Shellfish Waters Research Articles

Comparative study of lysine acetylation in Vesicomyidae clam Archivesica marissinica and the manila clam Ruditapes philippinarum: adaptation mechanisms in cold seep environments

BackgroundThe deep-sea cold seep zone is characterized by high pressure, low temperature, darkness, and oligotrophy. Vesicomyidae clams are the dominant species within this environment, often forming symbiotic relationships with chemosynthetic microbes. Understanding the mechanisms by which Vesicomyidae clams adapt to the cold seep environment is significant. Acetylation modification of lysine is known to play a crucial role in various metabolic processes. Consequently, investigating the role of lysine acetylation in the adaptation of Vesicomyidae clams to deep-sea environments is worthwhile. So, a comparative study of lysine acetylation in cold seep clam Archivesica marissinica and shallow water shellfish Ruditapes philippinarum was conducted.ResultsA total of 539 acetylated proteins were identified with 1634 acetylation sites. Conservative motif enrichment analysis revealed that the motifs -KacR-, -KacT-, and -KacF- were the most conserved. Subsequent gene ontology (GO) and Kyoto encyclopedia of genes and genomes (KEGG) enrichment analyses were conducted on significantly differentially expressed acetylated proteins. The GO enrichment analysis indicated that acetylated proteins are crucial in various biological processes, including cellular response to stimulation, and other cellular processes ( p < 0.05 and false discovery rate (FDR) < 0.25). The results of KEGG enrichment analysis indicated that acetylated proteins are involved in various cellular processes, including tight junction, motor proteins, gap junction, phagosome, cGMP-PKG signaling pathways, endocytosis, glycolysis/gluconeogenesis, among others (p < 0.05 and FDR < 0.25). Notably, a high abundance of lysine acetylation was observed in the glycolysis/glycogenesis pathways, and the acetylation of glyceraldehyde 3-phosphate dehydrogenase might facilitate ATP production. Subsequent investigation into acetylation modifications associated with deep-sea adaptation revealed the specific identification of key acetylated proteins. Among these, the adaptation of cold seep clam hemoglobin and heat shock protein to high hydrostatic pressure and low temperature might involve an increase in acetylation levels. Acetylation of arginine kinase might be related to ATP production and interaction with symbiotic bacteria. Myosin heavy chain (Ama01085) has the most acetylation sites and might improve the actomyosin system stability through acetylation. Further validation is required for the acetylation modification from Vesicomyidae clams.ConclusionA novel comparative analysis was undertaken to investigate the acetylation of lysine in Vesicomyidae clams, yielding novel insights into the regulatory role of lysine acetylation in deep-sea organisms. The findings present many potential proteins for further exploration of acetylation functions in cold seep clams and other deep-sea mollusks.

A comparison of the MPN and pour plate methods for estimating shellfish contamination by Escherichia coli.

Shellfish production areas are classified for suitability for human consumption using counts of Escherichia coli in shellfish samples. Two alternative laboratory methods are approved in the European Union and UK for measuring E. coli in shellfish samples; the most probable number (MPN) and pour plate methods. These methods have inherently different statistical uncertainty and may give different counts for the same sample. Using two approaches: simulated data and spiking experiments, we investigate the theoretical properties of the two methods to determine their reliability for shellfish waters classification. Assuming a Poisson distribution of E. coli in shellfish samples, we simulate concentrations in 10 000 samples using the MPN and pour plate methods. We show that for higher concentrations of E. coli the pour plate method becomes increasingly more reliable than the MPN method. The MPN method has higher probabilities than pour plate of generating results exceeding shellfish classification thresholds, while conversely having higher probabilities of failing to detect counts that exceed regulatory thresholds. The theoretical analysis also demonstrates that the MPN method can produce genuine extreme outliers, even when E. coli are randomly distributed within the sampled material. A laboratory spiking experiment showed results consistent with the theoretical analysis, suggesting the Poisson assumption used in the theoretical analysis is reasonable. The large differences in statistical properties between the pour plate and MPN methods should be taken into consideration in classifying shellfish beds, with the pour plate method being more reliable over the crucial range of E. coli concentrations used to determine class boundaries.

