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This study explored the characteristics of benthic animal communities in different water functional areas and the driving factors affecting changes in the community structure of four water functional zones of the Jiangsu section of the Yangtze River: the protection, buffer, reserve, and development and utilization zones. The results showed that the alpha diversity of the benthic animal communities in the protected and reserved zones was significantly higher than that of the buffer and development and utilization zones, and the benthic animal community structure differed significantly across different water functional zones. These zones indirectly affected the community of benthic fauna due to their environmental heterogeneity. Furthermore, the average degree, map density, and average clustering coefficient of the molecular ecological network were highest in the protected zone. The average path length was shorter, and there were more types and numbers of key species in the benthic animal community in the protected zone, indicating high levels of connectivity and efficiency in transferring substances, energy, and information between benthic animals. These results will provide a scientific basis for studying the characteristics and driving factors of benthic animal communities in the Yangtze River and have important significance for assessing and restoring aquatic ecology in the Yangtze River Basin. [ABSTRACT FROM AUTHOR]

The feeding upon large animals—even larger than the predator—by benthic cnidarians has been reported from many ecosystems but never exhaustively studied to date. By reviewing 38 papers on this topic, this review aims to recap the observations on the predatory behaviour of polyps, to establish feeding plasticity boundaries and to understand the contribute of this trophic strategy to the benthic–pelagic coupling. The reviewed documents published increasingly during the last two decades mostly reported observations on heterotrophic Anthozoa in shallow ecosystems collected through photo/video records. The main prey items are represented by gelatinous zooplankton and echinoderms. The lexical discordance in the considered papers highlights the need to standardize the terminology to describe the feeding behaviour of benthic Cnidaria, opportunistic and characterized by a strong plasticity. Given the importance of large prey in cnidarian trophism, we proposed an unambiguous terminology that will help the online search of literature and address future studies. We suggest identifying micro-predation (predator/prey size ratio ≥ 5:1) and macro-predation (predator/prey size ratio is ≤ 1:1) as distinct feeding modalities, because the capture of large prey involves peculiar movements of polyps, such as stretching and retracting of column and tentacles to pull the prey towards the mouth. [ABSTRACT FROM AUTHOR]

Mangroves are a diverse and rich ecosystem, in which many animals are associated, including benthos. Species composition and occurrence of these animals are driven by the mangroves and tidal conditions. To examine how the benthic animal is distributed in mangrove habitats from northern Vietnam, two surveys in 2019 were conducted in Tien Hai Wetland Nature Reserve, which resulted in a total of 89 species, belonging to 56 genera and 35 families of zoobenthos. This is the first publication of these animals in the study site. The two major groups of benthic animals in the ecosystem were Crustacea and Mollusca, which occupy 54.02% and 36.78% of the total species, respectively. There are several new records of these animals from the coastal mangroves of Vietnam. Two species were new data for northern Vietnam (Scopimera curtelsoma and Parasesarma eumolpe), and four species were new records for Vietnam (Laemodonta punctigera, Cassidula nucleus, Pythia cecillei and Microtralia alba). Also, the present study shows distributional characteristics of the benthic animal community in mangrove forests. The present study indicates that benthic animals show an increase in species diversity and density from the river mouth to the continent. Seasonally quantitative data of benthic from the study site are the first work in mangrove forests of Vietnam. Recent findings are fundamental data for further studies on zoobenthos and related issues to preserve biodiversity in the mangrove forests in Vietnam. [ABSTRACT FROM AUTHOR]

On Arctic shelves, benthic food-webs are tightly linked to overlying primary production. In the seasonal ice zone, sympagic (ice-associated) primary production can be a major source of carbon for the benthos on productive inflow shelves. However, the role of sympagic organic matter is less well-understood in food webs of heavily ice-covered, less- productive outflow shelves, such as the northeast Greenland shelf. Highly branched isoprenoid biomarkers (HBIs) were used to track the relative distribution of sympagic and pelagic organic matter in the water column, sediments, and benthic fauna of the northeast Greenland shelf and fjords. Low pelagic HBI presence throughout the study area indicated a generally low production by pelagic diatoms (at the time of sampling). This was reflected in the benthos, as ~90% of their assimilated carbon was estimated to come from sympagic sources, indicating a benthic food-web highly reliant on sympagic production. This reliance was higher in coastal areas than on the open shelf, where the potentially higher pelagic productivity and shallower water on banks likely increased contributions of pelagic organic matter. As declining ice cover and reduced production of fast-sinking ice algae projected for Arctic shelves will likely result in weaker coupling between ice algae and the benthos, with possible consequences for future benthic-community structure and function. [ABSTRACT FROM AUTHOR]

