz8eQlG+f23TZsY2Zglpy5DY+TbuQkMPMYSLCxMeSYSef23GYEamFj5sWjxR6k5Y+BBA8b/xvz35Y9t+0JajGQSD/ADCQl2CRyzJgZftxOJKhF4kYOw8EeAwkDNok3xpK9DbeT25gZm/H6hX9G+sMHPyrq7OX7cww//Phz23Z+e/PBDx/xaGFg4DE4AGcztoHJBnzqgYD9ARLnDwHFo2AUjIJRMCIBAMvAReeBIjZvAAAAAElFTkSuQmCC","orcid":"https://orcid.org/0000-0001-9904-3198","institution":"Federal University of Santa Catarina: Universidade Federal de Santa Catarina","correspondingAuthor":true,"prefix":"","firstName":"Eliziane","middleName":"","lastName":"Silva","suffix":""},{"id":375362811,"identity":"7b36c735-db5d-4cbb-a4cc-21fa9d93351b","order_by":1,"name":"Carlos Henrique Araújo de Miranda Gomes","email":"","orcid":"","institution":"UFSC: Universidade Federal de Santa Catarina","correspondingAuthor":false,"prefix":"","firstName":"Carlos","middleName":"Henrique Araújo de Miranda","lastName":"Gomes","suffix":""},{"id":375362812,"identity":"ede7b088-7c6d-40da-a14e-e7bea591eda6","order_by":2,"name":"Luis Hamilton Pospissil Garbossa","email":"","orcid":"","institution":"EPAGRI: Empresa de Pesquisa Agropecuaria e Extensao Rural de Santa Catarina","correspondingAuthor":false,"prefix":"","firstName":"Luis","middleName":"Hamilton Pospissil","lastName":"Garbossa","suffix":""},{"id":375362813,"identity":"e83973c4-bcc6-4513-a310-6617a5d80435","order_by":3,"name":"Claudio Manoel Rodrigues de Melo","email":"","orcid":"","institution":"UFSC: Universidade Federal de Santa Catarina","correspondingAuthor":false,"prefix":"","firstName":"Claudio","middleName":"Manoel Rodrigues","lastName":"de Melo","suffix":""},{"id":375362814,"identity":"aea7b8b6-497a-4733-9eb3-9a0f019fa842","order_by":4,"name":"Katt Regina Lapa","email":"","orcid":"","institution":"UFSC: Universidade Federal de Santa Catarina","correspondingAuthor":false,"prefix":"","firstName":"Katt","middleName":"Regina","lastName":"Lapa","suffix":""}],"badges":[],"createdAt":"2024-11-05 20:06:07","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-5397899/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-5397899/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":69938976,"identity":"e38f017a-daff-41b7-8016-0ba07b918a92","added_by":"auto","created_at":"2024-11-26 20:17:20","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":56531,"visible":true,"origin":"","legend":"\u003cp\u003eLocation of the study area. CBS represents the collection point in the South Bay: Caieira da Barra do Sul and SBQ represents the collection point in the North Bay: Sambaqui.\u003c/p\u003e","description":"","filename":"floatimage1.png","url":"https://assets-eu.researchsquare.com/files/rs-5397899/v1/d54f7e6bfe1f09cfca944cde.png"},{"id":69938973,"identity":"6be722cb-2baa-48db-b73a-bd054bc27b46","added_by":"auto","created_at":"2024-11-26 20:17:20","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":838048,"visible":true,"origin":"","legend":"\u003cp\u003ePositioning of the camera system and the submersible pump installed at the collection points. 1 - Camera system; 2 - In beige, beach sand; 3 - Submersible pump; 4 - In blue, seawater. Drawing: \u0026nbsp;Caique Sales de Miranda Gomes and João Germano Scabeni.\u003c/p\u003e","description":"","filename":"floatimage2.png","url":"https://assets-eu.researchsquare.com/files/rs-5397899/v1/fb704b25e0d0f70d3455fe5f.png"},{"id":69939173,"identity":"5d61879a-824d-482c-af43-287f67b76290","added_by":"auto","created_at":"2024-11-26 20:25:20","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":371397,"visible":true,"origin":"","legend":"\u003cp\u003eDiagram of the system used for data collection. 1 - System support; 2 - Central supply pipe; 3 - Chambers. Drawing: Caique Sales de Miranda Gomes and João Germano Scabeni.\u003c/p\u003e","description":"","filename":"floatimage3.png","url":"https://assets-eu.researchsquare.com/files/rs-5397899/v1/c82e3c7e69c7fd2acd93b12d.png"},{"id":69938968,"identity":"12d1c8f2-8969-4872-acdb-8e7715384845","added_by":"auto","created_at":"2024-11-26 20:17:20","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":47306,"visible":true,"origin":"","legend":"\u003cp\u003eDetailed view of the chamber, indicating the system’s water flow and the positioning of the mollusk within the chamber. 1 - Seawater inlet; 2 - Mollusk; 3 - Seawater outlet. Drawing: Caique Sales de Miranda Gomes and João Germano Scabeni.\u003c/p\u003e","description":"","filename":"floatimage4.png","url":"https://assets-eu.researchsquare.com/files/rs-5397899/v1/4adee9f8c244044a0d40e3be.png"},{"id":69939481,"identity":"8c23c9b6-91d6-4282-8241-5ec67b15f008","added_by":"auto","created_at":"2024-11-26 20:33:20","extension":"png","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":216296,"visible":true,"origin":"","legend":"\u003cp\u003eOrganization chart of the biodeposite production trials, showing the quantity of marine bivalve mollusks used and the procedures conducted for the production rate trials and the chemical characterization of the biodeposits. TOC, total organic carbon; TN, total nitrogen; TP, total phosphorus; TPM, total particulate matter; PIM, particulate inorganic matter.\u003c/p\u003e","description":"","filename":"floatimage5.png","url":"https://assets-eu.researchsquare.com/files/rs-5397899/v1/61ffb23014ee157f21c81b58.png"},{"id":69939482,"identity":"bbcbadde-10aa-4f8b-a462-4ac8abc598c8","added_by":"auto","created_at":"2024-11-26 20:33:20","extension":"png","order_by":6,"title":"Figure 6","display":"","copyAsset":false,"role":"figure","size":125734,"visible":true,"origin":"","legend":"\u003cp\u003eOrganic and inorganic composition, in percentages, of the biodeposits generated by the two species analyzed at the collection points. F - feces; PF - pseudofeces; CG - \u003cem\u003eC. gigas\u003c/em\u003e; PP - \u003cem\u003eP. perna\u003c/em\u003e; CBS - Caieira da Barra do Sul; SBQ - Sambaqui.\u003c/p\u003e","description":"","filename":"floatimage6.png","url":"https://assets-eu.researchsquare.com/files/rs-5397899/v1/100269c6f3561be17c26026e.png"},{"id":69939174,"identity":"9a3fcba7-84c5-48b8-b68f-13eec40c7fbf","added_by":"auto","created_at":"2024-11-26 20:25:20","extension":"png","order_by":7,"title":"Figure 7","display":"","copyAsset":false,"role":"figure","size":395847,"visible":true,"origin":"","legend":"\u003cp\u003eParticle filtration capacity and the chemical composition of particles ingested and excreted (as feces and pseudo-feces) by \u003cem\u003eC. gigas\u003c/em\u003e for CBS and SBQ over a one-hour period, based on the trials conducted (three trials for CBS and three for SBQ). The symbol ‘--’ indicates a value that was not determined because the concentration of TN in the samples was below the detection limit of the method used (2.0 mg/L). Drawing of the oyster: Matheus Lacerda Geiger.\u003c/p\u003e","description":"","filename":"floatimage7.png","url":"https://assets-eu.researchsquare.com/files/rs-5397899/v1/f31b7bb77ac1fbd6f09e9167.png"},{"id":69938970,"identity":"dd341c5c-aa7b-467c-953a-8ea2a0ee9675","added_by":"auto","created_at":"2024-11-26 20:17:20","extension":"png","order_by":8,"title":"Figure 8","display":"","copyAsset":false,"role":"figure","size":390832,"visible":true,"origin":"","legend":"\u003cp\u003eParticle filtration capacity and the chemical composition of particles ingested and excreted (as feces and pseudo-feces) by \u003cem\u003eP. perna\u003c/em\u003e for CBS and SBQ over a one-hour period, based on the trials conducted (four trials for CBS and three for SBQ). Drawing of the mussel: Matheus Lacerda Geiger.\u003c/p\u003e","description":"","filename":"floatimage8.png","url":"https://assets-eu.researchsquare.com/files/rs-5397899/v1/79a3e65fbb701d2742d27bd3.png"},{"id":74969038,"identity":"afe84fc8-d03f-4a88-860c-7c8311219d2e","added_by":"auto","created_at":"2025-01-28 22:56:16","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":3351646,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-5397899/v1/e4547972-4686-4289-b043-38845f7c2948.pdf"}],"financialInterests":"","formattedTitle":"\u003cp\u003ePhysicochemical Characterization of Feces and Pseudofeces Production by Bivalve Marine Mollusks Cultivated in the South Atlantic\u003c/p\u003e","fulltext":[{"header":"1. Introduction","content":"\u003cp\u003eIn 2020, global fisheries and aquaculture production totaled 214\u0026nbsp;million tons, encompassing both the capture and cultivation of aquatic animals, which comprised 83.17%, and algae, which constituted the remaining 16.83%, as reported by the Food and Agriculture Organization - FAO of the United Nations (FAO, 2022). When focusing solely on world aquaculture production, it constituted approximately 57.29% of the total global fishing and aquaculture production, with an estimated value of 264.8\u0026nbsp;billion dollars from aquatic animal trade. Marine and coastal aquaculture contributed 68.1\u0026nbsp;million tons to global aquaculture production (FAO, 2022).\u003c/p\u003e \u003cp\u003eIn marine and coastal aquaculture, the cultivation of marine mollusks holds significant importance. China stands as the world\u0026rsquo;s largest producer, with its production volume surpassing the combined total of all other mollusk-producing countries. In the American continent, the production of marine mollusks amounted to 688,077 tons live weight (FAO, 2022). In Brazil, the Brazilian Institute of Geography and Statistics (IBGE) reported a production of approximately 8,739 tons of marine mollusks in 2022, including varieties such as oysters, scallops, and mussels. Notably, Santa Catarina accounts for approximately 95% of Brazil\u0026rsquo;s total production of marine bivalve mollusks (IBGE, 2023).