Projections of climate-driven biogeographical changes of benthic mollusks in the Yellow Sea and East China Sea

Climate change influences the distribution of many marine species. To project the biogeographical changes of benthic mollusks in response to climate change in the Yellow Sea and East China Sea, ensemble species distribution models (SDMs) were applied. Ensemble SDMs performed well for ten of the thirteen selected benthic mollusks with environmental variables including temperature, salinity, current velocity, and depth. Six cold water mollusks, including bivalves Acila mirabilis, Ennucula niponica, Ennucula tenuis, Nuculana yokoyamai, Pendaloma otohimeae and Megayoldia japonica, were projected to contract their habitats and move northward in 2050s and 2100s under all of the RCP2.6, 4.5, 6.0 and 8.5 climate scenarios, with temperature being the most important environmental variable. Two warm water mollusks (bivalves Nucula tokyoensis and Leptomya minuta) were projected to lose their suitable habitats under future climate scenarios (all RCP scenarios), while two (the gastropod Cylichna biplicata and the bivalve Moerella hilaris) were projected to expand their habitats to the deeper water area. The most important environmental variable varied among warm water species between temperature, salinity and depth. This study will contribute to better understanding the marine species biogeographical changes under climate change, and thus we can better protect their biodiversity.

Comparative proteomic analysis of cold seep clam Archivesica marissinica and shallow water shellfish Ruditapes philippinarum provides insights into the adaptation mechanisms of deep-sea mollusks

IntroductionThe deep-sea environment is always characterized by high hydrostatic pressure, fluctuating temperatures, heavy metals, darkness, and others. The Vesicomyidae inhabit cold seep zones, hydrothermal vents, and other chemically reduced environments.MethodsTo enhance the understanding of the adaptation mechanisms of clams in extreme environments, a comprehensive proteomic study was conducted on the cold seep clam Archivesica marissinica and shallow water clam Ruditapes philippinarum.ResultsA total of 4,557 proteins were identified from the comparative groups. The Gene Ontology results indicated that the differentially expressed proteins (DEP) for the comparative group Rpgill vs. Amgill were enriched in the nitrogen compound metabolic process, and others. The comparative analysis for Amfoot vs. Amgill and Ammantle vs. Amgill revealed significant enrichment of the differential proteins that were involved in metal ion transport, divalent inorganic cation transport, and so on. The Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis for the comparative group Rpgill vs. Amgill was significantly enriched in the regulation of actin cytoskeleton, lysosome, and others. The proteins that exhibited differential expression in the cold seep clam’ different tissues were also enriched in important pathways, such as lysosome, fatty acid degradation, nitrogen metabolism.DiscussionThe further analysis identified crucial response proteins involved in various biological pathways. For example, the pattern recognition receptors, such as galectin and peptidoglycan recognition protein, participated in recognition of symbiotic microorganisms. The lysosome pathway members, such as cathepsin and saposins, were engaged in the degradation process of symbiont proteins during symbiont digestion. Profilin and gelsolin from actin cytoskeleton pathway might be pressure-related proteins. Furthermore, carbonic anhydrases from nitrogen metabolism KEGG pathway provide inorganic carbon for symbiotic bacteria. Additionally, Mn superoxide dismutase plays a role in the scavenging of superoxide anion radicals and antioxidant activity. Then, arginine kinases facilitate the low temperature adaptation of deep-sea shellfish with its cold adaptation characters. These findings offer novel perspectives on the proteins that are implicated in A. marisica’s response to cold seep environments, thereby contributing to the understanding of deep-sea biological adaptation and the preservation of deep-sea ecosystems.

Zoo-Chemical Profile Analysis of Ten Marine Mollusca Shells Using Different Solvents From Vedaranyam, South-East Coast of Tamilnadu, India

Zoochemicals are the animal equivalent of phytochemicals in plants. They are compounds in animals that are believed to provide health benefits beyond the traditional nutrients that food contains. In the present work investigates the qualitative evaluation of the major zoo-chemical present in the whole shells of ten different calms Anadara antiquata, Anadara rhombea, Chicoreus virgineus, Donax cuneatus, Mactra violacea, Pugilina cochlidium, Donax scortum, Turritella acutangula, Trachycardium asciaticum and Tonna dolium in three different extracts (Ethanol, methanol and acetone). Among the various extracts, ethanol extract has higher concentration of zoochemicals as compared to methanol and acetone extracts of Mollusca shells. The study has shown that as far as extraction yield, ethanol is the best solvent among the three ethanol, methanol and acetone. In fact, it also extracts a greater number and higher concentration of zoo-chemcials. On the basis of the extraction capacity of the solvent, ethanol extract was used for further antimicrobial activity. Overall, marine water Mollusca has shown interesting properties as a medicinal use.

