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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]

Fences disturb the movements of terrestrial species, altering migration patterns, limiting access to vital resources, and reducing genetic diversity. With almost 40% of the Earth's land surface converted for agriculture, farm fencing to protect crops and corral livestock is expected to stretch into the millions of kilometers. As semi‐terrestrial ectotherms, freshwater turtles are threatened by fences that limit access to resources and increase risks of desiccation, entanglement, and overheating, often resulting in death. To determine the effect of fences, we quantified the movement patterns for a population of eastern long‐necked turtles (Chelodina longicollis) inhabiting an agricultural landscape near Armidale, New South Wales, Australia from November 2022 to September 2023. There was considerable variation in the distance traveled, home range size, and movement corridor selection between turtles that was not explained by the morphological factors of size, mass, or the loss of a limb (likely due to predation attempts). On average, 38% ± 4.70 ( x ¯ $\bar{x}$ ± SE) of turtle movements were terrestrial (overland) during their active season (spring and summer) during which they encountered fences frequently because of a complex matrix of paddocks. Fence design dictated the distance turtles traveled to locate a suitable passage point. The majority of fences allowed turtles to pass (turtle‐friendly fences, 71.4% of total fence distance) as opposed to turtle‐unfriendly fences (28.6% of total fence distance). Turtles were required to travel almost 4 times the distance to locate a suitable crossing point (a gap or fault in the fence) when they encountered an unfriendly fence (85.32 m ± 29.81) compared to a turtle‐friendly fence (25.85 m ± 3.58). Our results highlight the need for land managers to avoid small‐diameter exclusion fencing and fence designs containing chicken wire that extend to or below ground level. In settings where small‐diameter wire fencing is required, we recommend the installation of turtle gates for small terrestrial fauna or elevating bottom wires at least 50 mm above ground level to facilitate fence permeability. [ABSTRACT FROM AUTHOR]

Dal Lake supports a diverse group of fauna, including fishes, aquatic birds, zooplankton, and macrobenthic invertebrates. This study is the first taxonomic documentation of the leech fauna of Dal Lake. A total of nine leech taxa belonging to four families were identified and described: Glossiphoniidae - Alboglossiphonia weberi, A. heteroclita, Glossiphonia complanata, Helobdella stagnalis, Hemiclepsis marginata asiatica, and Theromyzon sp.; Erpobdellidae - Erpobdella octoculata; Hirudinidae - Poecilobdella granulosa; and Haemopidae - Haemopis indicus. Leeches play key roles in prey-predator dynamics and host-parasite relationships in freshwater ecosystems and as bioindicators of water pollution. This study provides essential data for taxonomic accounts and the diversity of leech fauna in Dal Lake. [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]

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]

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]

Human pressures are changing ocean environments, such as a shift from fish‐ to squid‐dominated ecosystems in overfished, poorly oxygenated environments. After death, carcasses of upper ocean fauna sink to the seafloor where they provide food for demersal scavengers. It is unclear how shifts in carcass type impact abyssal scavengers. We performed baited benthic camera lander deployments in the Cabo Verde Abyssal Basin to test how a shift from fish‐ to squid‐dominated carrion could modify abyssal scavenger ecology. At the fish bait, peak scavenger abundance was greater and occurred later for the majority of observed fauna. However, removal rates of squid bait were up to 10‐fold greater, and a significantly different community composition developed, favoring faster organisms with lower chemosensory thresholds. At the fish bait, slower organisms were less disadvantaged as the bait persisted for longer periods allowing the development of a more complex community and dense amphipod aggregations. The rapid squid consumption indicates that the accumulation of this type of food fall at the seafloor may not occur, preventing scientific observations necessary to estimate the importance of squid carrion to the biological C pump and deep‐sea food webs. As such, the flux of squid carrion to the seafloor is likely greater than currently recognized in this part of the Atlantic. The differences observed between bait types indicate how future changes in upper ocean ecosystems may impact abyssal scavengers and their ecosystem functions, including controlling seafloor biomass, regulating the behavior of benthic fauna, and contributing to nutrient cycling and energy transfer. [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]

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]

Macrozoobenthos communities play significant ecological roles in coral reef ecosystems. However, they are frequently overlooked due to their cryptic appearance, and their diversity remains undiscovered, particularly in Indonesia. This comprehensive review of publications on the macrozoobenthos in the coral reef ecosystems of Java - the most populated island in Indonesia, was conducted to compile a species list and gain an overview of its community composition. We also assessed the existence of species that are frequently reported, endemic, protected, and threatened. Data analysis was performed with data from 53 publications appearing from the 1980s to 2022. In total, 482 species belonging to 4 phyla and 9 classes have been recorded. Mollusca is the most speciose phylum (n = 321), followed by Echinodermata (n = 106), Arthropoda (n = 49), and Platyhelminthes (n = 6). Generally, the northern part of Java is well studied and has larger numbers of recorded phyla and species. The highest species number (n = 266) has been recorded off the northern coast of West Java, while there are around 25–99 species in other regions. Echinoderms species such as Culcita novaeguineae, Diadema setosum, Echinothrix calamaris, and Holothuria atra had relatively higher occurrences than other taxa. We also noted the occurrence of giant clam Hippopus hippopus, which is protected by Indonesian law. This review provides fundamental knowledge of macrozoobenthic diversity in the coral reefs of Java, making it available to global audiences. However, it revealed a lack of research on benthic fauna in several areas with moderate to good coral cover conditions. Further research is needed to explore macrozoobenthic species richness in this region thoroughly, and periodic monitoring is essential to provide early warnings of possible changes and biodiversity loss. [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]