\u003c/p\u003e \u003cp\u003eThe farming of marine bivalve mollusks is widely regarded as sustainable due to their ability to filter particles from the water without requiring additional feed (Bayne, \u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e2017\u003c/span\u003e; Gosling, \u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e2003\u003c/span\u003e; Sakamaki et al., \u003cspan citationid=\"CR40\" class=\"CitationRef\"\u003e2022\u003c/span\u003e). Despite its significant advantages, particularly in terms of protein production and its direct impact on production costs, mollusk farming can also have negative environmental consequences. These may arise from the release and sedimentation of organic matter generated by these animals. The extent of these impacts is closely tied to the hydrodynamics of the farming locations, which can result in chemical alterations in the sediments, especially in areas with relatively stable hydrodynamic conditions (Sakamaki and Nishimura, \u003cspan citationid=\"CR39\" class=\"CitationRef\"\u003e2007\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eFarming at high mussel production densities can have significant impacts on the surrounding environment, particularly through the accumulation of biodeposits such as faeces and pseudofeces (Chamberlain, \u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e2002\u003c/span\u003e). The release of nitrogen and phosphorus from mollusk excretion and biodeposition at the seafloor directly affects nutrient cycling in the vicinity of farming areas (Cranford et al., \u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e2009\u003c/span\u003e). Furthermore, in addition to altered nitrogen and phosphorus loads resulting from biodeposit accumulation, there may be an increase in oxygen consumption due to bacterial growth associated with the oxidation of organic matter in the environment. Consequently, this can lead to oxygen depletion in the sediment and in the layers close to the seafloor (Filgueira et al., 2015; Grant et al., \u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e2012\u003c/span\u003e; Weise et al., \u003cspan citationid=\"CR48\" class=\"CitationRef\"\u003e2009\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eThe production of feces and pseudofeces is closely related to the presence of particles in the water, which directly affects the physiological rates in animals, thus influencing the duration of physiological processes. Assessing the rates of clarification, filtration, and production of feces and pseudofeces aids in comprehending the environmental conditions in which mollusks are cultivated.\u003c/p\u003e \u003cp\u003eIn addition to the challenge of biodeposition, high-density mollusk farming can lead to a reduction in planktonic biomass around the farming area and alter its composition. This reduction in the biomass directly impacts the mollusks\u0026rsquo; diet, potentially resulting in lower growth rates (Cranford et al., \u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e2009\u003c/span\u003e; Lima et al., \u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e2023\u003c/span\u003e). Moreover, aside from environmental concerns, conflicts arise over the utilization of marine areas. There is ongoing debate on how to manage coastal zones to foster global development while balancing economic, societal, and environmental needs. This entails the pursuit of efficient resource utilization and ensuring accessibility for various marine activities (Buck and Langan, \u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e2017\u003c/span\u003e; O\u0026rsquo;Shea et al., \u003cspan citationid=\"CR37\" class=\"CitationRef\"\u003e2022\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eUnderstanding the physical and chemical interactions within the environment where mollusk farms are established is pivotal in assessing the impact of mollusk farming on the environment (Sakamaki et al., \u003cspan citationid=\"CR40\" class=\"CitationRef\"\u003e2022\u003c/span\u003e; Silva et al., \u003cspan citationid=\"CR42\" class=\"CitationRef\"\u003e2019\u003c/span\u003e; Suplicy, \u003cspan citationid=\"CR45\" class=\"CitationRef\"\u003e2004\u003c/span\u003e). In this context, research focusing on characterizing compounds present in both water and biodeposits is essential for extrapolating results and generating data regarding the carrying capacity of the environment (Chamberlain, \u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e2002\u003c/span\u003e; Locher et al., \u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e2021\u003c/span\u003e; Newell, \u003cspan citationid=\"CR33\" class=\"CitationRef\"\u003e2006\u003c/span\u003e, \u003cspan citationid=\"CR34\" class=\"CitationRef\"\u003e2004\u003c/span\u003e; Walker et al., \u003cspan citationid=\"CR47\" class=\"CitationRef\"\u003e2014\u003c/span\u003e; Weise et al., \u003cspan citationid=\"CR48\" class=\"CitationRef\"\u003e2009\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eIn the state of Santa Catarina, mollusk farming predominantly takes place in the North and South Bays of Santa Catarina Island. However, few studies have assessed the production of biodeposits by farmed bivalve mollusks in these areas. As a result, both the general population and the scientific community have raised concerns regarding the carrying capacity of these environments (Nascimento et al., \u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e2022\u003c/span\u003e; Silva et al., \u003cspan citationid=\"CR42\" class=\"CitationRef\"\u003e2019\u003c/span\u003e; Suplicy, \u003cspan citationid=\"CR45\" class=\"CitationRef\"\u003e2004\u003c/span\u003e). Studies aimed at determining parameters related to farming are essential for developing policies that promote the activity, provide income for those involved, and mitigate irreversible environmental impacts (O\u0026rsquo;Shea et al., \u003cspan citationid=\"CR37\" class=\"CitationRef\"\u003e2022\u003c/span\u003e; Sakamaki et al., \u003cspan citationid=\"CR40\" class=\"CitationRef\"\u003e2022\u003c/span\u003e; Souza et al., \u003cspan citationid=\"CR43\" class=\"CitationRef\"\u003e2022\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eTo promote sustainable shellfish farming, it is crucial to investigate the environmental dynamics related to mollusk farming (Sakamaki et al., \u003cspan citationid=\"CR40\" class=\"CitationRef\"\u003e2022\u003c/span\u003e; Vasechkina, \u003cspan citationid=\"CR46\" class=\"CitationRef\"\u003e2023\u003c/span\u003e). Our study aimed to assess the physiological rates linked to biodeposit production and to chemically characterize these biodeposits in terms of total organic carbon, total nitrogen, and total phosphorus. This was conducted for the species \u003cem\u003eCrassostrea gigas\u003c/em\u003e (Thunberg, 1793) and \u003cem\u003ePerna perna\u003c/em\u003e (Linnaeus, 1758) in both the North Bay and South Bay of Santa Catarina Island.\u003c/p\u003e"},{"header":"2. material and methods","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003e2.1 Study area\u003c/h2\u003e \u003cp\u003eThe study was conducted at two sites within Santa Catarina Island Bay: one in the North compartment, Sambaqui (SBQ, 27\u0026deg;29\u0026prime;22.6\u0026Prime;S 48\u0026deg;32\u0026prime;16.9\u0026Prime;W), and the other in the South compartment, Caieira da Barra do Sul (CBS, 27\u0026deg;48\u0026prime;58.3\u0026Prime;S 48\u0026deg;33\u0026prime;50.0\u0026Prime;W) (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e).\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec4\" class=\"Section2\"\u003e \u003ch2\u003e2.2 Biodeposit collection system and animals studied\u003c/h2\u003e \u003cp\u003eBiodeposits were collected using a system (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e) similar to that used by Hawkins et al. (\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e1996\u003c/span\u003e) and adapted by Nascimento et al. (\u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e2022\u003c/span\u003e), in which the animals were placed in individual chambers (Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e). The system was installed at the collection sites (SBQ and CBS), and seawater was pumped in close proximity to the system\u0026rsquo;s attachment using a submersible pump. The system had 12 chambers with a maximum volume of 4 L. Each of the 10 chambers was assigned an individual mollusk for the collection of feces and pseudofeces (Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e). The flow rate of the chambers was controlled at 500 mL.min\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eA total of 130 animals were used in the study (60 of the \u003cem\u003eC. gigas\u003c/em\u003e species and 70 of the \u003cem\u003eP. perna\u003c/em\u003e species). The mollusks used were cultivated at their respective collection sites and were harvested on the same day the data was collected. Adult animals with the following height measurements were selected for the study: mean height of 92.6\u0026thinsp;\u0026plusmn;\u0026thinsp;7.5 mm for \u003cem\u003eC. gigas\u003c/em\u003e and 76.5\u0026thinsp;\u0026plusmn;\u0026thinsp;4.1 mm for \u003cem\u003eP. perna\u003c/em\u003e in SBQ and 83.6\u0026thinsp;\u0026plusmn;\u0026thinsp;6.9 mm for \u003cem\u003eC. gigas\u003c/em\u003e and 81.9\u0026thinsp;\u0026plusmn;\u0026thinsp;4.1 mm for \u003cem\u003eP. perna\u003c/em\u003e in CBS. Biometrics were carried out according to the method outlined by Galtsoff (\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e1964\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eThirteen collections were made at the end of the experiment, on different days between December 2021 and April 2022, including four trials of \u003cem\u003eP. perna\u003c/em\u003e biodeposit production and three of \u003cem\u003eC. gigas\u003c/em\u003e at the CBS site. For the SBQ site, we conducted three biodeposit production trials with \u003cem\u003eP. perna\u003c/em\u003e and three with \u003cem\u003eC. gigas\u003c/em\u003e. The sampling days were non-consecutive; therefore, water quality parameters were analyzed to detect potential differences between the collection sites.