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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]

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]

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]

The freshwater snails and mussels are recognized as ecosystem engineers owing to their ability to influence the ecological processes. We investigated the effect of the snail Filopaludina bengalensis and the mussel Lamellidens marginalis alone and in interaction with the macrophyte Lemna minor on the ecological processes (nutrient dynamics, microbial account, sediment properties and periphytic algal growth) of the freshwater ecosystem through a mesocosm experiment. Both the snail and mussel promoted the growth rate of L. minor; however, the presence of snail negatively influenced the growth of periphyton. The biogeochemical process was affected by the presence of snails and mussels. Macrophyte association further influenced this biogeochemical process. Snail and mussel enhance the growth of heterotrophic bacteria and phosphate solubilising bacteria in the sediment. Likewise, the presence of macrophyte also positively influences the microbial growth. The activities of the benthic fauna like the mussels and the snails can be considered a useful process for the sustenance of the microbes and the macrophytes representing a pattern of bottom-up regulation. [ABSTRACT FROM AUTHOR]

Little is known of the macrobenthos supported within stingray feeding pits. Compared to adjacent unpitted areas during low tide, macrobenthic abundance and biodiversity within the stingray pits might be expected to be (i) greater, the water-retaining pits functioning like rock pools; (ii) no different, since macrofaunal recolonisation can occur very rapidly; or (iii) less, consequent on the substratum changes that typify depressions in soft sediments. In both (i) and (iii) differences in composition of the supported assemblages would be expected, though not in (ii). To differentiate between these alternative hypotheses, faunal characteristics within intertidal stingray pits were compared to those in the adjacent background sandflat in Moreton Bay, Queensland, where the prey of the rays are the decapod crustaceans Trypaea and Mictyris that otherwise structure the benthic system. Results generally (though not totally) support hypothesis (ii), it being consistently found that feeding pits supported less macrobenthic abundance than the surrounding sandflat but subequal taxon density, evenness and patchiness of their faunas, and their taxonomic compositions were very similar. Such feeding pits undoubtedly structure many intertidal sandflats and increase both their topographical complexity and their habitat diversity, but this is not reflected in increased macrobenthic biodiversity. [ABSTRACT FROM AUTHOR]

Comparisons between vegetated and unvegetated intertidal habitats have led to the paradigm that benthic fauna are more abundant and diverse in the former. Mangroves are the dominant vegetation in estuarine intertidal zones of northern Brazil, however until now; there are no studies that investigated the macrobenthic fauna between vegetated and unvegetated intertidal habitats of estuaries at Amazon region. This study aimed to characterize the community structure of the macrobenthic fauna between an intertidal mudflat (non-vegetated area) and mangrove (vegetated area) of an estuarine gradient of salinity in the Amazon coast. Overall, finer sediments were found at the vegetated area and increased toward lower estuary. Overall, higher density and richness were found in the vegetated area and the values increased toward the lower estuary. The same pattern was found at the non-vegetated area. In general, our results showed the formation of a gradient of organism distribution along the estuary. Also, the results showed that the presence of the vegetation influences macrofaunal patterns. [ABSTRACT FROM AUTHOR]

The results of studies of bottom biocenoses in three types of littoral zone (rocky biotope, gravel-sand biotope, and surf zone with thickets of higher aquatic vegetation) of Lake Onego in 2013 and 2014 are presented. Our data show that, among the three types of coastal zone, the macrozoobenthos biomass is maximal in the rocky littoral zone (3.4–6.6 g/m2) and is minimal in the sandy zone (0.1–0.2 g/m2). The invasive species Gmelinoides fasciatus (Stebbing 1899) (CRUSTACEA: AMPHIPODA) has successfully naturalized in all types of littoral zones of the reservoir in recent decades. This species dominates both in number and biomass in the rocky type of biotope. [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]

No other group of animals typifies the uniqueness of Antarctic life more than Pycnogonida (sea spiders), with 20% of all known species found in the Southern Ocean, and 64% of these endemic to the Antarctic. Despite nearly 200 years of research into pycnogonids and other benthic phyla in Antarctica, the parameters which drive the distribution and diversity of benthic fauna are still poorly understood. This study aimed to investigate the diversity and connectivity of pycnogonid communities on either side of the Antarctic Polar Front, with an emphasis on the role of water depth, using an occurrence dataset containing 254 pycnogonid species from 2187 sampling locations. At depths shallower than 1000 m, communities to the north and south of the Antarctic Polar Front were distinct, while below this depth this geographic structure disintegrated. The Polar Front, or the expanse of deep ocean it bisects, seemingly acts as a semipermeable barrier to species exchange between well-sampled shallow communities. The less sampled and less understood deep sea appears to be better connected, with high levels of shared species following the northward flow of Antarctic Bottom Water. The exceptionally high diversity and endemism of Antarctic pycnogonids may reflect an apparent competitive advantage in cold waters which leaves them vulnerable to ongoing ocean warming, with increased competition and predation pressures. [ABSTRACT FROM AUTHOR]

The mid-Brunhes dissolution interval (MBDI; Marine Isotope Stage (MIS) 13 to 7; ~ 533–191 ka) is characterized by various paleoclimatic/paleoceanographic events in the world. We investigated fossil deep-sea benthic foraminifera and sediment geochemistry at the onset of the MBDI (~ 670–440 ka) using Ocean Drilling Program (ODP) Site 758 and core GPC03 in the northeast tropical Indian Ocean (TIO), primarily focusing on the relationship between the paleoceanographic conditions of the surface and deep oceans. Based on multi-dimensional scaling, MDS axis 1 is related to the specific depth habitats of benthic foraminiferal fauna, possibly at the trophic level. In MDS axis 1, the difference between the two core sites was smaller from ~ 610 to 560 ka, whereas it was larger from ~ 560 to 480 ka. In contrast, MDS axis 2 may be related to the low food supply at episodic food pulses/relatively stable and low food fluxes. MDS axis 2 showed generally similar stratigraphic variations between the two cores during ~ 610–560 ka, but was different during ~ 560–480 ka. The proportion of lithogenic matter to biogenic carbonate was relatively low from ~ 610 to 530 ka under the highstand when sediment transport to the study area was reduced. Thus, both the depth gradient in the distribution of benthic foraminiferal fauna and the lithogenic supply between the two cores changed coincidently across the MIS 15/14 (~ 570–540 ka) transition. Such paleoceanographic conditions across MIS 15/14 transition were attributed to the long-term weakening of the wind-driven mixing of surface waters, which might have been caused by the weakening of the Indian summer monsoon in the northeast TIO, possibly with the northward displacement of the InterTropical Convergence Zone in the Northern Hemisphere. In particular, the depth gradient in the distributions of benthic foraminiferal faunas represents the paleoceanographic linkage between the surface and deep oceans through particulate organic matter ballasting by calcareous plankton skeletons in addition to lithogenic matter, which changed transiently and significantly across MIS 15/14 transition close to the onset of the MBDI. [ABSTRACT FROM AUTHOR]