Mixing processes in lakes are important in determining sedimentation zones and in setting the so‐called "wash zone", the area of lake bottom in contact with an oscillating thermocline during wind‐driven internal seiche events. The wash zone also aligns with a sharp change in sediment roughness and hardness. Taken together, these rapid changes in temperature and sediment indicate that the wash zone is a distinctive ecotone in stratified lakes. Depth stratified randomised netting was used to develop count‐based habitat use models for three common benthic fish species as a function of depth or temperature covariates. Using data from two lakes with quite different wash zone depths, we show the wash zone to describe fish habitat for two of three benthic fish species by utilising the top 50% of estimated fish abundance as an indicator of habitat use. White sucker (Catostomus commersoni) habitat use was within the boundaries of the wash zone. Lake whitefish (Coregonus clupeaformis) habitat was adjacent and within the wash zone. Longnose sucker (C. catostomus) habitat use was in the deep areas of lakes dominated by sediment focusing and did not overlap white sucker. Lake whitefish habitat use overlapped both catostomids, but peak abundance of both lake whitefish and white sucker overlapped pointing to potential interactions between these species. Smaller lakes have less vigorous mixing processes and a narrower wash zone, so with a decline in lake size the likely area of the wash zone as habitat for benthic feeding fish would become smaller. [ABSTRACT FROM AUTHOR]

Background: Microplastics (MPs) are pervasive pollutants in the marine environment, exhibiting persistence in coastal sediment over extended periods. However, the mechanism of their uptake by marine organisms and distribution in habitat is less understood. The objective of the present study was to investigate the presence of MP contamination in burrow sediment, feeding pellets, and tissue of Dotilla blanfordi in the Gulf of Kachchh, Gujarat State. Methods: A total of 500 g of burrow sediment, 100 g of feeding pellets, and body tissue of 10 resident D. blanfordi were pooled as one replica. Such seven replicas from each site were analyzed for MP extraction from three sites, including Asharmata, Mandvi, and Serena, located in the Gulf of Kachchh. The standard protocol was used during the analysis of the collected samples in order to isolate MPs. Results: The abundance of MP was found higher in burrow sediment, feeding pellets and tissue of D. blanfordi at study site Mandvi, followed by Serena and Asharmata. The abundance of MP was found higher in D. blanfordi tissue, followed by burrow sediment and feeding pellet. A significant variation was observed in MP abundance among burrow sediment, feeding pellets, and tissue. MPs with various shapes (fiber, film, and fragment), sizes (1–2, 2–3, 3–4, and 4–5 mm), and colors (blue, green, black, pink, purple, red transparent) were recorded from all the study sites. Polyurethane and polyvinyl chloride were recognized as the chemical profile of the extracted MPs. The current investigation revealed greater accumulation of MPs in D. blanfordi's tissues compared to sediment and pellets, suggesting a risk of MP contamination in marine benthic fauna with a greater rate of bioaccumulation. D. blanfordi plays a significant role as a structuring agent for MP distribution in the intertidal flat through burrowing activity. [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]

Specimens belonging to a new species in the genus Protocirrineris have been found during surveys along the southwestern coasts of the Netherlands. Protocirrineris stormae sp. nov, as described herein, were collected from the muddy bottom sediments in enclosed marine waterbodies and estuaries. This species is characterized by branchiae commencing from the first chaetiger and tentacular filaments arranged in two groups arising from chaetigers 2–3 that present one/two pairs of lobes, each bearing a single dorsal tentacle. From the current records of this species, it seems that P. stormae has an affinity for enclosed marine environments or parts of estuaries with minimal variability in salinity, higher transparency, and normal temperature regime. The discovery and study of this species contributes to a comprehensive characterization of benthic fauna in locations subjected to particular environmental stresses. Considering the extensive dataset available from the Southwestern Netherlands due to many years of sampling, it is plausible that P. stormae is a pseudo-indigenous species as there seem to be no records of similar or unknown Protocirrineris before 2013. [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]

Simple Summary: Viruses present a significant challenge to the sustainable growth of the aquaculture sector. Perinereis, a valuable live-feed source in aquaculture, carries the risk of harboring unknown viruses, potentially jeopardizing the biosecurity of aquatic organisms. Despite this risk, there is a notable absence of research investigating novel viruses in Perinereis using meta-transcriptomic sequencing techniques. Therefore, it becomes imperative to explore the viral diversity within Perinereis. In this report, 12 previously unidentified viruses was documented in two distinct Perinereis species through meta-transcriptomic sequencing. These newly identified viruses were classified into four major viral families, shedding light on the intricate viral landscape within Perinereis. By unveiling these novel viruses, this research contributes to a broader knowledge base of the viral ecology in Perinereis, offering valuable insights into the potential risks and impacts associated with Perinereis in aquaculture settings. Such findings also highlight the need for enhancing biosecurity measures and disease management strategies within the aquaculture industry. Perinereis species are essential benthonic animals in coastal ecosystems and have significant roles as live feed in aquaculture, owing to their high-protein and low-fat nutritional profile. Despite their ecological importance, the viral communities associated with these organisms need to be better understood. In this study, we generated 2.6 × 108 reads using meta-transcriptomic sequencing and de novo assembled 5.3 × 103 virus-associated contigs. We identified 12 novel RNA viruses from two species, Perinereis aibuhitensis and P. wilsoni, which were classified into four major viral groups: Picobirnaviridae, Marnaviridae, unclassified Picornavirales, and unclassified Bunyavirales. Our findings revealed the hidden diversity of viruses and genome structures in Perinereis, enriching the RNA virosphere and expanding the host range of Picobirnaviridae, Marnaviridae, and Bunyavirales. This study also highlighted the potential biosecurity risk of the novel viruses carried by Perinereis to aquaculture. [ABSTRACT FROM AUTHOR]