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec5\" class=\"Section2\"\u003e \u003ch2\u003e2.3 Physicochemical characterization of biodeposits\u003c/h2\u003e \u003cp\u003eThe acclimatization period for the animals in the chambers was defined as the time taken until each animal initially produced biodeposits (approximately 30 min for \u003cem\u003eP. perna\u003c/em\u003e and ranged from 1 to 2 h for \u003cem\u003eC. gigas\u003c/em\u003e). Following the acclimatization period, the animals\u0026rsquo; feces and pseudofeces were collected over a 2-h period.\u003c/p\u003e \u003cp\u003eOut of the system\u0026rsquo;s 12 chambers, four received one individual each, and the collected material (both feces and pseudofeces) was analyzed for its chemical composition, specifically total organic carbon (TOC), total nitrogen (TN), and total phosphorus (TP) concentrations. Another six chambers each received one individual randomly, and the samples from these chambers were used to measure the rate of biodeposit production. The remaining two chambers did not receive any individuals. Figure\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003e outlines the procedure for each test conducted.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eThe feces and pseudofeces samples, generated for the analysis of TOC, TN, and TP in each test, were collected and stored in plastic containers with a capacity of 200 mL. After adding the collected biodeposits, the container was topped up to 200 mL with distilled water and refrigerated until the samples were processed the following day. The TOC, TN, and TP values for biodeposit production from one animal over 2 h, using seawater in the system described in Section 2.2, were established. These values were then standardized to production per hour to simplify data comparison with other analyzed parameters. TOC was analyzed according to the method described by Strickland and Parsons (\u003cspan citationid=\"CR44\" class=\"CitationRef\"\u003e1972\u003c/span\u003e), with a detection limit of 0.2 mg.L\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e; TN was analyzed according to APHA 4500 N C, with a detection limit of 2.0 mg.L\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e; and TP was analyzed according to APHA 4500-P E, with detection limits of 0.014 and 0.025 mg.L\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e.\u003c/p\u003e \u003cp\u003eThe biodeposit samples, collected for evaluating the biodeposit production rate, underwent filtration through a GF/C glass fiber microfilter, which typically retains particles of 1.2 \u0026micro;m in liquid. Prior to filtration, the filters were pre-washed, then burned, and finally weighed. After filtration, the samples were washed with 20 mL of ammonium formate (0.5 M) to remove the salt (Lysiak-Pastuszak and Andersens, \u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e2004\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eThe sample underwent an analysis, followed by a study in which the filters were dried at 60\u0026deg;C for 24 h and then weighed to determine the total particulate matter in both the feces and pseudofeces. Subsequently, the filters with the matter were burned in a muffle furnace at 450\u0026deg;C for 4 h. After cooling, they were weighed again; this resulted in only the inorganic matter remaining. By calculating the difference between total particulate matter (TPM) and particulate inorganic matter (PIM), we were able to determine the particulate organic matter (POM) in the feces and pseudofeces samples. This process enabled calculating the individual feces production rate (FPR) and pseudofeces production rate (PPR) for the animals. Furthermore, we computed the arithmetic mean and standard deviation for the analyzed parameters by species and collection site.\u003c/p\u003e \u003cp\u003eUsing the production rates of feces and pseudofeces as a basis, we calculated the total filtration rate (FR), clearance rate (CR), and ingestion rate (IR), using the methods described by Iglesias et al. (\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e1998\u003c/span\u003e). Calculating the physiological rates enabled the determination of the load of TOC, TN, and TP ingested and released into the environment as biodeposits.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec6\" class=\"Section2\"\u003e \u003ch2\u003e2.4 Physicochemical parameters of water quality\u003c/h2\u003e \u003cp\u003eIn each trial, measurements were taken for temperature (T), salinity (SAL), turbidity (TURB), TPM, PIM, POM, organic content of seston, chlorophyll (CP), TOC, TP, and TN in the seawater samples collected at the CBS and SBQ sites. TOC, TN, and TP analyses were conducted in accordance with the methods described in Section 2.3.\u003c/p\u003e \u003cp\u003eFor each trial, a composite sample of seawater was prepared for subsequent analysis of the parameters evaluated. To create the composite sample, an initial volume of 3 L of seawater was collected at the beginning of the biodeposit collection period and transferred into a container. Subsequently, every 30 min, an additional 3 L of seawater was collected and added to this container, resulting in a total of 15 L from five samples. Duplicate samples were taken from this composite sample to analyze the following parameters: TOC, TP, and TN (200 mL for each sample); CP (1 L for each sample); and TPM (1 L for each sample). The seawater samples were refrigerated and stored, then analyzed in the laboratory the following day. The results for these parameters were determined using the simple arithmetic average from duplicate analyses of a sample comprising five seawater aliquots collected over a 2-h trial period.\u003c/p\u003e \u003cp\u003eThe T, SAL, and TURB parameters were measured at the collection point; they were evaluated both at the beginning and at the end of the experiment. Turbidity was measured using a benchtop digital turbidimeter (model TB-2000), salinity was measured using a portable refractometer (model RHS-10), and temperature was measured using a portable thermometer. The methodology used to determine TPM, PIM, and POM followed the same protocol as that for the biodeposit samples mentioned in Fig.\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003e. The variables TPM, PIM, POM, and the PIM/POM ratio were determined according to the method described by Hawkins et al. (\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e1996\u003c/span\u003e).\u003c/p\u003e \u003c/div\u003e"},{"header":"3. Results","content":"\u003cdiv id=\"Sec8\" class=\"Section2\"\u003e \u003ch2\u003e3.1 Physicochemical parameters of water quality\u003c/h2\u003e \u003cp\u003eTable\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e presents the physicochemical parameters analyzed in the seawater samples. Water salinity remained at 35 g.kg\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e in all trials at both collection points. CP ranged from 0.25 to 4.74 \u0026micro;g.L\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e, while TURB ranged from 6.99 to 27.50 NTU. The T observed was similar across the sampling points (SBQ and CBS). TPM ranged from 5.72 to 44.87 mg.L\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e, PIM ranged from 4.68 to 40.36 mg.L\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e, POM ranged from 1.05 to 4.52 mg.L\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e, and the ratio of PIM/POM ranged from 3.34 to 8.94.\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\u003eMean values of physicochemical parameters analyzed in seawater samples by species and collection point on trial days. CP, chlorophyll (detection limit: 0.25 \u0026micro;g/L); TURB, turbidity; T, temperature; TPM, total particulate matter; PIM, particulate inorganic matter; POM, particulate organic matter; PIM/POM, ratio of PIM to POM. CBS represents Caieira da Barra do Sul and SBQ represents Sambaqui.\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=\"char\" char=\"\u0026plusmn;\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\"\u0026plusmn;\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\"\u0026plusmn;\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\"\u0026plusmn;\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\"\u0026plusmn;\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\"\u0026plusmn;\" class=\"colspec\" colname=\"c7\" colnum=\"7\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" 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 \u003cp\u003ePoint/ Specie\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eCP\u003c/p\u003e \u003cp\u003e(\u0026micro;g.L\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eTURB (NTU)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eT\u003c/p\u003e \u003cp\u003e(\u0026deg;C)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003eTPM\u003c/p\u003e \u003cp\u003e(mg.L\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c6\"\u003e \u003cp\u003ePIM\u003c/p\u003e \u003cp\u003e(mg.L\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c7\"\u003e \u003cp\u003ePOM\u003c/p\u003e \u003cp\u003e(mg.L\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c8\"\u003e \u003cp\u003ePIM/POM\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"1\" nameend=\"c9\" namest=\"c9\"\u003e\u0026nbsp;\u003c/th\u003e \u003c/tr\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSBQ\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/th\u003e \u003cth align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/th\u003e \u003cth align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/th\u003e \u003cth align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/th\u003e \u003cth