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A convolutional neural network (CNN) was used to construct a semantic segmentation model to examine the abundance of Phycosiphon incertum by identifying the trace fossil regions in core section images. The abundance of trace fossils provides information about the past activities of benthic animals affected by paleoenvironmental conditions. To quantify the intensity of bioturbation, it is necessary to extract regions of trace fossils and measure the proportion of bioturbated and the observed area of the outcrop section. In this study, a U-Net-type CNN model was used with residual connections and attention mechanisms to identify the trace fossil Phycosiphon. The model was trained to recognize the relationships between core section images from the International Ocean Discovery Program Expedition 362 Site U1480 and manually annotated trace fossil images. After training, the model successfully classified the pixels of the background, outcrop, and Phycosiphon for core section images other than the training data set. The bioturbation intensity estimated from the image predicted by the model was nearly equal to that from the ground truth image. A long-term (approximately past 10 Myr) variation in Phycosiphon abundance was estimated by applying the model to the core section images at Site U1480. Phycosiphon abundance negatively correlated with the number of sandstone layer intercalations, but it was not affected by the sediment accumulation rates. These findings may reflect resistance of Phycosiphon producers to environmental stress. The model developed in this study can be used for other ichnotaxa to reveal the general tendency of variation in bioturbation intensity and ichnodiversity. • A model was proposed for detection of trace fossil Phycosiphon in core sections. • Variation of frequency of Phycoisiphon in past 10 Myr was estimated. • Abundance of Phycosiphon was negatively correlated with turbidite frequency [ABSTRACT FROM AUTHOR]

The anthropogenic construction activities on the coasts, such as pile-driving, generate vibrations that propagate through the substrate. Such substrate-borne vibrations could potentially affect marine organisms inhabiting the benthic environments. However, there is a lack of documented studies on the effects of vibrations on benthic animals. To investigate whether anthropogenic substrate-borne vibrations such as pile-driving operation influence the fiddler crab, Austruca lactea , we measured their locomotion response under vibrations of 35, 120, 250, 500, and 750 Hz generated by a vibrator. We compared the locomotion of crabs between control and vibration-treatment groups using videography. The duration of movements was significantly lower under 120 Hz vibrations compared to the control. Moreover, crab velocity was significantly higher under vibrations of 120 Hz and 250 Hz compared to the control group. Our result suggests that A. lactea can detect low-frequency substrate-borne vibrations and experience stress, leading to increased energy consumption. [Display omitted] • Fiddler crabs can detect low-frequency (120–250 Hz) substrate-borne vibrations. • Austruca lactea reduced movement duration or increased velocity to such vibrations. • The locomotion of them suggests that such vibrations could pose a stressor. • Vibrational disturbances should be considered for coastal construction. [ABSTRACT FROM AUTHOR]

This study focuses on late Paleocene–middle Eocene planktonic and small benthic foraminiferal assemblages from the Khangiran Formation in the Kopet-Dagh Basin (NE Iran). The patterns of regional distribution of foraminiferal fauna were observed in this study, although many of the global foraminiferal index species are absent in the studied southernmost Peri-Tethys neritic section. Accordingly, this work proposes to update a regional biostratigraphic scheme and correlation with adjacent basins based on the first and last appearance of diagnostic species. Biozones correlative with Acarinina acarinata Zone, Morozovella subbotinae Zone, Morozovella aragonensis Zone, Acarinina bullbrooki Zone, and Acarinina rotundimarginata Zone of interregional zonal scheme based on planktonic foraminifera and biozones correlative with Annectina paleocenica Zone, Pseudogaudryina externa Zone, and Pseudogaudryina pseudonavarrana Zone based on small benthic foraminifera were recognized in the type section of the Khangiran Formation indicating Thanetian-middle Lutetian age. Toward the upper part of the studied section in the last phase of marine sedimentation regional oyster beds (Sokolowia spp.) point out late Lutetian-early Priabonian age. Possibly Arctic-Tethys communication systems through the early Paleogene epicontinental seas were responsible for the faunal assemblage similarities and suggest that the Kopet-Dagh Basin of Iran was connected to northern basins of Former Soviet Union and other Central Asian basins during the Paleogene. [ABSTRACT FROM AUTHOR]

The fauna of benthic foraminifers from the northern Laptev Sea has been analyzed to identify the relationship between the distribution of benthic foraminifers and environmental conditions in the eastern and western parts of the sea. The abundance of benthic foraminifer tests in the Laptev Sea is universally low, no more than 3–9 ind./g. Greater foraminifer abundances were found in the west, on the shelf of the Vilkitsky Strait. Foraminifers with agglutinated tests were dominant, 77–100%. In the east, the assemblages consisted almost entirely of agglutinated tests (90–100%). Calcareous Melonis barleeanus was common, up to 10–15%, on the shelf and the continental slope in the western part of the sea. Small specimens of the polar planktic species Neogloboquadrina pachyderma sin occurred. In one sample at an abyssal water depth of 2996 m, the abundance of its tests increased to 302 ind./g; the assemblage was composed predominantly of N. pachyderma sin., both small (juvenile) and large (adult) individuals with good preservation. The massive presence of the polar species N. pachyderma sin. at an abyssal depth in the eastern region indicates the dominant influence of Arctic waters there. [ABSTRACT FROM AUTHOR]

Mucilage events may severely affect the benthic fauna and flora in marine environment, likely causing serious mortality in marine life. The present study was made on a massive mucilage phenomenon in the Çanakkale Strait (Dardanelles) and North Aegean Sea in 2021. Blanket type of mucilage existed for five months between March and July in the Çanakkale Strait, impacting marine benthos, which lead to a likely ecological destruction at some locations. Saros Bay, Gökçeada, Bozcaada and Tavşan Islands (Mavriya) were also impacted by this massive mucilage phenomenon. The highest mean thickness of blanket type of mucilage was observed as 16.26±5.97 cm, while the lowest value was measured as 3.5±0.86 cm. Regarding mucilage aggregates-based mortality in marine invertebrates, 77 individuals of the Pennatulacean coral Pteroeides spinosum were found dead. Data of thickness on substratum of mucilage aggreates is reported for the first time in the inventory of the Turkish marine researches. [ABSTRACT FROM AUTHOR]

The dynamics of benthic communities of various reaches of the Kuibyshev Reservoir over a long-term observation period 1966 to 2016 has been statistically analyzed. The results of a comparison of the spatial-temporal distribution of structural indicators of chironomid (Chironomidae) communities, including the species diversity and abundance of 48 taxa based on hydrobiological survey data in nine large parts of the reservoir for different years, are presented. Nonparametric analysis of variance revealed a high statistical significance of the variability of the species composition of benthic communities under the influence of temporal and spatial factors. Using multidimensional ordination and generalized Procrustes analysis, the dynamics of the distribution of ecosystem objects (individual species and areas) in the coordinates of two latent axes of maximum variation is shown. A geometric analysis of the multidimensional trajectories of changes in the community of aquatic organisms in individual reaches for different periods of time is carried out. Similar developmental processes of chironomid communities were revealed in a longitudinal succession of reaches on the former channel and sunken floodplain, while the analogous structural characteristics of the Kamskiy reach and eutrophic Cheremshanskiy Bay are specific. The priority role of chironomids as the most important indicator group necessary for biotic assessment of long-term (50 years) changes in the ecological state of a large reservoir is considered. [ABSTRACT FROM AUTHOR]