Deep-water benthic foraminifera are investigated from Paleocene to Eocene sediments recovered from IODP Hole U1511B in the northeastern Tasman Sea. The recovered foraminifera display exceptional three-dimensional preservation: they are relatively unaltered by sediment diagenesis and compaction.We examined 33 samples from Cores U1511B-33R to -42R, and recovered 79 species of deep-water agglutinated foraminifera (DWAF) and 13 species of calcareous benthic foraminifera. The assemblage consists entirely of "cosmopolitan" forms originally described from the Carpathians, Caucasus, Trinidad, and the western Tethys, and other DSDP/ODP sites, implying that there is little or no endemism among deep-water benthic faunas in the semi-isolated Tasman Sea. The Paleocene--Eocene interval is characterized by successive acmes of Spiroplectammina, Trochammina, ammodiscids, and Karrerulina, and therefore bears striking similarity to previously studied sections in the western Tethys and Boreal North Atlantic. The taxonomic turnover among the DWAF is minor across the P/E contact, with only three apparent extinctions and three originations from the uppermost cores of the Paleocene and the lowermost cores of the Eocene. Calcareous benthic foraminifera were not observed in the Eocene samples, possibly a result of the shoaling of the CCD. [ABSTRACT FROM AUTHOR]

Few studies consider spatio‐temporal variation in egg‐laying for benthic insects in streams. However, such variation can have lasting effects on the numbers and distribution of offspring and subsquent life‐cycle stages. For species that require specific egg‐laying habitats, such as rocks that protrude from the water surface (emergent rocks, ER), densities of egg‐laying habitat can affect densities of benthic eggs and even larvae for some species. For such species, changes in water levels alter the spatio‐temporal distribution of ER and can affect densities of eggs and, potentially, larvae. Below dams, modified flow regimes may alter the temporal availability of ER. In this study we tested whether river regulation altered the availability of oviposition habitat and changed the phenology of oviposition compared to unregulated rivers.At multiple sites in two regulated (Murrumbidgee, Tumut) and three unregulated (Goobarragandra, Goodradigbee, Micalong) rivers (south‐east Australia), we surveyed densities of ER and egg masses of five species of caddisflies (family Hydrobiosidae) seasonally over 3 years (2019–2021). Samples of adults also were collected during two seasons using light traps.High flows in both regulated rivers submerged all rocks during spring and summer and low‐flow releases stranded rocks above the waterline at all (Murrumbidgee River) or most (Tumut River) sites during autumn and winter. No ER or egg masses were observed on any date in the Murrumbidgee River, despite relatively large catches of adults. On the Tumut River, low densities of ER and egg masses were twice observed at one site, during seasons (winter, autumn) when oviposition was low in the unregulated rivers.In unregulated rivers, ER and egg masses (five species, four genera) were present at all sites but with lower densities in winter than in other seasons. During peak oviposition periods, densities of egg masses per site were not strongly related to densities of ER. In summer 2019, ER in two unregulated rivers were blanketed by sheets of algae and sediment that appeared to prevent oviposition because no egg masses were observed at this time.In regulated rivers, aseasonal flows precluded egg‐laying by submerging (summer, autumn) or stranding (winter, spring) all or most ER. In contrast, ER were available all year in the unregulated rivers and egg‐laying occurred all year, except when ER were blanketed by algae and sediment. Within seasons, local densities of egg masses may be limited by numbers of gravid females, rather than numbers of ER, which differs from previous research.Identifying impediments to reproduction is critical to understanding variability in population numbers in natural and altered systems. Our observations of oviposition failure downstream of dams present a new hypothesis for why some insect species are absent from channels where flows are regulated for irrigation. Blankets of algae may similarly preclude reproduction in rivers with low‐flow conditions, but this remains untested. [ABSTRACT FROM AUTHOR]