align=\"left\" colspan=\"1\" nameend=\"c9\" namest=\"c9\"\u003e\u0026nbsp;\u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cem\u003eC. gigas\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e0.25\u0026thinsp;\u0026plusmn;\u0026thinsp;0.00\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e9.43\u0026thinsp;\u0026plusmn;\u0026thinsp;14.63\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c4\"\u003e \u003cp\u003e25.90\u0026thinsp;\u0026plusmn;\u0026thinsp;1.39\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c5\"\u003e \u003cp\u003e21.23\u0026thinsp;\u0026plusmn;\u0026thinsp;10.00\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c6\"\u003e \u003cp\u003e18.46\u0026thinsp;\u0026plusmn;\u0026thinsp;18.46\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c7\"\u003e \u003cp\u003e2.78\u0026thinsp;\u0026plusmn;\u0026thinsp;1.14\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e \u003cp\u003e6.64\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cem\u003eP. perna\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e4.74\u0026thinsp;\u0026plusmn;\u0026thinsp;4.46\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e27.50\u0026thinsp;\u0026plusmn;\u0026thinsp;6.54\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c4\"\u003e \u003cp\u003e27.63\u0026thinsp;\u0026plusmn;\u0026thinsp;0.71\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c5\"\u003e \u003cp\u003e44.87\u0026thinsp;\u0026plusmn;\u0026thinsp;7.15\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c6\"\u003e \u003cp\u003e40.36\u0026thinsp;\u0026plusmn;\u0026thinsp;8.03\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c7\"\u003e \u003cp\u003e4.52\u0026thinsp;\u0026plusmn;\u0026thinsp;0.93\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e \u003cp\u003e8.94\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eCBS\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colspan=\"1\" nameend=\"c9\" namest=\"c9\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cem\u003eC. gigas\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e0.87\u0026thinsp;\u0026plusmn;\u0026thinsp;0.81\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e6.99\u0026thinsp;\u0026plusmn;\u0026thinsp;5.04\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c4\"\u003e \u003cp\u003e22.77\u0026thinsp;\u0026plusmn;\u0026thinsp;1.17\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c5\"\u003e \u003cp\u003e5.72\u0026thinsp;\u0026plusmn;\u0026thinsp;0.39\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c6\"\u003e \u003cp\u003e4.68\u0026thinsp;\u0026plusmn;\u0026thinsp;0.39\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c7\"\u003e \u003cp\u003e1.05\u0026thinsp;\u0026plusmn;\u0026thinsp;0.05\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e \u003cp\u003e4.45\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"1\" nameend=\"c9\" namest=\"c9\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cem\u003eP. perna\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e1.54\u0026thinsp;\u0026plusmn;\u0026thinsp;0.92\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e7.24\u0026thinsp;\u0026plusmn;\u0026thinsp;7.63\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c4\"\u003e \u003cp\u003e24.90\u0026thinsp;\u0026plusmn;\u0026thinsp;2.00\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c5\"\u003e \u003cp\u003e7.81\u0026thinsp;\u0026plusmn;\u0026thinsp;1.80\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c6\"\u003e \u003cp\u003e6.01\u0026thinsp;\u0026plusmn;\u0026thinsp;1.80\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c7\"\u003e \u003cp\u003e1.80\u0026thinsp;\u0026plusmn;\u0026thinsp;0.43\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e \u003cp\u003e3.34\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"1\" nameend=\"c9\" namest=\"c9\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec9\" class=\"Section2\"\u003e \u003ch2\u003e3.2 Physiological rates and physicochemical characterization of biodeposits\u003c/h2\u003e \u003cp\u003eTable\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e presents Chemical characterization of the biodeposits and water, and the calculated physiological rates of molluks.\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\u003eMean TOC and TP values of the seawater samples, mean values and standard deviation of the production rates of feces (FPR), pseudofeces (PPR), filtration (FR), clarification (CR), ingestion (IR), and Total Organic Carbon (TOC), as well as Total Nitrogen (TN), and Total Phosphorus (TP) of the biodeposits. Samples that fell below the detection limit of the analysis method are denoted by --. TOC, total organic carbon; TP, total phosphorus; TN, total nitrogen. FPR represents the production rate of feces produced by the individuals analyzed; PPR represents the production rate of pseudofeces; FR the total filtration rate; CR, the clearing rate; IR the total ingestion rate; SBQ represents Sambaqui, and CBS represents Caieira da Barra do Sul. Note: *Out of 12 samples, only four showed values above the detection limit of the analysis method (2.0 mg/L). **Out of 12 samples, only one sample exceeded the detection limit of the analysis method (2.0 mg/L). For the chemical composition of the water, composite sampling was used. The results were presented as the simple average of analyses performed in duplicate on five aliquots of water collected over 2 h. In SBQ, six water samples were analyzed for \u003cem\u003eP. perna\u003c/em\u003e and another six for \u003cem\u003eC. gigas\u003c/em\u003e. In CBS, eight samples were analyzed for \u003cem\u003eP. perna\u003c/em\u003e and six for \u003cem\u003eC. gigas\u003c/em\u003e. For FPR and PPR in SBQ, 18 samples were used for each species analyzed. In CBS, 18 samples of \u003cem\u003eC. gigas\u003c/em\u003e and 24 samples of \u003cem\u003eP. perna\u003c/em\u003e were used. For the analysis of TOC, TN, and TP in SBQ, 12 samples from each species were analyzed. In CBS, 12 samples of \u003cem\u003eC. gigas\u003c/em\u003e and 16 samples of \u003cem\u003eP. perna\u003c/em\u003e were used. The TOC, TN, and TP results of the biodeposits were standardized to a duration of 1 h.\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=\"char\" char=\"\u0026plusmn;\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\"\u0026plusmn;\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\"\u0026plusmn;\" 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=\"char\" char=\"\u0026plusmn;\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\"\u0026plusmn;\" class=\"colspec\" colname=\"c7\" colnum=\"7\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\"\u0026plusmn;\" class=\"colspec\" colname=\"c8\" colnum=\"8\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\"\u0026plusmn;\" class=\"colspec\" colname=\"c9\" colnum=\"9\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\"\u0026plusmn;\" class=\"colspec\" colname=\"c10\" colnum=\"10\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\"\u0026plusmn;\" class=\"colspec\" colname=\"c11\" colnum=\"11\"\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\u003eWATER\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"8\" nameend=\"c11\" namest=\"c4\"\u003e \u003cp\u003eBiodeposits\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/th\u003e \u003cth align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e \u003cp\u003eChemical characterization\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"3\" nameend=\"c6\" namest=\"c4\"\u003e \u003cp\u003eChemical characterization\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"5\" nameend=\"c11\" namest=\"c7\"\u003e \u003cp\u003eRates\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePoint/\u003c/p\u003e \u003cp\u003eSpecie\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eTOC\u003c/p\u003e \u003cp\u003e(mg.L\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eTP\u003c/p\u003e \u003cp\u003e(mg.L\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eTOC\u003c/p\u003e \u003cp\u003e(mg.L\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e.ind\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003eTN\u003c/p\u003e \u003cp\u003e(mg.L\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e.ind\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c6\"\u003e \u003cp\u003eTP\u003c/p\u003e \u003cp\u003e(mg.L\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e.ind\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c7\"\u003e \u003cp\u003eFPR\u003c/p\u003e \u003cp\u003e(mg.h\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e.ind\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c8\"\u003e \u003cp\u003ePPR\u003c/p\u003e \u003cp\u003e(mg.h\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e.ind\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c9\"\u003e \u003cp\u003eFR\u003c/p\u003e \u003cp\u003e(mg.h\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e.ind\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c10\"\u003e \u003cp\u003eCR\u003c/p\u003e \u003cp\u003e(L.h\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e.ind\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c11\"\u003e \u003cp\u003eIR\u003c/p\u003e \u003cp\u003e(mg.h\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e.ind\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e)\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eSBQ\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c11\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cem\u003eC. gigas\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e0.69\u0026thinsp;\u0026plusmn;\u0026thinsp;0.30\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e0.03\u0026thinsp;\u0026plusmn;\u0026thinsp;0.00\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c4\"\u003e \u003cp\u003e75.17\u0026thinsp;\u0026plusmn;\u0026thinsp;35.39\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e124.60\u0026thinsp;\u0026plusmn;\u0026thinsp;18.64*\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c6\"\u003e \u003cp\u003e11.77\u0026thinsp;\u0026plusmn;\u0026thinsp;9.51\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c7\"\u003e \u003cp\u003e22.0\u0026thinsp;\u0026plusmn;\u0026thinsp;13.0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c8\"\u003e \u003cp\u003e57.0\u0026thinsp;\u0026plusmn;\u0026thinsp;29.0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c9\"\u003e \u003cp\u003e84.68\u0026thinsp;\u0026plusmn;\u0026thinsp;33.61\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c10\"\u003e \u003cp\u003e3.99\u0026thinsp;\u0026plusmn;\u0026thinsp;1.58\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c11\"\u003e \u003cp\u003e15.15\u0026thinsp;\u0026plusmn;\u0026thinsp;6.82\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cem\u003eP. perna\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e0.63\u0026thinsp;\u0026plusmn;\u0026thinsp;0.16\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e0.04\u0026thinsp;\u0026plusmn;\u0026thinsp;0.01\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c4\"\u003e \u003cp\u003e41.43\u0026thinsp;\u0026plusmn;\u0026thinsp;17.21\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e77.31**\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c6\"\u003e \u003cp\u003e10.18\u0026thinsp;\u0026plusmn;\u0026thinsp;7.58\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c7\"\u003e \u003cp\u003e13.0\u0026thinsp;\u0026plusmn;\u0026thinsp;6.0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c8\"\u003e \u003cp\u003e98.0\u0026thinsp;\u0026plusmn;\u0026thinsp;56.0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c9\"\u003e \u003cp\u003e113.64\u0026thinsp;\u0026plusmn;\u0026thinsp;61.88\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c10\"\u003e \u003cp\u003e2.53\u0026thinsp;\u0026plusmn;\u0026thinsp;1.38\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c11\"\u003e \u003cp\u003e-30.30\u0026thinsp;\u0026plusmn;\u0026thinsp;30.10\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eCBS\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c11\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cem\u003eC. gigas\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e0.72\u0026thinsp;\u0026plusmn;\u0026thinsp;0.12\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e0.03\u0026thinsp;\u0026plusmn;\u0026thinsp;0.01\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c4\"\u003e \u003cp\u003e229.85\u0026thinsp;\u0026plusmn;\u0026thinsp;62.63\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e--\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c6\"\u003e \u003cp\u003e10.52\u0026thinsp;\u0026plusmn;\u0026thinsp;2.83\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c7\"\u003e \u003cp\u003e16.0\u0026thinsp;\u0026plusmn;\u0026thinsp;4.0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c8\"\u003e \u003cp\u003e67.0\u0026thinsp;\u0026plusmn;\u0026thinsp;20.0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c9\"\u003e \u003cp\u003e78.34\u0026thinsp;\u0026plusmn;\u0026thinsp;35.23\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c10\"\u003e \u003cp\u003e13.68\u0026thinsp;\u0026plusmn;\u0026thinsp;6.15\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c11\"\u003e \u003cp\u003e2.35\u0026thinsp;\u0026plusmn;\u0026thinsp;9.00\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cem\u003eP. perna\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e0.97\u0026thinsp;\u0026plusmn;\u0026thinsp;0.70\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e0.03\u0026thinsp;\u0026plusmn;\u0026thinsp;0.00\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c4\"\u003e \u003cp\u003e365.56\u0026thinsp;\u0026plusmn;\u0026thinsp;204.02\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e144.44**\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c6\"\u003e \u003cp\u003e24.03\u0026thinsp;\u0026plusmn;\u0026thinsp;11.65\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c7\"\u003e \u003cp\u003e7.0\u0026thinsp;\u0026plusmn;\u0026thinsp;3.0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c8\"\u003e \u003cp\u003e37.0\u0026thinsp;\u0026plusmn;\u0026thinsp;19.0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c9\"\u003e \u003cp\u003e39.54\u0026thinsp;\u0026plusmn;\u0026thinsp;23.16\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c10\"\u003e \u003cp\u003e6.03\u0026thinsp;\u0026plusmn;\u0026thinsp;3.53\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c11\"\u003e \u003cp\u003e11.57\u0026thinsp;\u0026plusmn;\u0026thinsp;31.76\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\u003eTOC ranged from 0.63 to 0.97 mg.L\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e for water between SBQ and CBS, and 75. 17 and 365.56 mg.L\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e.ind\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e for biodeposits between SBQ and CBS; TP presents low variation for water and ranged from 10.18 to 24.03 mg.L\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e. ind\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e for biodeposits between SBQ and CBS.; TN varied between 77.31 and 144.44 mg.L\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e. ind\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e between SBQ and CBS, and only five samples reached the detection limit for biodeposits characterization. All seawater TN samples had values below the detection limit; therefore, their results are not presented.\u003c/p\u003e \u003cp\u003eBiodeposits rates ranged for 7.0 (CBS) to 13.0 (SBQ) mg.h\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e. ind\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e for \u003cem\u003eP. perna\u003c/em\u003e and 16.0 (CBS) to 22.0 (SBQ) mg.h\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e. ind\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e for \u003cem\u003eC. gigas\u003c/em\u003e for FPR; 37.0 (CBS) to 98.0 (SBQ) mg.h\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e. ind\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e for \u003cem\u003eP. perna\u003c/em\u003e and 57.0 (SBQ) to 67.0 (CBS) mg.h\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e. ind\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e for \u003cem\u003eC. gigas\u003c/em\u003e for PPR; 39.54 (CBS) to 113.64 (SBQ) mg.h\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e. ind\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e for \u003cem\u003eP. perna\u003c/em\u003e and 78.34 (CBS) to 84.68 (SBQ) mg.h\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e. ind\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e for \u003cem\u003eC. gigas\u003c/em\u003e for FR; 2.53 (SBQ) to 6.03 (CBS) L.h\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e. ind\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e for \u003cem\u003eP. perna\u003c/em\u003e and 3.99 (SBQ) to 13.68 (CBS) L.h\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e. ind\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e for \u003cem\u003eC. gigas\u003c/em\u003e for CR, and; -30.30 (SBQ) to 11.57 (CBS) mg.h\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e. ind\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e for \u003cem\u003eP. perna\u003c/em\u003e and 2.35 (CBS) to 15.15 (SBQ) mg.h\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e. ind\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e for \u003cem\u003eC. gigas\u003c/em\u003e for IR.\u003c/p\u003e \u003cp\u003eThe analysis of biodeposit particles allowed us to determine the percentages of organic and inorganic matter in the feces and pseudofeces, across species at the two collection points (SBQ and CBS) (Fig.\u0026nbsp;\u003cspan refid=\"Fig6\" class=\"InternalRef\"\u003e6\u003c/span\u003e).\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003e By analyzing the filtration rates, ingestion, and production of feces and pseudofeces, we determined the concentrations of TOC, TN, and TP in the particles ingested by the animals and the concentrations eliminated as feces and pseudofeces for each species analyzed, X and Y, and according to the data observed and calculated for each location (Figs.\u0026nbsp;\u003cspan refid=\"Fig7\" class=\"InternalRef\"\u003e7\u003c/span\u003e and \u003cspan refid=\"Fig8\" class=\"InternalRef\"\u003e8\u003c/span\u003e).\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e"},{"header":"4. Discussion","content":"\u003cp\u003eIn our study, we conducted the chemical characterization of mollusk feces and pseudofeces and quantified their production rates. Descriptive analyses of the obtained results were performed, enabling a comprehensive evaluation of the analyzed parameters. The results of this study allowed us to observe how the particles present in the North and South Bays of Santa Catarina Island influenced those ingested and excreted as feces and pseudo-feces by the oyster \u003cem\u003eC. gigas\u003c/em\u003e and the mussel \u003cem\u003eP. perna\u003c/em\u003e at the study site.\u003c/p\u003e \u003cp\u003eOur findings align with those of Lima et al. (\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e2023\u003c/span\u003e), Nascimento et al. (\u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e2022\u003c/span\u003e), and Ferreira et al. (\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e2006\u003c/span\u003e) regarding the disparities between the SBQ and CBS collection points for PIM, indicating that SBQ exhibits higher PIM values than CBS. The variation in PIM values between SBQ and CBS could be linked to differences in physical characteristics and chemical composition across the North and South regions of the Bay of Santa Catarina Island. The South section of the Bay, where the CBS collection point is situated, experiences significant tidal fluctuations, unlike the North section, and factors such as wind and ocean current velocities directly impact suspended particles in the water (Ferreira et al., \u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e2006\u003c/span\u003e; Garbossa et al., \u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e2014\u003c/span\u003e; Silva et al., \u003cspan citationid=\"CR42\" class=\"CitationRef\"\u003e2019\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eLima et al. (\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e2023\u003c/span\u003e) reported significant variations between SBQ and CBS as we observed in our study. This discrepancy could be attributed to the number of samples collected and the experiment duration conducted by these authors. Specifically, they collected 120 samples to evaluate water quality parameters. In contrast, our samples were collected at specific points in time. Therefore, in future studies, a larger number of water samples should be collected to more effectively demonstrate the differences between the analyzed collection sites.