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Shallow-sea environmental variations in the eastern Arabian Sea (EAS) have been related to monsoon variability, poorly ventilated intermediate water, and primary productivity changes. To understand these conditions, benthic foraminiferal assemblages, oxygen isotope ratios, and total organic carbon content have been examined in sediment Core SK291/GC13 from the EAS. We aim to retrieve decadal to centennial time-scale changes in past oxygenation and paleoproductivity during the last 7400 calibrated years before the present (cal yr BP). Our proxy data suggest that the oxic benthic foraminifera species were dominant during ∼7400–6000 cal yr BP. The change from oxic to dysoxic occurred during ca. 6000–3500 cal yr BP, and transition from dysoxic to suboxic environmental conditions happened at ca. ∼3500 cal yr BP. These changes are contemporaneous with weakening of the Indian summer monsoon beginning at ∼5500 cal yr BP which culminated into a major arid phase so-called ca 4.2 ka event in the Indian subcontinent. The EAS experienced low productivity during the early phase of our studied interval (∼7400–6000 cal yr BP) and higher productivity in the middle Holocene (6000–3000 cal yr BP), as revealed by the total organic carbon and benthic assemblages. Furthermore, productivity increased in the warm period and decreased in the Little Ice Age on a decadal scale. The spectral analysis of total organic content and suboxic species indicates a 23-year Hale (solar) cycle during the last millennium, indicating a close relationship between solar activity and monsoon variability. The strengthening of the El Nino-Southern Oscillation perhaps amplified due to increased solar activity in the last millennium, which influenced the climate of the EAS. The study highlights paleo-oxygenation shifts based on benthic foraminiferal assemblages, which are crucial for understanding changes in the oxygen minimum zones (OMZs) and their potential impacts on marine ecosystems. [ABSTRACT FROM AUTHOR]

Abstract Macro-benthic communities on the shallowest soft bottoms are impacted by hydraulic dredgers used for the harvesting of the striped venus clam (Chamelea gallina). Changes in macro-benthic assemblages were analysed across four areas in the Southern Adriatic Sea (Central Mediterranean Sea) during the winter and summer 2022 (low and high fishing pressures, respectively). Two sampling surveys were carried out collecting abundance data (N/100m2) of 69 species. Diversity indices (Shannon–Weiner and Equitability) were calculated and differences between seasons and areas were tested using non-parametric tests. Changes in the assemblage and feeding habits were explored by adopting permutational multivariate analysis of variance on 34 species. Moreover, environmental conditions of all areas in the two seasons were characterized by a set of 8 variables. Seasonal changes in diversity were only detected for the Shannon–Weiner index, with values significantly higher in winter than summer. Macro-benthic assemblages differed between the two seasons, and the winter assemblages were well-distinct in each area. In contrast, a high overlap was shown in the summer assemblages of the four areas. Changes in feeding habits showed an increase in filter feeding polychaetes and opportunistic/scavenger species during the summer. Temperature, Salinity and primary production were positively correlated to summer stations indicating potential thermic stress on the assemblages. The results provide information on the benthic community impacted by dredge disturbance and seasonal changes driven by environmental conditions, stressing the need to integrate these aspects in assessments on the health status of marine ecosystems required by European directives and fishery management plans.

Mass mortality events and anthropogenic impacts affecting Paramuricea clavata (Risso, 1826) have been increasingly documented during the last decades. These impacts have enhanced the settling of epibiont organisms on injured colonies. This epibiosis was studied using photographic sampling carried out on the granitic outcrops of the Tavolara Channel within the Tavolara–Punta Coda Cavallo marine-protected area (NE Sardinia) between 2017 and 2023 at 35–55 m. The number of colonies and percentage of surface involved in the epibiosis, the specific richness of the epibiont community, and the temporal evolution of the phenomenon were studied. Almost all the investigated gorgonians (93%) showed parts involved in epibiosis, with high percentages of surface covering (one-third of the surface). Out of the 37 epibiont species recorded, the most recurrent ones demonstrated an ecological succession dominated by Hydrozoa, Porifera, Bryozoa, Serpulidae, and the parasitic soft coral Alcyomiun coralloides. Nevertheless, single colonies studied over time revealed the unpredictability of the colonization process. The peculiar habitat of the granitic outcrops hosting the P. clavata forests is of a high naturalistic value and demonstrates a widespread condition of suffering, supported by both environmental and anthropogenic sources of stress. Such considerations make it necessary to review the current zonation of the area, where the actual vulnerability and usability evaluations are based on incomplete information. [ABSTRACT FROM AUTHOR]

Extensive seaweed aquaculture is a growing industry expected to expand globally due to its relatively low impact and benefits in the form of ecosystem services. However, seaweeds are ecosystem engineers that may alter coastal environments by creating complex habitats on previously bare mudflats. These changes may scale up to top‐consumers, particularly migratory shorebirds, species of conservation concern that regulate trophic webs at these habitats. Understanding how habitats are transformed and how this affects different species is critical to direct ecological applications for commercial seaweed management. We experimentally assessed through a Before‐After Control‐Impact design the potential changes exerted by Gracilaria chilensis farming on bare mudflats on the abundance, biomass, and assemblage structure of benthic macroinvertebrates, and their scaled‐up effects on shorebirds' habitat use and prey consumption. As predicted, experimental cultivation of G. chilensis significantly affects different components of biodiversity that scale‐up from lower to upper trophic levels. The total biomass of benthic macroinvertebrates increased with seaweed cultivation and remained high for at least 2 months after harvest, boosted by an increase in the median size of polychaetes, particularly Nereids. Tactile‐foraging shorebirds tracked these changes at the patch level increasing their abundance and spending more time foraging at seaweed cultivated plots. These results suggest that seaweed farming has the potential to impact shorebird populations by favoring tactile‐foraging species which could lead to a competitive disadvantage to species that rely on visual cues. Therefore, the establishment of new seaweed farms in bare mudflats at key sites for shorebirds must be planned warranting habitat heterogeneity (i.e., cultivated and non‐cultivated areas) at the landscape level and based on a previous experimental approach to account for local characteristics. Fostering properly designed extensive seaweed farming over other aquaculture industries with greater negative environmental impacts would provide benefits for human well‐being and for ecosystem functions. [ABSTRACT FROM AUTHOR]