Israelite Plain, southwestern Australia, a siliciclastic, late Quaternary Coorong analogue, without dolomite

The Israelite Plain, a narrow terrace at the western edge of the Great Australian Bight, is characterised by a series of schizohaline, ephemeral lakes leeward of a marginal marine eolianite dune complex that has many similarities to the Coorong Coastal Plain (CCP). The late Pleistocene and Holocene sediments are a mixture of dominantly quartzose sand and lesser carbonate components. Paleolagoon to shallow marine MIS 5e, mollusc-rich quartzose deposits are capped by calcrete or karst and contain a biota similar to the well-documented, coeval Glanville Formation on the CCP. Holocene sands with minor carbonate are also lagoonal and resemble many modern Coorong Lagoon deposits. Both deposits are interpreted to reflect marine accumulation during sea-level highstands. Lakes today range from dry to water-filled with most floored by calcareous quartzose sand. Microbial influenced sedimentary structures in the form of pustular to laminated mats veneer lake margin bedrock and sediment. Carbonate minerals are mostly calcite with abundant accessory magnesium-calcite, aragonite and traces of magnesite, monohydrocalcite and halite. Gypsum is minor but ubiquitous and floors one of the smaller, marginal-marine lakes. Although having a similar evaporative climate and evidence of groundwater resurgence like Coorong lakes, there is no significant synsedimentary dolomite. This aspect is interpreted to reflect the narrow width of the plain, and the Mg-poor source of groundwater from the nearby karst Nullarbor Plain to the north. The Israelite Plain, together with other coeval, young successions marginal to the Southern Ocean under a semiarid climate now illustrate the depositional variations and early diagenetic differences that can occur in similar environments adjacent to a cool ocean. KEY POINTS The Israelite Plain is a narrow, marginal marine terrace covered by Quaternary, lagoonal, eolian to lacustrine, calcareous siliciclastic sands, similar to several other calcareous terraces along the southern Australia coast. The interpreted sediment ages are late Pleistocene stage MIS 5e with the deposit sporadically overlain by similar Holocene deposits. Most 14C age dates are suspicious because of interpreted diagenesis or MIS 5e age, whereas U/Th age dates appear correct or altered by diagenesis. Pleistocene biota is dominated by the bivalve Anadara trapezia, whereas Holocene deposits contain a varied array of cooler water molluscs. The carbonates are similar to those on the Coorong Coastal Plain but do not contain any dolomite likely because of climate and lack of Mg-groundwater flow.

Using a weight of evidence approach to identify sources of microbiological contamination in a shellfish-growing area with “Restricted” classification

Shellfish-growing areas in rural catchments are occasionally affected by elevated faecal contamination from diffuse sources and may be subject to frequent harvest closures/classification downgrades. We combined traditional risk management methods based on sanitary surveys and monitoring of Escherichia coli in seawater and shellfish with faecal source tracking, bacterial source apportionment, and hydrometeorological modelling to determine the causes of elevated E. coli concentrations contributing to harvest closures in Papanui Inlet (Aotearoa New Zealand). These multiple lines of evidence were used to inform a weight of evidence assessment of bacterial contamination in the inlet. Ruminant livestock was estimated to contribute 80% of the faecal coliform loading. Concentrations of E. coli in seawater were low (≤ 87 MPN 100ml-1) whilst concentrations in tuaki/cockles/little neck clams (Austrovenus stutchburyi) occasionally exceeded the "Approved" classification limit (230 MPN 100g-1). The most frequent positive genetic markers in seawater were the seagull (Catellicoccus marimammalium) (54% of seawater samples), and in shellfish, the bovine and seagull markers (both 12.5% of shellfish samples). Solar radiation was negatively correlated with E. coli in tuaki. We found that the growing area is affected by faecal inputs from animal and, to a lesser extent, human (septic tank discharges) sources which elevate contamination to levels detectable in tuaki but not in seawater, particularly in the summer months. The innovative approach can enhance the management of shellfish-growing areas affected by intermittent contamination and enables more targeted action to reduce pollution to improve shellfish water quality.