Deep‐sea benthic communities are strongly controlled by the quantity and quality of organic matter sinking from the ocean surface. The interaction between benthic fauna and seafloor sediments mainly occurs through bioturbation that modifies substrate properties (e.g., geochemical profiles). The intensity of the bioturbation has long been linked with organic matter and measured as a diffusive process by considering the vertical particle reworking (endobenthic bioturbation), disregarding the seafloor horizontal mixing (epibenthic bioturbation). Here, a novel approach to quantify horizontal mixing is presented: Seafloor Bioturbation Intensity (SBI). SBI calculations were based on seafloor image datasets from eight stations that reflected different environmental conditions in the north‐western Pacific (e.g., chlorophyll a, silicate). To calculate SBI, we characterized the area occupied by all different types of traces (i.e., lebensspuren) related to epibenthic bioturbation, trace makers, and their ingested sediment thickness. Our results showed a weak negative correlation between organic matter and SBI. This relationship contrast with the traditionally held view on vertical bioturbation intensity, where a dominant positive correlation is expected. It is demonstrated that lebensspuren morphotypes contributed differently to SBI. Not all morphotypes—and, by extension, their corresponding trace makers—are equally controlled by the same environmental factors. This investigation does not dismiss the importance of organic matter content, but emphasizes the importance of other environmental variables that need to be considered when determining the long‐term relation between epibenthic fauna and bioturbation intensity. Finally, we emphasize the importance of characterizing horizontal bioturbation for approaching global biogeochemical cycles and conservational strategies. [ABSTRACT FROM AUTHOR]

Oxygen deficiency is a major problem in the Baltic Sea. To study the impact of hypoxia on the functional diversity of benthic fauna and the possibility of macrozoobenthos recovery, data were analyzed in a gradient of oxygen conditions in the Gdańsk Basin. The research conducted on the basis of biological traits analysis enabled us to analyze the number, type and spatial distribution of biological traits—a proxy for functions performed by macrozoobenthos. A significant depletion of macrofauna was already observed under conditions of reduced oxygen above the bottom, both in terms of functional diversity and biomass. Although taxa observed in hypoxia (DO < 2 mL L−1) perform a number of functions, the remaining species do not form complex structures in the sediments or cause deep bioturbation and bioirrigation. Moreover, their extremely low biomass plays an irrelevant role in benthic–pelagic coupling. Thus, benthic fauna under hypoxia is not an element that ensures the functioning of the ecosystem. We assess that traits important for species dispersal and the presence of taxa resistant to short-term hypoxia in the oxic zone above the halocline provide a "backup" for ecosystem functioning under altered diverse oxygen conditions below the halocline after cessation of hypoxia in the southern Baltic Sea. [ABSTRACT FROM AUTHOR]

The quantitatively most important process by which organic matter in marine sediments is mineralized is performed by sulfate‐reducing bacteria, resulting in the accumulation of total dissolved (free) sulfide (S2− = H2S + HS− + S2−) in porewater. S2− is toxic to benthic animals and vascular plants and measurements serve as a proxy for the deleterious effects of organic enrichment on benthic habitat, biodiversity, and ecosystem function. Methodologies for measuring S2− in water have been pursued for at least a century, and standard approaches employ colorimetry (methylene blue and iodometric titration) and potentiometry. These standard methods require between 1 and 200 mL of porewater, which can be laborious to obtain. The ion‐selective electrode method is widely employed as a practical approach for sediment S2− analysis but lacks analytical robustness and is highly prone to measurement biases that misinform research and environmental management decisions. A technically simple method is described, based on direct UV spectrophotometry, for the near real‐time field analysis of small porewater samples. The procedure prevents known measurement biases associated with particulate sulfide interference, S2− volatilization and oxidation, and represents a practical approach for monitoring organic enrichment and classifying benthic ecological quality status. Porewater concentrations between 200 and 15,000 μmol L−1 can be measured and instrument calibration is highly stable. The method has the capacity to rapidly process and analyze sediment samples at low cost, which helps resolve the problem of chronic under‐sampling associated with the use of traditional S2− methods. [ABSTRACT FROM AUTHOR]

