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

Gastrotricha are microscopic benthic animals found in almost all water bodies. To date, over 890 species distributed in 71 genera, 18 families, and two orders are known. There are 376 freshwater species, and several are also found in Italy; however, a compendium of the studies carried out so far, and a georeferenced distribution of the species, still need to be provided. This project summarizes information about the diversity and geographic distribution of Italian gastrotrichs. Diversity data, acquired over 239 years, were reviewed and corrected based on taxonomic and nomenclatural updates and, in addition to distribution information, were organized into a data matrix valuable for statistical analysis. The data were fed into geographic information system software to understand the overall figures more easily. The results indicated that Italy is one of the best-known countries regarding freshwater gastrotrichs. With 92 species in 17 genera and three families from 61 investigated localities, Italy counts 17 type localities and 19 endemic species. Despite this high biodiversity, many Italian regions still need to be investigated, and should, therefore, be the focus of future research. The implementation of a web-mapping plugin enabled the creation of interactive maps for an easy and modern method for sharing the work done, and the information acquired. [ABSTRACT FROM AUTHOR]

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

Carijoa riisei is an invasive octocoral whose dispersal in the tropics has increased considerably in recent years. This study evaluated the changes in the benthic fauna assemblages associated with C. riisei growing on rocks from a sea port and on the metal of a submerged shipwreck in the bays of Manzanillo, Colima, in the Mexican Central Pacific. Quarterly samples were collected between April 2021 and January 2022, with the presence or absence of C. riisei. The effect of C. riisei on the benthic fauna according to the type of substrate was evaluated with PERMANOVA models. The presence of C. riisei was found to affect taxonomic diversity. In the absence of the octocoral, 209 species were recorded, whereas in its presence, 190 were found. The decline of taxa occurred at the level of families, genera, and species. The interaction of the presence/absence of C. riisei and substrate generated significant changes in the Shannon (1D) and Simpson (2D) diversity indexes. However, the presence of C. riisei coincided with higher abundances of Ophiothela mirabilis, Ericthonius brasiliensis, and Pseudobranchiomma schizogenica. In conclusion, the snowflake coral favors the dominance of some species and reduces the biological diversity of several taxa, mainly mollusks, polychaetes, sipunculids, and anthozoans, generating significant changes in the structure of benthic communities. This study highlights the need to evaluate species composition in areas where the octocoral grows, to determine whether its presence has an ecological impact and whether control measures are required. [ABSTRACT FROM AUTHOR]

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

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

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]

An autonomous lander equipped with a video camera (dropcam) was used for in situ observations of the bento-demersal macrofauna on the upper continental slope off Punta Pichalo in northern Chile, an area of permanent coastal upwelling processes, located ~70 km north of Iquique. The lander was deployed at nine stations and between 227 and 798 m of depth. According to morphological characteristics, 34 operational taxonomic units (OTUs) were identified to the lowest taxonomic level; 24 belonged to macroinvertebrates and 10 to fishes. Macroinvertebrates comprised 9 OTUs of crustaceans, seven cnidarians, and six echinoderms. Fishes included 3 OTUs of the order Chondrichthyes, 3 belonging to macrourid. Perciformes, Anguilliformes, and Alepocephaliformes were represented by one OTU each. Also, we observed one species of lanternfish (Myctophidae). Apart from the brachyuran decapod Lophorochinia parabranchia Garth, 1969 and euphausiids, all species were observed at depths greater than 560 m. The presence of one individual identified as the granulate dogfish Centroscyllium granulatum Günther, 1887 extended the known distribution range of this species about 1000 km to the north. Images taken at 795 m showed Bathyraja peruana McEachran & Miyake, 1984. Our study suggests that the upper continental slope of northern Chile harbors nearly undiscovered biodiversity, worth to be studied more intensively to complete the comparable sparse knowledge about marine biodiversity and species distribution at the continental margin in front of Chile. [ABSTRACT FROM AUTHOR]