Performance of Storm Overflows Impacting on Shellfish Waters in England

Storm overflow (SO) discharges to shellfish growing waters are a concern for shellfish growers and may pose a health risk to consumers. We investigated the performance of permitted SOs with a shellfish water spill monitoring requirement against the design criterion of 10 spills per year (averaged over 10 years) used in England. Performance against this criterion over the period 2019–2021 differed between the five water companies whose data was analysed. Across all companies, over half of SOs spilled more frequently than this criterion (percentage greater than 10 spills: 52%, 55% and 57% for 2019, 2020 and 2021, respectively). The number of SOs with the monitoring requirement also differed considerably between the water companies and consequently some companies deal with a significantly higher ‘burden’ than others. The number of SOs spilling more than 100 times in a year also differed between water companies, from 0% (Wessex Water) to 16% (United Utilities). Discharges from SOs can lead to short-term reductions in water quality that may be missed by routine monitoring programmes using faecal indicator bacteria such as E. coli. Such discharges can lead to a higher incidence of norovirus in shellfish and thus potential illness in consumers. We conclude that site-specific impact assessments, supported by spill event-based monitoring, are required given the increased demands on sewerage networks from urban growth and climate change and the need to improve shellfish production area classifications.

Sublethal effects of zinc oxide nanoparticles induced toxicity and oxidative stress in Pila virens: A validation of homology modelling and docking

Materials of nano-range are ranked as the sixth most emerging pollutant which are reaching the aqueous ecosystem and causing harm to the inhabiting organisms. Nanomaterials of zinc oxide are applied in wide range of applications. However, the toxicity of zinc oxide nanoparticles (ZnONPs) on fresh water mollusc Pila virens is scarce. The median lethal concentration of ZnONPs on P. virens for 96 h was found to be 180.49 µg/L. In the present study P. virens were treated with sublethal concentration of 135 μg/L of ZnONPs for 24 and 96 h respectively. The reactive oxygen species, protein carbonyl and lipid peroxidation levels were increased in P. virens treated with 135 μg/L of ZnONPs in comparision to their control values at two different time intervals (24 and 96 h). Moreover, the glutathione sulfotransferase and glutathione peroxidase activity in P.virens exposed to 135 μg/L of ZnO NPs for 24 and 96 h were found to decrease when compared to their control values. An in silico approach was also taken to understand the loss of GST activity wherein the target protein was modelled and found to strongly bind with ZnONPs at its active site when subject to molecular docking. The current study affirms that P. virens are relevant invertebrate biomonitor to evaluate the nanoparticles toxicity.

Exopolysaccharyde production by Cryptococcus laurentii SD7 using molasses and corn steep liquor as substrates

Microbial polysaccharides are of great biotechnological and commercial interest and have wide application in the food, cosmetic and medicine industries. Exopolysaccharide (EPS) production by the yeast Cryptococcus laurentii SD7, isolated from fresh water molluscs, was studied using agro-industrial byproducts as substrates in the submerged fermentation. The Central Composite Design (CCD) 23 was used to study the influence of pH, different concentrations on sugarcane molasses and corn steep liquor (CSL), for 48 hours. According to the results, the highest EPS production occurred at the initial pH 5 and at 8.4% concentration of sugarcane molasses, which were statistically significant variable at 10% (p &lt; 0.1). The concentration of CSL had no influence in the studied range, thus, it can be used lowest concentration (0.3%). The time course of EPS production showed that while cell growth peaked within 48 hours, the highest EPS production (6.61 g L-1) occurred at 168 hours, with a productivity of about 0.04 g L-1 h-1. The pH of the medium remained approximately constant throughout the fermentation process. The yeast C. laurentii SD7 showed great potential for EPS production at a low cost and with sustainable substrates.

Development of fluorescence sensor and test paper based on molecularly imprinted carbon quantum dots for spiked detection of domoic acid in shellfish and lake water

Excessive levels of domoic acid (DA) in edible shellfish and water can seriously threaten human health and even cause death. Herein, we have developed a fluorescence sensor and test paper based on molecularly imprinted carbon quantum dots (B-CDs@MIPs) for DA analysis. In this research, the prepared carbon quantum dots (B-CDs) with good optical properties were used as the sensitive fluorescent signal probes, and the molecularly imprinted polymers (MIPs) instead of biological antibodies were employed as the specific recognition components because of their high stability and low cost. Due to the shielding effect of imprinted silicon layer and the influence of modified groups introduced in the MIPs preparation process, the fluorescence signal of B-CDs in MIPs is inhibited. Interestingly, the DA can cause the partial recovery of the fluorescence intensity of B-CDs@MIPs by passivating the modified groups on the surface of B-CDs in MIPs. According to this principle, the designed fluorescence sensor reveals outstanding stability, super anti-interference ability, and excellent sensitivity, with the detection limit down to 10 nM. The sensor has been successfully applied to the rapid and accurate spiked analysis of DA in edible shellfish and lake water, providing excellent recoveries. More importantly, the designed inexpensive and easy-to-operate fluorescent test paper can realize preliminary qualitative analysis of DA on site by naked eye, indicating its promising application potential in food and environmental analysis.