Benthic amphipod feeding groups are a well-established trophic classification that is mostly based on field observations and laboratory tests and are used in ecological studies to monitor the ecological state of benthic ecosystems. Globally, carbon and nitrogen stable isotope ratio investigations have provided confirmation of, and novel insights into, the trophic ecology of benthic animals, such as polychaetes. However, stable isotopic examinations of benthic amphipods have been limited. Here, we used microgram samples to compare the species-specific dietary sources, trophic positions, and isotopic niche overlap of selected benthic amphipods from the Gulf of Kachchh, Marine National Park, using elemental analyser-isotopic ratio mass spectrometry (EA-IRMS) of carbon and nitrogen. Overall, all primary carbon sources presented wide variation in the isotopic values of δ13C (6.3‰) and δ15N (greater than 13‰). Conversely, the amphipod taxa displayed relatively narrow range for δ13C (3.9‰) and wider range for δ15N (more than 10‰). The results of the Bayesian mixing model revealed that the benthic amphipods had species-specific feeding preferences. However, the predominant carbon source was organic matter in sediment which reinforced benthic pathways for energy flow for most species. According to the estimated trophic level values (1.62–3.39), these species play a significant role as primary and secondary consumers serving as crucial trophic intermediaries in the food chain, connecting the base to the top consumers. High overlapping ecological niche amongst species was detected by SIBER analysis which indicated co-existence of the benthic amphipods in their respective microhabitats. This signifies wider utilisation of resources and inter-specific feeding preferences with minimal competition amongst amphipod species. [ABSTRACT FROM AUTHOR]

Simple Summary: In this study, we explored the impact of saline–alkaline environments on the diversity and functional traits of benthic organisms. In environments with varying levels of salt, we noticed changes in living organisms, like improved swimming abilities and better adaptation to breathing in high-salinity conditions. These findings offer crucial insights to understand and manage ecosystems in saline–alkaline environments, particularly in the face of climate change. This study provides a practical foundation for conservation efforts, emphasizing the importance of recognizing the unique roles of benthic organisms across varying salinity levels. By revealing adaptive strategies and their ecological significance, our research contributes to global initiatives that address environmental challenges and promote enhanced ecosystem resilience. In this study, we investigated how changes in salinity affect biodiversity and function in 11 typical water bodies in the Altai region. The salinity of the freshwater bodies ranged from 0 to 5, the brackish water salinities ranged from 5 to 20, and the hypersaline environments had salinities > 20. We identified 11 orders, 34 families, and 55 genera in 3061 benthic samples and classified them into 10 traits and 32 categories. Subsequently, we conducted Mantel tests and canonical correlation analysis (CCA) and calculated biodiversity and functional diversity indices for each sampling site. The results indicated that biodiversity and the proportion of functional traits were greater in freshwater environments than in saline environments and decreased gradually with increasing salinity. Noticeable shifts in species distribution were observed in high-salinity environments and were accompanied by specific functional traits such as swimming ability, smaller body sizes, and air-breathing adaptations. The diversity indices revealed that the species were more evenly distributed in high-diversity environments under the influence of salinity. In contrast, in high-salinity environments, only a few species dominated. The results suggested that increasing salinity accelerated the evolution of benthic communities, leading to reduced species diversity and functional homogenization. We recommend enhancing the monitoring of saline water resources and implementing sustainable water resource management to mitigate the impact of salinity stress on aquatic communities in response to climate-induced soil and water salinization. [ABSTRACT FROM AUTHOR]