The Hersek Lagoon is a small lagoon located in the Marmara Sea. It is a breeding and feeding area for many bird species, which makes it an internationally important wetland despite its small size. However, it is under pressure due to the deterioration of the natural water regime and increasing pollution. Although macroinvertebrates are important indicators in the environmental monitoring, no study has been conducted on the macroinvertebrate fauna of this lagoon. The present study was conducted to evaluate the relationship between environmental parameters and benthic macroinvertebrates. Totally, 34 species were identified in the lagoon, two of which (Hydroides dianthus (Verrill, 1873), Lekanesphaera monodi (Arcangeli, 1934)) are reported from the Sea of Marmara for the first time. Three alien species were detected in the lagoon: Ruditapes philippinarum (A. Adams & Reeve, 1850), Polydora cornuta Bosc, 1802 and Hydroides dianthus (Verrill, 1873). Diversity index values at all stations showed that macrobenthic fauna is poor in terms of species diversity. Low levels of dissolved oxygen and the high total organic carbon content throughout the lagoon sediment seem to negatively affect the benthic fauna, especially at stations far from the open sea. The fact that the dominant species in the lagoon are resistant to organic pollution also supports this view. [ABSTRACT FROM AUTHOR]

To assess the distribution of macrozoobenthos and environmental conditions after river flooding events offshore of the Mimi River, the water quality, benthic conditions and macrozoobenthos communities were investigated at five stations over a 6-year period. At the station closest to the river mouth, sediment median grain size was coarser than that at the other stations. Also, the macrozoobenthos community at this particular station was dominated by crustaceans and differed from that observed at other stations. Because these changes in sediment and macrozoobenthos were related to the size of floods caused by typhoon rains, it is suggested that the outflow of relatively coarse sand from the river affected benthic communities at this station by changing the sediment conditions. The three offshore stations detected relatively fine sediment and polychaete-dominated communities, and they found no evidence of flood effects on both their environment and macrozoobenthos. At the remaining station, the environmental conditions and the macrozoobenthos community were somewhat changed as a result of the flood events, and the median grain size and community composition differed from those of the other stations. These changes may have depended on the transport capacity of coastal currents for coarse sediments at each flood event. Our results show that sediment supply derived from river flooding could significantly modify benthic conditions, resulting in increased macrobenthic biodiversity offshore a river mouth. [ABSTRACT FROM AUTHOR]

Benthic fauna caught by ring dredge and 2 m beam trawl at the NATURA 2000 Sylt Outer Reef (SAR) and Borkum Reef Ground (BRG) sites in the North Sea are examined in relation to the intensity of mobile bottom-trawling fisheries. Samples were taken from 33 stations in the two areas, and the collected benthic fauna, consisting of infauna, epifauna, and demersal fish was determined. A total of 123 species were found, consisting of the phyla Chordata, Mollusca, Arthropoda, Echinodermata, Annelida, Cnidaria, and Bryozoa, with Chordata and Mollusca being the most species-rich phyla. The species compositions of BRG and SAR are relatively clearly separated. There was greater species diversity at BRG, likely due to lower fishing pressure from mobile bottom trawling than at SAR. Long-term data acquisition and analysis will be needed to visualize past and future changes in biodiversity. [ABSTRACT FROM AUTHOR]

Morocco is a very rich country in terms of wetlands, including bays, estuaries, lagoons, lakes, and rivers, among others. However, many of them need to be well managed and better exploited, thus requiring baseline descriptive studies to assess faunal patterns and trends. Oualidia lagoon is not an exception. In fact, the studies conducted to date in the lagoon mainly focused on its oceanographic features and aquaculture capacities. The present paper presents the first study on the whole macrofaunal assemblages of Oualidia lagoon, having as main objectives analyze the composition and structure of the assemblages, as well as their relationships with the main environmental variables explaining their spatial distribution variability in the enclosed ecosystem of the Oualidia coastal lagoon. The benthic macroinvertebrates of Oualidia lagoon were studied in summer 2013 based on 43 stations spread over the whole lagoon by using a Van Veen grab. Two replicate samples were collected for macrobenthos and one additional replicate for sediment analyses at each station. Also, single water salinity and temperature measurements were recorded at each station. Fifty-one species from seven different taxa were recorded, among which mollusks (37%), polychaetes (25%) and crustaceans (25%) dominated in terms of species number. Peringia ulvae, Abra alba, Sphaeroma serratum, Cerastoderma edule and Corophium sp. accounted for 88% of total abundance. The benthos was structured along a downstream–upstream gradient, showing three assemblages, named according to the IndVal index: (1) Diopatra cf. marocensis, (2) Peringia ulvae, and (3) Cerastoderma edule, while the main factors driving their distribution were granulometry and salinity. The Biotic and Environmental analysis showed that the combination of granulometry and salinity was the major factors controlling the spatial distribution of the macrozoobenthos in the Oualidia Lagoon. [ABSTRACT FROM AUTHOR]