This article examines the conditions for the formation of the hydroecological regime of the Ivankov Reservoir according to data from complex hydrological, hydrochemical, and hydrobiological surveys carried out in August 2020−2022. The differences in hydroecological characteristics are associated with the peculiarities of weather conditions in the summer seasons. Despite the significant flow of the reservoir, in its bottom layer during prolonged hot weather, the formation of oxygen-free conditions is possible, affecting exchange processes with the bottom, hydrobionts, and methane emissions. The increased bioturbation of bottom sediments (BSs) by benthos under oxygen deficiency activates metabolic processes at the water–BSs boundary, including the release of methane. A strong "bloom" of the reservoir, characteristic of hot weather conditions in 2022, led to a reduction in the specific flux of methane from the surface due to its oxidation with an excess of oxygen in the surface layer. [ABSTRACT FROM AUTHOR]

In Büyük Akgöl, one of the most important lakes of Sakarya province in the Marmara region of Turkey, water and benthic sampling was carried out from five stations representing the lake seasonally between 2009 and 2010. As a result of the study, a total of 8736 individuals were collected from lake and that was a total of 24 species belonging to 36 taxa were identified. The benthic fauna community structure of the lake was classified with Turkish Biological Monitoring Working Party, Average Score Per-Taxon and Pielou's Evenness, Shannon–Wiener. According to the TR-BMWP scores were in the IV and the III class while the ASPT analysis was classified as moderate, and was as very poor. J' values ranged between 0.62 and 0.73, and H' values ranged from 1.74 to 2.14. The water quality parameters of the lake were classified as "unsuitable" by WQI and as "very polluted" according to HEI whereas the SAR, Na, and NPI were classified as 'excellent, good and no pollution.' According to the classification of water pollution control regulation it was showed 1st, 2nd and 3rd quality water characteristic. Pb, Hg, Al, Se, Cd concentrations and turbidity were exceeded the limit values set by WHO. [ABSTRACT FROM AUTHOR]

The diversity of bottom substrates is a primary driver of taxonomic richness and species abundance patterns of freshwater benthic insects in space and time. Here, we examine the influence of substrate composition on the seasonal patterns of benthic insect communities in streams of arid regions. Benthic insects were sampled monthly over a year at three sampling sites distributed along the Bouilef stream within the Belezma biosphere reserve (Algeria). Different substrate types (sand, gravel, pebbles, boulders, and emergent macrophytes) were sampled in the rainy and dry seasons. During the two sampling seasons, a total of 8599 insects belonging to six orders, 26 families, and 39 genera/species were sampled and identified. Student's t-test analysis showed that season influences significantly the mean abundance of benthic insects, which increases in the rainy season. However, the season does not affect taxa richness. Substrate types influence taxa composition and variation of benthic insect communities. The results showed that pebbles and boulders are the most populated by gathering and filtering collectors in terms of taxa abundance. Emergent macrophytes are more favorable for herbivores shredders. Principal Coordinates Analysis ''PCoA" also showed that pebbles and boulders differed significantly from other substrates, whereas sand and gravel substrates exhibited similar taxa mean abundance. Such assessments can help propose conservation measures needed to successfully safeguard these fragile ecosystems. [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]

Comparisons among vegetated and unvegetated intertidal habitats have led to the paradigm that benthic fauna are more abundant and diverse in the former. Mangroves and their associated saltmarshes are the dominant vegetation type in intertidal zones of the Ajuruteua Peninsula, northern Brazil, however until now, there no studies that investigate the benthic fauna among vegetated and unvegetated intertidal habitats. Therefore, the present study compares the macrobenthic fauna among red mangrove (Rhizophora mangle), saltmarsh (Spartina alterniflora) and adjacent unvegetated sediment (mangrove borders and saltmarsh borders) in the Furo Grande tidal channel in the Caeté estuary, northern Brazil. Overall, vegetated habitats have finer sediments, lower salinities and temperatures and higher organic matter and water content than unvegetated habitats. However, the macrofauna structure among the habitats did not fully correspond to this division, perhaps responding instead to differences among the four habitats in detrital production, tidal inundation frequency, leaf litter processing by crabs and rates of predation. Deposit feeding tubificid oligochaetes and capitellid polychaetes were particularly abundant in the mangrove and at mangrove borders probably due to greater availability of suitably processed detritus. [ABSTRACT FROM AUTHOR]

Although knowledge of Arctic benthic biodiversity has increased considerably in recent decades, some regions, such as Northeast Greenland, remain poorly studied. The aim of this study was to complement a previous macrofaunal inventory carried out in Young Sound, a High-Arctic fjord in this region (74°N). We sampled shallow benthic assemblages along a small inner/outer fjord gradient, including one station previously prospected two decades ago and three new stations. This sampling strategy revealed highly diversified benthic assemblages (166 species identified on a total sampling area of 1.32 m2), which considerably increases the number of species recorded for the fjord (i.e. 225 species vs 100 previously recorded). The outermost station was dominated in abundance by various assemblages of bivalves, while the middle stations showed greater species evenness, including numerous species of polychaetes, bivalves and crustaceans. The innermost station was dominated by ostracods, gammarid amphipods and tube-dwelling polychaetes. Overall, benthic assemblages varied little between the four stations and the transect as a whole exhibited characteristics typical of outer fjord habitats, reflecting the rather moderate impact of meltwater inputs in this part of the fjord. Finally, trophic plasticity and omnivory were observed in most of the recorded macrobenthic species, highlighting the adaptability of these species to low trophic availability in the ecosystem. Future biodiversity studies will need to explore the innermost and deepest areas to provide a more comprehensive inventory and understanding of the influence of environmental conditions on the structure and functioning of Young Sound benthic habitats. [ABSTRACT FROM AUTHOR]