The deep sea (>200m depth) off South Africa is largely unexplored, with most benthic macrofauna samples limited to depths shallower than 100m. The benthic infaunal diversity of the Agulhas Bank shelf edge has not yet been studied. We analysed seven grab samples that were opportunistically collected along the shelf edge at depths of 290-533 m. A total of 136 macrofauna items representing 75 species were identified, and the first species list of the infauna of the shelf edge was compiled, Polychaetes comprised 48% of total abundance, and the sites had an average similarity of 7% based on species abundance, Spearman rank correlation showed that depth and sediment particle size are important environmental drivers of community abundance and biomass variation on the shelf edge, Habitat heterogeneity is likely high along the Agulhas Bank shelf edge, Greater sampling effort in habitats for which data are scarce provides crucial information for offshore biodiversity assessment and management [ABSTRACT FROM AUTHOR]

Simple Summary: This investigation delves into the intricate world of aquatic life, specifically zoobenthos, and how they respond to a combination of environmental challenges: climate change, eutrophication, and pesticide contamination. These organisms play a vital role in aquatic ecosystems, affecting energy flow, nutrient cycling, and sediment decomposition. Unfortunately, these challenges have led to a decline in their numbers and changes in community structure. Notably, the warmer temperatures associated with climate change promote the abundance and diversity of zoobenthos while making these communities more similar across different sites. Pesticides like imidacloprid negatively impact the survival and growth of zoobenthos. Interestingly, when combined with warming, imidacloprid seems to mitigate its adverse effects, increasing species diversity. However, when nutrient loading is part of the equation, imidacloprid negatively affects species diversity. These findings reveal the intricate responses of zoobenthos to multiple stressors, offering valuable insights for ecosystem conservation and management. In simpler terms, this study explores how tiny underwater creatures react to a changing environment, which has consequences for our ecosystems. Multiple stressors, including climate change, eutrophication, and pesticide contamination, are significant drivers of the decline in lake zoobenthos. Zoobenthos play a crucial role in aquatic ecosystems, impacting energy dynamics, nutrient cycling, and sediment degradation. However, these stressors have led to a decrease in the abundance and diversity of zoobenthos, resulting in notable changes in species composition and structure. Eutrophication typically increases zoobenthos abundance while reducing taxonomic diversity. Climate change, such as warming and heatwaves, also affects the zoobenthos community structure, with different species exhibiting varying levels of adaptability to temperature changes. Additionally, pesticides like imidacloprid have negative effects on the survival and growth of zoobenthos. However, the interactions between imidacloprid and other stressors remain understudied. Here, we used 48 mesocosms (2500 L) to simulate shallow lakes. We combined nutrient loading, sustained warming, and the imidacloprid pesticide to test how these stressors interactively influence the survival and community of zoobenthos. The experimental results demonstrate that elevated temperatures have a significant impact on aquatic benthic organisms under different treatment conditions. The increase in temperature led to a notable rise in species richness and α-diversity, primarily attributed to the stimulation of metabolic activities in zoobenthos, promoting their growth and reproduction. This finding underscores the potential influence of climate change on aquatic benthic ecosystems, particularly in terms of its promoting effect on α-diversity. However, it is essential to note that elevated temperatures also reduced β-diversity among different sites, implying a potential trend toward homogenization in zoobenthos communities under warmer conditions. Moreover, this study revealed the interactive effects of multiple stressors on the diversity of aquatic benthic communities. Specifically, the pesticide imidacloprid's impact on zoobenthos is not isolated but demonstrates complex effects within various treatment interactions. In the presence of both temperature elevation and the addition of imidacloprid, the presence of imidacloprid appears to counteract the adverse effects of temperature elevation, resulting in increased species diversity. However, when imidacloprid coincides with nutrient input, it significantly affects α-diversity negatively. These findings highlight the complexity of zoobenthos responses to multiple stressors and how these factors influence both α-diversity and β-diversity. They provide valuable insights for further research on the conservation and management of ecosystems. [ABSTRACT FROM AUTHOR]

Red macroalgae in the genus Porphyra are widely collected for human consumption and increasingly harvested along the North Atlantic coasts but their ability to withstand repeated harvesting and maintain high cover and abundance on natural shorelines remains poorly explored, raising sustainability concerns. Therefore, we investigated the effect of frequent hand-harvesting on Porphyra dioica in a population in South Wales, UK, where it is commercially harvested. Twelve control and twelve treatment quadrats were installed in spring and six control and treatment plots in autumn. Monthly hand-harvesting of P. dioica individuals larger than 5 cm was performed in the treatment plots, while the control plots remained undisturbed. We monitored P. dioica percentage cover, yield, thallus length and recruit density, as well as benthic flora and fauna. Harvesting only impacted P. dioica thallus length, resulting in 41% smaller thalli compared to unharvested plots during summer, with possible long-term implications (e.g. reproductive output). Strong seasonality of P. dioica cover and yield was observed, peaking during spring and summer. The results suggest high resilience of the opportunistic life strategy of P. dioica under frequent harvesting, but to allow for full recovery, we urge for a recovery period of more than the tested 4 weeks. [ABSTRACT FROM AUTHOR]