Benthic foraminifera are one of the most widely and abundantly distributed organisms in the fjords of Svalbard and Norway. Due to their short life span and quick reactivity to environmental changes they can be used as indicators of the "atlantification" process. Here, we compare the benthic foraminifera assemblages along the latitudinal gradient, from the fjords of northern Svalbard to southern Norway to assess whether the "atlantification" process may homogenise the foraminiferal assemblages in terms of their abundance and species composition. Furthermore, the previously published data on benthic foraminiferal faunas was updated to identify changes in distribution that have occurred over the last few decades. For this purpose, fjord mouths in western and northern Svalbard (Isfjorden, Wijdefjorden and Rijpfjorden) and northern and southern Norway (Balsfjorden, Raunefjorden and Hjeltefjorden) were resampled. The analysis revealed similarities between the Svalbard and Norwegian foraminiferal assemblages of up to 30%; however, there were essential differences in terms of abundance and biodiversity. These results suggest that Svalbard fjords will remain distinct in the future, even under conditions of further warming or "atlantification". Svalbard fjords may be dominated by Atlantic Water- preferring species, whereas, in Norwegian fjords, pressure from human activity will probably be the main driver of environmental changes, leading to changes in the foraminiferal assemblages with the increasing dominance of opportunistic, hypoxia-tolerant species. [ABSTRACT FROM AUTHOR]

Large-scale research on seagrass-associated benthic fauna is very important for future regional marine conservation. In our study, we investigated spatial and latitudinal variation of benthic macroinvertebrate assemblages associated to Zostera noltei Hornemann, 1832 beds from five semi-enclosed coastal systems (SECSs) ranging from 23°N to 34°N along the Atlantic coast of Morocco. Overall, 17,320 individuals were reported as belonging to 96 taxa. The ecological community descriptors differ significantly at the level of the site. Specific richness showed an inconsistent significant pattern with latitude. The multivariate analyses of the assemblage's composition showed 57% of total variation observed in benthic assemblages, while the PERMANOVA analysis confirmed that this variation is significant at the level of the site. According to DistLM results, variations in belowground biomass, and percentage of mud, were the important predictor variables explaining this variation along the large scale of the studied SECS. However, such patterns could be related to other factors such as habitat heterogeneity and regional, biogeographic, and anthropogenic factors. The present study marked the first attempt on broad-scale ecological research of seagrass beds in Morocco and offers baseline data for planning the broad-scale conservation of biodiversity in seagrass beds that remain suffering from multiple human-induced threats such as coastal developments and climate change. [ABSTRACT FROM AUTHOR]

To better understand the biodiversity-biogeographic polar connections between southern South America and Antarctica (SSA & A), we used benthic communities of hydroids as a model to investigate marine assemblages by evaluating classic spatial divisions at different geographical resolutions. Using a georeferenced dataset of 249 species and multivariate analyses, we investigated species' distribution, composition and biogeographic connectivity, and defined assemblages of ecoregions and provinces for the area. Hotspots of rich biodiversity at risk of depletion were defined. Analyses of ecoregions have a more stratified biogeographic structure, and reveal critical regions susceptible to loss of diversity. Analyses of provinces show a clear division between Atlantic-Pacific and Antarctic-Subantartic assemblages, with high biogeographic isolation of the Subantarctic islands. Depending on spatial resolution, the biogeographic position of the Magellan area is spatially contradictory, clustering on the one hand with SSA ecoregions and on the other with Antarctic provinces. Our patterns appear to be driven by different combinations of processes and barriers, reflected in the stratified distribution of hydroids. The high level of endemism and concentration of species at the edge of distribution in the Magellan area and Scotia Arc suggest their transitional nature and particular importance for understanding the historical and ecological connections between SSA & A. [ABSTRACT FROM AUTHOR]