Discards remain among the main negative impacts of fishing activities, and their reductions are strengthened by the European Common Fisheries Policy (European Regulation 1380/2013). Trammel net fisheries appear more sustainable compared with other fishing techniques, especially from an ecological viewpoint. Despite this, reports show that trammel net fisheries deliver discard quantities between 10% and 43% of the total catch biomass. To supplement existing information, this current work attempts to address the discard reduction using guarding net in the small-scale fisheries of Egadi Islands MPA (Western Sicily, Central Mediterranean Sea). To assess the reduction of unwanted catches, 48 experimental fishing trials were conducted within a 6-month period. The experimental fishing trial employed a trammel net made up of 20 panels alternated with two different net configurations. The control panels (CN) held a large outer (180 mm) and small inner (31.25 mm) meshes. The test panels (GN) with guarding net constituted a three-mesh-high (50-mm mesh size) net placed between trammel net panels and a lead line. A total of 3,310 individuals belonging to 106 taxa and nine phyla were caught. Crustaceans were the most abundant unwanted catches in the control panels, whereas bioconstructions occurred in the guarding net panels. The discard ratios of CN and GN panels were statistically different (t-value = –2.55; p< 0.05). The analysis of catch per unit effort showed higher catches of CN panels for both commercial and discard fractions (p< 0.05). Moreover, the guarding net panels caught the main discarded species at 20% lower compared with the control. The overall value of the catch at the CN panels (€ 3,366.90) was higher than the total income (€ 2,043.70) generated using the GN panels, which suggests a significant commercial loss of 40% (p< 0.05).

Simple Summary: One-third of the Antarctic continental shelf is covered by ice shelves, floating extensions of the Antarctic Ice Sheet. Marine life beneath and bordering ice shelves is rarely investigated, yet likely to be highly impacted by climate change. As ice shelves retreat, marine environments transition into new open-water spaces, with potential for primary production and consequent food-fall to the seafloor. How Antarctic seabed assemblages (benthos) develop in such emerging spaces is influenced by neighboring and oceanographically-connected communities; thus, closing knowledge-gaps of benthic biodiversity near ice shelves underpins understanding of future ecosystem change. This study examined seafloor assemblages, and environmental differences, in a region that has experienced ice-shelf retreat, in a polynya adjacent to a marine margin at the forefront of climate change: the ice-shelf front. The study area, located in the Weddell Sea, is seldom accessible, and lies within a proposed international marine protected area. The study found a physically- and biologically-diverse seabed, complexity in potential environmental influences, and evidence of increasing megafaunal densities with increasing distance from an ice-shelf front. This research provides insights into seafloor habitats and inhabitants close to an evolving marine margin, and establishes ecological baselines from which biological responses to climate change can be evaluated to inform marine management. Ice shelves cover ~1.6 million km2 of the Antarctic continental shelf and are sensitive indicators of climate change. With ice-shelf retreat, aphotic marine environments transform into new open-water spaces of photo-induced primary production and associated organic matter export to the benthos. Predicting how Antarctic seafloor assemblages may develop following ice-shelf loss requires knowledge of assemblages bordering the ice-shelf margins, which are relatively undocumented. This study investigated seafloor assemblages, by taxa and functional groups, in a coastal polynya adjacent to the Larsen C Ice Shelf front, western Weddell Sea. The study area is rarely accessed, at the frontline of climate change, and located within a CCAMLR-proposed international marine protected area. Four sites, ~1 to 16 km from the ice-shelf front, were explored for megabenthic assemblages, and potential environmental drivers of assemblage structures were assessed. Faunal density increased with distance from the ice shelf, with epifaunal deposit-feeders a surrogate for overall density trends. Faunal richness did not exhibit a significant pattern with distance from the ice shelf and was most variable at sites closest to the ice-shelf front. Faunal assemblages significantly differed in composition among sites, and those nearest to the ice shelf were the most dissimilar; however, ice-shelf proximity did not emerge as a significant driver of assemblage structure. Overall, the study found a biologically-diverse and complex seafloor environment close to an ice-shelf front and provides ecological baselines for monitoring benthic ecosystem responses to environmental change, supporting marine management. [ABSTRACT FROM AUTHOR]

The article describes the evolutionary history of the development of the sedimentary complexes of the three regions composing the Late Paleozoic basin of Northeast Asia: the Verkhoyansk–Okhotsk, Indigirka–Omolon, and New Siberian–Chukotka. The main features of their ecosedimentogenesis are determined by the processes of the Late Paleozoic destruction, which determined the replacement of the Early–Middle Paleozoic epiplatform substantially carbonate series by Late Paleozoic sulfide-bearing black shale complexes of rift-related basins. A strong correlation between the change of different-type ecosystems and the corresponding tectonic rearrangements was established. The current ideas on the dependence of the Late Paleozoic biogeographic differentiation on climatic conditions are critically reviewed. It is shown that the uniqueness of Late Paleozoic rift-related ecosystems, previously considered as high-latitude and cold-water, is actually related to their bacterial lithotrophic basis in contrast to the phototrophic basis of assemblages of epiplatform basins. According to the literature and the author's data, analogs of the studied ecosystems in Late Paleozoic basins of Gondwana—Patagonia, New Zealand, Australia—were established. The features of the Late Paleozoic biogeography are considered as a consequence of the activation of the global tectonic regime. It is assumed that the latter resulted in a significant expansion of the area of deep-water systems, accompanied by intense removal of deep material, primarily methane and hydrogen sulfide, which determined the energy basis of the developing ecosystems. [ABSTRACT FROM AUTHOR]

The study of community structure changes in relation to environmental gradients can help assessing and predicting community response to anthropogenic disturbances; however, such types of studies are rare in semi-arid regions. This study aimed at investigating the macroinvertebrate community composition in response to environmental variables in rivers of a semi-arid mountainous region, i.e., the Zagros mountain range, southwestern Iran. Environmental variables and macroinvertebrates were sampled at 54 sites in four seasons during 2018–2019. A total of 101 families of benthic macroinvertebrates from 8 classes and 21 orders were identified. Diversity and evenness indices showed significant temporal variation (p < 0.05). Also, taxa richness and Ephemeroptera, Plecoptera, and Trichoptera taxa showed strong seasonal stability, whereas spatial variation among all metrics was significantly different (p < 0.05). Taxa richness and density weekly correlated with altitudinal gradient. Correlation analysis, cluster analysis, non-metric multidimensional scaling, and canonical correspondence analysis demonstrated associations between community composition and environment variables, including definition of site groupings according to aggregated quality estimates. The results suggest that both physico-chemical variables of water (nitrate, total dissolved solids, Escherichia coli, temperature, chemical oxygen demand, and dissolved oxygen) and habitat structure (wetted river width, altitude, and riffles presence) determined the community composition of macroinvertebrates. Seasonal variation of community indices and community composition in our region seemed to differ from those estimated from subarctic, temperate and subtropical ecosystems. Our study provides a strong basis for further research, planning, and conservation of macroinvertebrate communities in the Karun River basin and similar river systems in the region. [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]