This article presents the results of a study of zoobenthos of the Ural River in an area from the town of Verkhneuralsk to the city of Orenburg (about 1000 km) with sampling upstream and downstream of sources of anthropogenic impact: large cities, metallurgical plants, treatment facilities (TFs), and reservoirs. The degree of pollution was estimated using the Shannon and EPT indices, as well as the Woodiwiss index, an indicator that partially takes into account the first two indices. It is shown that the selected parameters decrease downstream of the sources of anthropogenic impact, thereby reflecting a decrease in the species diversity of benthic biocenoses and a decrease in the number of indicator species sensitive to pollution. Small streams are particularly affected; pools are subject to greater transformations than riffles. An integrated indicator of water quality based on biological parameters is proposed. It was used to rank all studied areas by the degree of pollution. It is shown that ten of the 23 studied river areas are assigned to the 1st class of water quality (conventionally clean areas), seven areas to the 2nd class (weakly polluted areas), three areas to the 4th class (dirty areas), and three areas to the 5th class (extremely dirty areas). This indicates that, despite multiple sources of pollution, the Ural River has a high self-purification capacity and most of the studied areas are quite clean and favorable for the habitation of benthic invertebrates. [ABSTRACT FROM AUTHOR]

Purpose: The vertical distribution of phosphorus (P) can vary depending on specific environmental factors like type of water body, soil type, land management and bioturbating macrofauna. To investigate how the benthic macrofauna affects vertical P distribution in aquatic sediment, a mesocosm laboratory experiment was conducted by using two muluscans: Bellamya aeruginosa and Corbicula fluminea. Materials and method: A 21-day mesocosm experiment was conducted with natural assemblages of two benthic macroinvertebrates (B. aeruginosa and C. fluminea). The Standard Measurements and Testing (SMT) method was used to acquire the migration, distribution, and transformation of P forms in benthic sediment bioturbation. Results and discussion: Results showed that the bioturbation of the benthic animals affected the decomposition and transformation of organic P (OP) in the sediment. The OP content in the sediment treated with benthic animal groups decreased dramatically during the experiment (p < 0.05). The non-apatite-inorganic-P (NAIP), inorganic-P (IP), and total-P (TP) of all treatment groups in the sediment layers increased over the experimental period. Comparing the two forms of bioturbation exerted, that of C. fluminea was significantly stronger compared to B. aeruginosa and the control groups. The apatite P content increased significantly in the 0–1-cm layer, and a significant decrease was observed in the 1–2-cm layer of the sediment (p < 0.05). Conclusion: This study shows that the bioturbation forces created by benthic macroinvertebrates B. aeruginosa and C. fluminea have significant impacts on the vertical distribution and transformation of sediment P forms and that the bioturbation effects of the C. fluminea on migration/transformation of P forms was stronger compared to B. aeruginosa. [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]

A new filamentous cyanobacterial strain (CHAB 4127) was successfully isolated from the algal mat during the field investigation of the open channel from Luanhe River to Tianjin, China. The polyphasic approach combining morphological, ultrastructural, ecological, and molecular features was used to characterize this studied strain. The strain is morphologically similar to the Microcoleus-like cyanobacterial taxa under light microscopy, and the radial arrangement of thylakoids is also consistent with that of Microcoleus-like groups. The phylogenetic position of CHAB 4127 based on 16S rRNA gene sequences, is shown to be clearly clustered into an independent clade with the newly established genus Microcoleusiopsis. The maximum similarity of 16S rRNA gene of the studied strain with other existing related cyanobacterial taxa is 93.97%, and the ITS secondary structures is also obviously different from other members of Microcoleaceae. Based on all the above evidence, we proposed the establishment of this novel cyanobacterial genus as Neomicrocoleus, with its type species, Neomicrocoleus tianjinensis. [ABSTRACT FROM AUTHOR]

Chitin is the most abundant natural polymer in the oceans, where it is primarily recycled by chitin-degrading microorganisms. Endozoicomonadaceae (Oceanospirillales) bacteria are prominent symbionts of sessile marine animals, particularly corals, and presumably contribute to nutrient cycling in their hosts. To reveal the chitinolytic potential of this iconic, animal-dwelling bacterial family, we examined 42 publicly available genomes of cultured and uncultured Endozoicomonadaceae strains for the presence of chitinase-encoding genes. Thirty-two of 42 Endozoicomonadaceae genomes harbored endo-chitinase- (EC 3.2.1.14), 25 had exo-chitinase- (EC 3.2.1.52) and 23 polysaccharide deacetylase-encoding genes. Chitinases were present in cultured and uncultured Endozoicomonadaceae lineages associated with diverse marine animals, including the three formally described genera Endozoicomonas, Paraendozoicomonas and Kistimonas, the new genus Candidatus Gorgonimonas, and other, yet unclassified, groups of the family. Most endo-chitinases belonged to the glycoside hydrolase family GH18 but five GH19 endo-chitinases were also present. Many endo-chitinases harbored an active site and a signal peptide domain, indicating the enzymes are likely functional and exported to the extracellular environment where endo-chitinases usually act. Phylogenetic analysis revealed clade-specific diversification of endo-chitinases across the family. The presence of multiple, distinct endo-chitinases on the genomes of several Endozoicomonadaceae species hints at functional variation to secure effective chitin processing in diverse micro-niches and changing environmental conditions. We demonstrate that endo-chitinases and other genes involved in chitin degradation are widespread in the Endozoicomonadaceae family and posit that these symbionts play important roles in chitin turnover in filter- and suspension-feeding animals and in benthic, marine ecosystems at large. [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]

Feeding features of juvenile muksun Coregonus muksun (Pallas, 1814) when growing in cages installed on the channel of the Lower Ob are considered. It was found that, along with artificial food, juveniles feed on zoobenthos and zooplankton organisms that enter cages during drifting, and consumption was noted from the first to the last days of rearing. The bulk of the food bolus was artificial food, 88.3–94.3%; aquatic invertebrates accounted for 1.3–5.7% of the weight of the food bolus where Chironomid larvae dominated. There were no statistically significant differences in the intake of invertebrates by young muksun before and after feeding (p = 0.442) at average values of 0.005 and 0.006 g, respectively. The ability of the transition of juveniles from artificial to natural food base at all stages of development was noted, which is an indicator of successful adaptation to environmental conditions during cage rearing in the channels of the Ob River. [ABSTRACT FROM AUTHOR]

