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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]

Anthropogenic activities alter the rivers' hydromorphological characteristics, affecting the ecosystems. River continuum interruption is identified as a principal cause of longitudinal quality variation. Macroinvertebrates, the most common biological quality indicator, are usually coupled with hydromorphological alteration assessment protocols. Environmental DNA (eDNA) metabarcoding is a recent advance in biomonitoring, complementing classical assessment, responding to time and cost-efficiency limitations. This study assesses the hydromorphological effects of two barriers (sluice and rock ramp) in a large Mediterranean modified river on the structure of macroinvertebrate assemblages using the classical method, coupled with eDNA metabarcoding while it further correlates them with the alteration of the riparian zone. Samplings were conducted at three stations for each barrier, one upstream and two downstream, during high and low flow periods. A range of statistical tests were performed for the assemblages' comparison, the diversity indices and the investigation of spatial and temporal patterns. The findings include differences among communities' composition for the two approaches with a moderate overlap between eDNA and classical taxonomy. The ramp had lower influence on biota in comparison to the sluice. Regarding the spatial pattern, no significant differences were revealed for both methods, but it could be attributed to the barriers' operation extent. As for a temporal pattern, there was a difference between the two methods and, while no separation was noted among the sites as a sum, site-specific differences were found. If some problems concerning the taxonomic assignment of ASVs, the sampling methodology and the primers selection are surpassed, eDNA proves a valuable tool. [ABSTRACT FROM AUTHOR]

• The Aptian-Albian benthic foraminifera of the Central Taurides are documented. • Stratigraphic ranges of the Aptian–Albian benthic foraminifera are discussed. • The new species " Palaeocornuloculina " taurica is described from the Aptian–Albian. The Lower Cretaceous carbonate successions of the Tauride Carbonate Platform(s) (TCP) are characterized by mostly restricted inner platform facies. The record of these stages is limited owing to frequent exposure of the platform to subaerial and supratidal settings during the Early Cretaceous. This study focuses on the Lower Cretaceous (Aptian–Albian) successions outcropping at two localities in the Geyik Dağı and Anamas Dağ areas, Central Taurides. These successions exhibit a peritidal shallowing upward trend evidenced by the dominance of mud-rich microfacies, lamination, fenestrae, oncoids, and changes in fossil content (benthic foraminifera, dasycladalean algae, rudists, etc.). The stratigraphic subdivisions of the studied successions utilize index taxa in the benthic foraminiferal assemblages which are documented and illustrated. Assemblage I (lower Aptian) is mainly characterized by Voloshinoides murgensis and Debarina hahounerensis ; Assemblage II (upper Aptian) by Mesorbitolina parva, Carseyella tunesiana and " Arenobulimina " geyikensis ; and Assemblage III (Albian) by Mesorbitolina gr. texana , Protochrysalidina elongata and Pseudonummoloculina heimi. Ranges and stratigraphic significance of some species through the Lower Cretaceous are discussed. Due to less favorable environmental conditions, the strata in the Anamas Dağ area have a low-diversity benthic foraminifera fauna and sparse macrofossils. In contrast, the strata in the Geyik Dağı area host rich and diverse larger benthic foraminifera as well as rudist bivalves and gastropods. A new species, " Palaeocornuloculina " taurica belonging to the family Ophthalmidiidae is described from these foraminifera-rich upper Aptian–Albian strata in the Geyik Dağı area. [ABSTRACT FROM AUTHOR]

[Display omitted] • Effects of the creation of land-water transitions on macroinvertebrates were tested. • Effects of new land-water transitions were mediated by hydrological connectivity. • Benthic fauna biomass was significantly higher in sites disconnected from open water. • Emergent insect biomass was significantly higher in disconnected sites. Land-water transition areas play an important role in the functioning of both aquatic and terrestrial ecosystems. Enhancing habitat complexity and heterogeneity by restoring or adding land–water transition areas to degraded aquatic ecosystems can be effective management to stimulate productivity by lower trophic levels – and hence increase food availability for biota of conservation interest, including fish and birds. Here, we studied whether hydrological connectivity can be used as an environmental indicator (connected or disconnected) for the development trajectories of newly constructed land–water transition areas in shallow lakes. We capitalized on a large-scale restoration project called "Marker Wadden", which created new land–water transition areas with and without hydrological connectivity in a degraded shallow lake in the Netherlands (Lake Markermeer). We compared how the new areas with and without hydrological connectivity developed with respect to abiotic parameters and biomasses of benthic, pelagic, and emergent macroinvertebrates. In sites disconnected from the open water, water depths became significantly lower than in hydrologically connected sites during summer, likely due to evaporation. In these shallower waters, daytime temperatures and organic matter content of the sediment were higher, while dissolved oxygen concentrations remained sufficient. Therefore, biomasses of benthic macroinvertebrates and emergent insects became higher in the disconnected sites. These lower trophic levels could provide higher food availability for benthivorous and insectivorous birds, while remaining inaccessible to fish. This puts forward that hydrological connectivity (connected or disconnected) can be used as an environmental indicator for aquatic food web development trajectories, and that it regulates relative food availability for fish and birds. Restoring land–water transition areas without hydrological connectivity provides higher biomasses of lower trophic levels, which are only accessible to birds. Restoring areas with hydrological connectivity results in relatively lower biomasses of invertebrates, but these provide food to birds feeding on invertebrates, and fish and fish-eating birds. Creating areas including both types of land–water transition zones, connected and disconnected to open water can benefit fish and birds of both feeding guilds. [ABSTRACT FROM AUTHOR]

The advent of bioturbation in the early Paleozoic and the subsequent intensification of sediment mixing by benthic animals dramatically altered marine ecosystems and biogeochemical cycling. However, the timing and pace of the transition to ubiquitous well-bioturbated sediments in the uppermost seafloor remain under debate. Skolithos 'piperock', a classic Cambrian ichnofabric composed of densely packed vertical burrows, has often been invoked as evidence for an early ramping up of infaunalization and intense sediment disruption, but its biogeochemical impact has not been quantitatively explored in this context. Here, we relate high-resolution sedimentological and bioturbation data from 182 m of the Zabriskie Quartzite of the Death Valley region of California—a locality known for hosting piperock—to a new numerical three-dimensional diagenetic model to investigate the effect of Skolithos on sediment oxygen penetration and organic carbon remineralization. Our modeling indicates that increasing Skolithos burrow density substantially expands the local oxic zone and, in contrast with other modes of bioturbation, can also result in decreased sulfur oxidation. However, our field data indicate true 'piperock' is relatively scarce in the Zabriskie Quartzite, even among horizons that are of identical lithology to those containing piperock and that house individual Skolithos burrows. This suggests that, in the Zabriskie and potentially other Cambrian piperock-bearing units, the broader impact of piperock on seafloor ecology, chemistry, and sediment properties may have been restricted in scope. • Bioturbation field data (ii, BPBI) is used to ground diagenetic modeling. • Field data show piperock is rare even in a classic 'piperock' unit. • A new 3D numerical diagenetic model is used to quantify the effect of bioturbation. • Skolithos burrows increase sediment oxygenation but decrease sulfur oxidation. [ABSTRACT FROM AUTHOR]

Oceanic anoxia is regarded as the immediate cause of the Late Devonian Frasnian–Famennian (F–F) bio-crisis and Annulata bio-event. The oceanic anoxia has been linked to continental weathering and input. However, some previous findings indicate oxic marine environments during the F–F bio-crisis. Moreover, the relative impact of terrestrial input on the Late Devonian oceanic redox conditions, when comparing a bio-crisis and a bio-event, remains unknown. Here, we present a decoupled oceanic redox model suggesting the redox conditions were different between shallow and deep water columns during the F–F bio-crisis, i.e., intensified euxinia in the photic zone and a more oxygenated condition at the seafloor. Geochemical (biomarker and trace metal) and sedimentologic evidence from the Late Devonian Seaway, eastern U.S., indicate that the shallow-deep decoupled oceanic redox conditions were regulated by terrestrial weathering and input. During the F–F bio-crisis, land nutrient input intensified photic zone euxinia through eutrophication, while hyperpycnal flows oxygenated seafloors. After the F–F bio-crisis, the seafloor redox conditions shifted from oxygenation to silled euxinia, and the watermass became hydrographically restricted. During this post-F–F interval, the euxinia at the seafloor intensified due to land nutrient runoff during the Annulata bio-event. Importantly, the land weathering and input during the F–F bio-crisis were more prominent than during the Annulata bio-event. This resulted in widespread and intense photic zone euxinia during the F–F bio-crisis, relative to the seafloor euxinia that developed in restricted areas during the Annulata bio-event. Our decoupled oceanic redox model may explain the preferential decimation of shallow-water organisms during the F–F bio-crisis. The seafloor euxinia during the Annulata bio-event may provide a niche for the turnover of benthic faunas adapting to low oxygen levels. This study suggests that continental weathering and influxes played an important role in regulating oceanic oxygen evolution and impacting life evolution and bio-diversity. • PZE intensified but seafloor became more oxygenated in the Late Devonian Seaway during the F–F bio-crisis. • Seafloor oxygenation may be caused by hyperpycnal flows. • Land input caused redox changes during the F–F bio-crisis and Annulata bio-event. • Seafloor shifted from oxygenation to silled euxinia after the F–F bio-crisis. • The redox model may explain the preferential decimation of shallow-water organisms in the Late Devonian Seaway during the F–F bio-crisis. [ABSTRACT FROM AUTHOR]