Taxonomic and functional trajectories of benthic assemblages were studied in shallow soft‐bottom sediments in the bay of Saint‐Brieuc (Western English Channel). Changes were assessed at different spatial and temporal scales using a macrobenthic dataset based on 38 stations sampled in 1987 and 2019, coupled with data from one station sampled annually between 2005 and 2019 as part of the European Water Framework Directive monitoring programme.Taxonomic trajectories indicated 1) changes in the structure and distribution of benthic assemblages, 2) an homogenization of the assemblages, and 3) significant functional shifts.Fishing activities and nutrient enrichment are probably strong drivers of the observed changes, as suggested by the higher mortality rate of fragile, flexible, tubiculous and burrowing species, and the increase in the abundance of opportunistic species in the assemblages. Certain populations of macroinvertebrates seem jointly controlled by climate change and by the aforementioned local factors of disturbance.The Community Trajectory Analysis framework appears as a new and interesting method to track ecological changes in marine ecosystems by measuring change with respect to a baseline state, to help define ecological recovery (station returning to the initial ecological state) and departure (station presenting increased changes over time), and to analyse trajectory similarity.According to the degradation of habitat over time, we identify the need for the implementation of knowledge‐based conservation strategies, especially within Natura 2000 sites. [ABSTRACT FROM AUTHOR]

There is limited information on the intra-annual variability of mesophotic coral ecosystems (MCEs), worldwide. The benthic communities, measured as % cover, of two geomorphologically different mesophotic sites (El Hoyo and Hole-in-the-Wall) were examined during 2009–2010 in southwest Puerto Rico. Depths sampled were 50 and 70 m. At each site/depth combination, two permanent transects, measuring 10-m long by 40-cm wide, were surveyed by successive photoquadrants, 0.24 m2 in area. Scleractinian corals, octocorals, macroalgae, crustose coralline algae (CCA), sponges and unconsolidated sediment were the main components along the transects. Significant community differences were observed both among sites and among depths. Differences among sites were greater at 50 m than at 70 m. The El Hoyo site at 50 m was the most divergent, and this was due to a lower coral and sponge cover and a higher algal cover (Amphiroa spp., Peyssonnelia iridescens, turf) relative to the other site/depth combinations. As a consequence, the differences in community structure with depth were larger at El Hoyo than at Hole-in-the-Wall. The communities at 70 m were distinguished from those at 50 m by the greater proportion of the corals Agaricia undata, Madracis pharensis and CCA, and a reduced cover of the cyanobacterium Schizothrix. Temporal variation in the benthic assemblages was documented throughout the year. For both mesophotic sites, the magnitude of change at 50 m was significantly greater than at 70 m. For both depths, the magnitude of change at El Hoyo was significantly greater than at Hole-in-the-Wall. All assemblages experienced almost the same temporal patterns, despite the differences in species composition across sites and depths. Changes in temporal patterns are driven by an increase in the percent cover of the macroalgae Dictyota spp., and a decrease in the percent cover of non-colonized substrata (sand, pavement or rubble). Relatively rapid, intra-annual changes are dictated by the negative correlation between cyclic Dictyota spp. cover and open substrata cover. Other observed mechanisms for rapid community changes in the photoquadrants were diseases and collapses of substrata along with their associated fauna indicating that small-scale disturbance processes may play an important role within MCEs.

With the increasing impact of human activities on marine ecosystems, there is a growing need to assess how the components of marine ecosystems (e.g., macrobenthos) respond to these anthropogenic pressures. In this work, the trait-based approach was used to assess the effects of anthropogenic pressures represented by the area of land-based aquaculture pond (Pond Area) and heavy metals on the macrobenthic communities in three intertidal zones[Aoshan Bay (AO), Wenquan River and Daren River (RW), and Xiaodao Bay (XD)] of Laoshan Bay, Shandong Peninsula, China. Compared with RW and XD, AO was under more pressure in terms of the average concentrations of heavy metals and total organic carbon (TOC) in sediments and also in the Pond Area. Fuzzy correspondence analysis (FCA) showed that there were significant differences in the composition of functional traits among the three regions (PERMANOVA; p < 0.05). In the highly polluted area, macrobenthic communities exhibited a combination of traits, such as relatively short life span, weak mobility, feeding on deposits, and more tolerant to organic matter, whereas in a less polluted area, they exhibited a combination of traits, such as relatively long life span, relatively high mobility, and more sensitivity to organic matter. The RDA results showed that the distribution of the trait modalities was significantly affected by heavy metals (Hg and Cd), TOC, Pond Area, and sampled location. Variation partitioning analysis (VPA) indicated that the shared influence of sediment-related pollution factors and Pond Area contributed most to the variance of the functional traits, which implied that human activities directly and/or indirectly lead to changes in functional traits of macrobenthic communities in the intertidal zones.

Ice shelves cover ~1.6 million km2 of the Antarctic continental shelf and are sensitive indicators of climate change. With ice-shelf retreat, aphotic marine environments transform into new open-water spaces of photo-induced primary production and associated organic matter export to the benthos. Predicting how Antarctic seafloor assemblages may develop following ice-shelf loss requires knowledge of assemblages bordering the ice-shelf margins, which are relatively undocumented. This study investigated seafloor assemblages, by taxa and functional groups, in a coastal polynya adjacent to the Larsen C Ice Shelf front, western Weddell Sea. The study area is rarely accessed, at the frontline of climate change, and located within a CCAMLR-proposed international marine protected area. Four sites, ~1 to 16 km from the ice-shelf front, were explored for megabenthic assemblages, and potential environmental drivers of assemblage structures were assessed. Faunal density increased with distance from the ice shelf, with epifaunal deposit-feeders a surrogate for overall density trends. Faunal richness did not exhibit a significant pattern with distance from the ice shelf and was most variable at sites closest to the ice-shelf front. Faunal assemblages significantly differed in composition among sites, and those nearest to the ice shelf were the most dissimilar; however, ice-shelf proximity did not emerge as a significant driver of assemblage structure. Overall, the study found a biologically-diverse and complex seafloor environment close to an ice-shelf front and provides ecological baselines for monitoring benthic ecosystem responses to environmental change, supporting marine management.