The present work is aimed at investigating the effects of seasonal changes and habitat conditions on reproductive state and gonadal development of two macrobenthic fauna. Echinometra mathaei and Tridacna squamosa were collected seasonally (summer and winter) in July 2019 and January 2020 from three sites along the Red Sea coast, Egypt: Hamraween, Sedy Malek, and Porto Ghalb. Sexual differences and gonadal maturation in the two species were determined by performing biopsies of their gonads followed by morphologic analyses. Hematoxylin and eosin–stained gonadal sections were examined and analyzed. In E. mathaei, reproductive behavior was more active in the summer than in the winter; in T. squamosa, reproductive behavior was active almost all the year, especially during the winter. The reproductive activity and gonadal maturation of both species were affected by environmental factors. The results indicated that temperature is a vital factor affecting the reproductive activity of both species. This study concluded that temperature fluctuations may pose significant challenges to coastal marine ecosystems. [ABSTRACT FROM AUTHOR]

Macrobenthic traits, for example feeding mode, life history, morphology, are increasingly used for determining responses of macrobenthic fauna to environmental change and influences on ecosystem functioning. Yet, trait information is scarce or non-existent in several parts of the world, such as New Zealand. This deficit makes collecting trait data a difficult and time-consuming task, limiting its potential use in trait-based assessments. Here, we present the New Zealand Trait Database (NZTD) for marine benthic invertebrates, the first comprehensive assessment of macrobenthic traits in New Zealand. The NZTD provides trait information for more than 700 macrobenthic taxa, categorised by 18 traits and 77 trait modalities. The NZTD includes five freely downloadable datasets, (1) the macrobenthic trait dataset, with outcomes from a fuzzy coding procedure, (2) the trait source information, (3) the references by taxa, (4) the full references list, and (5) the full taxa list used in the NZTD. Establishing the NZTD closes the trait knowledge gap in New Zealand and facilitates future research applying trait-based approaches to New Zealand's coastal macrofauna. [ABSTRACT FROM AUTHOR]

A lithofacies and bionomic study of the Artinskian–Kungurian boundary deposits of the Cisuralian Series of the Permian System in the Yuryuzan–Ai Depression was carried out with reference to the Mechetlino section (Southern Urals). This section was a candidate for GSSP of the lower boundary of the Kungurian Stage. Eight lithological facies rock types, or lithofacies, were recognized in terrigenous–carbonate deposits. On the basis of their combinations, the section was divided into packages composed of carbonate–terrigenous flysch rocks, detrital carbonate deposits initiated by storms, and blocky submarine slump deposits. Six ecological assemblages of small foraminifers, reflecting depositional environments in benthic fauna source areas, were identified. The mechanisms of mixing and transport of plant remains along with benthic, planktonic, and nektonic fauna remains are indicated. A model of formation of the Lower Permian sedimentary assemblages in the Yuryuzan–Ai Depression of the Ural foredeep, reflecting the bionomic specificity of the assemblages of biogenic remains in the boundary interval of the Artinskian and Kungurian stages, is proposed. [ABSTRACT FROM AUTHOR]

Benthic foraminiferal turnover during the Palaeocene–Eocene Thermal Maximum (PETM) has been extensively studied but numerous questions remained unresolved, question such as why some foraminiferal species went into extinction at a particular location but survive in another or why some species survive in extremely low oxygen environment. Because foraminiferal community interaction with the environment is driven by biological traits instead of taxonomic composition, this study has adopted trait-based approach to provide insight into the life strategies of foraminifera that enables them to survive in extreme environmental conditions. The result from this study shows that traits such as test composition, perforation, ornamentation and living habits play an important role in the ecological functioning and adaptability of foraminifera in the environment. The faunal assemblage in the studied site is dominantly cosmopolitan taxa suggesting the environment was perturbed during the PETM. Foraminiferal composition is characterised by faunal turnover indicated in extensive mortalities and extinction of both planktonic and benthic fauna. The ordination (non-metric dimensional scaling) of faunal composition also indicated ecological disturbance. The planktonic community was relatively stable before and after PETM but experienced a high level of ecological perturbation during the carbon isotopic excursion (CIE). The benthic community showed higher evidence of perturbation as the fauna assemblage ordination indicated that ecological stress started before the PETM with the disarray of samples in the ordination diagram. Only the recovery interval experienced some level of ecological stability. The environmental disturbance noticed in the fauna composition reflected on the trait. Benthic foraminiferal traits indicated instability throughout the studied section. The evidence of environmental disturbance in the benthic community suggests that the source of the light carbon that caused the PETM may have originated beneath sea floor in the Atlantic Ocean. [ABSTRACT FROM AUTHOR]

Corals are a dominant benthic fauna that occur across a vast range of depths from just below the ocean's surface to the abyssopelagic zone. However, little is known about the evolutionary mechanisms that enable them to inhabit such a wide range of environments. The mitochondrial (mt) genome, which is involved in energetic pathways, may be subject to selection pressures at greater depths to meet the metabolic demands of that environment. Here, we use a phylogenomic framework combined with codon-based models to evaluate whether mt protein-coding genes (PCGs) associated with cellular energy functions are under positive selection across depth in three groups of corals: Octocorallia, Scleractinia, and Antipatharia. The results demonstrated that mt PCGs of deep- and shallow-water species of all three groups were primarily under strong purifying selection (0.0474 < ω < 0.3123), with the exception of positive selection in atp6 (ω = 1.3263) of deep-sea antipatharians. We also found evidence for positive selection at fifteen sites across cox1, mtMutS, and nad1 in deep-sea octocorals and nad3 of deep-sea antipatharians. These results contribute to our limited understanding of mt adaptations as a function of depth and provide insight into the molecular response of corals to the extreme deep-sea environment. [ABSTRACT FROM AUTHOR]

The study and analysis of malacofauna from cores of bottom sediments and cores of the Azov spits showed the nature of the change during the transition from the Ancient Azovian to the New Azovian layers and the uneven distribution of communities in time and space. Shell material from littoral malacocenosis and shallow-water banks is the main component for the formation of spits. Based on a series of cores up to 25 m thick from the Dolgaya Spit, it is shown that its formation began about 2500 years ago, and carbonate material reflects the history of the development of the benthic fauna of the sea. [ABSTRACT FROM AUTHOR]