Harmful blooms of cyanobacteria may extend over long time spans due to self-sustaining mechanisms. We hypothesized that settled blooms may increase redox-dependent P release and unbalance the stoichiometry of benthic nutrient regeneration (NH4+:SiO2:PO43− ratios). We tested this hypothesis in the hypertrophic Curonian Lagoon, the largest in Europe. During summer, at peak chlorophyll and water temperatures, sediment cores were collected over 19 stations representing all the lagoon sedimentary environments. Sediment organic content, granulometry, aerobic respiration, and oxic and anoxic fluxes of dissolved inorganic nutrients and metals—Fe2+ and Mn2+—were measured. Loads and stoichiometry of regenerated nutrients were compared with those from the watershed. Analyzed sediments had elevated oxygen demand (−1.90 to −5.66 mmol O2 m−2 h−1), generally uncoupled to their variable organic matter content (1–23%) and median particle size (30–300 μm). Under oxic conditions, summer internal recycling equaled (SiO2) or exceeded, by a factor of ~66 and ~ 2, external loads of NH4+ and PO43−, respectively. Transient anoxia produced a general decrease of NH4+ and SiO2 regeneration, likely due to decreased macrofauna activity or inefficient mineralization, whereas it doubled average PO43− fluxes. In sandy, well-flushed areas, anoxia had a minor effect on PO43−, but stimulated a large production of Mn2+. Muddy sediments in lagoon areas with slow water renewal displayed large redox-dependent PO43− mobility, coupled to Fe2+ release. Settled algal blooms and hypoxic conditions might unbalance benthic regeneration stoichiometry and sustain blooms. The sedimentary pool of Mn4+ may represent a natural buffer preventing iron reduction and PO43− mobility. [ABSTRACT FROM AUTHOR]

Diversity and abundance of macrobenthic fauna have been extensively used to determine the quality of the aquatic environment. The Mae Klong River consists of several types of habitats which are important for human uses. The water quality of the river has deteriorated due to wastewater discharged from human activities. Although there have been many efforts to improve water quality in the past, problems still remain. This study used benthic macroinvertebrates as key indicators of water quality and sediment in the Mae Klong River and its tributaries. Spatio-temporal variability in water quality, sediment, and benthic macroinvertebrates in the Mae Klong River was investigated across 21 stations between April 2016 and March 2017, at an interval of three times per season (hot, rainy, and cold). Principal component analysis revealed that water quality variables in the cold season were clearly different from those in the hot and rainy seasons. Total organic matter, sulfide, and median grain size in the sediment were not different, whereas concentrations of copper, lead, cadmium, and zinc in the rainy and cold seasons were different from those in the hot season. Three phyla, 26 orders, 58 families, and 118 species of benthic macroinvertebrates were found. Species and their distributions were not different among the three seasons, but varied by location (upper, middle and lower parts of the river). The conditions of the upper Mae Klong River are satisfactory, but the lower Mae Klong River is contaminated with pollution. The main factors affecting the community structure, composition, and distribution of benthic macroinvertebrates in the Mae Klong River include conductivity, total organic matter, and sulfide. This present study also demonstrates that benthic macroinvertebrate taxa, including the families Ephemeridae, Baetidae, Caenidae (Ephemeroptera), Libellulidae (Odonata) and class Polychaeta (Perinereis) are useful for assessment of the health of Mae Klong River. [ABSTRACT FROM AUTHOR]

The present dataset contains information about aquatic macroinvertebrates and environmental variables collected before and after the implementation of a small "run-of-river" hydropower plant on the Saldur stream, a glacier-fed stream located in the Italian Central-Eastern Alps. Between 2015 and 2019, with two sampling events per year, we collected and identified 34,836 organisms in 6 sampling sites located within a 6 km stretch of the stream. Given the current boom of the hydropower sector worldwide, and the growing contribution of small hydropower plants to energy production, data here included may represent an important – and long advocated – baseline to assess the effects that these kinds of powerplants have on the riverine ecosystem. Moreover, since the Saldur stream is part of the International Long Term Ecological Research network, this dataset also constitutes part of the data gathered within this research programme. All samples are preserved at Eurac Research facilities. Measurement(s) Abundance of benthic macroinvertebrates • Physical and chemical water parameters • biodiversity assessment objective Technology Type(s) Surber sampler • Multiparameter probe • material sampling process Sample Characteristic - Organism Aquatic benthic macroinvertebrates Sample Characteristic - Environment englacial stream Sample Characteristic - Location Province of Bolzano-Bozen • Central Eastern Alps • Italy Machine-accessible metadata file describing the reported data: https://doi.org/10.6084/m9.figshare.14046554 [ABSTRACT FROM AUTHOR]

The Indian River Lagoon (IRL) is home to numerous species of plants and animals, including sessile benthic invertebrates. In addition to being an important component of the ecosystem, sessile benthic organisms may be of use to detect disturbances within the lagoon. This paper presents data from a long-term monitoring program of benthic invertebrate communities at a test site in the central lagoon since 2008. Over this time, these organisms endured the declining health of the IRL along with natural disturbances (i.e., cold snaps, algal blooms, tropical cyclones). Seasonal community composition was similar to what has previously been recorded, indicating that the health of the lagoon has not caused any long-term damage to benthic invertebrate community. However significant impacts were observed with barnacle and encrusting bryozoan cover as a result of various disturbances. Of the three types of disturbances investigated, the cold snap had no effect, the hurricane only had short-term impacts (weeks) and algal blooms had short- and long-term (months) impacts. Barnacle cover was severely reduced by algal blooms and at the same time the encrusting bryozoan cover increased. As algal blooms and anthropogenic disturbances become more frequent in the IRL, barnacles and encrusting bryozoans may be used as an indicator taxa for decreases in habitat quality. [ABSTRACT FROM AUTHOR]

The main objective of this study was to assess the quality of sediments collected from rivers in the Northeast of Algeria. A dual approach, including trace metals assessment as well as ecotoxicity tests (Microtox® solid and leachate phase assays), was conducted. Results showed that surface sediments were contaminated with Cd, Cu, Pb and Zn. By using sediment quality guidelines (SQGs) and potential risk index, we concluded that there was a significant potential risk for benthic fauna. Microtox® solid and leachate phase assays showed that sediments with the highest trace metal contents appear to be potentially ecotoxic for Allivibrio fisheri. In this study, in attempting to link chemical characteristics with ecotoxicity test results, we got a trend going in the right direction. Samples with highest metal contents appear to be potentially ecotoxic for A. fisheri. These results suggest the usefulness of a diversity of approaches in sediment quality assessment. [ABSTRACT FROM AUTHOR]

Ecological studies have traditionally treated fish species or populations as homogenous groups; however, numerous studies have shown that intrapopulation variation in resource use is widespread. Within‐species diet differences are evident in small and large freshwater systems and may influence trophic and population dynamics. In a previous study of young yellow perch, spatial intrapopulation diet variation was observed for stomach contents, a relatively short‐term diet indicator. In the current study, we build upon the earlier study of yellow perch in Saginaw Bay, Lake Huron, and assess patterns of long‐term diet indicators (stable isotopes and morphology) to assess consistency of diet variation over time and improve characterisation of trophic differences among sites. Specifically, we analysed soft tissue samples for carbon (δ13C) and nitrogen (δ15N) isotope ratios and used geometric morphometrics to describe morphological variation of young yellow perch. While both isotopes displayed significant spatial differences, δ15N values demonstrated a much clearer separation among sites, with greater δ15N values for yellow perch collected closer to the mouth of the Saginaw River. Morphological variation also was more apparent among sites rather than between years or months, with more streamlined yellow perch morphologies evident at sites where they consumed high proportions of zooplankton relative to benthic invertebrates. Somewhat unexpectedly, soft tissue δ13C values varied strongly between the two study years; however, the ultimate cause of such interannual variation in δ13C is unclear. These long‐term indicators showed consistent spatial differences, which suggests that individual fish are using resources at a particular site long enough to reflect a stable isotope or morphological signal. Yellow perch production at different locations seemingly relies on different prey resources, suggesting that annual variation in dominant trophic pathways may alter the performance of yellow perch at each location. [ABSTRACT FROM AUTHOR]