Previous studies indicated that artificial live rock (ALR) has the potential to be used as a substrate for coral juveniles. The present study reported a potential of ALR as an ideal substrate for future artificial reef structure. This study was conducted at three sampling sites, namely Teluk Salang, Teluk Bakau and Teluk Sanggit in Tioman Island, Pahang, Malaysia. The total of 96 samples of ALR (n = 48) and terracotta tiles (n = 48) were deployed and periodically retrieved with three-month interval for 15 months. Retrieved settlement plates were analyzed to compare the total abundance of epibionts and coral density between ALR and tiles. Results showed that ALR plates exhibited a significantly higher total benthic abundance compared to terracotta tile [Independent T-Test; t (22) = 2.650, p = 0.015]. On average, a total of 82.8 ± 5.2% of benthic organisms covered ALR's surfaces compared to terracotta tiles with 62.5 ± 5.6%. The number of coral spats was significantly higher on ALR by 60.7 ± 10.7% compared to terracotta tiles [Mann–Whitney U Test; U = 10.5, p = 0.003]. In addition, there was a significant difference between sites in the abundance of epibionts as determined by one-way ANOVA [F (2,21) = 11.945, p < 0.001] for both substrates. However, Kruskal–Wallis H test showed that there was no significant difference in terms of coral density at the sites of deployment [H (2) = 3.730, p = 0.155]. The results demonstrated ALR as a new suitable settlement substrate for benthic organisms which can be applied as a substrate for artificial reef, coral propagation and coral transplant. [ABSTRACT FROM AUTHOR]

This study was carried out in the Yenisei estuary and in the adjacent part of the Kara Sea shelf. We analyzed and compared the distribution patterns of the different benthic taxa and size classes (micro-, meio-, macro- and megabenthos) along a pronounced gradient of environmental factors. Four ecological zones were distinguished based on certain environmental parameters, from the upper riverine area to the mouth of the estuary and the Kara Sea slope, which had normal marine conditions. The distribution of the metazoan assemblages generally corresponded to the divisions of these zones and represented a series of species assemblages with coincident boundaries that changed successively along the estuarine gradient. For all three size classes of metazoan benthos, we detected three main species assemblages: brackish-water, transitional and marine. Each taxon showed, however, its own particular spatial pattern and, therefore, has a set of environmental variables that is responsible for its fine-scale distribution. The distribution of unicellular organisms showed a worse match with the division of the estuary into environmental zones. Foraminifers established a single association in most of the estuary but were absent in the upper desalinated part. Diatom algae were patchily distributed, with a number of local communities and many rare species.We conclude that the estuarine habitat appears to drive the distribution of the various benthic taxa in taxa-specific ways. The distribution of size classes (i.e., mega-, macro-, or meiofauna) that combine several high-level taxa demonstrates a better match with the multivariate environmental zonation than the distribution of the separate taxa. The role of different benthic taxa and size classes in biomonitoring studies is discussed.

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

Sea‐level rise, storm surges, ageing and wear are forcing upgrades to breakwaters and sea walls to protect coastal areas from erosion and inundation. Such upgrades involve the introduction of new material which may consequently act as an ecological disturbance that can alter established marine communities and ecosystem function. Mitigating ecological impacts requires an understanding of how species assemblages are affected by such works.Here, we use the major upgrade of a regularly wave‐overtopped breakwater as a case study to evaluate the impacts of upgrades to hard coastal protective infrastructure on benthic rocky reef communities. An asymmetrical Before‐After Control‐Impact (BACI) experimental design was used to test interactive effects of the infrastructure upgrades on benthic communities.While benthic assemblages were not significantly different from controls prior to the upgrade, improving the defensive capacity of the breakwater significantly changed community structure. Notably, most taxonomic groups showed higher cover at the control sites than at the impacted site post‐upgrade, with articulated calcareous algae (e.g. Corallina officinalis and Amphiroa anceps) showing an opposite trend.Synthesis and applications. Ecological implications and structural limitations make regular upgrading of existing infrastructure unsuitable as a long‐term management strategy. More sustainable alternatives need to be considered, such as decommissioning of structures and retreat from flood‐prone areas. This transition, however, will take time and requires a change of mindset and policies. Where upgrades are urgent, eco‐engineering techniques can mitigate impacts to habitats and associated taxa. [ABSTRACT FROM AUTHOR]

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

A depth gradient may influence both macrophytes and their associated epiphytic community through variations in hydrodynamics and light conditions, which in turn may affect the mobile organisms living on them. We investigated how a narrow depth gradient affects the associated peracarid assemblages in a Sargassum cymosum bed. This study was conducted on a rocky shore in Southeastern Brazil. A 20 × 3 m sampling area was defined parallel to the shore line, within which three perpendicular transects were sampled in October 1997 (spring), January 1998 (summer), April 1998 (fall), and July 1998 (winter). In each transect, three samples of Sargassum were randomly collected at three different depths—shallow (1 m), intermediate (2 m), and deep (3 m). Peracarid fauna was identified, quantified, and classified into feeding groups. Depth affected both species richness and total density only in January, with fewer species and individuals at the shallow depth, more species at the intermediate depth, and more individuals at the deep depth. The taxonomic and feeding group composition of peracarid assemblages were also affected by depth, with differences depending on the sampling period. Herbivores and omnivores were commonly more abundant at the shallow depth, while detritivores were more abundant at the deep depth. Carnivores seemed not to be affected by depth. Small-scale distribution patterns can be related to how peracarid species deal with the variability in turbulence and food availability imposed by a depth gradient, with morphological attributes and feeding habits guiding how species are distributed in the space and thus the peracarid assemblage as a whole. [ABSTRACT FROM AUTHOR]