Along the northern Mid-Atlantic Ridge (nMAR), in habitats under moderate (<10 °C) hydrothermal influence on the Snake Pit vent field (SP), large assemblages dominated by Bathymodiolin mussels remain poorly characterised, contrary to those in warmer habitats dominated by gastropods and alvinocaridid shrimps that were recently described. In this study, we assessed and compared the population structure, biomass, diversity and trophic interactions of two Bathymodiolus puteoserpentis assemblages and their associated fauna at SP. Three sampling units distanced by 30 cm were sampled in 2014 during the BICOSE cruise at the top of the Moose site (''Elan'' site), while few meters further down three others, distanced by ∼1 m were obtained in 2018 during the BICOSE 2 cruise at the edifice's base. We observed a micro-scale heterogeneity between these six sampling units partially explained by temperature variations, proximity to hydrothermal fluids and position on the edifice. Meiofauna dominate or co-dominate most of the sampling units, with higher densities at the base of the edifice. In terms of macrofauna, high abundance of Pseudorimula midatlantica gastropods was observed at the top of the vent edifice, while numerous Ophioctenella acies ophiuroids were found at the base. Contrary to what was expected, the apparent health and abundance of mussels seems to indicate a current climax stage of the community. However, the modification of B. puteoserpentis isotopic signatures, low number of juveniles decreasing over the two years and observations made during several French cruises in the study area raise questions about the fate of the B. puteoserpentis population over time, which remains to be verified in a future sampling campaign. • Assemblage heterogeneity at different scales linked to fluid proximity & location. • Meiofaunal groups dominated. Macrofaunal disparity between top and base of edifice. • Low number of mussel juveniles over time questions the future of the population. [ABSTRACT FROM AUTHOR]

In this study, Holocene paleoenvironmental changes were interpreted based on benthic foraminifers from a core (39°20′S-61°27′W) extracted from the Argentine Continental Shelf close to the Bahia Blanca Estuary, in the south of Buenos Aires Province. Foraminiferal fauna was determined, and found to include 44 species of 22 genera. From micropaleontological and sedimentological analysis, paleoenvironmental changes during the middle-late Holocene were recognized. Two stages were determined: from 8319–8045 to 7836-7623 Cal. yrs BP, the sediments reflected a shallow environment with estuarine conditions and low energy, enabling determination of a coastal depositional environment. As from ca. 7836–7623 up to ca. 651-557 Cal. yrs BP, the sediments indicated a passage towards to a shallow shelf environment with great marine influence, displaying a high degree of energy and oxygenation, which may have been related to a rise in sea level ca. 7836 -7623 Cal. yrs BP. The detailed study of the benthic foraminiferal fauna presented herein and the sedimentological and chronological analysis performed on the continental shelf next to the Bahía Blanca Estuary provide further proof of the relative location of the mean sea level during the middle Holocene transgressive hemicycle in Argentina. [ABSTRACT FROM AUTHOR]

Organisms with external phosphatic shells diversified and became abundant at the beginning of the Early Paleozoic but gradually declined and were rare by its end. The decreasing availability of phosphorus in oceans is thought to be responsible for this evolutionary trend. Responses of organisms to changes in the phosphorus cycle can be traced to the late Neoproterozoic, and likely had a significant role in the Cambrian explosion, the Great Ordovician Biodiversification Event (GOBE), and the Devonian nekton revolution. Effective use of phosphorus by vertebrates during the Devonian nekton revolution caused the phosphorus pool to shift from benthic external shells to the skeletons of pelagic vertebrates, and moved the marine faunas toward the dominance patterns and ecological structure of the Modern Evolutionary Fauna. Phosphorus had a key role in the Early Paleozoic radiation events. The decline of organisms with external phosphatic shells was caused by an increasing inaccessibility of phosphorus during the Early Paleozoic. The dominant phosphorus pool shifted from benthic groups to pelagic vertebrates during the Devonian. Recycling of phosphorus in the marine environment substantially moved phosphorous into the water column. The Devonian phosphorus pool pattern is one of the key factors controlling marine diversity and ecological patterns up to the present time. [ABSTRACT FROM AUTHOR]

• Picophytobenthos are potential contributors of harmful secondary metabolites. • Water quality is potentially threatened by overwintering benthic algae. • Overwintering stage is the critical period for algae control. Overwintering benthic algae not only directly impact drinking water safety, but also affect the algae recruitment in warm spring seasons. Thus, understanding the characteristics of overwintering benthic algae can provide scientific references for formulating preventative strategies of reasonable water resource. However, they have received less attention. In this study, the spatiotemporal variation of benthic algae and their harmful secondary metabolites were studied from autumn to summer in Qingcaosha Reservoir. Benthic algae (picophytobenthos accounting for 55.42%) had a high biomass during overwintering, and the groups of overwintering benthic algae included pico-Cyanobacteria, pico-Cryptomonas, pico-Chlorophyta, pico-Diatoms, Cyanobacteria, Chlorophyta, Cryptomonas and Diatoms , which were consistent with the planktonic algae species in warm seasons. In oligotrophic or mesotrophic water bodies, micronutrients of iron and manganese were key nutrient factors influencing the biomass of benthic algae. Furthermore, picophytobenthos were important potential contributors of harmful secondary metabolites. The content of microcystins, anatoxin-a, geosmin and 2-methylisoborneol in sediment were 15.75 µg/kg·FW, 48.16 µg/kg·FW, 3.91 ng/kg·FW, and 11.76 ng/kg·FW during winter, which had potential to be released into water bodies to impact water quality. These findings indicate that water quality monitoring programs need to consider sediment in winter as a potential source of toxins and preventative measures to prevent excessive proliferation of algae should be implemented in winter. [Display omitted]. [ABSTRACT FROM AUTHOR]

A 4000 m2 steel slag (SS) bed was constructed in the brackish water area for water quality remediation in 2017. This study demonstrates the ability of SS to stimulate carbon sequestration based on one-year pilot and in situ SS beds. The pilot SS bed increased the soil organic matter (SOM) content by 5.1 wt %, sequestering sewage-derived organic carbon (C org) as SOM. Notably, recalcitrant SOM increased by over 40 %, indicating long-term retention of C org in the sediment. SS increased the C org density in the sediment by approximately two times, exceeding that of the dense carbon ecosystems found in global seagrass meadows and peatlands. The complexation of the low-molecular-weight C org with iron in SS was the main pathway for C org fixation. Benthic animal investigations showed that SS capping fostered an anaerobic fauna ecosystem, aiding biotic C org sequestration. Algae proliferation on the SS bed suggested complex benthic ecosystems with photosynthetic carbon fixation. Overall, SS beds offer a new abiotic carbon sequestration pathway with environmental restoration benefits; in situ capping with metal-containing material is potentially more economical and sustainable compared to traditional landfilling. • Steel slag (SS) bed enhanced carbon sequestration in coastal sediments. • SS increased the organic carbon (C org) density in sediments by two times. • SS slowed down the degradation of C org by polymerization. • SS bed functioned for benthic fauna settlement and algal proliferation. [ABSTRACT FROM AUTHOR]

The significant changes in seafloor conditions during the Ediacaran-Cambrian transition presumably bear on the autecology of the benthic animals living in this time interval. However, little evidence shows morphological modifications and life strategy transitions in early animals in response to this substrate revolution. Dinomischidae is a family of diploblastic-grade with a sessile, suspension-feeding lifestyle, which includes Xianguangia , Daihua and Dinomischus. Here, we redescribe Calathites spinalis , a poorly known taxon from the early Cambrian (Epoch 2, Age 3, ∼518 Ma), as a new member of this family. Our new material reveals that the body of C. spinalis consists of a stalked calyx and 18 tentacle-sheath complexes, which is a typical trait of dinomischids. Our phylogenetic analyses recover Calathites as a sister group of Xianguangia and Daihua and support dinomischids being a monophyletic group. Members of dinomischids possess unique attachment structures that vary in shape and size, presenting a unique example of morphological adaptations of early sessile animals during the Cambrian substrate revolution. Comparison with early metazoan fossils reveals that dinomischids and other early basal metazoans lagged behind sessile bilaterians in terms of adaptations to substrate changes; the former tends to persist with attachment strategies adapted to Proterozoic-style seafloor conditions that were relatively firm. [Display omitted] • Exquisite fossils of Calathites exhibit traits typical of dinomischids. • Dinomischids have diverse types of attachment structures. • Dinomischids are categorized as shallow sediment stickers adapted to firm Proterozoic-style seafloor conditions. • Insights into adaptations of Chengjiang sessile metazoans to the Cambrian substrate revolution. [ABSTRACT FROM AUTHOR]

During the Devonian, the Gondwana occupied areas close to the South Pole and hosted many epicontinental seas, with a benthic fauna dominated by brachiopods. Due to the limited preservation of chronostratigraphic markers (e.g. conodonts and graptolites) on this paleocontinent, the study of ichnology and palynology has helped to track Devonian events in the South American and African continents. In the Paraná Basin, there are records of several transgressive and regressive cycles that occurred throughout the Devonian. Thus, this study considers changes in the size and shape of the brachiopod (Australocoelia palmata Morris and Sharpe, 1846) in the Lower-Middle Devonian Chapada Group (Early Pragian-Eifelian) in the state of Mato Grosso, Brazil as a proxy for paleoenvironmental change. Morphometric analysis (length, width and length x width) shows that fossils collected in transgressive strata (Lower Unit 2, Chapada Group) had the most diverse sizes. However, fossils from a regressive context (Upper 2 Unit, Chapada Group) tend to be 25% smaller in length and width. This case of dwarfism in Australocoelia palmata may be related to changes in the composition of marine waters, resulting from an anoxic moment, driven by sea-level fluctuations. • Transgressive and regressive cycles impacted the brachiopod fauna of the Paraná Basin. • Anoxic conditions in the Devonian of the Paraná basin hampered the growth of brachiopods. • The morphometric reduction of brachiopods indicates paleoecological stresses during the Emsian. [ABSTRACT FROM AUTHOR]