Diverse clades of fishes adapted to feeding on the benthos repeatedly converge on steep craniofacial profiles and shorter, wider heads. But in an incipient radiation, to what extent is this morphological evolution measurable and can we distinguish the relative genetic vs. plastic effects? We use the Trinidadian guppy (Poecilia reticulata) to test the repeatability of adaptation and the alignment of genetic and environmental effects shaping poecilid craniofacial morphology. We compare wild-caught and common garden lab-reared fish to quantify the genetic and plastic components of craniofacial morphology across 4 populations from 2 river drainage systems (n  = 56 total). We first use micro-computed tomography to capture 3D morphology, then place both landmarks and semilandmarks to perform size-corrected 3D morphometrics and quantify shape space. We find a measurable, significant, and repeatable divergence in craniofacial shape between high-predation invertivore and low-predation detritivore populations. As predicted from previous examples of piscine adaptive trophic divergence, we find increases in head slope and craniofacial compression among the benthic detritivore foragers. Furthermore, the effects of environmental plasticity among benthic detritivores produce exaggerated craniofacial morphological change along a parallel axis to genetic morphological adaptation from invertivore ancestors. Overall, many of the major patterns of benthic-limnetic craniofacial evolution appear convergent among disparate groups of teleost fishes. [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 pace of biological invasions has increased in recent decades, leading to multiple invasions and the potential dominance of invasive species, destabilizing local ecological networks. This provides opportunities to study new ecological species interactions, including predation. Tropical freshwaters have been particularly concerned by aquatic invasions and we focused here on the Martinique island (Lesser Antilles). We examined the predator–prey relationships involving invasive Thiarid snails (Tarebia granifera and Melanoides tuberculata) and the native Neritina punctulata, both confronted with a newcomer predator, the redclaw crayfish (Cherax quadricarinatus). We conducted several mesocosm experiments to assess the impact of crayfish predation on snail survival and the passive and active antipredator responses of snails. A first experiment indicated snail survival rates between 50% and 80%, depending on crayfish size and sex. Notably, there was a negative correlation between snail survival and male crayfish size and the predation method (shell crushing vs. "body sucking") varied with crayfish size. The second experiment suggested no refuge size for snails, with both very small (<5 mm) and very large (>5 mm) unable to escape predation, regardless of crayfish size (from 77 to 138 mm) or sex. Finally, we investigated the escape behavior of Thiarids regarding three crayfish cues. Melanoides tuberculata tend to bury in the substrate and T. granifera to climb up aquarium walls, what was expected from their shell morphologies, and both responding to crayfish cues within minutes. Overall, C. quadricarinatus proves to be an efficient snail predator with limited escape options for snails, potentially contributing to the decline of certain snail populations in Martinique. This omnivorous predator might impact other native species across different groups, including shrimps and fish. Our study underscores the urgent need for monitoring efforts, solidifying the redclaw crayfish reputation as a dangerous invasive species for freshwater macrobenthic faunas worldwide. [ABSTRACT FROM AUTHOR]

In the process of reworking sediments and thus shaping biogeochemical processes, marine bottom-dwelling animals are thought to play a pivotal role in many benthic environments. Bioturbation (particle reworking) includes the downward transport of particles into the sediment as a major process and is sometimes detected as subsurface maxima (peaks) of specific particulate substances (tracers). Here, we document the fact that subsurface peaks, such as those typically attributed to biological particle transport in sediments, may equally be generated by otter boards in bottom-trawling fishery. Boards can generate tracer peaks whereby they scoop sediment from the surface, flip it over, and deposit it onto the adjacent seafloor. These peaks are indistinguishable from those generated by benthic fauna burying surface material at sediment depth. We demonstrate this for the particle tracer chlorophyll a in silty sand from the western Baltic Sea with fauna that generally do not burrow deep in a global comparison. Our inability to distinguish the driving processes generating the peaks indicates limits to our understanding of the magnitude and spatial extent of bioturbation traces in this environment. It also poses a problem for the assessment of fishery resource use and benthic processes. However, based on natural fauna abundance, behavioral information, and fishery intensity data, we identify macrofauna and not otter boards as the dominant cause of peaks at the sites investigated here. [ABSTRACT FROM AUTHOR]

Simple Summary: Chironomids are probably the most speciose family among aquatic insects, colonizing almost all freshwater habitats. The emphasis of the present research is on: (1) taxonomic composition as the most efficient tool for describing biodiversity in natural habitats; and (2) natural habitat type as the most important factor able to explain different chironomid assemblages. This is because the habitat type summarizes a combination of different biotic and abiotic factors present at each site, determining taxa assemblages. Different spatial scales are often proposed as relevant factors for modeling community composition, but with regard to chironomids, spatial factors act only at a small scale, while environmental factors are the most important determinants for species distribution. Factors responsible for species distribution of benthic macroinvertebrates, including responses at different spatial scales, have been previously investigated. The aim of the present research was to review the most relevant factors explaining chironomid species distribution focusing on factors operating at different spatial scales, such as latitude, longitude, altitude, substrate, salinity, water temperature, current velocity, conductivity, acidity, dissolved oxygen, nutrient content etc. acting at regional levels and at a large or small water basin level. Data including chironomid species abundances from different lentic and lotic waters in Italy and other surrounding countries were analyzed using partial canonical correspondence analysis (pCCA) and multiple discriminant analysis (DISCR). Spatial analyses, including univariate Moran's I correlograms, multivariate Mantel correlograms and Moran's eigenvector maps (MEMs), were thereafter carried out. The results showed that habitat type, including different types of lotic waters (i.e., kryal, crenal, rhithral, potamal) and different lake types (i.e., littoral, sublittoral, profundal zones), is the most significant factor separating chironomid assemblages, while spatial factors act only as indirect influencers. [ABSTRACT FROM AUTHOR]