Quantitative sampling of sessile assemblages on temperate subtidal rocky reefs is expensive and severely time-limited by logistics. However, knowledge about distribution patterns of critical and endangered species and habitats at different spatial scales is needed for effective marine management strategies. To gain information of sessile community distribution on broader spatial scales (>1 km), visual imaging was employed for the first time on a reef complex in the south-western Baltic Sea. Analysis of 3000 images along 6 transects (in total 18 km long) from 10 to 40 m depth revealed high natural variation in reef physical structure, with well-defined changes in sessile species richness, cover and composition. Overall 14 morphological groups could be distinguished by imaging and 4 distinct community groups associated with specific habitat requirements were identified. Depth remained the best descriptor. However, data indicate that light intensity, concentration of organic carbon and suspended particulate matter have an effect on reef community distribution. Compared to fully marine conditions, the study revealed a unique zonation pattern in the circalittoral zone of the Fehmarnbelt brackish transition area, with an unexpected reef habitat in the trench. We conclude that towed camera platform imagery might help to close the information gap regarding rocky reefs in the temperate subtidal. It provides a valuable tool to assess the main distribution patterns of sessile assemblages on rough terrain, potentially applicable for management and conservation planning. [ABSTRACT FROM AUTHOR]

In order to elucidate how ecological interactions drive the abundances of marine benthic polychaete populations and the role that environmental variables play in their dynamics, we examined long-term dynamics of winter abundance in 13 polychaete species from benthic samples obtained over 15 years (1993 to 2007) at Punta Coloso, northern Chile on the Pacific coast of South America. We examined the relative importance of density dependence, winter sea surface temperature (SSTW) and Southern Oscillation Index (SOI) on polychaete dynamics. All species studied showed conspicuous abundance oscillations, consistent with negative density-dependent population feedbacks. Model selection across a suite of population dynamic models showed that for six species, the best model included the effect of environmental variables, SSTW in the previous year, while the SOI index was the relevant variable in two polychaete species. A pure density-dependent model best explained the population dynamics of the remaining five species. Our results contrast with traditional approaches, which focus on the importance of abiotic factors in structuring marine benthic systems, and demonstrate the importance of theoretical synthesis and analysis to understand long-term dynamics in these ecosystems. [ABSTRACT FROM AUTHOR]

Environmental assessment studies are usually required by a country's administration before issuing permits for any industrial activities. One of the goals of such environmental assessment studies is to highlight species assemblages and habitat composition that could make the targeted area unique. A section of the Oregon continental slope that had not been previously explored was targeted for the deployment of floating wind turbines. We carried out an underwater video survey, using a towed camera sled, to describe its benthic assemblages. Organisms were identified to the lowest taxonomic level possible and assemblages described related to the nature of the seafloor and the depth. We highlighted six invertebrate assemblages and three fish assemblages. For the invertebrates within flat soft sediments areas we defined three different assemblages based on primarily depth: a broad mid-depth (98–315 m) assemblage dominated by red octopus, sea pens and pink shrimps; a narrower mid-depth (250–270 m) assemblage dominated by box crabs and various other invertebrates; and a deeper (310–600 m) assemblage dominated by sea urchins, sea anemones, various snails and zoroasterid sea stars. The invertebrates on mixed sediments also were divided into three different assemblages: a shallow (~100 m deep) assemblage dominated by plumose sea anemones, broad mid-depth (170–370 m) assemblage dominated by sea cucumbers and various other invertebrates; and, again, a narrower mid-depth (230–270 m) assemblage, dominated by crinoids and encrusting invertebrates. For the fish, we identified a rockfish assemblage on coarse mixed sediments at 170–370 m and another fish assemblage on smaller mixed sediments within that depth range (250–370 m) dominated by thornyheads, poachers and flatfishes; and we identified a wide depth-range (98–600 m) fish assemblage on flat soft sediments dominated by flatfishes, eelpouts and thornyheads. Three of these assemblages (the two broad fish assemblages and the deep flat soft sediments invertebrate assemblage) seem to represent deeper examples of assemblages already known on the Oregon continental shelf, especially on soft sediments, while the assemblages in the pockmarks habitat (the narrower depth ranges) might be unique to the area. This diversity of assemblages in a relatively small section of the Oregon continental upper slope and shelf shows the importance of environmental assessment studies in helping limit future impacts of industrial activities on benthic communities. [ABSTRACT FROM AUTHOR]

Deception Island is an active volcano located at the southern end of the South Shetland Archipelago, in the Antarctic Ocean. After the last eruption in 1970, benthic recolonization took place within the bay, with echinoderms being the dominant epifauna (e.g., the ophiuroid Ophionotus victoriae , the echinoid Sterechinus neumayeri and the sea star Odontaster validus ), together with dense infaunal communities (mostly composed by oligochaetes, polychaetes, and bivalves). Here, we aim to describe the actual status of the marine benthic ecosystems inhabiting the shallow subtidal areas of this volcanic island. Benthic species were qualitatively scored as presence versus absence, considering the different sampling effort between localities done over the years. A total of 139 species of macroorganisms, belonging to 16 phyla were found, including fauna and flora, increasing the species richness values previously reported in all sites surveyed within the volcano caldera. Moreover, a dramatic increase in biodiversity was found towards the entrance of the bay. We suggest, however, that recolonization from external waters may not be the only reason for this pattern. In fact, sediment flux rates and substrate instability are common disturbances within the bay, probably being among the major factors determining benthic community assemblages. These processes probably favour deposit feeding communities at the innermost locations of the bay. This study provides a remarkably increased and updated species inventory from previous reports, altogether with a description of the main communities inhabiting the bay and the abiotic factors regulating this, mainly the bottom type. [ABSTRACT FROM AUTHOR]

Abstract: Recreational diving is a concern regarding its effects on benthic assemblages, especially on heavily dived coral reefs. However, spearfisher behaviour and the scale of damage they cause to corals remains unknown. The behaviour of recreational spearfishers was observed to determine their rate of physical contacts with corals. The experience level and fishes captured by spearfishers were assessed to establish their relationship with the number of contacts with corals. All spearfishers made contact with corals, at an average rate of 1.25 ± 0.1 SE touches per minute and caused physical damage at a rate 0.51 ± 0.04 per minute. Massive corals were most frequently touched and branching corals were most frequently damaged. Touches and damage occurred mainly through fin kicks, spearfisher bodies and spearguns. Contact rates varied according to spearfisher experience level and the fish they were targeting. Novice spearfishers showed no preference for specific targets while experienced spearfishers target mesopredator fishes. Spearfishing caused the highest known rates of touches and damage to corals among all the activities involving recreational diving. The activity may add to local stressors on corals, especially at sites with high visitation rates. Understanding how the factors that affect spearfisher behaviour and their effects on corals may help managers to develop strategies to mitigate the incidence of damaging behaviour. [ABSTRACT FROM AUTHOR]