Studies on the bathyal fauna of northern Pacific waters suggested that a transition or boundary between the North Pacific Province and Central Pacific Provinces would be found somewhere along the Emperor Seamount Chain. Strong currents flow west to east across the seamount chain in a region known as the Main Gap and it was proposed that any larvae produced either north or south of the Main Gap would not be capable of crossing the gap. An expedition to test the hypothesis that a faunal change would be found in the vicinity of the Main Gap was conducted in 2019. Eleven ROV dives were conducted, one on an unnamed seamount at the southern edge of Hess Rise, and 10 dives on seven seamounts along the Emperor Seamount Chain. Six dives were on seamounts north of the Main Gap, while four (including the dive on Hess Rise) were on the southern side. Of the six northern dives, three were at deeper depths (∼2000–1800 m) and three were shallower (∼1500–1100 m); of the southern dives two were at the deeper depths and two were shallower. One shallower dive occurred on Jingu Seamount, situated on the southern edge of the Main Gap. Analysis of the fauna from both collected specimens and annotations of the dive video produced four clusters: a , the four dives south of the Main Gap; b , the three deeper dives north of the Main Gap; c , the shallower dive at Jingu Seamount; and d , the four shallower bathyal dives north of the Main Gap. It was concluded that the bathyal fauna underwent a significant change from north to south across the area of the Main Gap and the adjacent Small Gap, in the area of 37–39 °N, covering distances as small as 75 km or as much as 400 km. [ABSTRACT FROM AUTHOR]

The subtidal soft-sediment macrobenthos of a residential coastal marina's 25 ha through-flow canal system was investigated in relation to that in the adjacent natural waterways. The marina, developed from a polluted brownfield island in a warm-temperate estuarine bay, straddles the interface between the axial estuarine channel and a smaller backwater creek separating the island from the mainland, one entrance/exit connecting the canals to each water mass. Although they shared a common pool of taxa, an epibenthic cerithioid microgastropod dominated the axial channel as a whole, a subsurface paraonid polychaete likewise the backwater creek, whilst, unusually, sediment/water interface crustaceans dominated the whole marina canal system, especially the amphipods Ampelisca and Grandidierella. In contrast, the abundance of opportunistic annelids in the marina was very low. Whilst coastal marinas have generally been considered ecological disasters, biodiversity in this one's canals was unusually high at 104 observed invertebrate taxa; 97% of those achieving >25 m−2 in the local axial estuarine channel also occurred in the marina, and additionally its canals supported a number of uncommon taxa not otherwise known from the estuarine bay. This South African marina atypically appears to constitute a biodiversity asset, the more valuable because of its brownfield-site origin; and such appropriately constructed and managed through-flow marinas could form potential refuges for threatened estuarine and coastal soft-sediment benthos. It is concluded that only new marinas with a through water flow should be permitted to be located in ecologically sensitive or conservationally important areas and that regular monitoring of soft-sediment benthos should form an essential part of marina management regimes. [Display omitted] • Subtidal soft-sediment macrobenthos of through-flow coastal marina canals studied. • 97% of common taxa in adjacent natural estuarine channel also present in marina. • Unusually, marina-canal benthos dominated by crustaceans, particularly amphipods. • The 25 ha of brownfield canals biodiverse, with >100 invertebrate macrobenthic taxa. • Such coastal marinas could provide refuges for local macrobenthic biodiversity. [ABSTRACT FROM AUTHOR]

Seamounts can have strong influence on the dynamics and production of waters surrounding them, sometimes creating a kind of oasis effect. To assess to what depths and under what conditions this effect may persist on seamounts, we analysed the fauna and recent history of the Valencia Seamount (VS), a deep, small seamount (summit depth: 1056 m) from an oligotrophic zone of the Mediterranean Sea. The (living) epibenthic fauna of the VS summit (up to 1300 m) was composed of filter feeders, surface deposit feeders and carnivores (63 species), structured in a trophic chain as indicated by the high positive relationship (r2 0.502) between the δN15and δC13 of the fauna analysed. This trophic linearisation (compared with Catalan and NW Mallorca slope sites at similar depths) may optimise the energy flux reaching the seamount, with rather high %TOC (0.93–1.19%) and C/N (5.0–5.5) in July. The Valencia Seamount can also act as a reservoir zone for fish (grenadiers: Nezumia aequalis , and Hymenocephalus italicus) and shrimps (Plesionika martia), which are distributed at shallower depths on adjacent slopes, where they are exploited. The specimens caught were mainly juveniles, suggesting that these species may rather form pseudopopulations. Tuna and cetaceans were regularly sighted on the surface of VS during a specific period of the year (June–July). Reconstructing the recent history of Valencia Seamount (MC2 sediment core taken at 1151 m in 2021) we evidenced a decline of zooplankton pteropods (primary consumers) since ca. the 1960s (MC2 dating after 210Pb, metals and microplastic analyses), linked to a decline of Si in sediments suggesting a decrease in primary production due to a decrease in rainfall and river runoff. An increase of vorticity (ω + values), i.e. of cyclonic gyres, and currents after the 1970s over the summit probably increased resuspension of organic matter, which in turn may enhance zooplankton aggegations at VS summit. We hypothesise that this would explain the parallel increase in mesopelagic myctophids in MC2 (from otolith records). Sediments of the Valencia seamount recorded several historical changes. Reconstruction studies carried out in oceanic areas can therefore help to understand the history and improve the management of fragile systems such as seamounts. • Valencia Seamount (VS) fauna composed mainly by filter and surface deposit feeders. • VS webs structured as chains (high correlation δN15 vs δC13) optimizing energy flux. • The VS acts aggregating mobile fauna, distributed shallower at adjacent slopes. • Pteropods decline (primary consumers) suggests an historic fall of primary production. • Decrease of primary production attributable to a decline of rainfall and river runoff. [ABSTRACT FROM AUTHOR]

[Display omitted] • Spatial patterns of benthic fauna diversity in the Yellow River, China were determined. • Factors affecting benthic fauna biodiversity shifts in different sections of the river were determined. • Spatial scales and environmental factors jointly affected biodiversity in intermediate spatial extents. • Scales of studies affected estimates of Spatial distributions of Benthic Invertebrates. One of the fundamental objectives in ecology is to investigate the ecological processes and associated factors governing the abundance and spatial distribution patterns of biodiversity. However, the reaction of biological communities to environmental degradation remains relatively unknown, even for ecologically crucial communities like macroinvertebrates in aquatic ecosystems. Here, we sampled 117 locations to quantify relative contributions of geographical and environmental factors, including water quality, land use, climate, and hydrological factors, to determine the absolute and relative compositions of macroinvertebrate communities and their spatial distribution in the Yellow River Basin (YRB), the sixth-longest river system on Earth. We assessed relative roles of species sorting and dispersal in determining macroinvertebrate community structure along YRB. Our results demonstrated that alpha and beta diversity indices showed an increase from the up- to low-reaches of YRB. The middle and low-reaches exhibited elevated species diversity and both regions exhibited relatively stable community compositions. The biodiversity of macroinvertebrates was influenced by a combination of geographical factors and environmental variables, with environmental factors predominantly serving as the principal determinants. Results of multiple linear regression and variance decomposition showed that the effect of environmental factors was approximately three times greater than that of spatial factors. These findings provide support for the hypothesis that species sorting, driven by environmental gradients, plays a significant role in shaping the community structure of macroinvertebrates in running water ecosystems at the basin scales. Moreover, the factors contributing to substantial shifts in biodiversity across different segments of YRB indicate that distinct river sections have been influenced by varying stressors, with downstream areas being more susceptible to the impacts of water pollution and urbanization resulting from human activities. [ABSTRACT FROM AUTHOR]

The studied middle-upper Eocene Garet Gehannam section exhibits moderate macrofossil diversity and notably high macrofossil abundance. Eleven molluscan species were identified and described, including five bivalves and six gastropods. Three macrobenthic assemblages were recognized: The turritelline-dominated assemblage, Carolia placunoides assemblage and Turkostrea multicostata assemblage. The Turritelline-dominated assemblage indicates high-nutrient environments, which typically exhibit normal to slightly below normal marine salinities, low sedimentation rates, and high-energy environments. Carolia placunoides assemblage indicates brackish water environment during times of sea level regression. Turkostrea multicostata assemblage provides compelling evidence of a prevailing hot climate and an environment rich in calcium, characterized by nutrient-rich water and low to moderate energy levels and high light availability. The investigation of the articulation of Carolia placunoides Cantraine1838 and Turkostrea multicostata (Deshayes, 1818) shells strongly suggests a parautochthonous assemblage. In terms of paleobiogeography, Turkostrea multicostata (Deshayes, 1818) first appeared during the Paleocene in the southern Tethys, specifically in Tunisia and Algeria, as well as in the Trans-Saharan Seaway in Mali. Consequently, its paleobiogeographic distribution can be allied to current circulation along the Tethys Ocean, firstly from its original area in the southern Tethys regions and Trans-Saharan Seaway to neighboring regions of the southern and northern Tethys, as well as the West Africa provinces. The paleobiogeographic map of the identified species shows that the identified species were prevailing in two bioprovinces during the middle – late Eocene epochs: i) the North-West, North, and South Tethyan Margins Province, ii) and the West Africa Province. • Eleven molluscan species have been identified from the middle-late Eocene Fayoum succession. • The paleobiogeography of the identified species suggests an affinity with the Tethys region. • The macrofaunal assemblages suggest progress the shallow up conditions. • The migration routes of the identified molluscan species have been studied. [ABSTRACT FROM AUTHOR]