Summary: In order to determine the present benthic fish fauna in the Sea of Marmara, sampling was conducted at a total of 10 stations for 2 weeks in August 2009, using a commercial twin beam trawling vessel with 18 and 36 mm stretched mesh sizes at the cod‐end. In addition, some physicochemical parameters that play important roles, such as temperature, salinity, dissolved oxygen, and pH, were measured for each station. As a result, 31 fish species from 23 families were found at a total of 10 stations in depths of 30–1000 m. At each station, the Shannon–Weaver diversity index, Simpson dominance index, species richness index, and evenness index were estimated. This study reports on species composition of the demersal fish catches in the Sea of Marmara for a preliminary assessment of the status of these fish communities. [ABSTRACT FROM AUTHOR]

The introduction of exotic species can generate changes in the composition of organic debris of alien origin in aquatic ecosystems close to the places of introduction. This new debris can cause impacts at the level of communities and ecosystems. Therefore, the present work aims to answer the following question: are the macroinvertebrate communities present in substrates formed by leaves of the exotic species Pinus caribaea Morelet (Pinaceae) and Eucalyptus grandis Hill ex Maiden (Myrtaceae) similar to those found in substrates composed by the mix of these two species and substrates composed by a mix of native species? For the collection of macroinvertebrates, sets of four types of artificial substrates were submerged in a stream inside the Ecological Station of Panga (Uberlândia—MG, Brazil). The treatments were: leaves of P. caribaea, leaves of E. grandis, leaves of both exotic species and leaves of two native species. In the 20 sample units, about 250 individuals were found, belonging to the orders Coleoptera, Diptera, Ephemeroptera, Heteroptera, Megaloptera, Odonata, Plecoptera and Trichoptera. The effects of the treatments were observed in the exponential decay of the substrate mass and in the structure of the benthic macroinvertebrates communities. The composition of these communities differed among treatments, with high dissimilarity observed between P. caribaea treatments and the mix of exotic species. Therefore, the results demonstrate the importance of substrate complexity for benthic macroinvertebrates, as well as the possible effects of biological invasion and co-invasion by species widely used in silviculture activities. [ABSTRACT FROM AUTHOR]

Investigating historical gene flow in species complexes can indicate how environmental and reproductive barriers shape genome divergence during speciation. The processes influencing species diversification under environmental change remain one of the central focal points of evolutionary biology, particularly for marine organisms with high dispersal potential. We investigated genome‐wide divergence, introgression patterns and inferred demographic history between species pairs of all six extant rock lobster species (Jasus spp.), which have a long larval duration of up to two years and have populated continental shelf and seamount habitats around the globe at approximately 40oS. Genetic differentiation patterns reflected geographic isolation and the environment (i.e. habitat structure). Eastern Pacific species (J. caveorum and J. frontalis) were geographically more distant and genetically more differentiated from the remaining four species. Species associated with continental shelf habitats shared a common ancestry, but are geographically distant from one another. Similarly, species associated with island/seamount habitats in the Atlantic and Indian Oceans shared a common ancestry, but are also geographically distant. Benthic temperature was the environmental variable that explained most of the genetic differentiation (FST), while controlling for the effects of geographic distance. Eastern Pacific species retained a signal of strict isolation following ancient migration, whereas species pairs from Australia and Africa, and seamounts in the Indian and Atlantic oceans, included events of introgression after secondary contact. Our results reveal important effects of habitat and demographic processes on the recent divergence of species within the genus Jasus, providing one of the first empirical studies of genome‐wide drivers of diversification that incorporates all extant species in a marine genus with long pelagic larval duration. [ABSTRACT FROM AUTHOR]

The spatiotemporal variations of megazoobenthos on soft bottoms in Buena Vista (BV) and San Juan de Los Remedios (SJR) bays, Cuba, were assessed to infer the effects of the elimination of bottom trawl fisheries and the creation of protected areas. Data were collected at 11 sites in 2010-2013 (six routines and five exploratories) and 11 sites in 2014-2017 (four routines and seven exploratories). Samples were obtained by dredging. Mollusks were the most frequent and diverse group, followed by echinoderms and crustaceans. Total density (7.60 ind m-2) and biomass (15.82 g m-2) of the benthic community were highest in SJR in 2015. Although total biomass was lower at BV (t = 2.21; P = 0.032), there were no significant differences in density between bays (t = 0.77; P = 0.444). The site with a lower total density and biomass was located at BV. There were no differences between years except at one site, where density increased between 2010 and 2017. Total density and biomass were not significantly different inside and outside of the Zone Under Special Regime of Use and Protection (ZUSRUP) at the beginning of the sampled period. However, both density and biomass were significantly higher within the ZUSRUP at the end (2017), which suggests this protected area's effectivity. The progressive increase in density at one site and greater density and biomass values at SJR, where bottom trawl fisheries were more intensive, suggest eliminating bottom trawl nets may have contributed to the benthic fauna recovery. [ABSTRACT FROM AUTHOR]

—During 79th cruise of R/V Akademik Mstislav Keldysh twelve trawl hauls were collected in Powell Basin and adjacent area at depths 370–3771 m. The structure of the benthic assemblages was highly variable when considered at the macrotaxon level. The main factors shaping the taxonomical structure of the sampled assemblages were depth, near-bottom current velocities and proportion of the hard fraction of the sediment. Hard substrate assemblages of the Antarctic peninsula slope and Philip Ridge with high percentage of filter-feeders (mainly sponges) were associated with the highest values of the near-bottom tide currents (up to 55.6 cm/s). In several trawl hauls indicator species of vulnerable marine ecosystems—mainly Demospongiae sponges, deep-sea corals Stylasteridae (Hydrozoa) and Primnoidae (Octocorallia)—were collected. [ABSTRACT FROM AUTHOR]

Size-latitude trends in the meiobenthic phylum Kinorhyncha, commonly known as mud dragons, have been explored in oceans worldwide. Generalized least squares regression was used to assess relationships between size and latitude, as well as between size, latitude, and two selected environmental variables that exhibit latitudinal gradation: the sea surface temperature and the net primary productivity. Different structures of spatial autocorrelation and potential confounding factors, such as the species richness and the number of kinorhynch records that could affect latitudinal gradients, were also addressed. In addition, generalized mixed models were used to determine the influence of the phylogeny on body size. Size-latitude relationships of Kinorhyncha were commonly found globally, as well as for particular geographic regions (hemispheres and/or coastlines), with important differences between taxonomic groups. These size-latitude trends were heterogeneous and implied the influence of the latitude itself, environmental variables, and phylogeny. These facts indicate that a single underlying process is not likely to explain the observed relationships but a complex interaction of several macroecological patterns both present and past. Perhaps, the inclusion of future new reports, conducted in undersampled areas, may shed some light on the matter and reveal more generalized size-latitude patterns. Nevertheless, it is also likely that broadly generalizable size-latitude relationships may not exist in meiofaunal communities. [ABSTRACT FROM AUTHOR]