The present study provides the first results of the exploratory research campaign to Gloria seamount (summit at 45.03°N, 15.54°W), a newly identified seamount in the NE Atlantic. New multibeam bathymetry and an 8 h remote operated vehicle footage and photography data were compiled and analyzed to give the first insights on the geological nature and benthic megafauna assemblages of Gloria seamount. Footage evidenced three distinct seafloor coverage areas, ranging from unconsolidated fine sediment with ripple marks, to increasingly coarser-grain sediment with large blocks, to outcrops with steep slopes along successive ridges, locally exhibiting volcanic structures. The deep-sea benthic assemblages differed with depth (2700−2450 m) and seafloor substrate type. In sediment habitats, pink holothurians (Elpidiidae) and brittle stars (Ophiuroidea) were recorded, whereas in hard substrates, sponges (Hexactinellida and Demospongiae) and stalked crinoids (Crinoidea) were mixed with distinct coral specimens, such as bamboo corals (Isidiidae) and Coralliidae (Scleralcyonacea). The integration of these data contribute to the geo-habitats knowledge of an unexplored seamount. • This is the first deep-sea data from Gloria seamount (45.03°N, 15.54°W), NE Atlantic. • High-resolution bathymetry was acquired for the area. • Footage, biological, geological, and oceanographic data was acquired. • Collected data provided information about the habitat structure of Gloria seamount. • Benthic community composition varied according to substrate type. [ABSTRACT FROM AUTHOR]

Coral reefs are under increasing pressure from a variety of stressors, highlighting the need for information about the status of coral reef communities including the distribution, abundance and composition of juvenile and adult coral assemblages. This information is currently limited for the Great Barrier Reef (GBR) and is necessary for understanding the impacts of disturbances and the system’s potential for recovery. This study reports juvenile and adult hard coral abundance and composition from 122 reefs on the GBR during a period of limited acute disturbance. The data represent baseline observations for juvenile hard coral assemblages spanning the longitudinal cross-shelf gradient of the GBR and 12 degrees of latitude and augment reported distribution of adult coral assemblages over the same scale with inclusion of additional reefs. Juvenile and adult coral assemblages reflected broad differences imposed by the gradient of environmental conditions across the GBR. The mean density of juvenile hard corals was lower in the inshore reefs (5.51 m2) than at either the mid-shelf (11.8 m2) or outer shelf reefs (11.2 m2). The composition of juvenile and adult coral assemblages covaried overall, although there were different relationships between these two life stages across the continental shelf and among community types. Dissimilarity between juvenile and adult coral assemblages was greater on inshore and outer shelf reefs than on reefs in the mid-shelf, although, there were differences in community types both within these shelf positions and those that spanned mid- and outer shelf reefs. Dissimilarity was greatest for Inshore branching Acropora and high for Southern Acropora communities, although very high coral cover and very low juvenile densities at these reefs precluded interpretation beyond the clear competitive dominance of Acropora on those reefs. Dissimilarity was also high between juvenile and adult coral assemblages of Turbid inshore communities suggesting water quality pressures, along with synergistic effects of other stressors, pose ongoing selective pressures beyond the juvenile stage. Conversely, relatively low dissimilarity between juvenile and adult coral assemblages on mid-shelf and lower latitude outer shelf reefs suggests pressures beyond those influencing settlement and early post-settlement survival were having less influence on the composition of adult coral assemblages.

Changes in coral reef health and status are commonly reported using hard coral cover, however such changes may also lead to substantial shifts in coral community composition. Here we assess the extent to which coral communities departed from their pre-disturbance composition following disturbance (disassembly), and reassembled during recovery (reassembly) along an environmental gradient across the continental shelf on Australia’s Great Barrier Reef. We show that for similar differences in coral cover, both disassembly and reassembly were greater on inshore reefs than mid- or outer-shelf reefs. This pattern was mostly explained by spatial variation in the pre-disturbance community composition, of which 28% was associated with chronic stressors related to water quality (e.g., light attenuation, concentrations of suspended sediments and chlorophyll). Tropical cyclones exacerbated the magnitude of community disassembly, but did not vary significantly among shelf positions. On the outer shelf, the main indicator taxa (tabulate Acropora) were mostly responsible for community dissimilarity, whereas contribution to dissimilarity was distributed across many taxa on the inner shelf. Our results highlight that community dynamics are not well captured by aggregated indices such as coral cover alone, and that the response of ecological communities to disturbance depends on their composition and exposure to chronic stressors.

Despite the ecological relevance of tropical reefs, information on species composition and coverage on sandstone reefs is very scarce. Most studies on reef systems have been conducted for true coral reefs, ecosystems that show calcareous formations with extensive coral cover and diversity. The aim of this study was to analyse the coverage of benthic assemblages in a submerged sandstone reef (22-24 m) in a relatively non-explored region (Tropical South-western Atlantic). In this area, filamentous algae (43.6%) and sponges (19.6%) are the main components of the benthic reef assemblages. Other benthic reef fauna (ascidians, corals and zoanthids) showed lower coverage, although their importance may vary depending on the area. A negative correlation between filamentous algae and slow-growing reef-building organisms (calcareous algae) was observed. High sand coverage (19.6%) over the reef revealed a high rate of silting. A low coral diversity (only two resilient species) was quantified, and most of the coral colonies were small-sized. The results provide a baseline assessment for a poorly known ecosystem with turbid-water benthic communities and higher sea-surface temperatures near the Earth's equator. [ABSTRACT FROM AUTHOR]