Understanding the ways in which human groups use the environment for their survival is one of the main fields of study in Prehistory. Subsistence strategies, understood as the set of techniques, processes and activities through which human groups organise the tasks related to their survival, are a fundamental element for understanding the economic and sociocultural processes derived from these practices in the past. In this sense, archaeozoological and taphonomic studies are the main tool to reconstruct the ways in which our ancestors acquired, processed, consumed, and managed meat resources for their survival. In this research we examine the ways in which hunter-gatherer groups in the Spanish Cantabrian region exploited ungulates through a palaeoecological and palaeoeconomic analysis of a total of 32 archaeological levels at 19 sites dated between 20 and 17 ky cal BP. To this end, through research on faunal resources in this region, we will address the ways in which prey was acquired and transported, the age ranges, the seasonality of the captures and the nutritional energy contribution to the diet of the human groups, taking into account the cost of acquiring them, thus generating an updated view of subsistence strategies in the Cantabrian region. • Palaeoecological and palaeoeconomic analyses allow to determine subsistence strategies in the Lower Magdalenian. • The Magdalenian groups hunted mainly red deer, being the prey that provided the greatest amount of caloric energy. • Environment and orography of the sites, together with the search, hunting and handling time, influence the subsistence. • Magdalenian hunter-gatherers tend to hunt the most economically beneficial animals first. [ABSTRACT FROM AUTHOR]

Understanding the responses of organisms to different environmental drivers is critical for improving ecosystem management and conservation. Estuarine ecosystems are under pressure from multiple anthropogenic stressors (e.g. increasing sediment and nutrient loads, pollution, climate change) that are affecting the functions and services these ecosystems provide. Here, we used long-term estuarine benthic invertebrate monitoring data (∼30 year time-series) to evaluate the responses of macrobenthic invertebrate communities and indicator species to climatic, oceanic, freshwater, and local environmental drivers in New Zealand estuaries. We aimed to improve our ability to predict ecosystem change and understand the effects of multiple environment drivers on benthic communities. Our analyses showed that the abundance and richness of macrobenthic fauna and four indicator taxa (bivalves known to have differing tolerances to sediment mud content: Austrovenus stutchburyi , Macomona liliana , Theora lubrica , and Arthritica bifurca) responded to unique combinations of multiple environmental drivers across sites and times. Macrobenthic responses were highly mixed (i.e., positive and negative) and site-dependent. We also show that responses of macrobenthic fauna were lagged and most strongly related to climatic and oceanic drivers. The way the macrobenthos responded has implications for predicting and understanding the ecological consequences of a rapidly changing environment and how we conserve and manage coastal ecosystems. • Long-term estuarine monitoring data (∼30 yrs) was used to evaluate the responses of macrofauna to environmental drivers. • Macrofauna responded to unique combinations of multiple environmental drivers. • Macrofaunal responses to environmental drivers were idiosyncratic and site-mediated. • Macrofaunal responses were mostly related to lagged permutations of climatic and oceanic drivers. • We highlight the complexity of predicting macrofauna responses to environmental change. [ABSTRACT FROM AUTHOR]

Bifenthrin (BF) is ubiquitous in aquatic environments, and studies have indicated that environmental concentrations of BF could cause neurotoxicity and oxidative damage in fish and decrease the abundance of aquatic insects. However, little information is available on the toxicity of BF in freshwater benthic mollusks. Bellamya aeruginosa (B. aeruginosa) is a key benthic fauna species in aquatic ecosystems, and has extremely high economic and ecological values. In this study, larval B. aeruginosa within 24 h of birth were exposed to 0, 30 or 300 ng/L of BF for 30 days, and then the toxic effects from molecular to individual levels were comprehensively evaluated in all the three treatment groups. It was found that BF at 300 ng/L caused the mortality of snails. Furthermore, BF affected snail behaviors, evidenced by reduced crawling distance and crawling speed. The hepatopancreas of snails in the two BF exposure groups showed significant pathological changes, including increase in the number of yellow granules and occurrence of hemocyte infiltration, epithelial cell thinning, and necrosis. The levels of ROS and MDA were significantly increased after exposure to 300 ng/L BF, and the activities of two antioxidant enzymes SOD and CAT were increased significantly. GSH content decreased significantly after BF exposure, indicating the occurrence of oxidative damage in snails. Transcriptomic results showed that differentially expressed genes (DEGs) were significantly enriched in pathways related to metabolism and neurotoxicity (e.g., oxidative phosphorylation and Parkinson disease), and these results were consistent with those in individual and biochemical levels above. The study indicates that environmental concentration of BF results in decreased survival rates, sluggish behavior, histopathological lesions, oxidative damage, and transcriptomic changes in the larvae of B. aeruginosa. Thus, exposure of larval snails to BF in the wild at concentrations similar to those used in this study might have adverse consequences at the population level. These findings provide a theoretical basis for further assessing the ecological risk of BF to aquatic gastropods. [Display omitted] • Bifenthrin changed behaviors of larval Bellamya aeruginosa and led to mortality. • Exposure to Bifenthrin caused a pathological change in hepatopancreas. • Exposure with Bifenthrin led to oxidative damage and transcriptomic changes. [ABSTRACT FROM AUTHOR]

Detecting the distribution and density of marine zoobenthos is crucial for monitoring healthy coastal ecosystems and for growth reference tracking in precision aquaculture. However, current detection algorithms for marine zoobenthos have high computational complexity and cannot guarantee a balance between accuracy and speed, limiting their deployment in fishery equipment. This study used a portion of the Augmented Underwater Detection Dataset, a large underwater biological dataset containing marine zoobenthos data. A marine zoobenthos recognition algorithm was proposed for sea cucumbers, sea urchins, and scallops based on an improved lightweight YOLOv5, which can recognize the three types of marine zoobenthos. In the image enhancement module, an underwater image enhancement algorithm based on color balance and multi-input fusion is used, which turns the blurred image into a natural appearance of the seabed image. The lightweight backbone network EfficientnetV2-S was chosen to replace the original YOLOv5 backbone network, reducing network parameter calculations and improving recognition speed. A Bottleneck Transformer was introduced into the backbone network, and an attention mechanism based on the convolution module was introduced to construct the embedded Convolutional Block Attention Module in the Neck structure of YOLOv5, thereby improving the recognition accuracy of the lightweight YOLOv5 model. The experimental results showed that the mAP of the proposed algorithm reached 0.941, which is an improvement of 0.002 compared with the original YOLOv5l algorithm. The computation of this algorithm is 37.0 FLOPs (G), the model size is 54 MB, and the inference time is 5.9 ms. Compared to the original YOLOv5l algorithm, the reductions are 66.1%, 40.5%, and 39.2%. The proposed algorithm efficiently identified and classified marine zoobenthos. • The paper proposes a new high-precision method for marine zoobenthos detection. • A lightweight high-precision Backbone fusing EfficientnetV2 and BotNet is proposed. • Introducing an underwater image enhancement module to improve underwater image quality. • Introducing CBAM in the Neck structure enhances the feature fusion capability. [ABSTRACT FROM AUTHOR]

• Significant cross-taxon congruence was found among bacteria, fungi, and zoobenthos. • Fungal community was more resistant to eutrophication compared to bacteria and zoobenthos. • Eutrophication decreased cross-taxon congruence in sediment biodiversity. • Bacteria worked as stabilizer in sediment ecosystem. Eutrophication is a major problem currently affecting sediment biodiversity in different kingdoms. Surveys at different spatial scales have suggested that nutrient enrichment drove the congruence in biodiversity across different kingdoms. In this study, we examined the diversity indexes of bacteria, fungi, and zoobenthos in Dongting Lake, which is undergoing different trophic levels. The species richness and Shannon index of bacteria, fungi, and zoobenthos were all consistent with the intermediate disturbance hypothesis along the content of TN and TP, with the hysteresis of fungal group. Significant cross-taxon congruence was found in species richness between bacteria and zoobenthos, and Shannon index between bacteria and fungi. Also, the strength of congruence in biodiversity among bacteria, fungi and zoobenthos would decrease along nutrient enrichment. Multi- and single-kingdom networks found that bacterial group contained more nodes and edges compared to fungal and zoobenthos groups, and bacterial removal led to the lowest natural connectivity. And highest positive interaction proportion and lowest absolute value of natural connectivity slope were observed in zoobenthos group. These results highlighted the importance of bacteria as stabilizer in sediment ecosystem, and the most sensitive feature of zoobenthos to nutrient enrichment. Taken together, our results confirmed the cross-taxon congruence between multi-kingdoms, and the effectiveness of bacteria as a potential bioindicator of ecological change. [ABSTRACT FROM AUTHOR]

[Display omitted] Natural purification of pollutants is highly recognized as regulating ecosystem services; however, the purification capacity of tidal flats remains largely unknown and/or unquantified. A 60-day mesocosm transplant experiment was conducted in situ to assess the purification capacity of natural tidal flats. We adopted the advanced sediment quality triad approach, monitoring 10 endpoints, including chemical reduction, toxicity changes, and community recoveries. The results indicated that contaminated sediments rapidly recovered over time, particularly > 50% within a day, then slowly recovered up to ∼ 70% in a given period (60 days). A significant early reduction of parent pollutants was evidenced across all treatments, primarily due to active bacterial decomposition. Notably, the presence of benthic fauna and vegetated halophytes in the treatments significantly enhanced the purification of pollutants in both efficacy and efficiency. A forecast linear modeling further suggested additive effects of biota on the natural purification of tidal flats, reducing a full recovery time from 500 to 300 days. Overall, the triad approach with machine learning practices successfully demonstrated quantitative insight into the integrated assessment of natural purification. [ABSTRACT FROM AUTHOR]