\u003c/p\u003e \u003cp\u003eThe SAL, T, and CP parameters at both sites are consistent with the findings reported by Nascimento et al. (\u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e2022\u003c/span\u003e) for the same collection sites. However, Ferreira et al. (\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e2006\u003c/span\u003e) identified a higher concentration of CP in the North Bay than in the South Bay. This variation seems to be associated with the extended duration of their study, during which data was collected bi-weekly over 14 years. In contrast, our study conducted weekly collections, which might have been more immediately impacted by variable factors such as wind and tide.\u003c/p\u003e \u003cp\u003eAccording to Ferreira et al. (\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e2006\u003c/span\u003e), water quality monitoring, including measurements of CP and TPM, suggested that the northern Bay provides a richer food source for bivalve mollusks compared to the South Bay. However, this food source may be less accessible due to the increased energy expenditure required by bivalves to select and metabolize the particles. The feeding behavior and metabolism of the fauna surrounding marine animal cultivation areas are directly influenced by the properties and composition of POM in seawater. This matter is selectively consumed by filter-feeding organisms, such as mollusks, which alters its composition, consequently impacting the feeding habits and biodeposition of marine bivalve mollusks (Sakamaki et al., \u003cspan citationid=\"CR38\" class=\"CitationRef\"\u003e2020\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eThe literature reports a wide range of production rates of biodeposits. These variations are attributed to different methodologies, model species, and the physical and chemical parameters of the water where the bivalve mollusks reside, as well as the physiological rates specific to each species and age (Callier et al., \u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e2006\u003c/span\u003e; Dame, \u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e1993\u003c/span\u003e; Lin et al., \u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e2016\u003c/span\u003e; Nascimento et al., \u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e2022\u003c/span\u003e). Rates are measured both individually (Callier et al., \u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e2006\u003c/span\u003e; Chamberlain, \u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e2002\u003c/span\u003e; Haven and Morales-Alamo, \u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e1966\u003c/span\u003e; Nascimento et al., \u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e2022\u003c/span\u003e; Navarro and Thompson, \u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e1997\u003c/span\u003e; Schmitt, \u003cspan citationid=\"CR41\" class=\"CitationRef\"\u003e2002\u003c/span\u003e) and collectively, as is the case with studies conducted directly in the environment (Boucher-Rodoni and Boucher, \u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e1990\u003c/span\u003e; Hayakawa et al., \u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e2001\u003c/span\u003e; Jaramillo et al., \u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e1992\u003c/span\u003e; Mallet et al., \u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e2006\u003c/span\u003e; Mitchell, \u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e2006\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eTaking into account the cultivation areas allocated to the bays of Santa Catarina Island, this analysis centers on the daily production of feces and pseudofeces in a marine mollusk farm. A farm may encompass an area of one hectare, for instance, comprising 10 longlines, each with 50 units of ropes (for mussels) or lantern nets (for oysters), with each unit housing 180 animals. Assuming an equal division of production between mussels and oysters, the total production of feces and pseudofeces for the entire farming area is approximately 171.18 kg per day, which equates to a density of about 17.12 g.m\u003csup\u003e\u0026minus;\u0026thinsp;2\u003c/sup\u003e in a single day. Understanding these values is crucial for building scenarios with physically-based numerical models, which help us grasp how particles behave in the environment, including how the generated material spreads and settles, as well as how it interacts and reacts with the seabed and water column.\u003c/p\u003e \u003cp\u003eThe Figure of 17.12 g.m\u003csup\u003e\u0026minus;\u0026thinsp;2\u003c/sup\u003e refers to the daily production of feces and pseudofeces, representing raw data on biodeposit generation. It is important to note that mollusks\u0026rsquo; feces and pseudofeces are consumed by free-swimming animals, decompose before reaching the seabed, and are transported by sea currents (affect horizontal velocities and dispersion radius). Therefore, by integrating this data into hydrodynamic models and accounting for the various factors influencing biodeposits, we can enhance the accuracy of determining the load and dispersion plume of feces and pseudofeces produced by mollusk farms in specific locations. Furthermore, the role of mollusks in providing ecosystem services is significant, as they are filter-feeding organisms that utilize suspended particles in the water for growth. Through this process, they contribute to critical environmental functions such as coastal stabilization, habitat provision for other species, nutrient cycling (phosphorus and nitrogen), and water purification via their filtration mechanisms (Catherine et al., \u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e2024\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eA study conducted in Mosquito Lagoon, Florida (USA), evaluated the chemical composition of biodeposits from juvenile \u003cem\u003eCrassostrea virginica\u003c/em\u003e in a laboratory setting. The study found that juveniles of this species exhibited higher rates of chlorophyll-α removal and ammonium release than their older counterparts. Moreover, their biodeposits contained higher concentrations of dissolved organic carbon, nitrate, and ammonium ion than the older oysters (Locher et al., \u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e2021\u003c/span\u003e). The age of mollusks also directly affects their metabolism and, as a result, influences the production of biodeposits (Bayne, \u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e2017\u003c/span\u003e). A higher concentration of TOC was found in the biodeposits produced by the mollusks in CBS than those produced by the mollusks in SBQ. This difference may be due to the greater amount of particles being rejected as pseudofeces (Locher et al., \u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e2021\u003c/span\u003e), which enriches the concentration of total biodeposits due to the increased load of inorganic particles, as also described by Newell and Jordan (\u003cspan citationid=\"CR36\" class=\"CitationRef\"\u003e1983\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eThe TOC data collected from the water were similar across the sampling sites (SBQ \u0026ndash; CBS), however, significant variation was observed in relation to the biodeposits., potentially attributable to the composition of particulate matter in the environment. These findings support those of Nascimento et al. (\u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e2022\u003c/span\u003e), who observed significant differences in particulate matter levels between the North Bay and the South Bay, consequently affecting the feeding rates of mollusks.\u003c/p\u003e \u003cp\u003eThe low concentration of TOC found in the biodeposits of the bivalve mollusks evaluated in the SBQ region appears to have an inverse relationship with the high PIM values found in the seawater of SBQ. In other words, when there is less organic matter in the water, the biodeposits produced by animals have lower concentrations of TOC than those produced by animals in environments with less inorganic matter, such as CBS. This factor might be associated with the animals\u0026rsquo; energy physiology. Among these aspects, the clearing rate stands out, showing significant differences between the species and sites analyzed. The rates were higher in CBS compared to SBQ, suggesting that the mollusks had to filter a larger volume of water in CBS to obtain the same particle load as in SBQ.\u003c/p\u003e \u003cp\u003e Furthermore, the variation in clearance rates may be linked to the energy physiology of the animals, particularly their ability to filter and select suitable particles for their diet and metabolism. Nascimento et al. (\u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e2022\u003c/span\u003e) observed a relationship between the clearance rate and the weight of the animal, TPM, and the PIM/POM ratio, for the same collection sites that we analyzed.