Most deep-sea organisms feed on the organic matter produced in surface waters and settle on the seafloor. In polar regions, sea ice algal detritus and phytoplankton detritus are the main food sources for benthic fauna that reach the seafloor in pulses. Climate change affects the extension and duration of sea ice cover, which may affect the quantity and quality of food reaching the seafloor, resulting in less ice algae and more phytoplankton biomass. We conducted onboard pulse-chase experiments using sediment cores collected from Baffin Bay, Amundsen Gulf, and the Beaufort Sea to study how macroinfaunal communities in the Canadian Arctic use both food sources. Dual-labeled (13C and 15N) diatoms, Thalassiosira nordenskioeldii (phytoplankton treatment) and Synedra hyperborea (ice algae treatment), were used as tracers of food consumption by macroinfaunal groups. Community structure was analyzed in each region and differences were found among sites. The total uptake of both food sources was higher in Baffin Bay; the macroinfaunal biomass was the highest, with facultative filter/surface-deposit feeders accounting for more than 70% of the total biomass. The Baffin Bay station was the only location where there were notable variations in the biomass-specific uptake of ice algae and phytoplankton detritus by the bivalves and polychaetes, as well as by the community as a whole. At the same time, both food sources were consumed in equal quantities at the Amundsen Gulf and Beaufort Sea stations. This suggests that ice algae are not preferentially uptaken, and macroinfaunal communities may be resilient to a decrease in ice algal input to the seafloor inflicted by sea ice reduction. [ABSTRACT FROM AUTHOR]

Benthic macroinvertebrate abundance and taxa richness associated with environmental variables were monitored monthly from September 2015 to August 2016 in the Nyamuhinga River. The benthic macroinvertebrate samples were collected using a D-frame aquatic net employing the man-time method. Environmental variables including pH, temperature, conductivity, and total dissolved solids (TDS) were measured using a Combo HI 98129 and GREISIN-GER 020 multimeters, and water flow was assessed using the Float Method procedure. The Shannon–Wiener and equitability indices were then calculated to assess diversity and richness, facilitating the comparison of diversity within sites or stations. A total of 35,142 macroinvertebrate individuals were collected from the 12 sampling sites belonging to 29 genera, 27 families, and 9 orders. Diptera were the most abundant (71.83%) followed by Odonata (9.13%) and Ephemeroptera (7.11%). The findings showed that taxa richness decreased from upstream to downstream. At the same time, absolute abundance increased from downstream to upstream due to riparian vegetation, substrate type, plant debris, and organic matter which are habitats for benthic macroinvertebrates in the river. Environmental variables such as flow, pH, temperature, conductivity, and TDS varied between sites and stations because of habitat disturbances, contaminant discharges into the catchment, and inflow of tributary waters into the river. The canonical correspondence analysis (CCA) results displayed that Eristalis and Chironomus were strongly associated with the flow, conductivity, TDS, temperature, and pH at the downstream sites related to anthropogenic activities from the catchment. From our results, the Nyamuhinga River needs conservation master plan/guidelines and increased awareness to reduce environmental impacts in Bukavu River catchments in the Lake Kivu basin. [ABSTRACT FROM AUTHOR]

Over the entire period of studies in the water bodies in the Ural River basin, comprehensive hydrobiological studies have not been carried out in many areas both on the main watercourses of the Ural and Sakmara rivers and on a large number of tributaries of different levels. The results of such studies carried out by the Water Problems Institute, Russian Academy of Sciences, during expeditions in the summer and autumn 2022 are discussed. A large body of data on phytoplankton, zooplankton, zoobenthos, and juvenile fish was collected and processed. [ABSTRACT FROM AUTHOR]