The Kurdistan region of northern Iraq contains world-class outcrops that make it possible to examine the Cretaceous deep and shallow marine Tethyan faunal succession. Six separate sections covering the Shiranish, Bekhme, Mergi and Qamchuqa formations have been investigated in this study from the Shiranish Islam area. A number of papers have been published on this area, but no comprehensive biostratigraphic record has been published that fully documents the Cretaceous stratigraphy and the chronostratigraphic interpretation of the succession. As a result, this has led to significant lithostratigraphic and chronostratigraphic uncertainties. The upper part of the Qamchuqa is pervasively dolomitized. Rare occurrences of foraminifera are found in less dolomitized intervals in thin-section indicating an early - middle Albian age for the top of the formation. A thin interval comprising the Gir Bir Formation is Cenomanian in age and is present between the top of the Qamchuqa Formation and the overlying conglomerate. Historical studies indicate that the Turonian Mergi Formation occurs between the Qamchuqa and Bekhme formations, but our field and analytical data does not support it as a discrete lithostratigraphic entity, as Turonian aged faunas were not recognized. The conglomerate separating the top of the Gir Bir and base of the Bekhme is subdivided into three units (A, B & C). Units Aand B are late Cenomanian to early Turonian age, whilst Unit C is of Campanian age. Asignificant hiatus separates the Gir Bir and the Bekhme, which encompasses the intra Turonian to Santonian. The limestone facies of the lower part of the Bekhme Formation contains rich benthic foraminiferal faunas (miliolids, Pseudedomia, Cuneolina) of early - early middle Campanian age. This lower - lower middle Campanian section at Shiranish Islam is considered to be equivalent of the upper part of the Sa'di Formation in central Iraq and is therefore re-assigned on the basis of chronostratigraphic attribution to the Sa'di (equivalent) herein. The top of the early - early middle Campanian biofacies is abruptly truncated by an omission surface, marked by an erosive base, an influx of clastic material and a major up-section biofacies change characterized by an influx of Pseudosiderolites and Orbitoides representing an intra-Campanian hiatus. The bioevent sequence suggests that this hiatus at Shiranish Islam comprises at least the middle Campanian (upper part of the G. elevata Zone) into the late Campanian (intra R. calcarata Zone), from approximately 80.64 Ma to 76.09 Ma with 4.55 my missing. The middle part of the Bekhme Formation comprising the Pseudosiderolites - Orbitoides facies is thin (c. three meters) and is re-assigned to the Lower Bekhme Member. The boundary between the Lower Bekhme Member and the Upper Bekhme Member is conformable and marked by a gradual up-section reduction in the size and presence of larger benthic foraminifera (Orbitoides, Pseudosiderolites) and an increase in the planktic component (small planktics and calcispheres). This trend of gradually increasing water depth continues into the Shiranish Formation, with no apparent major breaks in deposition. The Campanian - Maastrichtian boundary falls within Unit A of the Shiranish Formation. Deposition of the Shiranish continued into the earliest late Maastrichtian and is unconformably overlain by the Danian Kolosh Formation. The hiatus between the top of the Cretaceous and the Paleocene extends from the early late Maastrichtian (c. 68.86 Ma) to the upper part of the Danian (62.2 Ma) with an estimated duration of 6.66 my. [ABSTRACT FROM AUTHOR]

Ecological flows across ecosystem boundaries are typically studied at spatial scales that limit our understanding of broad geographical patterns in ecosystem linkages. Aquatic insects that metamorphose into terrestrial adults are important resource subsidies for terrestrial ecosystems. Traits related to their development and dispersal should determine their availability to terrestrial consumers. Here, we synthesize geospatial, aquatic biomonitoring and biological traits data to quantify the relative importance of several environmental gradients on the potential spatial and temporal characteristics of aquatic insect subsidies across the contiguous United States. We found the trait composition of benthic macroinvertebrate communities varies among hydrologic regions and could affect how aquatic insects transport subsidies as adults. Further, several trait–environment relationships were underpinned by hydrology. Large bodied taxa that could disperse further from the stream were associated with hydrologically stable conditions. Alternatively, hydrologically variable conditions were associated with multivoltine taxa that could extend the duration of subsidies with periodic emergence events throughout the year. We also found that anthropogenic impacts decrease the frequency of individuals with adult flight but potentially extend the distance subsidies travel into the terrestrial ecosystem. Collectively, these results suggest that natural and anthropogenic gradients could affect aquatic insect subsidies by changing the trait composition of benthic macroinvertebrate communities. The conceptual framework and trait–environment relationships we present shows promise for understanding broad geographical patterns in linkages between ecosystems. [ABSTRACT FROM AUTHOR]

The biodiversity of freshwater fauna of the Arctic Islands of the Russian Federation is currently poorly studied and to date there are insufficient molecular genetic data concerning most of the taxa. This study presents the new data on species composition and distribution of freshwater benthic invertebrates in lakes of the Novaya Zemlya Archipelago and Vaigach Island based on both the published and the original records. A total of 29 species of invertebrates in 4 classes and 14 orders were found. Considering the published data, the list of species expands to 136 species. The copepod Mesocyclops leuckarti, the pontoporeid amphipod Monoporeia affinis, the ostracod Leucocythere mirabilis, and the mollusk Euglesa globularis were recorded for the first time from the Novaya Zemlya Archipelago. The oligochaete Rhyacodrilus coccineus, the stonefly Nemoura sahlbergi, the caddisflies Agrypnia obsoleta, Micrasema gelidum and Philarctus bergrothi were registered for the first time from Vaigach Island; P. bergrothi was also recorded for the first time from Europe. The crane fly larvae of Tipula (Arctotipula) were recorded as inhabitants of the bottom layer of Arctic lakes for the first time. The obtained molecular data are in accordance with the tabula rasa hypothesis that the invertebrate fauna of the Novaya Zemlya Archipelago and Vaigach Island are the result of recent species immigration after the Last Glacial Maximum. Our data can be used in further ecological studies and conservation management. The molecular data are of considerable interest for the taxonomy and biogeography of the fauna of the Arctic islands during the Pleistocene. [ABSTRACT FROM AUTHOR]

In Australia, the deep-water (bathyal and abyssal) benthic invertebrate fauna is poorly known in comparison with that of shallow (subtidal and shelf ) habitats. Benthic fauna from the deep eastern Australian margin was sampled systematically for the first time during 2017 RV 'Investigator' voyage 'Sampling the Abyss'. Box core, Brenke sledge, and beam trawl samples were collected at one-degree intervals from Tasmania, 42°S, to southern Queensland, 24°S, from 900 to 4800 m depth. Annelids collected were identified by taxonomic experts on individual families around the world. A complete list of all identified species is presented, accompanied with brief morphological diagnoses, taxonomic remarks, and colour images. A total of more than 6000 annelid specimens consisting of 50 families (47 Polychaeta, one Echiura, two Sipuncula) and 214 species were recovered. Twenty-seven species were given valid names, 45 were assigned the qualifier cf., 87 the qualifier sp., and 55 species were considered new to science. Geographical ranges of 16 morphospecies extended along the eastern Australian margin to the Great Australian Bight, South Australia; however, these ranges need to be confirmed with genetic data. This work providing critical baseline biodiversity data on an important group of benthic invertebrates from a virtually unknown region of the world's ocean will act as a springboard for future taxonomic and biogeographic studies in the area. [ABSTRACT FROM AUTHOR]