\u003c/p\u003e \u003cp\u003eThe filtration and ingestion rates did not show any significant differences, which we believe can be attributed to the occasional collections. The variation in these rates is related to the presence of organic and inorganic particles in the water, and we can link these rate results to the observed PIM/POM ratio. Ratio values higher than 6 can lead oysters or mussels to produce more pseudofeces than feces. According to (Adams et al., 2019), there is an inverse relationship between IR and the PIM/POM ratio, which can indicate the resuspension of sediments in the environment, which directly affects the physiological processes undertaken by mollusks. We observed that the lower rates of whitening in SBQ are indicative of higher PIM/POM ratio results when compared to those in CBS. Our data corroborates the results obtained by Galimany et al. (2017), who observed when studying \u003cem\u003eC. virginica\u003c/em\u003e that this mollusk can reject inorganic matter and increase its CR when the content of organic matter decreases.\u003c/p\u003e \u003cp\u003eThe concentrations of TOC, TN, and TP in the water are crucial for understanding nutrient cycling and are essential in determining the amounts ingested by mollusks, as well as those expelled and returned to the environment. This information highlights the importance of understanding the effects of marine aquaculture farm installations on the benthic environment. Dan et al. (\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e2021\u003c/span\u003e), in a study conducted in Daya Bay, China, found that biodeposits - specifically feces, pseudofeces, and uneaten fish feed - constitute over 40% of the organic matter found in the sediment beneath aquaculture systems.\u003c/p\u003e \u003cp\u003eStudies that examine the concentration of nitrogen in both water and biodeposits, with appropriate detection limits for the samples, are essential for comprehending the processes subsequent to the release of biodeposits into the water. Dalrymple and Carmichael (\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e2015\u003c/span\u003e) affirm the significance of conducting such studies. They demonstrated that the quantity of nitrogen released in biodeposits did not differ between age groups. However, they noted variances in metabolism and assimilation between juvenile and adult age groups.\u003c/p\u003e \u003cp\u003eConcentrations of TP play a crucial role as they are closely associated with the growth of marine organisms, particularly phytoplankton (Newell et al., \u003cspan citationid=\"CR35\" class=\"CitationRef\"\u003e2005\u003c/span\u003e). Despite its significant influence on various environmental processes, there are limited studies focusing on phosphorus concentrations, particularly in biodeposits (Magni et al., \u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e2000\u003c/span\u003e; Newell et al., \u003cspan citationid=\"CR35\" class=\"CitationRef\"\u003e2005\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eThe physicochemical characterization of particles in water and biodeposits facilitates the estimation of calculations such as mass balance, which is pivotal for comprehending the chemical reactions occurring in the environment. This data will enable the extrapolation of calculations to determine the environment\u0026rsquo;s carrying capacity, which in turn, will aid in developing sustainable mariculture and identifying management strategies to preserve the environment (Buck and Langan, \u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e2017\u003c/span\u003e; Sakamaki et al., \u003cspan citationid=\"CR40\" class=\"CitationRef\"\u003e2022\u003c/span\u003e; Silva et al., \u003cspan citationid=\"CR42\" class=\"CitationRef\"\u003e2019\u003c/span\u003e). Ferreira et al. (\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e2006\u003c/span\u003e) highlighted the necessity of conducting studies to monitor shellfish farming at the sites we investigated, to enable the industry\u0026rsquo;s growth without causing environmental harm. These data also highlight the ecological significance of mollusks, given the wide range of ecosystem services they provide (Catherine et al., \u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e2024\u003c/span\u003e).\u003c/p\u003e"},{"header":"5. Conclusions","content":"\u003cp\u003eThe study enabled successful physicochemical characterization of the biodeposits from \u003cem\u003eC. gigas\u003c/em\u003e and \u003cem\u003eP. perna\u003c/em\u003e cultivated at collection sites in the North and South Bays of Santa Catarina Island. Additionally, it was possible to determine the production rates of feces, pseudofeces, filtration, clarification, and ingestion. The results revealed a noteworthy disparity in particulate inorganic matter between the collection sites, with SBQ exhibiting higher levels than CBS. Moreover, the total organic carbon content of the biodeposits was greater in CBS compared to SBQ for both species. Significant differences in clearance rates were observed among species and collection sites. The chemical characterization of the biodeposits and the observed physiological rates in this study will pave the way for further research aimed at determining the carrying capacity of the North and South Bays for the farming of marine bivalve mollusks.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eCRediT authorship contribution statement\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eEliziane Silva\u003c/strong\u003e: Performed the research, Collected data, Performed the analysis, Wrote the manuscript with input from all authors, Discussed the results and contributed to the final manuscript. \u003cstrong\u003eCarlos Henrique Araujo de Miranda Gomes:\u003c/strong\u003e Carried out the implementation of experiments, Collected the data, Discussed the results and contributed to the final manuscript. \u003cstrong\u003eLuis Hamilton Pospissil Garbossa:\u003c/strong\u003e Helped to write manuscript and designed the study, Discussed the results and contributed to the final manuscript. \u003cstrong\u003eClaudio Manoel Rodrigues de Melo:\u003c/strong\u003e Responsible for funding acquisition, Supervising the research activities, Discussed the results and contributed to the final manuscript. \u003cstrong\u003eKatt Regina Lapa:\u003c/strong\u003e Responsible for funding acquisition, Supervising the research activities, Discussed the results and contributed to the final manuscript.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003e\u003cstrong\u003eDeclaration of competing interest\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003e\u003cstrong\u003eData availability\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eData will be made available on request.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003e\u003cstrong\u003eAcknowledgments\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors would like to thank Epagri for supporting carrying out the experiments, and Fazenda Marinha Para\u0026iacute;so das Ostras for their availability as a location for collection.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003e\u003cstrong\u003eFunding\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis study was financed by the \u0026lsquo;Coordination for the Improvement of Higher Education Personnel \u0026ndash; Brazil (CAPES) \u0026ndash; Finance Code 001\u0026rsquo; and by the Federal University of Santa Catarina (249/2016). The authors also thank the \u0026lsquo;National Council for Scientific and Technological Development (CNPq),\u0026rsquo; who provided a scholarship to Claudio De Melo. The present work was supported by FAPESC, call for proposals 53/2022.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003e\u003cstrong\u003eEthics approval\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAccording to Brazilian law, authorization for the use of invertebrates, including oysters, is not required in the conduct of scientific experiments.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eBayne, B., 2017. Biology of Oysters. Academic Press. https://doi.org/10.1038/150544c0\u003c/li\u003e\n\u003cli\u003eBoucher-Rodoni, R., Boucher, G., 1990. In situ study of the effect of oyster biomass on benthic metabolic exchange rates. Hydrobiologia 206, 115\u0026ndash;123. https://doi.org/10.1007/BF00018637\u003c/li\u003e\n\u003cli\u003eBuck, B.H., Langan, R., 2017. Aquaculture Perspective of Multi-Use Sites in the Open Ocean: The Untapped Potential for Marine Resources in the Anthropocene. https://doi.org/10.1007/978-3-319-51159-7\u003c/li\u003e\n\u003cli\u003eCallier, M.D., Weise, A.M., McKindsey, C.W., Desrosiers, G., 2006. Sedimentation rates in a suspended mussel farm (Great-Entry Lagoon, Canada): Biodeposit production and dispersion. Mar Ecol Prog Ser 322, 129\u0026ndash;141. https://doi.org/10.3354/meps322129\u003c/li\u003e\n\u003cli\u003eCatherine, PCS, Nandan, SB, Hershey, NR (2024). Diversidade de moluscos bivalves, seus servi\u0026ccedil;os ecossist\u0026ecirc;micos e impactos potenciais das mudan\u0026ccedil;as clim\u0026aacute;ticas. In: Joseph, S., Pradeepkumar, A. (eds) Avalia\u0026ccedil;\u0026atilde;o de servi\u0026ccedil;os ecossist\u0026ecirc;micos para o desenvolvimento sustent\u0026aacute;vel. Springer, Singapura. https://doi.org/10.1007/978-981-97-4688-0_7\u003c/li\u003e\n\u003cli\u003eChamberlain, J., 2002. Modelling the Environmental Impacts of Suspended Mussel (Mytilus edulis L.) Farming. Napier University - Edinburgh.