Impacts of land use on water quality and the viability of bivalve shellfish mariculture in the UK: A case study and review for SW England

This paper examines how land use affects water quality and how this impacts the viability of shellfish mariculture (marine aquaculture) in the UK through a synthesis of the current literature, stakeholder workshops and targeted engagement of cross-sector organisations across a case study in South West England. We examine the importance of water quality as a constraint for shellfish mariculture in South West England and explore how current and projected future land uses are likely to influence ongoing viability. Currently, faecal material from agricultural runoff and municipal wastewater discharges is the main water quality issue affecting the viability of shellfish mariculture. Most UK Shellfish Waters, including those in SW England (~90%), do not consistently meet regulatory standards for faecal indicator organisms (FIOs) in shellfish, designed to ensure they are safe for direct human consumption. Other pollutants currently impacting shellfish mariculture include persistent organic pollutants and metals, suspended solids and excess nutrient inputs. Emerging pollutants with the potential to impact on mariculture include a range of consumer- industrial- and agri- chemicals, including biocides, pesticides, veterinary and human medicines. We evaluated possible changes in water quality conditions through deriving and exploring a range of future scenarios, considering policies and trends in land use including regenerative and intensive agriculture, renewable energy generation, afforestation, urban development and climate change. Our findings highlight possible trade-offs and synergies between land and water-based food production systems, applicable in SW England and across other regions of the UK and internationally, for helping to inform environmental policy development and implementation.

Palaeo-ecological development and interpretation of the macrofauna inventory (Bivalvia and Gastropoda) in marine Eemian deposits at Warnow Bay (NE Germany)

For the palaeo-ecological development and interpretation of the macrofauna (Bivalvia and Gastropoda) of the Eemian Sea in the southwestern Baltic Sea region (NE Germany), up to date studies and summarising assessments are largely missing. With the main goal of revising the Eemian marine fauna, the authors have undertaken numerous new samplings in recent years. This study begins by focusing on the Warnow Bay in today's Warnow valley near Rostock. In addition to examining older data from the literature, the sandpit at Schwaan and drillings of the State Geological Survey from Boitin, Reez and Rostock were studied. Parallel to this, was also undertaken pollen analyses.Despite hundreds of drillings from the region of the former Warnow Bay, evidence of the marine Eemian was relatively rare. Apparently the sandy sediments were reworked and redistributed by glaciotectonic, glaciofluvial and fluvial processes during the Weichselian glaciation. There is as yet no definite proof of autochthonous marine sediments.They are predominantly shallow-marine sands several meters thick which are found mostly at a depth of about 30–20 m b.s.l. but more rarely also relatively close to the surface in opencast mining or cliff sections.The sands are rich in marine mollusc fauna of which 29 species have been identified so far and which also include Lusitanian specimens such as Acanthocardia paucicostata, Lucinella divaricata or Polititapes senescens. Account was also taken of accompanying marine fauna such as barnacles and echinoderms. In addition, the sediments contain fresh water molluscs also including the interglacial indicator species Belgrandia germanica.

PROXIMITY TO THE RIVER A MUTUAL ROLE: A PHENOMENOLOGICAL STUDY

The mutual role of the river's nearby residents creates balance and benefit in the coexistence of humans and their immediate environment. The study focused on the experiences of residents near the San Juan River in Aborlan, Palawan, employing a descriptive phenomenological approach and the seven steps of Colaizzi's (1978) method. The following themes were identified: river benefits, threats encountered, and initiatives, participation, and advocacy. All of the participants have prior swimming experience, with the majority of them learning in the river itself. Aquatic products such as milk fish, shellfish, and fresh water prawns have been observed in the river, but not in sufficient quantities to sustain a livelihood due to a handful catch at a time. Quarrying is the river's most serious threat, and it has been forced to halt due to a petition. Residents demonstrated care and concern for the river by collecting garbage, educating visitors, involving their families in tree planting activities in the area, and suggesting to community leaders or the LGU to develop policies and plans for the river's utilization, conservation, and protection, such as livelihood and ecotourism projects. With of the participants' proximity to the river, they pledge their full support for river protection if the community is led by someone. A conservation model was developed in collaboration with the local government, academia, and the community.