Benthic macrofauna is regularly used in monitoring programmes, however the vast majority of benthic eukaryotic biodiversity lies mostly in microscopic organisms, such as meiofauna (invertebrates < 1 mm) and protists, that rapidly responds to environmental change. These communities have traditionally been hard to sample and handle in the laboratory, but DNA sequencing has made such work less time consuming. While DNA sequencing captures both alive and dead organisms, environmental RNA (eRNA) better targets living organisms or organisms of recent origin in the environment. Here, we assessed the biodiversity of three known bioindicator microeukaryote groups (nematodes, foraminifera, and ciliates) in sediment samples collected at seven coastal sites along an organic carbon (OC) gradient. We aimed to investigate if eRNA shotgun sequencing can be used to simultaneously detect differences in (i) biodiversity of multiple microeukaryotic communities; and (ii) functional feeding traits of nematodes. Results showed that biodiversity was lower for nematodes and foraminifera in high OC (6.2%–6.9%), when compared to low OC sediments (1.2%–2.8%). Dissimilarity in community composition increased for all three groups between Low OC and High OC, as well as the classified feeding type of nematode genera (with more nonselective deposit feeders in high OC sediment). High relative abundant genera included nematode Sabatieria and foraminifera Elphidium in high OC, and Cryptocaryon‐like ciliates in low OC sediments. Considering that future sequencing technologies are likely to decrease in cost, the use of eRNA shotgun sequencing to assess biodiversity of benthic microeukaryotes could be a powerful tool in recurring monitoring programmes. [ABSTRACT FROM AUTHOR]

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

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

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

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

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

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

Submarine canyons play pivotal roles in the physical, biological and ecological processes of coastal areas, especially in closed or semi-closed basins as the Mediterranean Sea, influencing the biodiversity and the abundance of the benthic fauna. On February 2013, during the Tyrrhenian Gravity Flows (TyGraF) campaign, samples have been collected along the Gioia Canyon Basin (Italy) with the aim to describe the taxonomical composition and the abundances of the macrobenthic assemblages, filling the gap of knowledge in this area. A total of 93 taxa were identified, and the Annelida was the phylum with the highest number of specimens and most diversified (46 taxa). The polychaetes Sternaspis scutata, Prionospio cirrifera and Monticellina sp., the bivalves Thyasira sp.1 and Saccella commutata and the amphipods belonging to the genera Ampelisca and Harpinia showed the highest densities in the studied area; however, results suggest low values of the abundances of the macrobenthos if compared with those generally reported for other canyons, both inside and outside the Mediterranean Sea. The marine biotic index (AMBI) highlights that the canyon system and the surrounded area were slightly disturbed and characterized by a high percentage of tolerant taxa. This study is the first baseline for future analyses of the macrobenthic communities of this area. [ABSTRACT FROM AUTHOR]

Although benthic fauna in the Pechora Sea (SE Barents Sea) is generally well-studied, information on the bottom communities in the shallows near islands and the mainland is still sparse. Shallow marine areas in the Pechora Sea serve as important feeding grounds for numerous benthophagous fish, waterfowl and marine mammals, including the Atlantic walrus (Odobenus rosmarus rosmarus). To study the patterns of macrozoobenthic distribution in the shallows and evaluate the ecological state of the zoobenthic populations close to walrus haul-outs, sampling was performed in 2014 and 2016 around an archipelago in the Pechora Sea. In 2014, the average biomass, the Shannon's Diversity Index and the predominance of filter feeders in benthic communities were, in general, similar to the respective characteristics in neighboring deeper areas studied in the 1990s. In 2016, significant differences in species number and in biomass were recorded compared to 2014. An increase was observed in Atlantic boreo-Arctic species. Analysis of the trophic structure showed a slight decrease in the proportion of filter feeders and a significant increase in the proportion of subsurface deposit feeders. However, the Shannon's Diversity and Ecological Stress Indices indicated that the macrozoobenthos in the study area was in a state of equilibrium. Changes in the zoobenthos may result from several factors, such as an increase in water temperature, sediment re-deposition under wind-induced waves and the plowing of bottom sediments by walruses during their foraging. [ABSTRACT FROM AUTHOR]

An anomalous El Niño-associated sea surface temperature stress event was predicted to affect tropical Australian reefs, including those in North Western Australia in the summer of 2015/2016. Thermal stress events are well known to result in widespread hard coral mortality events, but other symbiotic organisms such as soft corals, giant clams and sponges can also be affected. Here, we examine whether the 2016 thermal stress event deleteriously impacted coral reef communities in the remote Bonaparte Archipelago, central inshore Kimberley bioregion, North West Australia. Our results confirm the region experienced a thermal stress event of similar magnitude to other regional localities (i.e., southern Kimberley and Scott Reef), but contrary to those locations that experienced widespread bleaching events, we find no evidence to suggest widespread mortality events occurred among photosymbiotic organisms in the Bonaparte Archipelago. Photosymbiotic organisms in this region are assumed to be well adapted to fluctuating environmental conditions; however, in this instance, a greater magnitude of night-time cooling may have driven variability in regional susceptibility to thermal stress. The Bonaparte Archipelago is emerging as a globally significant ecological refuge for photosymbiotic benthic fauna that are threatened by cumulative anthropogenic and climate stressors in other parts of their distribution. [ABSTRACT FROM AUTHOR]