Detailed facies and sequence stratigraphic analysis of an Aptian shallow-marine succession illustrates the evolution of sedimentary environments and their benthic faunal associations in a marginal bay developed in northeastern Iberia (Maestrazgo Basin, Oliete Subbasin). In this bay, marine circulation was hampered by wide stationary shoals located in the low-subsidence transitional areas between subbasins. The Aptian sedimentary record of this bay (Josa and Oliete formations) is composed of four transgressive–regressive (T–R) sequences bounded by major unconformities generated during relative sea-level falls. The Josa Fm (formally defined herein) encompasses an asymmetrical T–R cycle (sequence J). It comprises transgressive prodelta clays with episodic orbitolinid blooms, grading upwards to regressive freshwater-influenced littoral and delta-front sandstones and sandy limestones which yield diverse bivalve communities dominated by trigoniids. The Oliete Fm encompasses three T–R cycles (sequences O1–O3), mostly deposited in a protected lagoon. The transgressive hemicycle of each sequence is dominated by marls containing low-diversity faunal associations composed of ostracods and mm-sized gastropods and bivalves, indicating stressed (probably dysoxic) conditions in the deepest parts of the lagoon, related to a lack of water circulation. The regressive hemicycle of sequences O1 and O2 is characterised by low-energy intertidal to shallow subtidal deposits including sponge spiculites, mud-dominated accumulations of articulated bivalves and gastropods with low-diversity microfaunal associations composed mainly of Choffatella and few other textulariids, and marginal oyster-serpulid patches. The uppermost part of sequence O2 is characterised by the development of siliciclastic tide-influenced coastal plains. Sequence O3 consists of massive intertidal to shallow subtidal glauconite accumulations related to the transgressive reworking of siliciclastic deposits. Foraminiferal associations in sequence O3 show an increase in diversity (including miliolids, lageniids and diverse textulariids), which was probably fostered by a more stable connection with open seas, caused by tectonic activity in the bounding shoal areas. The analysis of these four sequences represents a comprehensive and detailed characterisation of shallow-to-marginal marine benthic communities integrated in a sequence stratigraphic framework. • The detailed sedimentary evolution of a marginal-marine bay is presented. • Four T–R sequences are bounded by maximum regressive surfaces. • Faunal associations are put in a sequence-stratigraphic context. • Massive glauconite accumulations in intertidal to lagoonal settings [ABSTRACT FROM AUTHOR]

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]

• 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]

The thirteen springs of Cracow-Częstochowa Upland were analized in respected of their geological structure, hydrogeology, physical and chemical water conditions, and groundwater pollution. The study of the causes and consequences of land-use and other human induced changes was examined by the estimation of biodiversity and environmental requirements of individual species. The studied biotic variables in spring habitats referred to diatoms (algae), mosses, vascular flora and benthic fauna. The species presence was controlled by both natural and anthropogenic factors. The results showed that the heterogeneity of diatoms, mosses and vascular flora of springs are mainly constrained by physical and chemical water parameters. Among other factors reflecting species requirements (including benthic fauna) in the springs were the mineralogical diversification of bottom sediment, discharge and flow velocity, physical and chemical water parameters and anthropopressure. The most natural springs were large outflows Centuria and Błękitne Źrodła. The springs Pióro and Łączki Kobylańskie are among the most anthropogenically modified springs. Various taxa such as postglacial relict Crenobia alpina were found in selected springs (Pilica-Piaski and Centuria). Tracking changes in springs using hydrogeological monitoring and analysis of related bioindicators is the only valuable method for testing long-term trends in our environment. [ABSTRACT FROM AUTHOR]

Living (rose Bengal stained) benthic foraminiferal faunas, grain size, geochemical parameters (total organic matter, chlorophyll-a, pheophytin-a, molecular markers, and vertical flux of particulate organic matter) were investigated in 14 stations in two submarine canyons Almirante Câmara and Grussaí considered mature and immature, respectively, and on the adjacent continental slope, from 400 to 1300 m water depth, in the southwestern Atlantic Ocean. Samples were retrieved during two campaigns, in the austral winter 2008 and the austral summer 2009. The density, richness, and species composition of the benthic foraminiferal fauna decrease with depth in the canyons and along the adjacent slope transects, reflecting the availability and quality of sedimentary organic matter. Both canyons act as traps of labile organic matter, mainly towards the head of the Almirante Câmara canyon, promoting high specimen density, species richness, and the occurrence of species indicative of pulses of phytodetritus (e.g., Bolivina pacifica , Nonionella opima , and Nonionella stella). Towards the deeper regions of Almirante Câmara canyon and in the adjacent slope area, the lower abundance, diversity, and richness reflect more oligotrophic conditions and an adverse environment in terms of easily metabolizable organic matter. This multiproxy study demonstrates that the canyons in the southeastern Brazilian continental margin play an important role in accumulating organic matter. • Response of benthic foraminifera for particulate organic matter flux. • Behavior of benthic foraminifera to organic compounds in canyons. • Canyons as traps of organic matter in an oligotrophic area. • Colonization by benthic foraminifera after events of sediment disturbance. [ABSTRACT FROM AUTHOR]

Seawater chemistry has been highly variable during Earth's history. Whereas variations in the ratio of organic relative to inorganic carbon burial in oceanic basins are considered to trigger positive shifts in global seawater δ13C values, those in δ18O are related to Earth's climate fluctuations. Positive shifts in the carbon isotope record known from Cambrian marine carbonates on a global scale have provided invaluable stratigraphic insights. Carbon and oxygen isotope data from Middle-Upper Cambrian shallow marine carbonates of the Mila Formation, eastern Alborz Ranges, Iran are presented herein. Accordingly, the Furongian SPICE (Steptoean Positive Carbon Isotope Excursion) event is documented from the Qol-Qol Member of the Mila Formation at two stratigraphic exposures where this prominent and globally recorded isotopic event is detected in micrites/skeletal limestone with a maximum δ13C value of +4‰ at both localities. The positive shift initiates at the base, reaches the climax in the middle, and then declines in upper part of the Qol-Qol Member. Therefore, the base of the latter denotes the base of Furongian Series/Paibian Stage in the Alborz Ranges. The event occurred in the Palaeadotes – Torifera and Prochuangia trilobite Zones but detailed biostratigraphic studies are yet to be undertaken. The occurrence of glauconite and abundant benthic fauna in some intervals within the rock unit can be interpreted as recurring slightly-reduced and oxygenated sea floor circumstances during deposition of the Qol-Qol Member of the Mila Formation. • Carbon and oxygen isotopes from Middle-Upper Cambrian of NE Iran investigated. • The Steptoean Positive Carbon Isotope Excursion (SPICE) event identified. • The base of Furongian Series/Paibian Stage in the eastern Alborz Ranges is defined. • SPICE event occurs in the Palaeadotes – Torifera and Prochuangia trilobite Zones. • Abundance of glauconite and benthic fauna imply oscillating oxic-slightly reduced environments. [ABSTRACT FROM AUTHOR]

The early Toarcian Oceanic Anoxic Event (Jenkyns Event) was associated with major world-wide climatic changes with profound effects on the global carbon cycle. This review revisits the available literature covering the Jenkyns Event applying an updated common stratigraphic definition, allowing illustration of the development and evolution of anoxia in the Alpine-Mediterranean Tethys, north African margin, and North European epicontinental basins within a high-resolution temporal framework. The survey combines geographic and stratigraphic distribution of black shale, organic-matter properties (total organic carbon content and composition), variations in benthic fauna, distribution of euhedral and framboidal pyrite, and redox conditions reconstructed on the basis of both inorganic and organic geochemical data. The compilation demonstrates that bottom waters were generally well oxygenated prior to the negative carbon-isotope excursion of the Toarcian Oceanic Anoxic Event whose onset was marked by the synchronous deterioration in bottom-water oxygen conditions at supra-regional scale. Persistent euxinia was dominantly confined to the north European epicontinental basins and sub-basins, paralleled by a supraregional decline in oxygen content at the seafloor also in the Alpine-mediterranean Tethys area. In the interval of time represented by the core of the negative carbon- isotope excursion the most extreme redox conditions were reached along with intense euxinia extending periodically into the photic zone accompanied by deposition of black shales whose organic-matter content reached maximum values. Recovery to better oxygenated conditions was a diachronous process that started, in most places, at a time immediately following the end of the negative carbon-isotope excursion. The Alpine-Mediterranean Tethys became well oxygenated, while north European epicontinental areas experienced anoxia with less intense and intermittent sulphidic conditions interspersed with brief periods of oxygenation. Δ18O variations reflect a progressive increase in fresh-water input to the northern European epicontinental basins and sub-basins that reached its acme in correspondence with the lowest values of the negative carbon-isotope anomaly. In these areas, the proximity to sources of fresh-water input and the local physiography or geographic restriction limited water exchange with the Tethys Ocean, favouring the onset of anoxia/euxinia and organic-matter preservation. These basins and sub-basins, due to their relatively closed physiography and redox conditions, acted as pools of dissolved divalent manganese associated with accumulation of iron sulphides. Part of the soluble manganese spilled out of these basins in oxygen minimum zones, being deposited/precipitated at the edge of the more oxygenated Tethys Ocean, and thereby leading to the formation of local manganese-rich carbonates deposited during the Jenkyns Event. • Widespread anoxia/euxinia started to develop at the onset of the negative CIE. • Anoxia-euxinia mainly developed in north European epicontinental basins. • Most extreme conditions correlate with lowest values of the δ13C anomaly. • Recovery from anoxia-euxinia occurred diachronously. • Unstable anoxia-euxinia persisted in north European areas after the negative CIE. [ABSTRACT FROM AUTHOR]

• eDNA metabarcoding demonstrated effective monitoring of freshwater snail biodiversity. • Environmental DNA methods can be used for early detection of invasive species. • eDNA technology could be applied to assess the ecological risk situation in lakes. Freshwater snails are a crucial benthic animal group that plays a pivotal role in algae regulation and ecosystems while serving as intermediate hosts for certain parasites. Environmental DNA (eDNA) technology offers numerous advantages for biodiversity assessment. However, the utilization of eDNA techniques for freshwater snail monitoring remains limited. In this study, we screened primers for assessing freshwater snail diversity using eDNA technology and constructed a comprehensive database for Poyang Lake. Using eDNA technology, a total of 21 species of snails were detected in Poyang Lake, while traditional methods detected only 11 species. Notably, all species collected by traditional methods were also detected by eDNA technology. Additionally, environmental DNA methods detected the invasive snail Pomacea canaliculata , while traditional methods did not. In this study, eleven intermediate host snail species for parasitic disease were identified using eDNA methods, while six were detected through traditional sampling techniques. The eDNA metabarcoding analysis showed that the α and β diversity levels of snails in Poyang Lake did not vary significantly, indicating that results obtained by eDNA sampling are not influenced by the season in which samples were collected. The correlation analysis between the community structure of snails and environmental factors in Poyang Lake revealed significant impacts of total nitrogen, chlorophyll a , water depth, and water temperature on the snail community structure. These results confirm that eDNA technology can be exploited to monitor freshwater snail biodiversity. [ABSTRACT FROM AUTHOR]