Faecal contamination and prevalence of pathogenic E. coli in shellfish growing areas along south-west coast of India

Seasonal prevalence of faecal coliforms in Indian black clam (Villorita cyprinoides), sediment and harvesting waters from shellfish harvesting areas along Cochin estuary was evaluated. Enumeration was done by 5 tube most probable number (MPN) method. High prevalence of faecal coliforms was observed in shellfish, sediment and harvesting waters during monsoon and post-monsoon seasons compared to pre-monsoon season. Escherichia coli was isolated and identified by biochemical methods and further confirmed by PCR based detection of uid A gene. A total 125 E. coli strains were isolated; out of which 99 (79.2%) could be serotyped and comprised of 17 diverse serotypes. Approximately 89.06% of the serotyped strains belonged to 5 different pathogenic serotypes. Enterotoxigenic strains were the most prevalent, followed by enterohaemorrhagic, uropathogenic, enteropathogenic and enteroinvasive strains. Enterohaemorrhagic E. coli O157 strains were isolated from shellfish and sediment samples (7.07%). Multiplex PCR analysis revealed the presence of shiga toxin genes (stx1, stx2), intimin (eae) gene and enterohemolysin gene (hlyA). The overall prevalence of toxigenic genes among the strains was 78.1%; in shellfish (84%), sediment (78.1%) and water (69%). Shiga toxin gene stx2, showed the highest prevalence (54.3%), followed by eae (36.2%), stx1(20%), and hlyA (6.7%) genes. To the best of our knowledge, the present study is the first report on the isolation of E. coli O157 from shellfish harvesting areas along the Indian coast. Higher levels of faecal contamination along with the presence of pathogenic E. coli may pose potential health hazards to the consumers.

Study of diversity of fresh water Molluscs from Ujani wetland, Maharashtra, India

The objectives of the present study were to explore the diversity of mollusc’s fauna at different habitats. Molluscs are considered the most diverse and dominant benthic fauna both from lentic and lotic aquatic ecosystems. Present study is an attempt to study diversity of fresh water molluscs from Ujani wetland area, Indapur, Pune, Maharashtra. In present study, 20 species belong to 11 genera and 02 classes were recorded. 11 species belong to class gastropods and 09 species from class Bivalvia. Thus, family Unionidae was the most dominant family exploring 30% of species. Survey was done from April 2020 to September 2020 during day time from 8 A.M. to 6 P.M. every weekend.

Evaluation of remotely sensed prediction and forecast models for Vibrio parahaemolyticus in the Chesapeake Bay

Over the last decade, an increase of gastrointestinal illness due to Vibrio parahaemolyticus in the consumption of raw shellfish has been reported in multiple regions around the United States. Studies mainly attribute this increase to rising sea surface temperatures and prolonged warm seasons in the mid-latitudes. Historically, temperature has been the main environmental determinant used to predict V. parahaemolyticus concentrations in shellfish and surface water. However, studies using in situ sampling campaigns have shown that additional water quality parameters can be useful in predicting the bacterium. While the time and cost of obtaining in situ samples throughout the Chesapeake Bay at regular time intervals can exceed available resources, satellite remote sensing has the potential to provide predictions at higher temporal and spatial resolutions. This study uses satellite ocean color remote sensing and sea surface temperature (SST) from the Moderate Resolution Imaging Spectroradiometer (MODIS) to investigate the utility of remotely sensed information for Vibrio parahaemolyticus predictions in the Chesapeake Bay and whether additional remotely sensed information can improve predictions over conventional SST-based models. We find that the addition of remotely sensed salinity, total suspended solids, and chlorophyll-a generally improves presence and abundance predictions compared to SST-only models. Models using remote sensing reflectances and SST also show potential for V. parahaemolyticus predictions, which could bypass the intermediary step of deriving water quality products from reflectances. Remotely sensed ocean color products and SST from one week prior to in situ V. parahaemolyticus measurements are evaluated and shown to be useful in bacterium predictions, which could provide lead-time for management decisions. The forecast models using ocean color products in addition to SST showed improvement over SST-only forecast models. The results of this study suggest that remote sensing can be a valuable tool to aid in higher resolution V. parahaemolyticus predictions and forecasts in the Chesapeake Bay, particularly when multiple environmental predictors are employed. However, the complexities of using remotely sensed data for ecological modeling applications and evaluating model performance also highlight the need for more research in this area.