\u003c/li\u003e\n\u003cli\u003eCranford, P.J., Hargrave, B.T., Doucette, L.I., 2009. Benthic organic enrichment from suspended mussel (Mytilus edulis) culture in Prince Edward Island, Canada. Aquaculture 292, 189\u0026ndash;196. https://doi.org/10.1016/j.aquaculture.2009.04.039\u003c/li\u003e\n\u003cli\u003eDalrymple, D.J., Carmichael, R.H., 2015. Effects of age class on N removal capacity of oysters and implications for bioremediation. Mar Ecol Prog Ser 528, 205\u0026ndash;220. https://doi.org/10.3354/meps11252\u003c/li\u003e\n\u003cli\u003eDame, R.F., 1993. Bivalve Filter Feeder in Estuarine and Coastal Ecosystems Processes, Bivalve Filter Feeders. NATO ASI Series G: Ecological Sciences 33. Springer. https://doi.org/10.1007/978-3-642-78353-1_7\u003c/li\u003e\n\u003cli\u003eDan, S.F., Li, S., Yang, B., Cui, D., Ning, Z., Huang, H., Zhou, J., Yang, J., 2021. Influence of sedimentary organic matter sources on the distribution characteristics and preservation status of organic carbon, nitrogen, phosphorus, and biogenic silica in the Daya Bay, northern South China Sea. Science of the Total Environment 783, 146899. https://doi.org/10.1016/j.scitotenv.2021.146899\u003c/li\u003e\n\u003cli\u003eFerreira, J.F., Besen, K., Wormsbecher, A.G., Dos Santos, R.F., 2006. Physical-Chemical Parameters of Seawater Mollusc Culture Sites in.\u003c/li\u003e\n\u003cli\u003eFilgueira;, R., Guyondet;, T., Comeau;, L., Mckindsey, C.W., 2015. Modelling Carrying Capacity of Bivalve Aquaculture: A Review of Definitions and Methods, Encyclopedia of Sustainability Science and Technology. https://doi.org/10.1007/978-1-4939-2493-6\u003c/li\u003e\n\u003cli\u003eFood and Agriculture Organization of the United Nations, 2022. The State of World Fisheries and Aquaculture 2022, The State of World Fisheries and Aquaculture 2022. FAO. https://doi.org/10.4060/cc0461en\u003c/li\u003e\n\u003cli\u003eGaltsoff, P.S., 1964. The American Oyster Crassostrea virginica Gmelin. Fishery bulletin of the Fish and Wildlife Service 64, 1\u0026ndash;15.\u003c/li\u003e\n\u003cli\u003eGarbossa, L.H.P., Vanz, A., Fernandes, L., Souza, R.V. de, Vianna, F.L., Rupp, G., 2014. MODELLING AND VALIDATION OF THE SANTA CATARINA ISLAND BAYS HYDRODYNAMICS BASED ON ASTRONOMIC TIDES AND MEASURED TIDES, in: 11th International Conference on Hydroinformatics. New York - USA.\u003c/li\u003e\n\u003cli\u003eGosling, E., 2003. Bivalve Molluscs: Biology, Ecology and Culture, Syria Studies. Fishing News Books.\u003c/li\u003e\n\u003cli\u003eGrant, C., Archambault, P., Olivier, F., McKindsey, C., 2012. Influence of \u0026lsquo;bouchot\u0026rsquo; mussel culture on the benthic environment in a dynamic intertidal system. Aquac Environ Interact 2, 117\u0026ndash;131. https://doi.org/10.3354/aei00035\u003c/li\u003e\n\u003cli\u003eHaven, D.S., Morales‐Alamo, R., 1966. Aspects of Biodeposition By Oysters and Other Invertebrate Filter Feeders. Limnol Oceanogr 11, 487\u0026ndash;498. https://doi.org/10.4319/lo.1966.11.4.0487\u003c/li\u003e\n\u003cli\u003eHawkins, A.J.S., Smith, R.F.M., Bayne, B.L., H\u0026eacute;ral, M., 1996. Novel observations underlying the fast growth of suspension-feeding shellfish in turbid environments : Mytilus edulis. Mar Ecol Prog Ser 131, 179\u0026ndash;190.\u003c/li\u003e\n\u003cli\u003eHayakawa, Y., Kobayashi, M., Izawa, M., 2001. Sedimentation flux from mariculture of oyster (Crassostrea gigas) in Ofunato estuary, Japan. ICES Journal of Marine Science 58, 435\u0026ndash;444. https://doi.org/10.1006/jmsc.2000.1036\u003c/li\u003e\n\u003cli\u003eIBGE - Instituto Brasileiro de Geografia e Estat\u0026iacute;stica, 2022. Quantidade produzida de ostras, vieiras e mexilh\u0026otilde;es em 2021. https://cidades.ibge.gov.br/brasil/sc/pesquisa/18/0?tipo=ranking\u0026amp;indicador=16488 (accessed 10 February 2023).\u003c/li\u003e\n\u003cli\u003eIglesias, J.I.P., Urrutia, M.B., Navarro, E., Ibarrola, I., 1998. Measuring feeding and absorption in suspension-feeding bivalves: An appraisal of the biodeposition method. J Exp Mar Biol Ecol 219, 71\u0026ndash;86. https://doi.org/10.1016/S0022-0981(97)00175-5\u003c/li\u003e\n\u003cli\u003eJaramillo, E., Bertr\u0026aacute;n, C., Bravo, A., 1992. Mussel biodeposition in an estuary in southern Chile. Mar Ecol Prog Ser 82, 85\u0026ndash;94. https://doi.org/10.3354/meps082085\u003c/li\u003e\n\u003cli\u003eLima, R. de C.D., Ferreira, J.P.R., Santo, C.M. do E., Silva, F.C. da, Gomes, C.H.A. de M., Melo, C.M.R. de, 2023. Spat of pacific oysters ( Crassostrea gigas ) grown in subtropical environments. Journal of Applied Aquaculture 00, 1\u0026ndash;23. https://doi.org/10.1080/10454438.2023.2231432\u003c/li\u003e\n\u003cli\u003eLin, J., Li, C., Zhang, S., 2016. Hydrodynamic effect of a large offshore mussel suspended aquaculture farm. Aquaculture 451, 147\u0026ndash;155. https://doi.org/10.1016/j.aquaculture.2015.08.039\u003c/li\u003e\n\u003cli\u003eLocher, B., Hurst, N.R., Walters, L.J., Chambers, L.G., 2021. Juvenile Oyster (Crassostrea virginica) Biodeposits Contribute to a Rapid Rise in Sediment Nutrients on Restored Intertidal Oyster Reefs (Mosquito Lagoon, FL, USA). Estuaries and Coasts 44, 1363\u0026ndash;1379. https://doi.org/10.1007/s12237-020-00874-2\u003c/li\u003e\n\u003cli\u003eLysiak-Pastuszak, E., Andersens, H.C., 2004. Chemical measurements in the Baltic Sea: Guidelines on quality assurance. ICES Techniques in Marine Environmental Sciences.\u003c/li\u003e\n\u003cli\u003eMagni, P., Montani, S., Takada, C., Tsutsumi, H., 2000. Temporal scaling and relevance of bivalve nutrient excretion on a tidal flat of the Seto Inland Sea, Japan. Mar Ecol Prog Ser 198, 139\u0026ndash;155. https://doi.org/10.3354/meps198139\u003c/li\u003e\n\u003cli\u003eMallet, A.L., Carver, C.E., Landry, T., 2006. Impact of suspended and off-bottom Eastern oyster culture on the benthic environment in eastern Canada. Aquaculture 255, 362\u0026ndash;373. https://doi.org/10.1016/j.aquaculture.2005.11.054\u003c/li\u003e\n\u003cli\u003eMitchell, I.M., 2006. In situ biodeposition rates of Pacific oysters ( Crassostrea gigas ) on a marine farm in Southern Tasmania ( Australia ). Aquaculture 257, 194\u0026ndash;203. https://doi.org/10.1016/j.aquaculture.2005.02.061\u003c/li\u003e\n\u003cli\u003eNascimento, V.S. do, Lapa, K.R., Gomes, C.H.A. de M., Gray, M., Silva, G. da, Garbossa, L.H.P., Suplicy, F.M., Melo, C.M.R. de, 2022. Filtration and biodeposition rates of Crassostrea oysters for southern Brazilian waters. Reg Stud Mar Sci 56, 102677. https://doi.org/10.1016/j.rsma.2022.102677\u003c/li\u003e\n\u003cli\u003eNavarro, J.M., Thompson, R.J., 1997. Biodeposition by the horse mussel Modiolus modiolus (Dillwyn) during the spring diatom bloom. J Exp Mar Biol Ecol 209, 1\u0026ndash;13. https://doi.org/10.1016/0022-0981(96)02681-0\u003c/li\u003e\n\u003cli\u003eNewell, R.I.E., 2006. A framework for developing \u0026ldquo;ecological carrying capacity\u0026rdquo; mathematical models for bivalve mollusc aquaculture. Bull. Fish. Res. Agen. 19.\u003c/li\u003e\n\u003cli\u003eNewell, R.I.E., 2004. Ecosystem influences of natural and cultivated populations of suspension-feeding bivalve molluscs: A review. J Shellfish Res 23, 51\u0026ndash;61.\u003c/li\u003e\n\u003cli\u003eNewell, R.I.E., Fisher, T.R., Holyoke, R.R., Cornwell, J.C., 2005. Influence of Eastern Oysters on Nitrogen and Phosphorus Regeneration in Chesapeake Bay, USA. 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Aquaculture 288, 239\u0026ndash;253. https://doi.org/10.1016/j.aquaculture.2008.12.001\u003c/li\u003e\n\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"oyster, mussel, biodeposits, physicochemical characterization","lastPublishedDoi":"10.21203/rs.3.rs-5397899/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-5397899/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eIn order to comprehend carrying capacity of environments conducive to mollusk cultivation, investigations into the chemical properties and determination of biodeposit production rates are imperative. The aim of our study was to conduct physicochemical characterizing the biodeposits production from marine bivalve mollusks in the North and South bays of Santa Catarina Island, observing the rate of production of feces and pseudofeces and C, N e P the biodeposits of \u003cem\u003ePerna perna\u003c/em\u003e and \u003cem\u003eCrassostrea gigas\u003c/em\u003e. Feces and pseudofeces were gathered utilizing an individual chamber system, facilitating controlled seawater flow at a rate of 500 mL.min⁻\u0026sup1;. Organisms were individually accommodated within these chambers, and biodeposits were amassed over a two-hour period. A total of 130 animals were utilized for the study (60 individuals of \u003cem\u003eC. gigas\u003c/em\u003e and 70 individuals of \u003cem\u003eP. perna\u003c/em\u003e), across 13 collections, between December 2021 and April 2022. We quantified the production rates of feces, pseudofeces, total phosphorus, total organic carbon, and total nitrogen. The results provide insight into the influence of the physicochemical characteristics of the environment on the production rates of feces and pseudofeces, as well as the concentrations of carbon, phosphorus, and nitrogen in the biodeposits produced by the animals cultivated at each sampling site. The outcomes of this study facilitate the determination of biodeposit production rates and the chemical characterization of feces and pseudofeces from scientific species, thereby advancing research concerning environmental carrying capacity and striving for the sustainability of malacoculture in Santa Catarina.\u003c/p\u003e","manuscriptTitle":"Physicochemical Characterization of Feces and Pseudofeces Production by Bivalve Marine Mollusks Cultivated in the South Atlantic","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2024-11-26 20:17:15","doi":"10.21203/rs.3.rs-5397899/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"3cbc3f9c-25d2-4963-96bd-8f0fef01a1f9","owner":[],"postedDate":"November 26th, 2024","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2025-01-28T22:48:09+00:00","versionOfRecord":[],"versionCreatedAt":"2024-11-26 20:17:15","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-5397899","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-5397899","identity":"rs-5397899","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}