Accurate knowledge of geographic ranges of species is essential for effective conservation management. Species with large distributions and good connectivity are presumed to be resilient to adverse localized/regional conditions, whereas those with small ranges and, thus, smaller population sizes are more likely to be vulnerable. The rich benthic assemblages across the Southern Ocean are generally considered "Antarctic" with some input from South America contributing to diversity on the sub-Antarctic island shelves. However, molecular work over the past two decades is challenging the paradigm of a general Antarctic benthic fauna, with evidence mounting for assemblages being regionally unique in terms of genetic diversity, regardless of formal taxonomic species composition. The widely distributed brittle star, Amphiura belgicae, is one element of the Southern Ocean benthic assemblage that has a complex historical taxonomic background hinting that it may in reality be a complex of species, each with small geographic range and little connectivity. Our study identified deep genetic divisions between geographically isolated populations, particularly between those on the Patagonian shelf and elsewhere. Indeed, populations on the Patagonian shelf were more closely related to the sympatric sister species A. eugeniae than to any other Southern Ocean population. We compare our data with a study of Ophiuroglypha lymani from similar collections, highlighting that both show highly regionalized populations, particularly on Island shelves, and both share the curious phenomenon of a presumed outgroup species being an element of the ingroup. We suggest that the isolated populations of both these species are following distinct evolutionary and ecological trajectories and that both should be treated as species complexes. [ABSTRACT FROM AUTHOR]

The invasive colonial tunicate, Didemnum vexillum Kott, 2022 was initially observed in Atlantic Canada in Nova Scotia in 2013 and has since been expected to spread to the western side of the Canadian Bay of Fundy due to colonies known to be present in nearby Eastport, Maine. Since 2018, we collected water environmental DNA (eDNA) samples at eight sites in the Quoddy Region in the western side of the Canadian Bay of Fundy. In 2021 and 2022 we used diver-based visual surveys and sample collection, as well as a surface-deployed near-seafloor optical imaging system to document the presence and extent of D. vexillum in the Head Harbour/West Isles/Passages Ecologically and Biologically Significant Area (EBSA) within the Quoddy Region. Forty-one dive sites were surveyed via SCUBA, and seven near-seafloor camera transects were conducted at depths deeper than dive limits (~ 30 m), collecting continuous highdefinition video and periodic high-resolution still images. Didemnum vexillum was detected at two sites from eDNA metabarcoding and quantitative PCR in 2018, 2020 and 2021, and observed by divers at 11 sites, two of which exhibited extensive tunicate coverage. Of the 1945 m² area surveyed by the near-seafloor drift camera system, D. vexillum occurred at depths to 118 m and across a spatial extent of 858 m², of which 170 m2 contained numerous tunicate patches and/or a homogenous mat. Didemnum vexillum was observed extensively overgrowing benthic substrates and fauna, possibly threatening the diversity of natural benthic habitats in the EBSA and adjacent areas supporting numerous commercial fisheries. This study is the first to report D. vexillum presence in the Canadian western Bay of Fundy, and the first to observe colonies at depths exceeding previous records of 81 m. We conclude by providing advice on how to improve coastal invasive species surveys from the combination of biodiversity metrics. [ABSTRACT FROM AUTHOR]

In the context of global climate change, monitoring focused on temperature and benthic animals in intertidal flats and the development of metrics to assess climate change and ecosystem responses are essential for a sustainable society. However, few studies have assessed the relationship between intertidal sediment temperature and the distribution of benthic animals. To address this gap, in the present study, intertidal sediment temperatures were observed in 12 intertidal flats in 11 survey areas over 335 days, from October 2, 2019, to August 31, 2020, using water temperature data loggers. The characteristics of intertidal sediment temperatures were variable among the survey areas, and a correlation analysis suggested that such characteristics are possibly influenced by various spatial-scale factors, such as geographical, basin, and habitat scales. Furthermore, two sentinel crab species, Macrophthalmus japonicus and Macrophthalmus banzai were collected, and the number of wintering individuals of each species was estimated based on their carapace width to analyze the changes in abundances of the two species in each survey area. The results show that the number of days with daily minimum temperature ≥ 19 °C was the factor that influenced the abundance rate, suggesting that M. japonicus and M. banzai populations may decrease and increase, respectively, according to future climate change in Japan. Our findings emphasize the importance of long-term monitoring of sediment temperatures and benthic animals in intertidal flats to evaluate the influence of future climate change. [ABSTRACT FROM AUTHOR]