The Jiangchuan Biota from the Jiucheng Member (Mb.) of the Dengying Formation (Fm.), discovered in Jiangchuan, eastern Yunnan, China, is marked by copious macrofossils at the apex of the Ediacaran strata. This fauna features benthic algae with varied holdfasts and other fossils of indeterminate taxonomic affinity and is compositionally unique compared to the Shibantan and Gaojiashan biotas of the Dengying Fm. and the Miaohe and Wenghui biotas of the Doushantuo Fm., elsewhere in China. One novel benthic saccular macroalgal fossil, named here Houjiashania yuxiensis gen. and sp. nov., from the Jiangchuan Biota is based on fossils that are sausage‐shaped, elongate, tubular, ranging from 0.3 to 4 cm in length, and up to 0.8 cm in diameter. One terminus is blunt and rounded to an obtuse angle, the other is bent with a spread‐out surface resembling a holdfast, suggesting a three‐dimensional thallus. Thin, stipe‐shaped outgrowths, likely vestiges of sessile saccular life forms, are prevalent in macroalgal fossils of analogous size and shape, as well as present brown algae Scytosiphonaceae, such as Colpomenia and Dactylosiphon. The new findings augment the diversity of benthic algae, such as those known from the Early Neoproterozoic Longfengshan Biota in North China. The benthic algal macrofossils in the Jiucheng Mb. add to knowledge of Late Ediacaran metaphyte diversification and offer more clues about the evolutionary positioning of primitive macroalgae. The co‐occurrence of numerous planktonic and benthic multicellular algae and planktonic microbes might have facilitated ecologically the more extensive later Cambrian explosion evidenced by the Chengjiang Biota in Yunnan. [ABSTRACT FROM AUTHOR]

Eulimidae is a highly diverse family of gastropods that are often parasites of echinoderms. They are cosmopolitan and live from the intertidal to great depths. Despite its wide geographic and bathymetric distribution, no species of Eulimidae have been reported for the Salas & Gómez Ridge to date. In this study, we describe Melanella martarum sp. nov., which was collected during the EPIC oceanographic cruise onboard RV Mirai (JAMSTEC, Japan) in 2019. Seven specimens were collected with a modified Agassiz trawl on the summit of seamount "Pearl'' (Zhemchuznaya) in the Salas & Gómez Ridge (25.59°S, 89.13&lowbar;W) at 545 m depth. The morphology of M. martarum sp. nov. was compared with other Melanella species reported for the area, including Chile and Rapa Nui. DNA was extracted and partial sequences of the mitochondrial genes Cytochrome Oxidase 1 (COI) and 16S rDNA, and the nuclear gene Histone 3 (H3) were sequenced. Melanella martarum sp. nov. has morphological characteristics that separate it from other species of Melanella, such as the thickness and color of the shell, and the shape of the protoconch. In addition, M. martarum sp. nov. was genetically differentiated from other Melanella spp. sequences (uncorrected p distances from 18,1&lowbar;8.6% in mitochondrial COI and 16S rDNA to 3% in nuclear H3 sequences). Although there is not much molecular data available for Eulimidae, the phylogenetic analysis confirms the results obtained by morphology, placing the species found on the Salas & Gómez Ridge within the genus Melanella. The current study advances the understanding of the poorly known benthic fauna found on seamounts in the easternmost part of the Sala & Gómez ridge, a location distinguished by a high level of endemism. [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]

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]

The study compares the structure of invertebrate communities inhabiting two types of bottom sediments in Krzynia Reservoir, known also as Lake Krzynia (on the Słupia River, northern Poland). The lake is prone to intensive sedimentation because it is limnic. This limnicity is due to the impact of the river, rather than to surface runoff from the catchment area, where the heavy predominance of natural habitats over transformed ones slows the transport of mineral suspensions from adjacent terrain. In the organic-poor sediments dominated by sand and gravel, the mean density of benthic invertebrates was ten-fold higher than in silty, organic-rich sediments, while invertebrate biomass was only slightly and non-significantly higher in organic-poor sediments than in organic-rich sediments. Simultaneously, the mean invertebrate body weight was markedly lower in organic-poor sediments (0.03 g) than in organic-rich sediments (0.18 g). No significant differences in taxonomic diversity (number and Shannon index of taxa) were found between the studied sediment types in the analysed communities. Among the major invertebrate groups, the Oligochaeta and Mollusca significantly differed in density between sediment types, while the Oligochaeta and Chironomidae differed in biomass. An increased percentage of silt fraction in bottom sediments resulted in a drastic decrease in abundance of benthic fauna, but their biomass declined only slightly. Thus, plans to construct new reservoirs should aim to reduce the rate of silt accumulation in them, in order to preserve their primary function and support biodiversity in transformed river valleys. [ABSTRACT FROM AUTHOR]