Aquatic macroinvertebrates are widely used as bioindicators for water quality assessments involving different kinds of disruptive factors, such as hydrological regime variations or pollutant spills. Recently, they demonstrated to be effective in monitoring effects of climate change in alpine stream and rivers. Indeed, since the distribution of macroinvertebrates in glacier-fed streams has been succesfully investigated and described by several authors, the discrepancy in presence/absence and quantity of specific taxa from the established models may represent an early warning of the effects of climatic changes occurring in alpine riverine ecosystems. New information Together with the present paper, we provide a dataset covering a period of 6 years (2010-2015) sampling of aquatic macroinvertebrates along a longitudinal transect of a glacier-fed stream located in the Italian Alps, inside the International Long Term Ecological Research (ILTER) macrosite of Matsch|Mazia (IT-25). Data were collected during the glacial melt period (April - September), with monthly resolution. Owing to the unique temporal resolution of the dataset, we aim to produce a reliable tool (i.e. reference point) for future ecological assessment on the same stream, but also to similar streams worldwide. [ABSTRACT FROM AUTHOR]

We describe the invertebrate assemblages in the Middle Jurassic to lowermost Cretaceous of the Agardhfjellet Formation present in the DH2 rock-core material of Central Spitsbergen (Svalbard). Previous studies of the Agardhfjellet Formation do not accurately reflect the distribution of invertebrates throughout the unit as they were limited to sampling discontinuous intervals at outcrop. The rock-core material shows the benthic bivalve fauna to reflect dysoxic, but not anoxic environments for the Oxfordian-Lower Kimmeridgian interval with sporadic monospecific assemblages of epifaunal bivalves, and more favourable conditions in the Volgian, with major increases in abundance and diversity of Hartwellia sp. assemblages. Overall, the new information from cores shows that abundance, diversity and stratigraphic continuity of the fossil record in the Upper Jurassic of Spitsbergen are considerably higher than indicated in outcrop studies. The inferred life positions and feeding habits of the benthic fauna refine our understanding of the depositional environments of the Agardhfjellet Formation. The pattern of occurrence of the bivalve genera is correlated with published studies of Arctic localities in East Greenland and northern Siberia and shows similarities in palaeoecology with the former but not the latter. Ammonite biostratigraphy is used as a tool to date bivalve assemblage overturning events to help identify similar changes in other sections. [ABSTRACT FROM AUTHOR]

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Highlights • Suprabenthic assemblages from the Blanes Canyon and adjacent slope were analysed. • High-energy hydrodynamic events and topography are drivers of biodiversity. • Suprabenthic assemblages were similar in the canyon and slope at greater depths. • "Canyon effect" on suprabenthic assemblages was suggested at depths 1200 m). At shallowest depths, the canyon sites were characterized by a high contribution of motile omnivores while the slope sites were characterized by a high contribution of detritivores to the total abundance. Highly motile predators on zooplankton were dominant at deepest sites in both environments. Our results suggest that taxonomic and trophic diversity in the northwestern Mediterranean may be influenced by the abrupt topography and its interaction with hydrodynamic conditions (intensification of currents; variable intensity of disturbance/hydrodynamic events; food pulses linked to food availability). These are major drivers which influence the spatial and temporal availability of food sources to the various faunal compartments eventually propagating up the food web. [ABSTRACT FROM AUTHOR]