Rapid population growth and poor waste management practice are among the main drivers of plastic pollution in modern times, thus making Africa a hotspot for plastic pollution both now and in the future. This study is a review of plastic pollution reports from the African aquatic environment with regard to causes, current status, toxicological implications and implications for ecosystem services. A total of 59 plastic pollution studies from 1987 to September 2020 were reviewed. They comprised 15 from North Africa (NA) (Algeria, Egypt, Morocco and Tunisia), six from East Africa (EA) (Ethiopia, Kenya, Tanzania and Uganda), 13 from West Africa (WA) (Ghana, Guinea-Bissau, Mauritania and Nigeria), and 25 studies from Southern Africa (SA) (South Africa). This shows that plastic pollution studies in Africa, according to the sub-regions, are in the order: SA > NA > WA > EA. High human population in the basins of African large aquatic systems is identified as the greatest driver enhancing plastic surge in the aquatic environment. The occurrence of plastics was mostly reported in the estuarine/marine environment (42 studies) compared to the freshwater environment (only 17 studies). Plastics have also been reported in the three compartments of the aquatic environment: water column, benthic sediment and animals. Zooplankton, annelids, molluscs, insects, fishes and birds were reported as bioindicators of plastic ingestion in the inland and coastal waters of Africa. Polyethylene, polyethylene terephthalate (polyester) and polypropylene were the common plastic polymers observed in the African aquatic environment. In situ toxicological implications of the ingested plastic polymers were not reported in any of the studies. However, reports from laboratory-controlled experiments showed that these polymers are deleterious to aquatic animal health. More research efforts need to delineate the plastic pollution status of the East, West and North of Africa. Furthermore, such studies are required to identify the plastic polymers and in situ ecotoxicological impacts of plastics on both animal and human health. [ABSTRACT FROM AUTHOR]

Conserving biogeographic regions with especially high biodiversity, known as biodiversity 'hotspots', is intuitive because finite resources can be focussed towards manageable units. Yet, biodiversity, environmental conditions and their relationship are more complex with multidimensional properties. Assessments which ignore this risk failing to detect change, identify its direction or gauge the scale of appropriate intervention. Conflicting concepts which assume assemblages as either sharply delineated communities or loosely collected species have also hampered progress in the way we assess and conserve biodiversity. We focus on the marine benthos where delineating manageable areas for conservation is an attractive prospect because it holds most marine species and constitutes the largest single ecosystem on earth by area. Using two large UK marine benthic faunal datasets, we present a spatially gridded data sampling design to account for survey effects which would otherwise be the principal drivers of diversity estimates. We then assess γ‐diversity (regional richness) with diversity partitioned between α (local richness) and β (dissimilarity), and their change in relation to covariates to test whether defining and conserving biodiversity hotspots is an effective conservation strategy in light of the prevailing forces structuring those assemblages. α‐, β‐ and γ‐diversity hotspots were largely inconsistent with each metric relating uniquely to the covariates, and loosely collected species generally prevailed with relatively few distinct assemblages. Hotspots could therefore be an unreliable means to direct conservation efforts if based on only a component part of diversity. When assessed alongside environmental gradients, α‐, β‐ and γ‐diversity provide a multidimensional but still intuitive perspective of biodiversity change that can direct conservation towards key drivers and the appropriate scale for intervention. Our study also highlights possible temporal declines in species richness over 30 years and thus the need for future integrated monitoring to reveal the causal drivers of biodiversity change. [ABSTRACT FROM AUTHOR]

• The metabolism of diet As was investigated in food fish during chronic exposure • Arsenic adaption involved reduced As bioaccumulation and increased As biotransformation • The bioavailability of dietary arsenite was lower than that of arsenate • Arsenite was largely formed in fish muscle at earlier stage of arsenate exposure Dietary uptake is the major way that inorganic arsenic (iAs) enters into benthic fish; however, the metabolic process of dietborne iAs in fish muscle following chronic exposure remains unclear. This was a 40-day study on chronic dietborne iAs [arsenite (AsIII) and arsenate (AsV)] exposure in the benthic freshwater food fish, the crucian carp (Carassius auratus), which determined the temporal profiles of iAs metabolism and toxicokinetics during exposure. We found that an adaptive response occurred in the fish body after iAs dietary exposure, which was associated with decreased As accumulation and increased As transformation into a non-toxic As form (arsenobetaine). The bioavailability of dietary AsIII was lower than that of AsV, probably because AsIII has a lower ability to pass through fish tissues. Dietary AsV exhibited a high potential for transformation into AsIII species, which then accumulated in fish muscle. The largely produced AsIII considered more toxic at the earlier stage of AsV exposure should attract sufficient attention to human exposure assessment. Therefore, the pristine As species and exposure duration had significant effects on As bioaccumulation and biotransformation in fish. The behavior determined for dietborne arsenic in food fish is crucial for not only arsenic ecotoxicology but also food safety. Image, graphical abstract [ABSTRACT FROM AUTHOR]

Pelagic primary production is the main input of organic energy for benthic production below the photic zone. In the Baltic Sea, spring phytoplankton blooms are dominated by diatoms that sink out rapidly and export nutritionally favorable matter to benthic secondary production, while the summer blooms have more variable sedimentation rates and nutritional profile. Changes in phytoplankton species composition and bloom dynamics, as a consequence of climate change and eutrophication are reducing high quality diatoms reaching the benthic fauna, while promoting cyanobacteria. Here, we test uptake and assimilation of changing phytoplankton composition for three common benthic invertebrates, a clam, an amphipod and a polychaete under varying degrees of spring‐bloom associated diatoms (Skeletonema costatum) and summer‐bloom associated cyanobacteria (Nodularia spumigena). The phytoplankton were labeled with stable isotopes (15N and 13C, respectively) in order to trace assimilation in consumers' tissues. We found that all three macrofauna species fed on both diatoms and cyanobacteria. A linear pattern was found for all three species in assimilation of carbon and nitrogen from diatoms, with increasing assimilation associated with higher proportion of diatoms. There was no clear pattern found between proportion of cyanobacteria and assimilation of carbon and nitrogen for any of the species. This study shows that the investigated macrofaunal species display a selective feeding behavior with preference for spring‐bloom associated diatoms. Thus, changes in phytoplankton bloom composition are likely affecting benthic species composition and production. [ABSTRACT FROM AUTHOR]

The Nanhai No. 1 Shipwreck is a wooden ship sunk 800 years ago during the Southern Song Dynasty of China. The zoobenthic shellfish communities in the sediments covering the wreck came from 296 species from 5 phylums, of which 290 were molluscs. These molluscs were mainly composed of local marine fauna based on the literature. By comparing the structural parameters of the zoobenthic debris communities and their changes among the different sediment layers, it is notable that the seabed environment was influenced by the wreck within a short period of time, and corroded metal objects from the ship could impact the mollusc communities. Because of the relatively continuous and stable particle deposition in the sea, the wreck was quickly covered in sediment. During this deposition process, the seabed level of the shipwreck site gradually returned to similar conditions prevalent in the surrounding area. Sedimentation sealed the wooden objects of the hull from the sea water and relatively anaerobic conditions between the sediment and the wood structures were formed. This anaerobic environment inhibited the eroding effect of aerobic bacteria and wood boring animals, thereby preserving the shipwrecked hull. [ABSTRACT FROM AUTHOR]

Holocene and Pleistocene marine sediment records in the North Pacific record multiple dysoxic events proximal to continental margins and oxygen minimum zones (OMZs). High‐resolution paleoenvironmental studies in the Gulf of Alaska (GoA) were previously restricted to the last ∼17,000 years, limiting our knowledge of oxygenation in the high latitude North Pacific. Here we develop a ∼54,000‐year‐long record of co‐registered benthic foraminiferal assemblages and redox sensitive metal concentrations (Mo/Al and U/Al) at Site U1419 in the upper OMZ of GoA to reconstruct the history of OMZ extent and intensity at multi‐centennial resolution. Using multivariate analyses of total benthic foraminiferal assemblages, we develop quantitative dissolved oxygen estimates that are robust to differences in the benthic foraminiferal size fraction analyzed, replicate modern oxygenation patterns in the GoA, and are cross‐validated by redox sensitive metal concentrations. We identify dysoxic events in the early Holocene and in the Bølling‐Allerød (B/A), consistent with previous studies, as well as two dysoxic events during MIS 3 that are comparable in severity to the B/A event and lower in oxygen than the modern GoA OMZ. We further record short‐duration (<300 years) dysoxic events during glacial times similar to those recorded at more southern latitudes. Rates of oxygenation change can be abrupt with transitions exceeding 1 ml/L O2 in 100 years. Quantitative estimates of paleo‐oxygenation, such as those possible with benthic foraminiferal assemblages, are important for forecasting future oxygenation changes in OMZs and their potential impacts on the marine ecosystems. Key Points: Benthic foraminiferal faunas indicate dysoxia was more severe than in the modern Gulf of Alaska during the Bølling‐Allerød and MIS 3Changes in oxygenation can exceed 1 ml/L O2 per 100 years and dysoxic conditions persist for <300 to ∼4,000 yearsThe frequency and timing of low‐oxygen events in the Gulf of Alaska are similar to lower latitudes in the North Pacific [ABSTRACT FROM AUTHOR]