Prediction of biophysical processes under the conditions of a rapid change in the composition of the interacting components of a biosystem requires flexible approaches and a logical analysis of the direction, time, and level of strength of systemic interactions. It is unrealistic to construct a predictive model based on the methods developed by the author for organizing hybrid computing structures for a key component of a biophysical system (such a link is usually considered the most valuable population for the economy) without a scheme for the mutual influence of factors acting on the biotic environment. Direct interaction of the "predator–prey," "parasite–host," or "resource–consumer" equations does not fully describe the dynamics of a real biosystem, especially after invasions of aggressive species. This article is devoted to the application of cognitive formalisms of model structuring of conceptual information about the interaction of natural and anthropogenic factors based on the development of graph theory methods. The purpose of the work is to mathematically formalize how a change in one factor will affect the state of other components of biosystems. The new model allowed us to explore mediated interactions that are not always immediately visible, but are critical. To understand the processes after invasions, we will develop a method for analyzing the distribution of indirect effects in biosystems on directly disconnected components. The results of computational studies are logically followed step by step by a theoretical interpretation of the observed changes in the behavior of the model trajectory. A formal analysis of impulses in a sign digraph in the context of the studied situation of bioresources degradation in the Caspian Sea after a large-scale intervention in the biosystem and due to the penetration of the harmful stenophora Mnemiopsis leidyi has been carried out. It is shown that the choice of a mathematical approach to the description of the situation is successfully based on the results of the analysis of cycles of influence of ecological interlinkages. Previously unaccounted-for links that led to the low efficiency of attempts to artificially reproduce bioresources were revealed. It was confirmed on the basis of the impulse process in the cognitive graph that the purposeful introduction of alien mollusks from the Black Sea into the Caspian Sea to increase the biomass of bottom fauna was one of the factors in the degradation of valuable biological resources with an increase in the level of the Caspian Sea. Alien mollusks (Abra ovata, Mytilaster lineatus) replaced the native benthic fauna. At the end of the 1980s, the salinity of the Northern Caspian decreased; then, the invaders adapted to more saline water drastically reduced the biomass. Competition in the trophic chains of unstable biosystems should not be aggravated in order to increase their productivity for valuable populations. The mass release of juveniles of valuable fish is not a panacea for the degradation of the entire Caspian biosystem. The results of the impact distribution analysis in the cognitive graph are applied to the original hybrid dynamic system for modeling the efficiency of artificial reproduction of the Caspian sturgeon. The model showed that degradation of the Caspian biosystem could have been avoided as early as 2005. [ABSTRACT FROM AUTHOR]

Hydrobiological surveys (plankton and benthos, including snow crab) were carried out in the southwestern region of the Chukchi Sea in the summer of 2003–2020. At the western, eastern, and northern edges of C. opilio distribution area in the Chukchi Sea, the abundance of crabs was five to ten times lower due to the limit of the species tolerance to hydrological factors and shortage of food resources, low mass of zoobenthos. Aggregations of snow crab C. opilio in northern regions of the Chukchi and the East Siberian seas can be considered dependent on replenishment from southern regions of the Chukchi Sea. The southern regions of the Chukchi Sea are some kinds of the nursery for development and growth of snow crab larvae and juveniles until 1–2 years age, from where they migrate into northern deeper regions of the Chukchi Sea, and then farther to the northeastern region of the East-Siberian Sea. [ABSTRACT FROM AUTHOR]

Quantifying the flow resistance in step-pool streams is of importance for studying the restoration of benthic animals and bedload transport. The Darcy–Weisbach friction factor of the total flow resistance is partitioned into components associated with grains, spills, and loose-packed particles. By extending the two-dimensional hydraulic radius, a new proposed roughness height is applied to evaluate resistance components induced by spills and loose-packed particles. Three morphological patterns induced by different-magnitude floods can be classified to form different flow resistance components, depending on the morphological variation. The three components varying with hydraulic and geometric parameters by considering the closest-1 NSEI and smallest RMSE and MRE have been examined. It is found that the grain resistance factor component, in comparison with other factors, has a slight impact on hydraulic parameters. Hydraulic and geometric parameters have a significant influence on the spill resistance component, accounting for the main proportion of the total resistance. The resistance associated with loose-packed particles correlates with parameters due to the initial random movement of particles and abundant sources. [ABSTRACT FROM AUTHOR]

The results of long-term studies are used to present, for the first time, the structural organization of zoobenthos communities and the dynamics of their density and biomass in rivers and brooks of the the Khektsir Ridge, including the boundaries of the Bol'shekhekhtsirskii Reserve, Khektsirskii Wildlife Reserve (the southern part of the Russian Far East). The benthic organisms were found to contain 23 groups (22 groups in the spring and summer, 19 groups in the autumn, and 8 groups in the winter). Leading in the occurrence frequency (>90%) were chironomids, mayflies, and oligochaetes. The chironomids and amphipods accounted for 37.0 and 19.1% of the total benthos density, and mollusks and amphipods, for 32.1 and 29.7% of the total biomass, respectively. Dominants in terms of density and biomass were amphipods; chironomids dominated in terms of density, and mollusks, in terms of biomass. The mean density of benthic organisms was 637 ± 21 spec./m2, and the mean biomass was 1.8 ± 0.2 g/m2. The benthic communities of rift segments in the rithral zone were found to be most productive. It is shown that the seasonal and long-term dynamics of zoobenthos communities is pronounced and can be traced in the group composition, structure, and quantitative characteristics. [ABSTRACT FROM AUTHOR]

Cold seeps are characterized by typical endemic communities with associated microorganisms that depend on sulfide, methane, reduced nitrogenous compounds, and metals as electron donors for their survival through chemosynthesis. The discovery of an active cold seep site in January 2018 in the Krishna-Godavari (K-G) basin of Bay of Bengal was followed by a transit cruise in March 2018 to investigate the distribution and diversity of macrofauna. Further, the ambient sediment and pore water biochemistry were estimated to understand its relationship with macrofauna and the microbial associates of the sediment. Samples were collected at a water depth of around 1750 m at 3 stations: SP1, SP2, and SP3, using the box corer. The benthic fauna at the sites consisted mainly of Bivalvia, shrimps of Caridea family, Gastropoda species, Malacostraca species, Polychaeta, and few species of Echinoidea, Ophiuroidea, and Echiura. A total of 2313 macrofaunal individuals belonging to 8 classes, 18 families, and 20 species were identified from all the three stations. The communities were diverse at these sites with an average Shannon diversity index of 1.64 and are closely related to the lineages previously studied in ecologically similar environments. Most of the macrofauna were found to be filter feeders preferring a low organic carbon environment. Relict vesicomyid clams at the present study site suggest the succession from vesicomyids to the present composition of bivalve mussels and siboglinid worms. The microbial associates in the sediment significantly correlated with methane and hydrogen sulfide concentrations. The study suggests that the K-G basin cold seep serves as a conducive environment for the flourishing of benthic communities and therefore can support a rich biodiversity. [ABSTRACT FROM AUTHOR]