Silvofishery is a system that combines mangrove and fishery to protect mangrove ecosystems and restore their functions, one of which is as a habitat for macrozoobenthos. Investigate the mollusks and mangrove density. Mollusk sampling was carried out on sub-plots measuring 1 x 1 m² in the mangrove vegetation transect, and mangrove density was measured by counting the number of trees directly on all of the mangrove species at two silvofishery ponds. A total of 16 species of mollusks were found at the observation site, consisting of gastropods and bivalves. The density of mollusks in July was 20 ind/m2 in pond I, while it recorded 9 ind/m2 in pond II. In October, after pond II rehabilitation, the density was inversely proportional to July, and the highest density was found in pond I at 10 ind/m2, while pond II measured 9 ind/m2. After rehabilitation, the index value H' decreased in pond I and pond II from 2.82 and 2.98 to 2.52 and 2.68, respectively. The mangrove density was 887 ind/ha in pond I and 686 ind/ ha in pond II. The substrate in both ponds was clay. Nitrate concentration values in the substrate in both ponds ranged from 0.27% to 0.29%, phosphate recorded a percentage of 0.07--0.09%, and C-organic ranged from 3.00% to 5.72%. The water's physicochemical parameters and the type and content of the substrate were still suitable for mollusk life. [ABSTRACT FROM AUTHOR]

The use of towed underwater unmanned vehicles equipped with photo, video, and sonar systems has proven its effectiveness in studying the seafloor surface in integrated research of the World Ocean. This class of devices solves a wide range of tasks, including biological studies of benthic fauna and surveys of underwater technogenic objects. The towed vehicle "Videomodule" was developed at the Shirshov Institute of Oceanology, Russian Academy of Sciences, and has been successfully employed for such surveys for several years. The paper discusses the technical features and application issues of working with the "Videomodule." [ABSTRACT FROM AUTHOR]

The outer membrane protein (OMP) is a kind of biofilm matrix component that widely exists in Gram-negative bacteria. However, the mechanism of OMP involved in the settlement of molluscs is still unclear. In this study, the mussel Mytilus coruscus was selected as a model to explore the function of ompR, a two-component system response regulator, on Pseudoalteromonas marina biofilm-forming capacity and the mussel settlement. The motility of the ΔompR strain was increased, the biofilm-forming capacity was decreased, and the inducing activity of the ΔompR biofilms in plantigrades decreased significantly (p < 0.05). The extracellular α-polysaccharide and β-polysaccharide of the ΔompR strain decreased by 57.27% and 62.63%, respectively. The inactivation of the ompR gene decreased the ompW gene expression and had no impact on envZ expression or c-di-GMP levels. Adding recombinant OmpW protein caused the recovery of biofilm-inducing activities, accompanied by the upregulation of exopolysaccharides. The findings deepen the understanding of the regulatory mechanism of bacterial two-component systems and the settlement of benthic animals. [ABSTRACT FROM AUTHOR]

Background: Bivalves are benthic animals existing in coastal habitats, particularly mudflats and tidal. Because of their availability, rich protein content and cheaper cost, they contribute a major portion of the small-scale fishery resource worldwide. Limited information has been available on the food-feeding and habitat structures of bivalves along Indian waters. Therefore, the present investigation was carried out to know the food-feeding and habitat preferred by wedge clam, Donax cuneatus off Thoothukudi, Gulf of Mannar, India. Methods: Soil, water and wedge clam samples were collected from the selected site from September 2019 to March 2021 and soil texture, water quality parameters and gut contents were analyzed at the laboratory. Result: During the study period, salinity, water temperature, pH and dissolved oxygen (DO) were in the range from 31-37‰, 24- 28oC, 7.7-8.7 and 4.1-5.8 mg/l, respectively. Wedge clams were mainly observed at sandy beaches up to 10 cm in depth. Donax cuneatus mainly feeds on detritus (65%), followed by phytoplankton (31%) and zooplankton (4%). Hence, the diverse fluctuation of food particles, season-specific food and feeding biology and local environmental conditions at the studied region might be the responsible features for the availability of Donax cuneatus. [ABSTRACT FROM AUTHOR]