[Display omitted] • Global warming drives microeukaryotes to move northward in the coastal sediments. • Microeukaryotic benthos stride over the ecological barrier of 32°N between the ECS and the YS under the global change. • Water depth restricts the connectivity between the continental slope community from the SCS and the continental shelf communities from the ECS and YS. • Higher phylogenetic diversity was detected in SCS than those in ECS and YS. • The depth, temperature and latitude significantly influence the microeukaryotes community in the coastal sediments. The marine flora and fauna along the China seas include the Indo-West Pacific warm-water fauna and the North Pacific temperate fauna. The latitude of 32°N is recognized as the ecological barrier for benthic fauna in the China Seas. However, the ecological barrier on macrobenthos community gradually weakened because of global warming. Microeukaryotes are major components of marine food webs and can quickly response to environmental changes. We hypothesis that microeukaryotic benthos can stride over the ecological barrier of 32°N from the East China Sea (ECS) to the Yellow Sea (YS) under the global change, but their distribution is still limited by depth gradients between the South China Sea (SCS) and the ESC. Therefore, we investigated the distribution of benthic microeukaryotes in the China Seas using RNA metabarcoding. Higher OTU richness and phylogenetic diversity were detected in the SCS than those in the YS and ECS. The YS and ECS communities clustered together firstly and then clustered with the SCS community. Unexpectedly, communities from the 33°N in the YS clustered with those from the ECS. Similar pattern was also detected for Cercozoa, Diatomea, Amoebozoa and Fungi. These findings indicated that microeukaryotic benthos strode over the ecological barrier of 32°N under the global change. Source-sink analyses indicated more than 50% sources of the 33°N community were attributed to the ECS community, while only 12.5% from the YS community. Depth, temperature and latitude showed significant influence on communities in the China Seas. This study highlights the response of active microeukaryotes to the global warming in the coastal sediments. [ABSTRACT FROM AUTHOR]

The article presents data on the activity of the radionuclide 137Cs in seawater, sediment, macroalgae, and zoobenthos from different locations in Admiralty Bay, King George Island, maritime Antarctica. The activity of 137Cs in the macrophytobenthos remained relatively stable across species, oscillating at the level of 1 Bq kg−1dw. However, a few individuals exhibited higher activity, particularly at stations closer to the glacier front. This result could have been caused by specific conditions resulting from melting glaciers and meltwater inflow and mixing with oceanic water. The activities of 137Cs in zoobenthic were in the range from 0.12 Bq kg−1dw (Asteroidea) to 24.2 Bq kg−1dw (Porifera) and the total doses in marine species were several orders of magnitude lower than reference levels. Stable isotopes of δ13C and δ15N suggest that the main factor influencing 137Cs activity may be the source of carbon (marine vs. terrestrial/glacial), rather than feeding strategy or trophic niches. [Display omitted] • 137Cs in Antarctic biota were still detected. • Low activity of 137 Cs is observed in most cases of the Antarctic ecosystem. • Carbon cycling may affect radionuclides activity in zoobenthos. • Total dose from 137Cs in Antarctic species was negligible. [ABSTRACT FROM AUTHOR]

Anthropogenic activities including coastal industries, urbanization, extensive agriculture and aquaculture as well as their cumulative impacts represent major sources of perturbation of marine coastal systems. Macrobenthic communities are useful ecological indicators for monitoring the health status of marine environments (or polluted environments). The present study reports, for the first time, the response of benthic macrofauna sampled during two years survey (2015–2016) to multiple anthropogenic pressures on the coastal zone south of Sfax (Tunisia). A total of 12 stations were monitored seasonally at locations downstream from the main potential sources of disturbance. 106 macrobenthos taxa, belonging to six animal phyla and 70 families, were identified with a dominance of polychaetes (42%), crustaceans (35%) and molluscs (18%). We used an ANOVA test and cluster analysis to identify spatial gradient linked to environmental and anthropogenic factors, including depth, sedimentary texture and anthropogenic activities (i.e. phosphogypsum discharges).The macrofauna present lowest species number and abundance on stations undergoing anthropogenic inputs, which are extremely polluted by heavy metals (Cd, Cu, F and N) and excess of organic matter. Univariate parameters reveal a general trend of increasing species diversity with increasing distance from the pollution source. The polluted stations are strongly dominated by carnivores, and selective deposit feeders, and more closely linked to the availability of trophic resources than to anthropogenic constraints. The seasonal changes in macrobenthic abundance, diversity indices and community structure are mainly linked to the biological cycle (e.g. recruitment events) of the dominant species. Biotic indices (AMBI and BO2A) classified the coastal zone south of Sfax as moderate and good ecological status. This study suggests that initiating a long-term monitoring programme would improve our understanding of the temporal changes of macrobenthic communities of this ecosystem, contributing to the assessment of effective management and conservation measures in this disturbed area. Image 1 • Coastal zone south of Sfax (Tunisia) is subject to intensive anthropogenic pressures. • Macrofauna community is poorly diversified at shallowest stations undergoing to anthropogenic pressures. • Three macrobenthic assemblages are identified in the coastal zone linked to environmental and anthropogenic factors. • Using the biotic indices, the coastal zone of Sfax can be classified as moderate to good ecological status. [ABSTRACT FROM AUTHOR]

The middle Homerian biotic crisis resulted in the almost complete eradication of graptolites. The shale-dominated Kosov Quarry section, central Bohemia, preserves the most complete graptolite record across the crisis in peri-Gondwanan Europe. The pre-extinction graptolite assemblage of the upper lundgreni Biozone, composed of ten species vanished in three extinction phases recognized in an interval 1.6 m thick. The crisis commenced with the increasing dominance of generalist taxa and subsequent extinction of several abundant species including Cyrtograptus lundgreni. The second phase coincided with the extinctions of genera Cyrtograptus and Testograptus , whereas long-ranging, generalist monograptids prevailed before they became extinct as the crisis culminated in its third phase in the flemingii Biozone. The lower part of the overlying parvus Biozone contains only Pristiograptus parvus , which became abundant in the upper part of the biozone, together with incoming Gothograptus nassa. The recovery interval is marked by a moderate diversification of monograptids and retiolitids. The extinction did not affect the diversity of pelagic cephalopods although their abundance was reduced. A bivalve-dominated benthic fauna disappeared throughout the extinction interval and re-appeared not earlier than in the latest Homerian. It was temporarily replaced by a time-specific fauna of anachronistic trilobites and brachiopods. The extinction interval coincided with sea-level fall, indicated by limestone slump-beds in a generally shaly succession. The post-extinction interval corresponds with a lowstand systems tract with deposition of condensed shelly limestone and burrowed shale. A positive carbon isotope excursion started in the flemingii Biozone and δ13C values increased up to the lower parvus Biozone above which the plateau of the first peak started. The beginning of the graptolite extinction predated the early phase of the late Homerian carbon isotope excursion. The terminal phase of the extinction, nevertheless coincided with the onset of the carbon isotope excursion and change in benthic fauna. • Mid-Homerian graptolite extinction consists of three successive phases. • Rise of dominance preceded major drop in species richness. • Complex specialized forms became extinct before long-ranging generalists. • Graptolite crisis coincided with temporary change in deeper water benthic fauna. • Major extinction predated both carbon isotope excursion and sea-level lowstand. [ABSTRACT FROM AUTHOR]

How nutritional quality of dietary resources affects species richness of consumer communities is poorly understood. We used fatty acids as indicators of nutritional quality of sedimentary organic matter to evaluate the effects of highly unsaturated fatty acid (HUFA) content in sediments and fatty acid diversity in sedimentary organic matter on species richness of deposit feeders. We sampled benthic animals and sedimentary organic matter, a potential dietary source for deposit feeders, at 54 locations in two bay ecosystems. The species richness of deposit feeders ranged between 1 and 29 and had a parabolic relationship with the organic carbon content of sediments. At intermediate range of sedimentary organic carbon content, the species richness of deposit feeders was positively related to HUFA content and fatty acid diversity. These findings indicate that nutritional quality is one of the important factors determining species richness. In particular, HUFA content and fatty acid diversity are useful indicators of the nutritional quality of potential diets and good predictors of the occurrences of benthic invertebrates in marine habitats. • Fatty acids were used as indicators of nutritional quality of SOM for deposit feeders in enclosed bay ecosystems. • High species richness of benthos was observed at high HUFA and fatty acid diversity in sediment when SOM was intermediate. • Nutritional quality of dietary sources seems to be an important factor for species richness in marine benthic communities. [ABSTRACT FROM AUTHOR]

Benthic macrofauna is an important component linking pelagic and benthic ecosystems, especially in productive coastal areas. Through their metabolism and behaviour, benthic animals affect biogeochemical fluxes between the sediment and water column. Mechanistic models that quantify these benthic-pelagic links are imperative to understand the functioning of coastal ecosystems. In this study, we develop a dynamic model of benthic macrofauna to quantify the relationship between organic matter input and benthic macrofaunal biomass in the coastal zone. The model simulates the carbon dynamics of three functional groups of benthic macrofauna and their sediment food sources and is forced by a hydrodynamic-biogeochemical model simulating pelagic physical and biological dynamics. The model reproduces measured time-series of macrofaunal biomass from two coastal sites with contrasting sedimentation in the Baltic Sea in 1993–2005 with comparatively high accuracy, including a major increase at one of the sites dominated by the bivalve Limecola (Macoma) balthica. This shift in community composition suggests altered pathways of organic matter degradation: 39% of simulated sedimentation was mineralised by macrofauna in 2005 compared to 10% in 1995. From the early 2000s onward macrofaunal biomass seems to be food-limited, as ca 80% of organic carbon sedimentation was processed by the deposit-feeding macrofauna at both sites. This model is a first step to help quantify the role of macrofauna in marine coastal ecosystem functioning and biogeochemical cycles and build predictive capacity of the effects of anthropogenic stressors, such as eutrophication and climate change, on coastal ecosystems. • A new mechanistic model quantifies benthic-pelagic coupling in coastal ecosystems. • Macrofaunal metabolism is central in organic matter cycling. • Organic matter supply is main driver of macrofaunal biomass in two coastal sites. [ABSTRACT FROM AUTHOR]