In Greece, the implementation of the Water Framework Directive for rivers is based mainly on benthic macroinvertebrates and uses a semi-quantitative method with a D-frame net, which is certified by the International Organization for Standardization. Before the official adoption of this method, a quantitative shovel sampler ("Cretan shovel") was used in southern Greece (Crete), which has been implemented for almost three decades due to the specific river habitats found in Crete (e.g., seasonal flow, narrow riverbeds, and coarse substrates). In this study, we compared community metrics, diversity indices, feeding groups, locomotion types, and ecological quality derived from data collected using timed semi-quantitative kick samples and quantitative shovel samples collected from the same sites simultaneously. In total, 20 samples from the north and south of Greece were collected. The majority of community metrics, diversity indices, and traits were comparable between samplers. However, there were statistically significant differences in the relative abundance of Ephemeroptera, Plecoptera, and Trichoptera, passive filterers' and the (semi) sessil groups, and Pielou's index. Most differences in the ecological quality between the kick and shovel samples were observed in 50% of the sites in northern Greece because the shovel is less effective at capturing motile zoobenthos. The ecological quality assessment in Crete by the Cretan shovel is comparable with the D-frame net in 75% of the samples. Thus, the Cretan shovel could efficiently sample the Cretan streams, which are characterized by coarse, narrow, turbulent, and hydrologically fluctuating river habitats. Such comparisons could improve sampling effectiveness and make additional data available to assess ecological quality. [ABSTRACT FROM AUTHOR]

Antarctica is a remote place, the continent is covered by ice and its surrounding coastal areas are frozen for the majority of the year. Due to its peculiarity the observation of the underwater organisms is particularly difficult, complicated by logistic factors. We present a long-term dataset consisting of 755 images acquired by using a non-invasive, autonomous imaging device and encompassing both the Antarctic daylight and dark periods, including the corresponding transition phases. All images have the same field of view showing the benthic fauna and part of the water column above, including fishes present in the monitored period. All the images are manually annotated after a visual inspection performed by expert biologists. The extended monitoring period and the annotated images make the dataset a valuable benchmark suitable for studying the dynamics of the long-term Antarctic underwater fauna as well as for developing and testing algorithms for automated image analysis focused on the recognition and classification of the Antarctic organisms and the automated analysis of their long-term dynamics. Measurement(s) Coastal Benthic Megafauna Technology Type(s) Autonomous Imaging Device Factor Type(s) None Sample Characteristic - Organism Sterechinus neumayeri • Odontaster • Trematomus • Polynoidae • Diplasterias • Ophiuridae • Ammothea • Neobuccinum eatoni • Staurocucumis • Flabegraviera mundata Sample Characteristic - Environment coastal sea water Sample Characteristic - Location East Antarctica [ABSTRACT FROM AUTHOR]

Benthic fluxes of oxygen and carbon in coastal zones are poorly resolved in mechanistic models due to the lack of understanding of the diverse interactions among the physical, chemical, and biological drivers of biogeochemical fluxes. To inform modelling efforts we used ex-situ incubation experiments to identify spatial and seasonal patterns of oxygen and dissolved inorganic and organic carbon (DIC and DOC) fluxes in the coastal southern Baltic Sea. We used boosted regression trees to identify important drivers of the studied fluxes. Our results demonstrate that benthic communities, in addition to sediment parameters, played a dominant role in shaping oxygen and DIC fluxes, while neither benthic community, environment, season, nor sampling location could account for the highly variable DOC fluxes. DIC fluxes were partly decoupled from oxygen fluxes, since carbonate dissolution, anaerobic respiration, and submarine groundwater discharge affected DIC fluxes in the study region. Boosted regression trees proved to be a useful tool to study drivers of biogeochemical fluxes as it allowed to identify non-linear effects of biological and environmental variables on benthic fluxes. [ABSTRACT FROM AUTHOR]

Human activities in riverine water bodies can cause loading of nutrients and other pollutants in receiving systems, affecting species interactions and population dynamics. The present study aimed to investigate the influence of anthropogenic alteration on an artificial water body, i.e., the Shahid Rajaee reservoir, in Iran that is experiencing a serious water crisis. The reservoir is subject to high anthropogenic nutrient loads from the Shirinroud and Sefidroud rivers, the effect of which needs to be evaluated considering the strategic importance of the reservoir as a source of drinking water. A field sampling campaign was carried out at seven stations (one in each of the two river mouths and five in the reservoir itself) each month from April to July 2016. The study entailed sampling of benthic macroinvertebrate fauna at the river mouths and plankton communities at the reservoir stations. In addition to macroinvertebrate and plankton, abiotic and nutrient variables were measured at all stations. Substantial loading of organic matter, mainly from the Shirinroud River, was detected throughout the sampling period, with a detrimental effect on both benthic and plankton communities. The decline in plankton diversity was particularly noticeable at stations close to the river mouths during June and July, with a bloom of Dinoflagellata and Cyanobacteria and strong dominance of larger zooplankton taxa, e.g., Copepoda. Our results suggest that river water quality, affected by human activities, alters the planktonic communities in Rajaee reservoir. Our assessment indicates that measures on both the Shirinroud River and the reservoir are required to mitigate and prevent even stronger eutrophication of the reservoir ecosystem. [ABSTRACT FROM AUTHOR]

Developments in animal electronic tagging and tracking have transformed the field of movement ecology, but interest is also growing in the contributions of tagged animals to oceanography. Animal-borne sensors can address data gaps, improve ocean model skill and support model validation, but previous studies in this area have focused almost exclusively on satellite-telemetered seabirds and seals. Here, for the first time, we develop the use of benthic species as animal oceanographers by combining archival (depth and temperature) data from animal-borne tags, passive acoustic telemetry and citizen-science mark-recapture records from 2016–17 for the Critically Endangered flapper skate (Dipturus intermedius) in Scotland. By comparing temperature observations to predictions from the West Scotland Coastal Ocean Modelling System, we quantify model skill and empirically validate an independent model update. The results from bottom-temperature and temperature-depth profile validation (5,324 observations) fill a key data gap in Scotland. For predictions in 2016, we identified a consistent warm bias (mean = 0.53 °C) but a subsequent model update reduced bias by an estimated 109% and improved model skill. This study uniquely demonstrates the use of benthic animal-borne sensors and citizen-science data for ocean model validation, broadening the range of animal oceanographers in aquatic environments. [ABSTRACT FROM AUTHOR]