Abstract Biogenic habitats play important roles in shallow-water ecosystems, but their roles in deeper waters are less well-studied. We quantitatively assessed 19 glass sponge reefs in the Salish Sea for live reef-building sponge cover and biodiversity, explored potential drivers behind variation observed among reefs, and quantified individual and collective roles the reefs play in filtration and carbon removal. The reefs support diverse and abundant communities of invertebrates and fish, with 115 unique taxonomic groups observed. Sponge cover varied widely between reefs: percent live reef-building sponge cover ranged from 0.2 to 17.5% and proportion of live reef habitat category ranged from 0.2 to 92%. These differences were predominantly driven by the seabed terrain characteristics such as seafloor rugosity, curvature, and depth; human pressure measures explored in this study − density of anthropogenic objects and fishing footprint over the past 17 years – did not mask the natural influence of seabed terrain. The difference in sponge cover between the reefs led to wide variation in ecosystem function with individual reefs processing between 465 and 47,300 L/m2 per day. Collectively, each day the 19 reefs filter 1.04 × 1011 L of water which corresponds to 1% of the total water volume in Strait of Georgia and Howe Sound combined. The reefs remove up to 1 g of carbon per m2 per day, comparable to carbon sequestration rates reported for terrestrial old growth forests and to "blue carbon" sequestration rates by marine vegetation. Implications for sponge reef conservation and monitoring are discussed. Highlights • 19 glass sponge reefs in the Salish Sea vary in live sponge cover. • Live sponge cover is driven by seabed terrain despite significant human pressure. • Over 115 unique taxonomic groups of invertebrates and fish live on the reefs. • Reefs collectively filter 1.04 × 1011 L of water daily, 1% of basin water volume. • Reefs remove up to 1 gC/m2 daily, comparable to terrestrial and kelp forests. [ABSTRACT FROM AUTHOR]

Continuous modelling and discrete classification (aka typology) are two approaches commonly used to partition natural, spatial variability, and ultimately gauge anthropogenic effects on biodiversity loss and other valued ecosystem services. Using benthic invertebrate assemblages of boreal lakes and streams, we tested the efficacy of continuous modelling and discrete classification for partitioning natural variability of sites judged to be in reference condition. We anticipated that species distributions and assemblage composition would be more accurately predicted by models in general and specifically that models based on suites of predictor variables would outperform models based on a limited number of variables. Furthermore, we predicted that more flexible typologies would perform better than approaches using sets of mandatory categorical variables. Our results showed that models were more accurate at estimating species distributions and assemblage composition than typologies. Furthermore, models calibrated with only a few typology based variables were as accurate as full models, indicating that the main environmental gradients were captured by the classification variables used in our study. Continuous modelling also had lower incidences of false positives (<7%) compared to typological approaches (3.8–56%), i.e. a lower frequency of classifying reference sites as possibly impaired. The findings that continuous modelling outperformed discrete classification and that the latter had substantially higher frequencies of false positives is somewhat disconcerting given the relatively widespread use of typologies in bioassessment and management. Misclassification results in the unnecessary use of resources to re-classify sites, or more seriously implementation of unwarranted measures of rehabilitation. [ABSTRACT FROM AUTHOR]

Scleractinian cold-water corals (CWCs) are one of the most important habitat engineers of the deep sea. Although the South China Sea (SCS) abuts the biodiversity center of scleractinian CWCs in the western Pacific, only a few sporadic records are available. We discovered new CWC sites by means of trawl sampling and video observation along the continental shelf of the northwestern SCS. All trawled scleractinian CWC specimens were identified to species level according to skeleton morphology and structure. The living CWCs and associated fauna recorded in the video were -identified to a higher level of classification. Scleractinian corals were identified to genus level, while non-scleractinian CWCs were identified to family level and given general names such as gorgonian corals, bamboo corals and black corals. Associated benthic dwellers were divided into major categories. A total of 28 scleractinian CWC species were identified to 7 families, 15 genera, and 1 additional subgenus. Among them, 13 species were colonial, including important habitat-forming species in the genera Eguchipsammia, Dendrophyllia and Cladopsammia. Non-scleractinian CWCs were identified to 7 families, including 4 families gorgonian corals, 1 family bamboo corals, and 2 families black corals. Gorgonian corals were the most abundant non-scleractinian CWCs in this region. Meanwhile, starfish, sea anemones, fish, gastropods, echinoderms, and other associated benthic fauna were recorded in the CWC habitats, with starfish belonging to the order Brisingida being most common. New scleractinian CWC assemblages were discovered along the continental seabed mounds in the northwestern SCS. This study highlights the remarkable diversity of cold-water scleractinian corals in the whole SCS, and shows the potential widespread distribution and conservation prospect of CWC habitats in this region. • The first study of cold-water corals was conducted in the South China Sea by the combined method of trawling and video observation. • New scleractinian CWC assemblages were discovered with high diversity along the continental seabed mounds. • The presence of CWC habitat was confirmed with many non-scleractinian CWCs and other associated benthic taxa. [ABSTRACT FROM AUTHOR]