High resolution multibeam bathymetry revealed the occurrence of numerous craterlike depressions, so-called pockmarks, in the sea floor of the North Yellow Sea Basin (NYSB). To investigate whether these pockmarks are related to any type of fluid flow or gas seepage from subsurface stratum, acoustic survey and box samplings were conducted in a selected area containing several typical pockmarks. This allowed for an integrated analysis of the morphology, distribution, and subsurface strata as well as a direct comparison of seafloor characteristics among different areas inside and outside of a pockmark. Additionally, surface sediments were analyzed for particle structure and grain size. Based on the combination of multibeam bathymetry and backscatter intensity data, 282 seafloor depressions were accurately identified. Moreover, the formation of pockmark can be attributed to existence of gas chimneys and other shallow gases revealed by shallow seismic profile records in the subsurface strata. Sediments inside and outside the pockmark showed remarkable discrepancies in terms of grain size, and benthic fauna. Additionally, strong internal reflection area was observed inside the depressions where benthic habitats are abundant and sediments contain strawberry pyrite and carbonate cementation. Side scan sonar also recorded sediment plumes in the water column, which indicates that the pockmarks are still active. Several "pearl-string-like" accumulations of pockmark were found in the study area, which well agree with the distribution of buried channels and lakes. These results thus provide new insights in interpreting shallow water fluid seepage, with implications for our current knowledge of overall sedimentation process in offshore continental shelves. • Active fluid seepage in shallow water continental shelf environment • Shallow-gas related acoustic features recorded on sub-bottom acoustic data • Benthic fauna anomalies, and strawberry pyrite associated with seafloor seeps • The large but shallow pockmarks can be ascribed to low fluid pressure. • String like distribution of pockmarks controlled by subsurface buried channels. [ABSTRACT FROM AUTHOR]

We have studied benthic foraminiferal assemblages in a marine sediment section (Pefka E section) from the Lindos Bay Formation deposited during the early Pleistocene to provide new insights into the paleo-ecologic and neotectonic evolution of the SE part of the island of Rhodes (NE Mediterranean Sea). Relatively high amounts of eutrophic/low oxygen tolerant species and a comparatively high foraminiferal diversity indicate generally mesotrophic conditions at the sea floor and the presence of well-oxygenated bottom waters. These conditions are attributed to generally elevated surface water productivity and related organic matter fluxes during the early Pleistocene, which is in contrast to the modern oligotrophic conditions in this region. The abundance of individual species shows orbital-driven variability in the obliquity (41 kyr) and precessional (∼23 kyr) bands. Obliquity-driven changes in food availability are indicated by increased percentages of Cassidulina carinata s.l. during marine isotope stages (MIS) 44 and 42, reflecting enhanced food fluxes under glacial conditions. Precession-driven changes are observed for Ca. carinata s.l., Cibicidoides pseudoungerianus s.l., Cibicidoides mundulus and Gyroidinoides altiformis. These changes likely reflect prolonged near-coastal phytoplankton blooms triggered by local fresh-water runoff at times of Northern-Hemisphere insolation maxima, coeval to the formation of sapropels in the adjacent deep-sea basins. The application of a benthic foraminiferal transfer function allowed for the identification of a number of short-term subsidence-uplift cycles, superimposed by overall long-term subsidence of the SE coast of Rhodes. Estimated average uplift and subsidence rates vary between ∼4.2 and ∼10.3 mm/yr. These rates of tectonic motions are distinctly higher compared to most other estimates from Rhodes and suggest a complex neotectonic history of the island during the early Pleistocene, involving both large-scale and local motions associated with alternating compressional and extensional regimes. • An early Pleistocene marine sediment section from SE Rhodes was studied. • Mesotrophic conditions in the Early Pleistocene are reflected by the benthic fauna. • Obliquity- and precession-driven changes in food availability are identified. • Short-term vertical tectonic motions between ∼4.3 and 10.2 mm/yr are calculated. [ABSTRACT FROM AUTHOR]

The anthropogenic marine debris, especially abandoned, lost or otherwise discarded Fishing Gear (ALDFG), represents a rising concern, because of its potential harmful impact on the marine animal forests. We carried out 13 km of video recordings, by means of a remotely operated vehicle, from 10 to 210 m depth, in an anthropised area of the Tyrrhenian Sea (Mediterranean Sea). This site, for its high ecological importance and biodiversity value, has been identified for the establishment of a new marine protected area (MPA). The aim of this paper was to assess marine litter abundance and its effects on the benthic fauna. The debris density, in the study area, ranged from 0.24 to 8.01 items/100 m2, with an average of 3.49 (±0.59) items/100 m2. The derelict fishing gear, mainly fishing lines, were the main source of marine debris, contributing 77.9% to the overall litter. The impacts of debris on the benthic fauna were frequently recorded, with 28.5% of the litter entangling corals and impacting habitats of conservation concern. These impacts were exclusively caused by the derelict fishing gear (91.2% by longlines), and the highest percentage (49.1%) of ALDFG causing impacts was observed from 41 to 80 m depth, in the coralligenous biocenosis. The results of the present study will help the fulfilment of "harm" monitoring, as recommended by the Marine Strategy Framework Directive (MSFD) and the UN Environment/MAP Regional Plan on the marine litter management in the Mediterranean Sea. Regarding the actions to reduce the derelict fishing gear, preventive measures are usually preferred instead of the extensive removals based on cost-effectiveness and sustainability. The establishment of a new MPA in the area could be a good solution to reduce ALDFG, resulting in the improvement of the ecological status of this coastal area. Image 1 • Marine litter was quantified within a new Marine Protected Area. • Litter density ranged from 0.24 to 8.01 items/100 m2 (mean = 3.49 items/100 m2). • Derelict fishing gear represented 77.9% of the total litter items. • Fishing lines have been recognized as a cause of coral damage. The derelict fishing gear, mostly fishing lines, were the main source of marine debris, contributing 77.9% to the overall litter observed in the Milazzo Marine Protected Area. [ABSTRACT FROM AUTHOR]

The end-Ordovician mass extinction (EOME) is widely interpreted as consisting of two pulses associated with the onset and demise of the Gondwana glaciation, respectively, with the second pulse eradicating the distinctive, glacially related Hirnantian benthic biota (HBB). A global review of occurrence data of latest Ordovician benthic marine organisms reveals that virtually all warm-water benthic assemblages previously assigned to the HBB comprise two distinct and clearly postglacial faunas, both younger (middle and late Hirnantian, respectively) than the cool-water Hirnantia fauna (latest Katian to early Hirnantian). The newly recognised three Transitional Benthic Faunas (i.e., TBFs 1–3) can be closely tied to graptolite, conodont, and chitinozoan biozonations, the Hirnantian Isotope Carbon Excursion (HICE), and the glaciation, thereby providing an integrated, much higher-resolution timescale for understanding the tempo and nature of the EOME. At this finer resolution, we postulate a more profound impact of the first pulse of the EOME than hitherto envisaged, as evidenced by opportunistic expansion of the Hirnantia fauna globally and the complete absence of metazoan reefs in its immediate aftermath. We also argue, based on high-quality data from well-documented benthic groups in South China (i.e., brachiopods, tabulate and rugose corals, trilobites, and sponges), that the magnitude of the second pulse of the EOME caused by the deglaciation has been overestimated because the two postglacial faunas (i.e., TBFs 2–3) were part of a subsequent recovery phase of marine ecosystems rather than contributing to biodiversity decline. Thus, it is more plausible to reinterpret the EOME as a single-pulse, rapid event that was followed by a prolonged initial recovery intermittently impeded by climatic shocks through the Hirnantian, prior to the onset of a progressive reestablishment of marine ecosystems during the early Silurian (Rhuddanian and Aeronian) associated with an overall amelioration of climatic conditions. [ABSTRACT FROM AUTHOR]

Abstract In the U.S. West Coast groundfish bottom trawl fishery, lengthy sweeps (>85 m) that maintain seafloor contact are traditionally used. While these sweeps are effective at herding groundfishes, their bottom tending characteristics increase the potential to cause seafloor disturbances, and injury and unobserved mortality to benthic organisms. In this study, we examined if changing from conventional to modified sweeps (with sections elevated 6.5 cm off bottom) would affect catch efficiency of target groundfishes and seafloor interactions. We used a DIDSON imaging sonar to observe how each sweep configuration interacted with the seafloor. An altimeter was periodically placed on the modified sweep to measure height off bottom. Results detected no significant catch efficiency effect of changing from conventional to modified sweeps. The DIDSON and altimeter data showed the modified sweeps exhibit elevated sections where infaunal and lower-profile epifaunal organisms can pass under without disturbance. Results demonstrate that seafloor interactions can be substantially reduced using elevated sweeps in this fishery without impacting catch efficiency. Further, findings from this research could be potentially applicable to other fisheries nationally and internationally. [ABSTRACT FROM AUTHOR]