The article describes the features and results of using the autonomous underwater vehicle (AUV) MMT-3000 for research of Antarctic ecosystems and deep-sea biological resources of the South Seas. The methodology for working with an AUV in the extreme conditions of Antarctica and the technical solutions used to visually assess the distribution of bottom animals are discussed. The results of processing the data obtained by AUV during deep-sea missions in the Atlantic sector of the Antarctic during the expedition of the RV Akademik Mstislav Keldysh (cruise 79) in 2020 are presented. At the same time, the data of image analysis and trawl catch were compared. Based on the experience gained, the requirements to be implemented in the new AUV MMT-3500, which is designed and manufactured to effectively carry out deep-sea research in subsequent expeditions in the Southern Ocean, are determined. [ABSTRACT FROM AUTHOR]

The aquatic ecological health status was focused on the Huai River Basin (HRB) from the aspects of water quantity, water quality, water ecology, river connectivity, and riparian habitat environment. Ten monitoring sections were set up in the middle and upper reaches of HRB, and 5 experiments of each section were conducted in July and December from 2012 to 2014. Thus, relevant data on the species, the density of phytoplankton, zooplankton and benthic animals, the concentration of water physicochemical variables, and riparian habitat quality were obtained. Eleven key impact factors were chosen using frequency statistics, theoretical analysis, and correlation analysis methods, forming the evaluation index system of aquatic ecological health. Then, the indicator weight value was determined by the combined weight method, and the health degree was evaluated by the comprehensive index method. On the whole, the aquatic ecological health degree of the upper sections (D1 ~ D3) of the Shaying River ranges from 0.334 to 0.927, which is generally in a "sub-healthy" state. The aquatic ecological health degree of the main section of the Huai River (D8 ~ D10) ranges from 0.362 to 0.777, which is in the "critical" or "sub-healthy" state. The Huaidian Sluice (D5) and Fuyang Sluice (D6) in the middle and lower reaches of the Shaying River had the worst aquatic ecological health. Its water ecological health range is 0.283–0.523, and most of them are under "sub-pathologic." The research results have important theoretical and practical significance. They can enrich the evaluation theories and methods of river aquatic ecological health, help to grasp the aquatic ecological health status in HRB, and provide basic support for aquatic ecological protection and water pollution control in sluice-controlled rivers. [ABSTRACT FROM AUTHOR]

The influence of hydrodynamic factors on the formation of zoobenthos communities in the coastal zone exposed to active wind-wave mixing, as well as in the deep part of water bodies characterized by the silt accumulation is considered for the Curonian Lagoon. The features of the qualitative and quantitative distribution of zoobenthos and their effect on determining the water quality using zoobenthos parameters are analyzed. Recommendations are given for the placement of hydrobiological monitoring stations based on zoobenthos parameters. [ABSTRACT FROM AUTHOR]

The waters adjacent to the northeastern coast of Sakhalin Island, Russia, are an important feeding ground for the endangered western gray whale. Data on the energy available to foraging whales from their prey resources is required for researchers interested in modeling the bioenergetics of whale foraging, but little energy content information is available for the benthic prey communities of gray whales in this region. In this study, we describe the energy density (ED), biomass, and total energy availability (ED × biomass) of benthic prey sampled from two gray whale foraging areas adjacent to Sakhalin Island: the nearshore and offshore feeding areas. ED varied almost seven-fold among benthic taxa, ranging from 1.11 to 7.62 kJ/g wet mass. Although there was considerable variation within most prey groups, amphipods had the highest mean ED of all of groups examined (5.58 ± 1.44 kJ/g wet mass). Small sample sizes precluded us from detecting any seasonal or spatial differences in mean ED within or among taxa; however, mean biomass in the offshore feeding area was, in some cases, an order of magnitude higher than mean estimates in the nearshore feeding area, resulting in higher mean total energy available to foraging gray whales offshore (958–3313 kJ/m2) compared to nearshore (223–495 kJ/m2). While the proportion of total energy accounted for by amphipods was variable, this prey group generally made up a higher proportion of the total energy available in the benthos of the offshore feeding area than in the benthos of the nearshore feeding area. Data presented here will be used to inform bioenergetics modeling of the vital rates of mature females in an effort to improve understanding of population growth limits for western gray whales. [ABSTRACT FROM AUTHOR]

The objectives of this study were to test an artificial substrate sampler method for aquaculture ponds and assess the water quality based on the benthic macroinvertebrate community living in fishpond sediment at four farms with tilapia production in the Baixa Mogiana region of São Paulo State, Brazil. Benthic macroinvertebrates were monitored every 15 days for 3 months. Approximately 500,000 organisms distributed in 47 taxa were collected. Chironomidae, Glossiphonidae, Hirudinidae, Libelullidae, Oligochaeta, and Polycentropodidae were present in all collected samples, with the dominance of Chironomidae in the benthic community. Polycentropodidae, a sensitive family to organic pollution, had a greater abundance in fish farms with better environmental conditions. Significant differences in dissolved oxygen and pH were observed among fishponds at different fish farms. Biomonitoring with artificial substrate is a simple and low-cost alternative to monitoring water quality of tilapia culture in fishponds. The artificial substrate sampling method was effective, but the evaluation of more critical conditions of water quality would improve the method and enhance the knowledge of taxa and ecology of macrobenthic organisms in fishponds. [ABSTRACT FROM AUTHOR]