Long term reductions of faecal indicator organisms in Chichester Harbour (England) following sewerage infrastructure improvements in the catchment

Quantitative information relating sewerage infrastructure schemes to microbial water quality improvements in recreational and shellfish harvesting areas is lacking. In this study, we assessed the effect of two sewerage schemes on concentrations of faecal indicator organisms (FIO) in Chichester Harbour, an important oyster fishery and water recreation area in the UK. The sewerage schemes comprised the installation of activated sludge and UV disinfection plants and increase in the storage capacity of storm tanks at sewage treatment works that discharge to tidal waters. Analysis of FIO data covering the period 2007–2018 indicated log-order reductions in FIO concentrations in the harbour after the sewerage schemes, which was reflected by better compliance with the E. coli and enterococci limits for “excellent” of the Bathing Waters Directive. Mean concentrations of E. coli in shellfish reduced ≤0.5log10 and compliance of commercial shellfish beds with the limits of Regulation (EC) No 854/2004 either maintained or upgraded to class B status during the 11-year period. However, compliance with the guideline E. coli standard of the Shellfish Water Protected Areas Directions was not consistently achieved. We suggest that better harmonisation of monitoring practices used in the various statutory programmes would help in understanding if the observed discrepancy in FIO compliance between waters and shellfish is due to actual pollution levels at compliance sites or other factors. Nevertheless, this study demonstrates that fortnightly sampling can provide data to evidence long-term water quality improvements following sewerage schemes.

Human health risk assessment of TPHs in brackish water prawn (Nematopalaemon hastatus, AURIVILLUS, 1898)

Edible aquatic brackish water shellfish (Nematopalaemon hastatus) obtained from the coastal waters of Ondo state, Nigeria was analyzed between 2017 and 2018 for the concentration of Total Petroleum Hydrocarbons (TPHs). TPHs level in the sampled species was measured using gas chromatography-flame ionization detector (GC/FID). Possible human health risks associated with the ingestion of the sampled species were determined by estimated dietary intake (EDI) and health risk index (HRI). The TPH level observed in the biota species (Nematopalaemon hastatus) varied across the period of study. The highest concentration was recorded in February (3401.55 mg/kg) while the lowest was recorded in April (1995.99 mg/kg). The TPH values of the analyzed fish species exceeded the threshold value of 50 mg/kg for fish. Petroleum aliphatic hydrocarbons attained higher concentration in n-Hentriacontane, n-Tridecane, n-Nonane, n-Tetradecane, n-Triacontane, n-Tetracosane and n-Octacosane with mean concentration values of (2242.02, 189.60, 40.90, 40.72, 25.79, 15.40 and 8.73 mg/kg) respectively. The EDI and HRI had their peak dose and index value (1.19 and 2.37) in February and lowest dose an index value (0.70 and 1.39) in April respectively. In addition, the HRI exceeded the safety limit of one (1). The findings from this study reveal a significant carcinogenic health risk connected with the consumption of the sea species. Thus, the species is therefore considered unfit and unsafe for consumption.

Commentary on: Abundance and distribution of microplastics within surface sediments of a key shellfish growing region of Canada.

This formal comment is in response to “Abundance and distribution of microplastics within surface sediments of a key shellfish growing region of Canada” written by Kazmiruk and colleagues in 2018. This article presents microplastics concentrations in sediment, primarily microbeads, within Baynes Sound, British Columbia, which are some of the highest that have been reported anywhere in the world. The authors cite the local shellfish industry as the likely source of this high degree of contamination and present the industry as a substantial risk to the environment. However, the authors do not sufficiently justify the efficacy of their methodology, and there are several flaws which call into question the legitimacy of their findings. In this commentary, we address the microplastic abundances reported by the authors, and methodological concerns. Furthermore, we provide additional data to elucidate some of this study’s more contentious findings. Specifically, we seek to clarify the visual identification of microbeads and microfibres, and the microplastic concentration within shellfish populations, water, and sediment, within the Baynes Sound shellfish growing region.