Profound environmental changes, such as drastic sea-ice decline, leave large-scale ecological footprints on the distribution and composition of marine biota in the Arctic. Currently, the impact of such stressors is not sufficiently understood due to the lack of pan-Arctic data that allow for estimating ecological baselines as well as modelling current and forecast potential changes in benthic biodiversity and ecosystem functioning. Here, we introduce the PAN-Arctic data collection of benthic BIOtas (PANABIO) and discuss its timeliness, potential, and details of its further development. The data collection contains individual datasets with records (presence, counts, abundance, or biomass) of benthic fauna, usually at genus level or species level, which were identified in field samples obtained at point-referenced locations (stations) by means of grabs, towed gear, or seabed imaging. The data cover the entire pan-Arctic realm, i.e. the central Arctic Ocean, Chukchi Sea, East Siberian Sea, Laptev Sea, Kara Sea, Barents Sea (including the White Sea), Svalbard waters, Greenland Sea, Norwegian Sea, Canadian Archipelago, Beaufort Sea, and Bering Sea as well as some adjacent sub-Arctic regions (Sea of Japan, Gulf of Okhotsk). Currently (as of 14 December 2023), PANABIO includes 27 datasets with a total of 126 388 records of 2978 taxa collected from 11 555 samples taken at 10 596 stations during 1095 cruises between 1800 and 2014. These numbers will increase with more data becoming available over time through contributions from PANABIO users. The data collection is available in a PostgreSQL-based data warehouse that can be accessed and queried through an open-access front-end web service at https://critterbase.awi.de/panabio (last access: 27 February 2024). A snapshot of the current data collection and its 27 individual datasets is also available from the data publisher PANGAEA (10.1594/PANGAEA.963640, Piepenburg et al., 2023). [ABSTRACT FROM AUTHOR]

Many river ecosystems in the boreal zone have faced remarkable changes due to intensive human activities, including land‐use changes in the catchments and channelization. Recently, restoration efforts have increased, hoping to restore a more natural hydromorphology. We studied the community structure of benthic macroinvertebrates (zoobenthos) in seven rivers in Eastern Finland, using samples that covered pre‐ and post‐restoration periods, to examine how environmental metrics relate to the zoobenthos community structure, and the fatty acid (FA) composition and content of Ephemeroptera, Plecoptera, and Trichoptera nymphs and larvae. We also analyzed the FA composition and content of land‐locked salmon (Salmo salar m. sebago) in three of the rivers and brown trout (Salmo trutta) in two of the rivers. Zoobenthos communities differed significantly among most of the rivers: 24% of the differences between the zoobenthos communities were driven by water quality parameters related to the loading of terrestrial organic matter (water color, pH, and iron concentration). Temporal changes in zoobenthos communities could not be fully attributed to restorations. The FA composition of zoobenthos was mostly explained by phylogenetic origin (47%). However, especially mayfly Heptagenia sulphurea (Ephemeroptera: Heptageniidae) had variable FA composition and content among the rivers suggesting an environmental quality indicator role for this species. FA composition and content of salmonids were mostly size‐dependent (24%), but river identity also influenced their FA composition (22%). Our results indicate that water quality affects the availability of essential FAs for consumers by altering the zoobenthos community structure and their FA composition and content. [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]

Sediment reworking by benthic infauna, namely bioturbation, is of pivotal importance in expansive soft-sediment environments such as the Wadden Sea. Bioturbating fauna facilitate ecosystem functions such as bentho-pelagic coupling and sediment nutrient remineralization capacities. Yet, these benthic fauna are expected to be profoundly affected by current observed rising sea temperatures. In order to predict future changes in ecosystem functioning in soft-sediment environments like the Wadden Sea, knowledge on the underlying processes such as sediment reworking, is crucial. Here, we tested how temperature affects bioturbation and its associated ecosystem processes, such as benthic nutrient fluxes and sediment oxygen consumption, using luminophore tracers and sediment incubation cores. We used a controlled mesocosm experiment set-up with key Wadden Sea benthos species: the burrowing polychaetes Arenicola marina and Hediste diversicolor, the bivalve Cerastoderma edule, and the tube-building polychaete Lanice conchilega. The highest bioturbation rates were observed from A. marina, reaching up to 375 cm²yr-1; followed by H. diversicolor, with 124 cm²yr-1 being the peak bioturbation rate for the ragworm. Additionally, the sediment reworking activity of A. marina facilitated nearly double the amount of silicate efflux compared to any other species. Arenicola marina and H. diversicolor accordingly facilitated stronger nutrient effluxes under a warmer temperature than L. conchilega and C. edule. The oxygen uptake of A. marina and H. diversicolor within the sediment incubation cores was correspondingly enhanced with a higher temperature. Thus, increases in sea temperatures may initially be beneficial to ecosystem functioning in the Wadden Sea as faunal bioturbation is definitely expedited, leading to a tighter coupling between the sediment and overlying water column. The enhanced bioturbation activity, oxygen consumption, and facilitated nutrient effluxes from these invertebrates themselves, will aid in the ongoing high levels of primary productivity and organic matter production. [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]