Hydrozoans are one of the main and most characteristic zoological groups of Antarctic benthic communities, yet there are Antarctic areas where the hydrozoan fauna is completely unknown (e.g. the Admunsen Sea, West Antarctica) or scarcely known (e.g. Adélie Land, East Antarctica). Hitherto, only one study, published in 1972, has been devoted to hydroids inhabiting marine bottoms off Adélie Land. The present study contributes to a better knowledge of the benthic hydroid fauna of this region by studying material from the Antarctic Specially Protected Area of Pointe Géologie Archipelago (ASPA 120), area of considerable biological value and great importance for scientific research. 35 species of benthic hydroids were found, belonging to 14 families and 18 genera. 15 species represent new records for the area, bringing the number of species reported in the zone to 45. Leptothecata is dominant, with 30 species, while Anthoathecata is represented by just five species. Symplectoscyphidae is the most speciose family, with 11 species (31%), whereas Kirchenpaueriidae has the highest biomass due to Oswaldella terranovae, the species with the highest abundance and biomass and that could be considered a true habitat builder and biodiversity hotspot. The study of the hydroid assemblages has revealed the overwhelming dominance in the area of a community characterised mainly by O. terranovae; three other assemblages are present, albeit much less represented. The hydroid fauna is clearly dominated by eurybathic species (65%) and most of the species studied (88%) are restricted to Antarctic or Antarctic/sub-Antarctic waters, with 65% endemic to the Antarctic region. [ABSTRACT FROM AUTHOR]

Our study focused on quantifying the alterations of streamflow at a weir site due to the construction of a mini-hydropower plant in the Gurugoda Oya (Sri Lanka), and evaluating the spatial responses of benthic macroinvertebrates to altered flow regime. The HEC–HMS 3.5 model was applied to the Gurugoda Oya sub-catchment to generate streamflows for the time period 1991–2013. Pre-weir flows were compared to post-weir flows with 32 Indicators of Hydrologic Alteration using the range of variability approach (RVA). Concurrently, six study sites were established upstream and downstream of the weir, and benthic macroinvertebrates were sampled monthly from May to November 2013 (during the wet season). The key water physico-chemical parameters were also determined. RVA analysis showed that environmental flow was not maintained below the weir. The mean rate of non-attainment was ~ 45% suggesting a moderate level of hydrologic alteration. Benthic macroinvertebrate communities significantly differed between the study sites located above and below the weir, with a richness reduction due to water diversion. The spatial distribution of zoobenthic fauna was governed by water depth, dissolved oxygen content and volume flow rate. Our work provides first evidence on the effects of small hydropower on river ecosystem in a largely understudied region. Studies like this are important to setting-up adequate e-flows. [ABSTRACT FROM AUTHOR]

Collecting in shallow water (water depth: ~30 m) is an emerging field that requires robotics for replacing human divers. Soft robots have several promising features (e.g., safe interaction with the environments, lightweight, etc.) for performing such tasks. In this article, we developed an underwater robotic system with a three-degree-of-freedom (3-DoF) soft manipulator for spatial delicate grasping in shallow water. First, we present the design and fabrication of the soft manipulator with an opposite-bending-and-stretching structure (OBSS). Then, we proposed a simple and efficient kinematics method for controlling the spatial location and trajectory of the soft manipulator's end effector. The inverse kinematics of the OBSS manipulator can be solved efficiently (computation time: 8.2 ms). According to this inverse kinematics method, we demonstrated that the OBSS soft manipulator could track complex two-dimensional and three-dimensional trajectories, including star, helix, etc. Further, we performed real-time closed-loop pick-and-place experiments of the manipulator with binocular and on-hand cameras in a lab aquarium. Hydrodynamic experiments showed that the OBSS soft manipulator produced little force (less than 0.459 N) and torque (less than 0.228 N·m), which suggested its low-inertia feature during the underwater operation. Finally, we demonstrated that the underwater robotic system with the OBSS soft manipulator successfully collected seafood animals at the bottom of the natural oceanic environment. The robot successfully collected eight sea echini and one sea cucumber within 20 minutes at a water depth of around 10 m. [ABSTRACT FROM AUTHOR]

Wetlands are one of the richest habitats of biodiversity, provide food and shelter to organisms that thrive in. During the present investigation 22 genera of macrozoobenthos were recorded. Out of 22, 8 genera belong to phylum annelid, 8 to mollusca, and 6 to arthropod. The mean density shows that molluscan dominates and constituted 36.66% of the total macrozoobenthos population was followed by annelids (34.66%) and arthropods (28.66%). Among the benthic population was chiefly constituted by Tubifex sp followed by Gammarus sp., Chironomus sp., Lymnaea sp., Pila sp., Branchiura sp., Lumbriculus sp. Erpobdella sp. and Lamellidens sp. [ABSTRACT FROM AUTHOR]

The importance of flow‐related factors to benthic organisms, as well as the role of habitat conditions in shaping aquatic communities during low‐flow periods, have been recognised. Despite this, the preferences of macroinvertebrates to the ratio of lentic to lotic habitats at the reach scale have not been accurately quantified in most instances.Aquatic invertebrates and habitat features in a range of temporary rivers in Sardinia were investigated. The investigation focused on the flow‐related characteristics that contribute to defining the lentic–lotic condition of the river reaches. The relation of habitat features to benthic taxa distributions was assessed using multidimensional scaling. The main aim of the paper was to quantify the responses of taxa to the different lentic and lotic habitat conditions by applying hierarchical logistic regressions. Finally, taxon optima were aligned along the lentic–lotic gradient and the responses of different taxonomic groups compared.Unbroken waves and imperceptible flow were correlated with benthic taxa variability, suggesting local hydraulics and turbulence have a major role in regulating community composition. The overall lentic–lotic character of the river reaches was also clearly related to the benthic taxa distribution. More than 80% of taxa were significantly related to the lentic–lotic gradient, and an asymmetrical response curve was the predominant model.Benthic groups showed taxon optima clustered in different ranges of the lentic–lotic gradient. Odonata, Coleoptera, Hemiptera, and Mollusca preferred clearly lentic conditions. Diptera mainly ranged on the lotic side of the gradient, while Trichoptera were relatively uniformly distributed across the gradient. Ephemeroptera taxa clustered in intermediate lentic–lotic conditions, with two species preferring extremely lentic habitats. In general, optima converged at intermediate and extremely lentic conditions, presumably due, respectively, to the coexistence of different lentic and lotic features and to the highly diverse environmental characteristics under extremely lentic situations.These results support the conclusion that dissimilar ecological factors act on benthic taxa along the lentic–lotic range and species favouring different lentic–lotic conditions are subjected to pressures of different nature. This should not be ignored when defining species preferences and studying community structure or relationships between species in Mediterranean rivers, which cyclically vary their habitat composition. In addition, the uneven distribution of optima of different groups along the lentic–lotic gradient might affect macroinvertebrate metrics when assessing ecological status or establishing reference conditions under variable climatic conditions. [ABSTRACT FROM AUTHOR]