This study is the first to present data on local (=beach) and gamma diversity of beach nematode assemblages from the Persian Gulf. We investigated four beaches near the city of Bandar Abbas, Iran. On each beach, we sampled three stations at 50-m intervals, with increasing distance from a local pollution source, mostly domestic sewage. A total of 39 genera from 17 families was recorded. This gamma diversity is low and suggests that the entire area experiences substantial stress. Five genera together comprised 75% of nematode abundance. There were significant differences in abundance as well as genus diversity between locations, but these did not unequivocally correlate with known drivers of benthic assemblage structure like sediment granulometry and hydrodynamics. The location exposed to the strongest local pollution input had the lowest nematode diversity and a very low abundance at the station nearest the pollution source. Distance from local pollution sources also significantly impacted genus diversity, but this pattern was only pronounced in two of the four beaches. Our data demonstrate that local sources of anthropogenic disturbance are a major driver of assemblage diversity and structure in this area, despite an overarching effect of natural (salinity, temperature) and anthropogenic stressors. [ABSTRACT FROM AUTHOR]

Marine spatial planning (MSP) should assist managers in guiding human activities toward sustainable practices and in minimizing user conflicts in our oceans. A necessary first step is to quantify spatial patterns of marine assemblages in order to understand the ecosystem's structure, function, and services. However, the large spatial scale, high economic value, and density of human activities in nearshore habitats often makes quantifying this component of marine ecosystems especially daunting. To address this challenge, we developed an assessment method that employs abiotic proxies to rapidly characterize marine assemblages in nearshore benthic environments with relatively high resolution. We evaluated this assessment method along 300 km of the State of Maine's coastal shelf (<100 m depth), a zone where high densities of buoyed lobster traps typically preclude extensive surveys by towed sampling gear (i.e., otter trawls). During the summer months of 2010-2013, we implemented a stratified-random survey using a small remotely operated vehicle that allowed us to work around lobster buoys and to quantify all benthic megafauna to species. Stratifying by substrate, depth, and coastal water masses, we found that abiotic variables explained a significant portion of variance (37-59%) in benthic species composition, diversity, biomass, and economic value. Generally, the density, diversity, and biomass of assemblages significantly increased with the substrate complexity (i.e., from sand-mud to ledge). The diversity, biomass, and economic value of assemblages also decreased significantly with increasing depth. Last, demersal fish densities, sessile invertebrate densities, species diversity, and assemblage biomass increased from east to west, while the abundance of mobile invertebrates and economic value decreased, corresponding mainly to the contrasting water mass characteristics of the Maine Coastal Current system (i.e., summertime current direction, speed, and temperature). Integrating modeled predictions with existing GIS layers for abiotic conditions allowed us to scale up important assemblage attributes to define key foundational ecological principles of MSP and to find priority regions where some bottom-disturbing activities would have minimal impact to benthic assemblages. We conclude that abiotic proxies can be strong forcing functions for the assembly of marine communities and therefore useful tools for spatial extrapolations of marine assemblages in congested (heavily used) nearshore habitats. [ABSTRACT FROM AUTHOR]

This study reveals the relationship of biotic assemblages to their environments in the Central Highland Ecoregion rivers (Ken, Paisuni and Tons). Such knowledge will enhance our predictive abilities in the ecological studies and resource management in the concerned region. Rivers of an ecoregion are expected to harbour similar flora, fauna, and communities. This hypothesis was examined by tracking the spatial variation in richness, density, and taxonomic composition of benthic diatom and macroinvertebrate assemblages in three Plateau rivers whose course lay within 3°N latitude. Taxonomic richness and density decreased with the reduction of substrate size from the headwaters to the lowlands. Cluster and ordination analyses indicate prevalence of intrabasin rather than interbasin gradients of abundance. In both assemblages, the most abundant taxon is rarely similar longitudinally or across the river sections in the ecoregion. Hence, proximate factors govern the assemblages rather than ecoregional properties (latitude, altitude). This, and the high richness of diatom flora, points to diverse assemblages from the headwater to the lowland section in each river and among the rivers of the ecoregion. [ABSTRACT FROM AUTHOR]

The Trindade and Martin Vaz island group (TMVIG) is located at about 1,120 km off the Brazilian coast. Despite its importance, highlighted by the presence of several endemic fish species, the TMVIG lacks detailed information on the structure of fish and benthic assemblages. Presented here is the first quantitative assessment of reef fish and benthic assemblages of the TMVIG in a depth gradient ranging from 5 to 45 m. Additional qualitative information on reef assemblages between 45 and 100 m was obtained using advanced gas diving techniques (TRIMIX) and a remotely operated vehicle (ROV). Similarly to other Brazilian oceanic islands, the TMVIG possesses depauperated fish and benthic assemblages, possibly due to its isolation and small size in comparison to the mainland. Depth was the most important factor affecting the structure of fish assemblages, with the density of most fish species declining with depth. Deep reefs (> 45 m) were characterized by the presence of extensive rhodolith beds and rocky reefs sparsely covered with crustose coralline algae, black coral (Cirripathes sp.) and a few massive or plate-like reef corals. Part-time or obligatory planktivorous fishes (e.g. Cephalopholis furcifer and Clepticus brasiliensis) also dominated deep reefs. Similar characteristics were recorded in mesophotic reef ecosystems across the Western Atlantic. Evidence of overfishing (obtained here and in other recent studies), the presence of four endemic and restricted range fish species, as well as the increase in number of new (and still undescribed) endemic taxa, indicates that the adoption of precautionary conservation measures are urgently needed in order to maintain the fragile and unique ecosystems of the TMVIG.O conjunto insular de Trindade e Martin Vaz (CITMV) está localizado a aproximadamente 1.120 km da costa brasileira. Apesar de sua importância, salientada pela presença de diversas espécies endêmicas de peixes, não existem informações detalhadas sobre as assembléias de peixes e bentos do CITMV. É apresentada aqui a primeira caracterização quantitativa das assembléias de peixes e bentos do CITMV em um gradiente de profundidade entre 5 e 45 m. Informações qualitativas adicionais sobre assembléias recifais entre 45 e 100 m foram obtidas utilizando-se técnicas avançadas de mergulho (TRIMIX) e um veículo de operação remota (VOR). Assim como outras ilhas oceânicas brasileiras, a CITMV possui assembléias depauperadas de peixes e bentos, possivelmente devido ao seu isolamento e pequeno tamanho em comparação ao continente. A profundidade foi o fator que mais afetou a estrutura das assembléias de peixes, com a densidade da maioria das espécies declinando com o aumento da profundidade. Os recifes profundos (> 45 m) foram caracterizados pela presença de bancos extensivos de rodolitos e recifes rochosos esparsamente cobertos por algas coralináceas incrustantes, corais negros (Cirripathes sp.) e alguns corais massivos e em de forma de placa. Peixes parcialmente ou obrigatoriamente planctívoros (e.g. Cephalopholis furcifer and Clepticus brasiliensis) também dominaram em recifes profundos. Características similares foram registradas para recifes mesofóticos ao longo do Atlântico Ocidental. Evidências de sobrepesca (obtidas aqui e em outros estudos recentes), a presença de quatro espécies de peixes endêmicas e com distribuição restrita, e o aumento no número de espécies novas ainda não descritas, indicam que a adoção de medidas de conservação baseadas no princípio da precaução é urgentemente necessária para garantir a manutenção dos ecossistemas frágeis e únicos do CITMV.