Deep-sea sponge grounds are distributed globally and are considered hotspots of biological diversity and biogeochemical cycling. To date, little is known about the environmental constraints that control where deep-sea sponge grounds occur and what conditions allow high sponge biomass to develop in the deep sea. Here, we characterize oceanographic conditions at two contrasting high- and low-sponge-biomass sites off the northern Labrador Shelf in Canadian waters. Unique data for the region were collected by year-long benthic lander deployments equipped with current meters, turbidity and chlorophyll-a sensors, and sediment traps. Additionally, the regional oceanography was described by analysing vertical conductivity/salinity-temperature-depth (CTD) and Argo float profiles for the Northern Labrador Shelf from 2005 to 2022, including those from the CTD casts taken at the benthic lander stations. Benthic fauna stable isotopes were analysed to identify potential food sources. Our results revealed strong (0.26 ± 0.14 m s-1; mean ± SD) semidiurnal tidal currents at the high-sponge-biomass site, but twofold weaker currents (0.14 ± 0.08 m s-1; mean ± SD) at the low-sponge-biomass site. These tidal currents cause periodic temperature fluctuations, sediment resuspension, intense vertical flows across the slope, which during spring, contribute to transport of organic material to the seafloor during a diurnal tidal cycle. Periodic fluctuations in bottom water temperature confirm the amplified transport across the shelf break at the high-sponge-biomass site. The high-sponge-biomass area is situated where the Hudson Strait Ouflow, the Irminger Current, and the West Greenland Current converge, which could lead to downwelling. Bottom silicate concentrations were increased at the high-biomass sponge ground due to advection of silicate-rich bottom water from Baffin Bay. Finally, the arrival of chlorophyll-a rich material in spring at both the low- and high-sponge-biomass sites demonstrated tight benthic-pelagic coupling prior to the onset of stratification. Mass fluxes of trapped material were higher and consisted of less degraded material at the high-sponge-biomass site. Stable isotope signatures indicated that soft corals (Primnoa resedaeformis) fed on suspended particulate organic matter, while massive sponges (Geodia spp.) likely utilized additional food sources. Our results imply that benthic fauna at the high-sponge-biomass site benefit from strong tidal currents, which increases food supply, and favourable regional ocean currents that increase nutrient concentration in bottom waters. [ABSTRACT FROM AUTHOR]

In the deep sea, interactions between benthic fauna and seafloor sediment primarily occur through bioturbation that can be preserved as traces (i.e. lebensspuren). Lebensspuren are common features of deep-sea landscapes and are more abundant than the organisms that produce them (i.e. tracemakers), rendering lebensspuren promising proxies for inferring biodiversity. The density and diversity relationships between lebensspuren and benthic fauna remain unclear, and contradicting correlations have been proposed (i.e. negative, positive, or even null correlations). To approach these variable correlations, lebensspuren and benthic fauna were characterized taxonomically at eight deep-sea stations in the Kuril-Kamchatka Trench area, together with two novel categories: tracemakers (specific epibenthic fauna that produce these traces) and degrading fauna (benthic fauna that can erase lebensspuren). No general correlation (overall study area) was observed between diversities of lebensspuren, tracemakers, degrading fauna, and fauna. However, a diversity correlation was observed at specific stations, showing both negative and positive correlations depending on: (1) the number of unknown tracemakers (especially significant for dwelling lebensspuren); (2) the lebensspuren with multiple origins; and (3) tracemakers that can produce different lebensspuren. Lebensspuren and faunal density were not correlated. However, lebensspuren density was either positively or negatively correlated with tracemaker densities, depending on the lebensspuren morphotypes. A positive correlation was observed for resting lebensspuren (e.g. ophiuroid impressions, Actiniaria circular impressions), while negative correlations were observed for locomotion-feeding lebensspuren (e.g. echinoid trails). In conclusion, lebensspuren diversity may be a good proxy for tracemaker biodiversity when the lebensspuren–tracemaker relationship can be reliable characterized. Lebensspuren–density correlations vary depending on the specific lebensspuren residence time, tracemaker density, and associated behaviour (rate of movement). Overall, we suggest that lebensspuren density and diversity correlations should be studied with tracemakers rather than with general benthic fauna. On a global scale, abiotic (e.g. hydrodynamics, substrate consistency) and other biotic factors (e.g. microbial degradation) may also play an important role. [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]

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]

Spatial changes in environmental characteristics strongly influence the structure of benthic communities on sandy beaches, where the patterns of occurrence are mainly controlled by morphodynamic characters and biological interactions. Despite being very abundant and extensive, the Amazonian sandy beaches are among the coastal environments less well known to science. On these beaches, the ghost shrimp Lepidophthalmus siriboia Felder and Rodrigues, 1993 is an important component of the intertidal macrofauna. The present study describes the small-scale distribution patterns of L. siriboia and of the macrobenthic communities in a dissipative macrotidal Amazonian sandy beach. Samples were collected in the intertidal zone of two areas: Area 1, next to a tidal channel; and Area 2, away from the tidal channel. In Area 1, with finer sediments, there was a higher burrow density of L. siriboia and higher density and species richness of macrofauna. In both areas, the burrow density of L. siriboia increased towards the sea. The faunal distribution patterns can be explained by changes in flooding and the type of substratum across the shore and alongshore. These findings add to our knowledge of tropical sandy beach ecology and reinforce the idea that tropical macrotidal beaches have a complexity of morphological features, which are drivers of macrofaunal structure. [ABSTRACT FROM AUTHOR]