Macrozoobenthos and submerged macrophytes interact closely. However, studies in China have focused on the middle and lower reaches of the Yangtze River, where shallow lakes are concentrated, rather than on temperate lakes. To clarify the responses of taxonomic and functional groups of macrozoobenthos in temperate lakes to changes in submerged macrophyte biomass (BMac) on a large scale, 19 temperate lakes within Baiyangdian Lake were investigated in this study. The BMac differed greatly across the 19 lakes, and Potamogeton crispus was the dominant species. According to the BMac, the 19 lakes were divided into 4 groups. One-way analysis of variance and Pearson correlation analysis showed that the water environmental parameters were different among the 4 groups, and the BMac was significant correlated with all the physical and chemical parameters of water bodies (except for water depth). Forty-one taxa of macrozoobenthos were identified in the 19 lakes, with oligochaetes, Hirudinea, gastropods, crustaceans, chironomid larvae, and aquatic insects (excluding chironomid larvae) represented by 9, 1, 4, 2, 19, and 6 species, respectively. Chironomid larvae and oligochaetes dominated by density, and gastropods and chironomid larvae dominated by biomass. Canonical correspondence analysis showed that the BMac was the most important factor affecting the macrozoobenthos community structure in group 1 to group 4. Macrozoobenthos with low pollution tolerance values were mainly found in areas with high BMac, while species with high pollution tolerance values were mainly distributed in areas with low BMac and high nutrient contents. Different taxonomic and functional groups of macrozoobenthos responded differently to changes in BMac. As BMac increased, density and biomass of oligochaetes and chironomid larvae tended to decrease, while those of gastropods and aquatic insects tended to first decrease and then increase. Collectors had more species than any other functional group in group 1 to group 4. As BMac increased, density and biomass of collectors gradually decreased, while density of predators, shredders, and scrapers tended to first decrease and then increase. [ABSTRACT FROM AUTHOR]

This study is based on biological trait analysis (BTA), which provides a link between the distribution and biological characteristics of species. The paper investigates differences in the structure and functional diversity of benthic fauna in terms of seven biological traits (mobility, habitat, feeding type, habitat modification, body form, body size and feeding apparatus) in nine Baltic coastal lakes whose salinity ranged from 0.1 to 7.3 PSU. Mobile organisms were more common in lakes with higher salinity, while sessile and semi-mobile species preferred low-salinity or freshwater environments. There were also noticeable differences connected with feeding type: collectors and scrapers were more common in brackish lakes, and collectors were significantly dominant in freshwater and transitional ones. This indicates that Baltic coastal lakes are inhabited by similar species of benthic fauna, but that certain biological traits occur with different frequencies. We therefore identified features that may affect the functioning of coastal lakes with a relatively narrow salinity gradient (0.1–7.3 PSU). It seems to confirm the possibility of using BTA methods to determine key characteristics that are helpful for understanding the differences between aquatic ecosystems. The results may provide a basis for further research on changes in the functional diversity of lakes along the southern coast of the Baltic Sea, particularly in view of climate change, given their being small, shallow and less resilient lakes. [ABSTRACT FROM AUTHOR]

The summer structure of the zoobenthos in several thermal and low-temperature springs of the Bol'shezemel'skaya Tundra hydroecosystem (Pymvashor Creek) is examined. Compared with cold springs, thermal springs feature a lower diversity of benthic faunal groups but a higher species richness in some of these groups. In terms of abundance, oligochaetes and dipteran (family Chironomidae) larvae prevail in communities of hydrothermal biotopes; while cold karst waters are predominated by dipteran (family Chironomidae) larvae and ostracodes. Mollusks, oligochaetes, or dipterans (family Tipulidae) feature the greatest biomass in thermal springs; in low-temperature springs, chironomids and mollusks predominate in terms of biomass. The fauna consists mainly of widespread eurythermal species, but stenothermal hydrobionts are present as well. No endemic forms typical for thermal waters in other parts of the world were discovered; however, for the first time, representatives of the extrazonal fauna were found in Bol'shezemel'skaya Tundra. Within the studied stretch of Pymvashor Creek, the zoobenthos structure is fairly homogenous regardless of the warming or cooling effects of the springs. [ABSTRACT FROM AUTHOR]

Bio-monitoring freshwater bodies using macro-invertebrates is an excellent way to detect biological water quality. Organic contamination in aquatic settings is well indicated by benthic macro-invertebrates. The use of macro-invertebrates to bio-monitor freshwater bodies is an effective method for determining biological water quality. Benthic macro-invertebrates are excellent indicators of organic pollution in aquatic environments. In the present study, the distribution of pollution-sensitive and pollution-tolerant families of benthic macro-invertebrates from 33 different locations along the Ganga River in Uttarakhand, Uttar Pradesh, Bihar, and West Bengal was studied. Benthic macro-invertebrates collected from different studied locations were identified up to family level and it was observed that a total of 15 pollution-sensitive families belong to four taxonomic orders, while eight pollution-tolerant families come from two taxonomic orders. Several moderately tolerant families have also been observed, but in this paper the distribution of only pollution-sensitive and pollution-tolerant families is presented as they reflect the extreme states of organic pollution. In the majority of locations, the pollution-sensitive Ephemeroptera family Ameletidae predominated. Likewise, the pollution-tolerant families Chironomidae (order—Diptera) and Naididae (order—Oligochaeta) dominated the Ganga River locations. Besides, the relationship between macro-invertebrate diversity and physicochemical factors (pH, water temperature, and dissolved oxygen) was investigated, and 3D surface distribution maps were displayed for qualitative interpretation. The correlation coefficients for all parameters were found to be positive. Macro-invertebrate pollution indices for bio-monitoring are based on community impacts and assist in evaluating the success of action plans to prevent industrial and anthropogenic pollution that contributes to the Ganga. [ABSTRACT FROM AUTHOR]

Sponges (Porifera) are a key component of many coral reef ecosystems. In some biogeographic regions, they are considered the dominant benthic fauna and they have the capacity to fulfil many similar roles to reef-building scleractinians. Certainly, sponges predominate at depth, below the critical thresholds of most coral species. The biological and physical attributes of these biogenic communities contribute essential resources for many reef-associated fishes. However, while fish–sponge interactions have been widely documented, there is no global synthesis of the literature on these interrelationships from the perspective of fish ecology. Here we evaluate coral reef fish–sponge relationships, including the role of sponges in providing food and shelter for fishes, the influence fishes have on sponge distribution and abundance and possible outcomes of climate change on fish–sponge interactions. To date, 16 fish families have been shown to associate with 56 different sponge genera, using them as either a source of shelter (n = 17) or a food source (n = 50), although methodologies for the latter currently lack consistency. We demonstrate that a more comprehensive understanding of fish–sponge interactions has been garnered from tropical Atlantic coral reefs, which has resulted in a strong biogeographic bias. While it is evident that in some areas of the Caribbean fish are key in shaping the distribution and abundance of sponges, it is not yet known whether this conclusion applies to the Indo-Pacific. With increasing stresses such as bleaching events impacting coral reef ecosystems, further work is needed to evaluate whether sponges can fulfil similar functional roles to those previously provided by reef-building scleractinians. Similarly, determining whether sponge expansion will compensate for the negative effects of reef degradation, or contribute to their decline, is vital. [ABSTRACT FROM AUTHOR]