The species composition of one of the main zoobenthos groups in Vaya Lake - Chironomidae (Diptera) in the period 2003 - 2007 was studied. A total of 27 taxa were identified, of which 18 species from 11 genera were identified and 9 taxa at the level of sp. The results showed a change in the species composition of chironomids compared to the period 1953 - 1957 (Zashev and Angelov, 1959) when the only systematic studies of the lake so far were performed. [ABSTRACT FROM AUTHOR]

This study investigated temporal changes in the vertical distribution of invertebrates during periods of low flows in the Tafna wadi, a semi-arid Mediterranean river characterised by a general decline in average flows. The hyporheos was sampled along a 130-m stretch at depths of 0.3, 0.6 and 1 m in a pool-riffle sequence and a lateral gravel bar. Benthic fauna was collected on each sampling occasion from different locations in the studied sections. Sampling was conducted in two consecutive years (2014 and 2015) at the end of the spring (high waters) and over a 2-month period during the low summer flow. The results indicated that high surface water temperatures may initiate the movement of some taxa into the interstitial habitat, thus supporting the hyporheic refuge hypothesis. In the hyporheic zone, the low oxygen rates recorded deeper in the sediment and in the last low-flow months caused significant declines in taxonomic richness, and lower pH values resulted in a reduction in invertebrate abundances. In the benthic zone, high flow velocities increased richness but decreased invertebrate abundances. A large number of taxa were found in the gravel bar section reflecting the more suitable living conditions in this habitat compared with the river reach (high DO rates). [ABSTRACT FROM AUTHOR]

Studies on biodiversity management and conservation have often focused on tidal flats and estuaries. Macrobenthic assemblages in these habitats generally show local and geographical variations. Therefore, understanding about their spatial structure is important in assessing their biodiversity. This study aims to examine the spatial hierarchical composition of macrobenthic diversity in Ruditapes philippinarum fishery grounds covering a large (1,700 km) geographic range of Japan. Four diversity measures according to the sensitivity parameter q = 0, 1, 2 and Inf were used to evaluate the contribution of four spatial levels (site, area, region and total). Observed assemblages had a few abundant and many rare taxonomic units. Although the abundant taxonomic units, including Ruditapes, occurred over larger spatial levels, the between‐region β diversity (diversity increment from the region to the total level) contributed most to the diversity of the total area. Comparisons of four diversity measures further revealed that the contributions of the between‐region β diversity were more pronounced in the rare taxonomic units than the abundant ones. Null model analysis confirmed these results although different null models generated some variations in the hierarchical composition of the diversities. [ABSTRACT FROM AUTHOR]

During the regular surveys on coral monitoring for setting their developmental level, health status and likely threats responsible for mortality, a massive mucilage phenomenon was identified in the largest coral habitats in the Çanakkale Strait (Dardanelles) in December 2020. This study was performed to determine the effect of mucilage event on corals mainly observed at the depth level of 39-51 m in two stations, one in the European and the other in the Anatolian side of the strait. A massive mucilage with expanding cloud and floc types of aggregates was detected only in the Eceabat region (European side). A false-benthos mucilage was also identified at depths 4-20 m in the following control surveys. The current report is of the first circalittoral observation of this damaging event in the northernmost region of the Mediterranean Sea. Previous records of massive mucilage were reviewed and the first deep infralittoral record of massive mucilage event in 2008 is also described. [ABSTRACT FROM AUTHOR]

In fluctuating lake ecosystems, the severity of anthropogenic disturbance is often difficult to assess because the magnitude of natural dynamics rivals or surpasses that of ecosystem alteration due to human impact. Consequently, it is also difficult to evaluate the resilience of these ecosystems' plant and animal communities to that impact. Unfortunately, lake ecosystem response to natural cycles of lake‐level and salinity fluctuation at multi‐annual time scales is poorly understood, due to complex relationships between hydrological dynamics and the local availability or distribution of ecological niches. We present a 1650‐yr‐long paleoecological record from Lake Naivasha in Kenya (East Africa) which traces community assembly and turnover in two prominent groups of benthic invertebrates (chironomids and ostracods) in response to a climate‐driven sequence of 10 major lake‐level fluctuations. Over this time period, lake depth (inferred from sedimentology) fluctuated between ~3 and >35 m, and salinity (inferred from fossil diatom assemblages) varied between ~100 and ~23,500 µS/cm. Prior to ~780 yr ago, the unique community response to salinity was stronger than to lake depth. Around that time the lake transitioned to a more open hydrology, relatively stable freshwater conditions and greater prevalence of macrophyte‐associated benthic habitat, so that community response to variations in lake depth (and surface area) became stronger. Notably, major community restructuring in the course of this transition was not synchronous between the two groups, because it depended on the proliferation of key freshwater species in each group. Our results imply that (1) climate‐sensitive lake ecosystems are more likely controlled by salinity change if both its amplitude and frequency are large enough to induce ecological species sorting; (2) community response to such salinity changes may be predictable, and likely to show coherence across different groups of aquatic biota; and (3) the timing of major community restructuring strongly depends on the ecology of key species, and whether the species sorting is driven by salinity change itself or indirectly by the salinity‐dependent availability of ecological niches. [ABSTRACT FROM AUTHOR]

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This study focuses on the Dombrovska pit lake, near the city of Kalush in Ukraine, which is a former potassium salt mine filled with brine and freshwater. The water level is still increasing and as a result the salinity is decreasing. We analyzed the benthic fauna communities and the genome instability by assessing the rearrangements in the polytene chromosomes of Chironomus salinarius and the physicochemical parameters of the near-bottom water (pH, conductivity, mineralization, major ions, NO3−, NH4+, metals Cd, Pb, Cu, Mn, and Fe) and sediment (pH, organic matter and metals Cd, Pb, Cu, Zn, Mn, and Fe) at four sites. The water mineralization ranged from 17.3 to 26.2 g dm−3 which are classified as mesohaline and polyhaline waters, respectively. The biodiversity of the benthic fauna was low, and the dominant species was C. salinarius. The density of C. salinarius varied spatially and changed from 637 ind./m2 at a depth of 5 m to 8167 ind./m2 at a depth of 2.5 m. The genome instability was analyzed by examining the structural and functional changes in the salivary gland chromosomes of C. salinarius. The exposure of C. salinarius damaged the chromosomes and the activities of key structures, such as the Balbiani ring and nucleolar organizer, were partially or completely suppressed. [ABSTRACT FROM AUTHOR]

Sint Eustatius (Statia) is a 21 km2 island situated in the northeastern Caribbean Sea. The most recent published sources of information on that island's marine fish fauna is in two non-governmental organization reports from 2015-17 related to the formation of a marine reserve. The species-list in the 2017 report was based on field research in 2013-15 using SCUBA diving surveys, shallow "baited underwater video surveys" (BRUVS), and data from fishery surveys and scientific collections over the preceding century. That checklist comprised 304 species of shallow (mostly) and deep-water fishes. In 2017 the Smithsonian Deep Reef Observation Project surveyed deep-reef fishes at Statia using the crewed submersible Curasub. That effort recorded 120 species, including 59 new occurrences records. In March-May 2020, two experienced citizen scientists completed 62 SCUBA dives there and recorded 244 shallow species, 40 of them new records for Statia. The 2017-2020 research effort increased the number of species known from the island by 33.6% to 406. Here we present an updated catalog of that marine fish fauna, including voucher photographs of 280 species recorded there in 2017 and 2020. The Statia reef-fish fauna likely is incompletely documented as it has few small, shallow, cryptobenthic species, which are a major component of the regional fauna. A lack of targeted sampling is probably the major factor explaining that deficit, although a limited range of benthic marine habitats may also be contributing. [ABSTRACT FROM AUTHOR]