Abstract The bioavailability and biomagnification of organophosphate esters (OPEs) were investigated in a food web in the Zhushan Bay of Taihu Lake, China. The organisms included mainly three biological groups: plankton, invertebrates, and fish, which displayed distinctly different compositional profiles of OPEs. In general, the log BAFs (bioaccumulation factor) of OPEs displayed a significant correlation with their log K ow (octanol-water partitioning coefficient), suggesting that the bioaccumulation was mainly controlled by the hydrophobicity. The log BAFs of the more hydrophobic OPEs in benthic invertebrates were higher than in fish, suggesting that ingesting sediment constituted additional exposure route for benthic invertebrates. The log BSAFs (biota-sediment accumulation factor) in the benthic invertebrates increased with log K ow in the range of 1.44–5.73 and decreased afterwards. The depressed bioavailability of the highly hydrophobic OPEs was attributed to their strong adsorption to the sediment. The biomagnification potency of OPEs was affected by hydrophobicity of the compounds and biotransformation properties in the organisms at different trophic levels. 2-Ethylhexyl diphenyl phosphate biomagnified in the fish food web of Taihu Lake with a TMF (trophic magnification factor) of 3.61, which was due to the combined results of its relatively high hydrophobicity (log K ow of 5.73) and decreased metabolism potential in the high-trophic-level fish. The constant metabolism diminished the biomagnification potency of hydrophobic compounds triphenyl phosphate and tricresyl phosphate in this food web. Graphical abstract Unlabelled Image Highlights • Plankton, invertebrates, and fish displayed distinctly different OPE profiles. • Log BAFs of hydrophobic OPEs in benthic invertebrates were higher than in fish. • Parabolic relationship was obtained between log BSAF and log K ow for OPEs. • The OPE biomagnification was also affected by metabolisms in different organisms. • EHDPP biomagnified in the fish food web of Taihu Lake with a TMF of 3.61. [ABSTRACT FROM AUTHOR]

Abstract The aim of this study was to develop a simple methodology using foraminifera to distinguish between sediment that has been displaced downslope (as in a turbidity current) and in-situ hemipelagic sediment. These same methods will also be useful to identify seafloor foraminiferal faunas that have suffered considerable taphonomic modification (e.g., through dissolution, winnowing, mixing), which render them unsuitable as modern analogues for paleoenvironmental reconstructions. To help develop this methodology we used Late Quaternary samples from cores containing identified turbiditic sand-mud couplets that had been deposited at lower bathyal to upper abyssal depths (1400–3000 m) off the earthquake-prone east coast of New Zealand. Comparison of the proportions of the total planktic and benthic foraminiferal tests in each of three size categories (63–125 μm, 125–250 μm, >250 μm) with those in unmodified, in-situ modern bathyal faunas from off New Zealand showed an increased proportion of larger tests in the lower sandy turbidite layers and a slight increase of smaller tests in the upper muddy layers presumably as a result of winnowing processes during deposition. A regression formula was used to estimate depositional depths based on the relative abundance of planktics in the Quaternary foraminiferal faunas (>63 μm). In all but one of our core samples, these depth estimates were considerably shallower than the cores' present depth and suggested that most sediment (both sand and mud) had been transported downslope. Modern Analogue Technique (MAT) was used to estimate depths of deposition of the core samples based on a modern benthic foraminiferal dataset (>63 μm) from around New Zealand. There was no great difference between estimates based on species % and on genus %. Some MAT depth estimates were inconsistent with those from the other foraminiferal and sedimentological proxy methods that suggested turbiditic displacement. Because of the inconsistent results and the much greater work required to acquire the species census data we exclude the MAT method from our suggested methodology. Genera were lumped into groups with similar bathymetric range and the relative abundances of these groups in each core sample were used to infer sediment provenance and mixing during downslope transport. We recommend a methodology using three elements: Test size distribution, planktic percentage, and relative abundance of bathymetric groups of benthic genera. The first two require the least amount of work and can reliably identify the majority of displaced and taphonomically-modified faunas. The third requires some taxonomic skills to identify key genera but gives more information on the provenance depth and amount of mixing in displaced turbiditic sediment. Although developed using New Zealand modern and Late Quaternary foraminiferal data, we contend that these methods should be applicable for use throughout most of the Neogene in other temperate and subtropical parts of the world's oceans. Before use elsewhere, studies in the local region may be needed to test, recalibrate and tweak the modern analogue data on local test-size distribution and planktic percentage. Our study also suggests that these methods can be useful to identify seafloor foraminiferal faunas that have suffered considerable taphonomic modification (e.g., through dissolution, winnowing, mixing), which render them unsuitable as modern analogues for paleoenvironmental reconstructions. Highlights • Simple method proposed to distinguish in-situ from transported foraminiferal faunas. • Relative abundance of foraminiferal test sizes is modified by transport and dissolution. • Relative abundance of planktic foraminiferal tests aids recognition of transported faunas. • Many benthic genera can be grouped based on their live bathymetric distribution. • Relative abundance of benthic bathymetric groups of genera aids recognition of provenance. [ABSTRACT FROM AUTHOR]

Abstract Interest in the presence of pharmaceutically active compounds in the aquatic environment has been growing for over 20 years, yet very few studies deal with the metabolism of pharmaceuticals in marine organisms. In this study, the bioaccumulation under short-term conditions and metabolism of diclofenac were investigated. Mytilus trossulus was used as a representative of the Baltic benthic fauna. The mussels were exposed to diclofenac at a concentration of 133.33 μg/L for five days, following a five-day depuration phase. The highest concentration of diclofenac (7.79 μg/g dw) in tissues was determined on day 3. Subsequently, the concentration of diclofenac in tissues decreased rapidly to 0.86 μg/g dw on day 5. After five days of depuration, the concentration of diclofenac was 0.21 μg/g dw. Hydroxylated diclofenac metabolites were found both in tissues of mussels and water. This study shows that M. trossulus has the potential to accumulate diclofenac and metabolize it to 4-OH and 5-OH diclofenac. Highlights • Diclofenac is absorbed and accumulated in soft tissues by M. trossulus • M. trossulus metabolize diclofenac to 4-OH diclofenac and 5-OH diclofenac • Absorption and accumulation of diclofenac by M. trossulus depends on exposure time • Diclofenac undergoes partial degradation in artificial seawater [ABSTRACT FROM AUTHOR]

This study was conducted to assess the effect of heavy metals (Cd, Hg, Cu, Mn, Zn, Pb, Cr, and Sn) on the fatty acid profiles of Catla catla, Labeo rohita, and Cirrhinus mrigala collected from two polluted sites in the Chenab River and Jhelum River (non-polluted site). The heavy-metal levels were determined using atomic absorption spectrophotometry. The results showed that the levels of Cd, Hg, Cu, Mn, Zn, Pb, Cr, and Sn in the river water exceeded the permissible limits recommended by various international agencies. Some important fatty acids were not detected in the muscle samples of the fish species collected from the highly polluted site (HPS). Caprylic acid (C8:0) and lauric acid (C l2:0) we reundetectable in Catla catla and Cirrhinus mrigala. Palmitoleic acid and eicosapentaenoic acid were present in Catla catla alone, and they were not found in Labeo rohita and Cirrhinus mrigala harvested from a less polluted site (LPS). More saturated fatty acids and less fatty acids were detected in the muscle samples of Catla catla, Labeo rohita, and Cirrhinus mrigala collected from HPS than in those collected from LPS. The untreated discharge of domestic and industrial waste probably causes a reduction in the fatty acids in the biomass of microalgae and zoobenthos and, ultimately, adversely affects the upper links of the food chain in the river. [ABSTRACT FROM AUTHOR]

Abstract The bioturbation potential of macrobenthos communities (BPc) is an important parameter in marine ecology. Based on macrobenthos field surveys, BPc values were estimated in Bohai Bay, China. The horizontal distribution of BPc values changed across seasons while showing a certain level of continuity over time. The maximum BPc value was recorded in summer while the minimum occurred in winter. Although only a few environmental variables showed a statistically significant (p < 0.05) correlation with BPc, about 20 environmental variables exhibited a moderate correlation with BPc (0.3 < r < 0.5). The depth of the redox potential discontinuity (RPD) measured in situ changed across seasons, and the biogenic mixing depth values derived from the BPc index exhibited a relationship with the lowest RPD depth measurements. Our results suggest that the RPD depth can be predicted from BPc values, thereby showcasing a useful application of the BPc index in marine benthic pollution and environmental management research. Highlights • Estimation of bioturbation potential in Bohai Bay, China • Macrobenthic bioturbation potential has spatial and seasonal variations. • Correlation between BPc and environmental variables • BMD derived from BPc shows potential of estimating sediment status. [ABSTRACT FROM AUTHOR]

Abstract The bioavailability of trace elements (As, Cd, Co, Cr, Cu, Hg, Ni, Pb, Zn) in lowly to moderately contaminated coastal sediments from the Berre lagoon, France, was assessed by comparing their potentially bioavailable concentrations and bioaccumulated concentrations in the polychaete Alitta succinea. No linear correlations were observed contrarily to what is generally observed in similar works in areas with highly contaminated sediment. Correlations between trace and major elements (Fe, Ca, S, Mg, P, Al) in Alitta succinea tissues and their distribution in organism tissues show that, in such lowly to moderately contaminated sediments, biological variabilities should be considered. Normalization procedures allow to take into account these variabilities and to identify that sediment contamination is partly involved in the benthic ecosystem degradation of the Berre lagoon. Alitta succinea cannot be used as relevant bioindicator for Zn and Co bioavailability in sediment, since these elements are regulated by this organism. Highlights • In moderately contaminated sediments bioaccumulation is not correlated with the bioavailable form of contaminants in sediment • Biological variabilities of the target organism, such as the polychaeta Alitta succinea, must be considered • Geochemical measurement of major elements in organism tissues may allow normalization procedures • Sediment contamination in the Berre lagoon is partly involved in the benthic ecosystem degradation • Such method cannot be applied for biologically regulated trace elements (i.e., Co and Zn in this study) [ABSTRACT FROM AUTHOR]