Site‐occupancy modelling is widely used in ecology for understanding species distribution, habitat‐use and community changes but its application is still limited in paleoecology, where incomplete detection is also routine. Here, we make extensive expansions to an earlier multispecies occupancy model used to estimate the dynamics of relative species abundance in fossil communities. These expansions include incorporating counts of individuals at sites, explicitly allowing for the inclusion of specimens assignable to genus – but not species‐level, a situation common in paleontology, and modelling regional presence/absence. We provide simulations to check the performance of this new model, as well as simulations to quantify the benefits of using individual count data versus subsample occupancy data, and model estimates versus face‐value (raw) estimates, respectively. We also provide an empirical case study using occupancy data from a community of marine benthic colonial animals preserved in the Pleistocene of New Zealand. We find that the new model performs well, especially when it comes to recovering relative abundance dynamics and that it is well worth the effort to both collect individual count data and to include individuals unidentified to species‐level in the site‐occupancy modelling framework. This extended model can be widely applied in paleoecological settings and is necessary when both the average and uncertainty values of relative abundance dynamics need to be robustly estimated. [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]

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]

The rock units in the Gawran Gorge, Sagirma Mountains (from the High Folded Zone), near the Sulaimaniyah city, in the Kurdistan Region, NE Iraq, were investigated in order to describe and biostratigraphically date the sedimentary succession. Twenty-seven species of larger benthic foraminifera were identified belonging to 16 genera. Several other fossil groups were also recognized, including echinoid, bryozoan, bivalve, gastropods and coral remains. Two biozones were recognized--the Praerhapydionina delicata-Austrotrillina asmariensis/Peneroplis evolutus Assemblage Zone and the P. delicata/Austrotrillina howchini Interval Zone, which indicate a late Oligocene-lowermost Miocene age for the succession. This section was correlated to the surrounding successions having a similar age in the High Folded Zone of Iraq, and to sediments in other countries, so as to indicate the wider distribution of the lithostratigraphic unit. [ABSTRACT FROM AUTHOR]

Given the limited understanding of benthic fauna along the Algerian coast, this study was conducted to explore the diversity of bivalve mollusks specifically on the Algerian west coast. The primary objectives of this study were to create a comprehensive but not exhaustive inventory of bivalve species in this region and to analyze the distribution of these species within the study areas and neighboring regions. The research involved the investigation of numerous sandy beaches across four sectors of the Algerian west coast: Tlemcen, Béni-Saf, Ain-Temouchent, and Oran. Between June 2019 and April 2020, a random collection of empty bivalve shells was carried out in the foreshore zones of 16 beaches within these sectors. This extensive collection of 10,076 shells resulted in the identification of 56 bivalve mollusk species, categorized into 22 families. Among these families, the most prominent were Cardiidae, Donacidae, Glycymerididae, and Veneridae, serving as the most representative families across all four sectors. Notably, the Glycymerididae family was the most abundant along the Oran coast, with nearly 2,000 individuals, although they were less prevalent on the beaches of the Béni Saf sector. In contrast, the Veneridae family was prevalent on the beaches of the Tlemcen, Béni Saf, and Aïn-Témouchent sectors. Within the Veneridae family, there was remarkable diversity, featuring 11 species, followed by the Cardiidae family with 6 species, and the Limidae and Pectinidae families with 5 species each. Finally, among the identified species, the most abundant ones included Acanthocardia tuberculata (Linnaeus, 1758), Chamelea gallina (Linnaeus, 1758), Glycymeris nummaria (Linnaeus, 1758), and Donax trunculus (Linnaeus, 1758), each belonging to the Cardiidae, Veneridae, Glycymerididae, and Donacidae families, respectively. [ABSTRACT FROM AUTHOR]

Benthic food‐web structure and organic matter (OM) utilization are important for marine ecosystem functioning. In response to environmental changes related to the ongoing climate change, however, many benthic species are shifting their ranges to colder regions, which may lead to altered community composition, but it remains largely unknown how it will affect ecosystem functioning. Here, stable isotope analysis was used to study benthic OM utilization and food‐web structure and to assess whether their spatial patterns reflect today's community differentiation among biogeographic regions and depth zones. Benthic fauna and OM mixtures were collected from two depth zones (100–150 m vs. 200–250 m) within a temperate, two sub‐Arctic, and an Arctic fjord along a latitudinal gradient (59–78° N) that was used as a space‐for‐time substitution to assess the impact of climate change. Our results showed that Arctic and temperate communities are functionally different. Arctic communities were characterized by a strong resource partitioning among different feeding types, irrespective of depth zone. In contrast, all feeding types in temperate communities seemed to rely on sedimentary OM. The sub‐Arctic presented a transition zone. In the sub‐Arctic, shallower communities resembled Arctic communities, suggesting a functional transition between temperate and sub‐Arctic regions. Deeper sub‐Arctic communities resembled temperate communities, suggesting a functional transition between the sub‐Arctic and Arctic regions. This implies that the regions north of the current transitions (deep Arctic and shallow sub‐Arctic) are most likely to experience functional changes related to an altered OM utilization in benthic food webs in response to climate change. [ABSTRACT FROM AUTHOR]

Eighteen Cibicidoides Rotaliid benthic foraminiferal species were erected from three localities in the Southern Tethys Chile, Egypt and Pakistan. An American diagnostic west hemisphere species C. vulgaris is added to the assemblage, which was later is also recorded from another localities in the eastern hemisphere in the Southern Tethys: Egypt and Iran . One of the identified species is believed here to be new: C. chilensis. Environmental conditions of the identified species of the genus Cibicidoides represent middle-outer neritic environment (100- 200 m) and show an affinity with Midway-Type Fauna "MTF". [ABSTRACT FROM AUTHOR]

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