Aim: We incorporated genetic structure and life history phase in species distribution models (SDMs) constructed for a widespread spiny lobster, to reveal local adaptations specific to individual subspecies and predict future range shifts under the RCP 8.5 climate change scenario. Location: Indo‐West Pacific. Methods: MaxEnt was used to construct present‐day SDMs for the spiny lobster Panulirus homarus and individually for the three genetically distinct subspecies of which it comprises. SDMs incorporated both sea surface and benthic (seafloor) climate layers to recreate discrete influences of these habitats during the drifting larval and benthic juvenile and adult life history phases. Principle component analysis (PCA) was used to infer environmental variables to which individual subspecies were adapted. SDM projections of present‐day habitat suitability were compared with predictions for the year 2,100, under the RCP 8.5 climate change scenario. Results: In the PCA, salinity best explained P. h. megasculptus habitat suitability, compared with current velocity in P. h. rubellus and sea surface temperature in P. h. homarus. Drifting and benthic life history phases were adapted to different combinations of sea surface and benthic environmental variables considered. Highly suitable habitats for benthic phases were spatially enveloped within more extensive sea surface habitats suitable for drifting larvae. SDMs predicted that present‐day highly suitable habitats for P. homarus will decrease by the year 2,100. Main conclusions: Incorporating genetic structure in SDMs showed that individual spiny lobster subspecies had unique adaptations, which could not be resolved in species‐level models. The use of sea surface and benthic climate layers revealed the relative importance of environmental variables during drifting and benthic life history phases. SDMs that included genetic structure and life history were more informative in predictive models of climate change effects. [ABSTRACT FROM AUTHOR]

Trait‐based approaches are increasingly used as a proxy for understanding the relationship between biodiversity and ecosystem functioning. Macrobenthic fauna are considered one of the major providers of ecosystem functions in marine soft sediments; however, several gaps persist in the knowledge of their trait classification, limiting the potential use of functional assessments. While trait databases are available for the well‐studied North Atlantic benthic fauna, no such trait classification system exists for Australia. Here, we present the South Australian Macrobenthic Traits (SAMT) database, the first comprehensive assessment of macrobenthic fauna traits in temperate Australian waters. The SAMT database includes 13 traits and 54 trait‐modalities (e.g., life history, morphology, physiology, and behavior), and is based on records of macrobenthic fauna from South Australia. We provide trait information for more than 250 macrobenthic taxa, including outcomes from a fuzzy coding procedure, as well as an R package for using and analyzing the SAMT database. The establishment of the SAMT constitutes the foundation for a comprehensive macrobenthic trait database for the wider southern Australian region that could facilitate future research on functional perspectives, such as assessments of functional diversity and changes to ecosystem functioning. [ABSTRACT FROM AUTHOR]

Novel 3-D passive particle tracking experiments were performed in the northwest Atlantic to elucidate connectivity among areas closed to protect vulnerable marine ecosystems. We examined (1) the degree of vertical movement of particles released at different depths and locations; (2) the location of potential source populations for the deep-sea taxa protected by the closures; and (3) the degree of functional connectivity. A long-term oceanographic dataset (EN4) was queried to characterize the temperature and salinity regimes in each of the closed areas as a basis for interpreting recently published climate change projections. Using the Parcels Lagrangian particle tracking framework and the BNAM hydrodynamic model, we found enhanced connectivity over previously developed 2-D models and unexpected, current-driven, strong (to a maximum of about 1340 m) downward displacement at depth (450, 1000 and 2250 m), with weaker upward displacement except for the release depth of 2250 m which showed upward movement of 955 m with a drift duration of 3 months. The current velocities create down-stream interdependence among closed areas and allow redundancy to develop in some of the areas of the network, with some of the larger areas also showing retention. Source populations for sponges in the upstream closure are likely in adjacent waters of the Canadian continental shelf. Collectively this information can be used to inform management decisions related to the size and placement of these closed areas, and vertical velocity surfaces have potential for use in species distribution modeling of benthic species and habitats. [ABSTRACT FROM AUTHOR]

The occurrence of microplastics in the environment, together with increasing temperatures as a result of climate change, has become a global concern. However, few reports are available on microplastic ingestion in lower benthic marine animals sampled from their natural environment during different seasons of the year. This study investigated microplastic uptake in Dotilla fenestrata (Hilgendorf 1869), Holothuria cinerascens (Brandt 1835)and Pyura stolonifera (Heller 1878)sampled from their natural environment during winter and summer. Animals sampled were cleaned of sand and attached animals and transported on ice to the laboratory. D. fenestrata, H. cinerascens (guts), and P. stolonifera (soft tissues) were digested in 10% potassium hydroxide (KOH) solution for 24 hours at 60°C and analysed for microplastics. The per cent occurrences of microplastics found in sampled animals were more than 95 % in both seasons, and fibres were the most predominant microplastic types found. Season significantly affect microplastic uptake in Dotilla fenestrata (t-test: t-value = 2.915, df = 58, p = 0.01) while it had no effect in H. cinerascens and P. stolonifera sampled. A significantly higher number of microplastics were found in D. fenestrata than H. cinerascens (ANOVA HSD: df = 2, p = 008) and P. stolonifera (ANOVA HSD: df = 2, p = 000) in winter while H. cinerascens had a higher number of microplastics than P. stolonifera in summer (ANOVA HSD: df = 2, p = 002). These results show that microplastic uptake in some ectotherms may be season-dependent and that feeding method impacts the accessibility of marine invertebrates to microplastics in their environment. [ABSTRACT FROM AUTHOR]

Meiofauna includes an astonishing diversity of organisms, whose census is far from being complete. Most classic ecological studies have focused on hard-bodied Ecdysozoan taxa (notably Copepoda and Nematoda), whose cuticle allows determination at species-level after fixation, rather than soft-bodied, Spiralian taxa, which most often lose any diagnostic feature in fixed samples. Yet, metabarcoding studies have recently revealed a species-richness of soft-bodied taxa comparable, and in cases superior, to that of Copepoda and Nematoda together. However, given objective difficulties inherent to their study, which necessarily has to be performed on living individuals, and their limited utilisation for ecological and applicative research, taxonomic expertise on soft-bodied organisms has declined over the years, and diversity of these phyla in most areas of the world is presently completely unknown. Here we present an expert-based survey of current knowledge on the composition and distribution of soft-bodied meiofaunal taxa in Italy, with special references to the predominantly or exclusively meiobenthic phyla Gastrotricha, Gnathostomulida, Platyhelminthes, Rotifera, Xenacoelomorpha, and macrofaunal taxa with conspicuous meiofaunal representatives (Annelida, Mollusca and Nemertea). A total of 638 described species have been reported from Italian coasts; furthermore, the existence of a large number of undescribed species is mentioned. Knowledge of Annelida, Gastrotricha, and Rotifera appears particularly detailed, placing Italy among the best-known country worldwide. In contrast, knowledge of Platyhelminthes and Xenacoelomorpha appears patchy, and limited to few areas. Sampling effort has been uneven, with most species recorded from the Tyrrhenian Sea, while large sections of the Adriatic and Ionian seas have been poorly explored. Results highlight the role that Marine Biological Stations, notably the Zoological Station "Anton Dohrn" in Naples, have had in promoting the study of soft-bodied taxa in Italy. [ABSTRACT FROM AUTHOR]