Gastrotricha are microscopic benthic animals found in almost all water bodies. To date, over 890 species distributed in 71 genera, 18 families, and two orders are known. There are 376 freshwater species, and several are also found in Italy; however, a compendium of the studies carried out so far, and a georeferenced distribution of the species, still need to be provided. This project summarizes information about the diversity and geographic distribution of Italian gastrotrichs. Diversity data, acquired over 239 years, were reviewed and corrected based on taxonomic and nomenclatural updates and, in addition to distribution information, were organized into a data matrix valuable for statistical analysis. The data were fed into geographic information system software to understand the overall figures more easily. The results indicated that Italy is one of the best-known countries regarding freshwater gastrotrichs. With 92 species in 17 genera and three families from 61 investigated localities, Italy counts 17 type localities and 19 endemic species. Despite this high biodiversity, many Italian regions still need to be investigated, and should, therefore, be the focus of future research. The implementation of a web-mapping plugin enabled the creation of interactive maps for an easy and modern method for sharing the work done, and the information acquired. [ABSTRACT FROM AUTHOR]

The determination of potentially toxic element concentrations in fish is an important topic from the point of view of both nature conservation and human consumption. The aim of this study was to assess the concentrations of S, K, Ca, Cr, Mn, Fe, Zn, Rb, Sr, Mo, and P in benthic and pelagic fish species in the Karatal river, which is fed by melting glaciers from the Dzungarian Alatau in Kazakhstan. In September 2022, 48 fish samples were collected. It has been demonstrated that the accumulation of chemical elements in fish species can be explained by both the physiological parameters of the fish species and the influence of glaciers that feed river habitats. The data presented in this study provide a synergistic view of pollutants affecting fish populations. Benthic fish contained more manganese and strontium than pelagic species, while the mutual accumulation of potassium, chromium, rubidium, and molybdenum was higher in pelagic fish. The synergistic concentration of calcium and phosphorus in pelagic fish was higher than that in benthic species, while the amount of zinc and sulfur was higher in benthic animals. Relatively elevated levels of mercury in fish were found. The study contributes to the discussion about the role of glacial environments in loading pollutants to aquatic systems. [ABSTRACT FROM AUTHOR]

Upper Cambrian to Middle Ordovician radiolarian chert successions from Kazakhstan were studied to clarify the history of the emergence of benthic animals in ocean floor sediments. Radiolarian tests and clay were deposited for a period of 30 Myr without experiencing an influx of continent‐derived coarse clastic materials. Red, grey and black cherts of the Upper Cambrian to the upper mid‐Darriwilian are thinly laminated, and no trace of benthic animal activity is recognized in that time interval. Bioturbation structures and burrow traces in mid‐Darriwilian stage red chert in Kazakhstan suggest that benthic animals colonized the location where radiolarian chert formed, but that there was a significant delay in colonization when compared with similar reported occurrences in Australia and Canada. [ABSTRACT FROM AUTHOR]

To understand the health status of aquatic ecosystem in Lake Erhai, the community structure of benthic animals was investigated based on 27 samples from 11 typical monitoring sections in March, June, September and December 2021, and the benthic index of biotic integrity (B-IBI) assessment system was also established. The results showed that Lake Erhai contains 56 genera and species of benthic animals, which refers to 4 phyla, 6 classes, 28 families and 54 genera. The assessment system of B-IBI for Lake Erhai consists mainly of the total number of classification units, proportion of chironomid individuals, and BMWP index, which obtained by range test, discriminatory power and Pearson correlation screen. The health status of aquatic ecosystem in Lake Erhai can divide into five grades according to ratio scoring method, i.e., >2.61, 2.10~2.61, 1.82~2.10, 1.42~1.82 and <1.42, representing health, sub-health, fair, poor and very poor health status, respectively. Based on above method and standard, the health of aquatic ecosystem for Lake Erhai in 2021 is fair status. Specifically, five, six, five, nine and two sampling sites were in health, sub-health, fair, poor and very poor health status, accounting for 18.5%, 22.2%, 18.5%, 33.3% and 7.4% of the total sites, respectively. [ABSTRACT FROM AUTHOR]