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The boundary between land and sea, i.e. the littoral zone, is home to a large number of habitats whose distribution is primarily driven by the distance to the sea level but also by other environmental factors such as littoral's geomorphological features, wave exposure, water temperature or orientation. Here we explore the relative importance of those major environmental factors that drive the presence of littoral rocky habitats along 1100 Km of Catalonia's shoreline (Spain, NW Mediterranean) by using Geographic Information Systems and Generalized Linear Models. The distribution of mediolittoral and upper infralittoral habitats responded to different environmental factors. Mediolittoral habitats showed regional differences drawn by sea-water temperature and substrate type. Wave exposure (hydrodynamism), slope and geological features were only relevant to those mediolittoral habitats with specific environmental needs. We did not find any regional pattern of distribution in upper infralittoral habitats, and selected factors only played a moderate role in habitat distribution at the local scale. This study shows for the first time that environmental factors determining habitat distribution differ within the mediolittoral and the upper infralittoral zones and provides the basis for further development of models oriented at predicting the distribution of littoral marine habitats. [ABSTRACT FROM AUTHOR]

Corals reefs and communities support a wide range of flora and fauna. The complete richness and abundance of faunal communities in either coral reefs or communities is not fully understood. This is especially true for high-latitude coral communities. In this work, we carried out an analysis of an Alveopora japonica associated mollusk assemblage, in Jeju Island, Korea. A. japonica is one of the major coral species present in high abundance (88-155 colonies m), with a high recruitment rate (7.8 juvenile corals m yr) in Jeju Island, and may serve as a habitat for other benthic organisms. In 2012, a total number of 579 A. japonica colonies with sizes ranging between 15.1-346.7 cm in the surface area were collected from a 1m× 10m quadrat installed at a depth of 10 m at Keumneung, on the northwest coast of Jeju Island. Numerous benthic invertebrates were found to be associated with A. japonica colonies. Twenty-seven bivalves and gastropods were identified, including a boring mytilid, Lithophaga curta, and an arcid, Barbatia stearnsi. A zonalgeographical examination of the distribution ranges of these mollusks revealed a majority of warmer water species. Our observations also showed that A. japonica may be providing a habitat to grazing gastropod, Turbo cornutus, and encrusting Spondylidae and Chamidae bivalves. A. japonica forms a coral carpet with a distinct assemblage of bivalves. It is thought that the presence of these mollusks species in the coral indicates its use as a nursery for juvenile species, a ready food supply of organic detritus, and a refuge from predators. [ABSTRACT FROM AUTHOR]

To evaluate the effects of diffuse contamination, biological measurements were applied in a scrap cargo harbour, a marina and an industrial area. Metal accumulation and biomarkers (survival in air, digestive gland and gonad histopathology, lysosomal membrane stability, intralysosomal metal accumulation, transcription of vitellogenin and MT20 , peroxisome proliferation and micronuclei formation) were measured in transplanted mussels, together with metrics of benthic invertebrates. Benthic species were classified into ecological groups and univariate indexes were calculated. The marina showed high richness (16) and percentage of opportunistic species (55.1%) and low metal accumulation. Mussels in the scrap cargo harbour showed high metal accumulation, up-regulation of MT20 transcription, reduced health status (LP < 6 min) and increased micronuclei frequencies (up to 11.3‰). At the industrial area, low species richness (4) and badly organised assemblages were detected and chemical analyses indicated significant amounts of bioavailable metals. Overall, selected biological measurements showed potential for the assessment of diffuse contamination. [ABSTRACT FROM AUTHOR]

The basal portion of the Permian Rio do Rasto Formation (Serrinha Member), Passa Dois Group, Paraná Basin, Brazil, records an entirely new bivalve fauna intercalated between the underlying Pinzonella neotropica assemblage (uppermost portion of the Teresina Formation) and the overlying Leinzia similis assemblage (Rio do Rasto Formation). Mollusks of these assemblages lived in marginal shallow-water habitats of an immense epeiric sea and were dominated by endemic bivalve species. Taxonomic analysis revealed the presence of Terraia curvata (60.61%), Astartellopsis prosoclina (19.70%), Cowperesia emerita (10.61%), Leinzia curta (4.55%), Terraia bipleura (3.03%) and Beurlenella elongatella (1.52%), which are associated with conchostracans and plant remains. Species composition, abundance, and dominance in this novel assemblage differ notably from the preceding ones, suggesting a substantial evolutionary turnover. Regional-scale environmental changes recognized based on taphonomy, facies analysis, and geochemical data consist of progressive freshening of the marginal habitats of the Paraná Basin and taxic changes that include the following: (a) loss of genera, (b) decrease in bivalve abundance and ecological guilds, (c) disappearance of the dominant bivalve group (Pinzonellinae) and (d) diversification of Terrainae bivalves. The ecological signature also changed notably because only infaunal suspension-feeding bivalves are present, indicating a significant loss of functional diversity at the regional scale. Likely stressor factors (among others) are tied to freshening events, suggesting profound changes in (a) salinity, (b) primary productivity and (c) a lack of coarse, stable substrates coupled with high bioturbation rates. Hence, our regional example could offer valuable clues to benthic (bivalve) community responses in a habitat subjected to (a) rapid climate changes and (b) freshening events in shallow-water settings. Finally, the stratigraphic range of the dominant species ( T. curvata ) appears to be restricted to the basal portion of the Rio do Rasto Formation. Based on the presence of this species and of C. emerita , the novel assemblage is tentatively correlated with that of the Permian Gai-As Formation in the Huab region of Namibia, thus supporting previous assumptions of a seaway connecting both basins during the Guadalupian Epoch. [ABSTRACT FROM AUTHOR]