The organic pollution of the Upper Vistula waters has been significantly reduced since the mid-20th century. Also salinity has gradually decreased, following an increase observed until the 1990s. Furthermore, the number of alien species has systematically increased. The above-mentioned changes have affected the richness and composition of the benthic fauna. They are particularly remarkable in the river stretch between the town of Oswiecim and the city of Kraków. The improvement of water quality has resulted in the increased number of taxa, mainly those characteristic of moderately polluted water, and the disappearance of taxa typical of strongly polluted or deoxygenated water. Despite the increased salinity level persisting for many years, only three benthic species of brackish waters (Gammarus tigrinus, Paranais frici and P. litoralis) were found in the Upper Vistula. Taxa considered to be euryhaline or halophilous were more numerous. In the 1960s, only one alien species (Physa acuta) was found, but the increased number of non-indigenous species in the last decades is visible, particularly among gammarid crustaceans (Amphipoda, Gammaroidea). The presence of alien species has not caused any visible changes in the species abundance of oligochaetes and mollusks. [ABSTRACT FROM AUTHOR]

Benthic invertebrates support numerous ecosystem functions and services including shellfish production, energy flow to fishes, and biogeochemical cycles. The decline of marine biodiversity worldwide has raised concerns about effects on ecosystems. To examine biodiversity trends of Narragansett Bay over time, a list was compiled of all benthic invertebrate species collected from the bay since 1834. The list covers 104 studies spanning 182 years and currently holds 1214 unique taxa from 21 phyla, the majority of all animal phyla on Earth. A permuted estimator of number of species suggested there are about 300 more yet to be discovered. Widely varying sampling gear and sieve mesh sizes precluded the use of abundance data. Instead, multidimensional scaling and taxonomic distinctness were used with presence-absence data to examine biodiversity trends. The changes in community composition and decline of benthic biodiversity (p < 0.01) since 1855 are what would be expected of a community that gradually deteriorated in the face of increasing anthropogenic stressors. Taxonomic distinctness had negative correlations (p < 0.05) with human population in the watershed, total nitrogen inputs, and inputs of metals. This loss of benthic biodiversity has implications for ecosystem functions and services. As some of the stressors waned in the last two or three decades, following passage of environmental legislation in the 1970s, biodiversity appeared to show a partial recovery. An inventory of species, how it has changed over time, and understanding what caused those changes are important for assessing whether remediation programs are achieving improved water quality and ecosystem health. [ABSTRACT FROM AUTHOR]

In order to determine the Mollusca fauna of species in Akyaka Azmak Stream, seasonal samplings were made from 2 stations between September 2008-May, 2009. After collecting benthic materials by using a hand-net with 500 μm mesh size and Ekman grab, after sifted, they fixed in 4% formalin solution. As a result of study, totally 10 taxa were determined; all of them belong to Gastropoda as Galba truncatula, Theodoxus anatolicus, Theodoxus fluviatilis, Theodoxus heldreichi, Gyraulus albus, Potamopyrgus antipodarum, Bithynia tentaculata, Bythinella byzanthina, Valvata cristata and Pseudamnicola roddail. The genera of Thedoxus is important for water quality. In the study, they are found very richness at the first station. Also, it has determined some physico-chemical parameter and discussed. [ABSTRACT FROM AUTHOR]

Patagonia is by far the largest glacierized area in South America. However, little is known about ecology, functioning and biodiversity of glacier-fed streams facing global warming. We investigated changes in environmental features and macroinvertebrate communities along a longitudinal gradient of glacier influence of two Patagonian systems that differ in glacier cover magnitude and the spatial sequence of lotic and lentic phases. Both glaciers, Torrecillas (~ 5.5 km 2 , Torrecillas system) and Cónico (~ 0.44 km 2 , Baggilt system), are retreating. Longitudinal distribution of benthic invertebrates partially fitted to predictions for glacierized temperate systems, with Diamesinae spp. dominating at closest sites to the Cónico, and Orthocladiinae increasing downstream, but patterns were unclear at Torrecillas. Generalized Linear Model identified chlorophyll a and conductivity as having significant effect on richness and density respectively at Torrecillas; detritus biomass and gravel influenced species richness, and boulder percentage and water temperature affected density, at Baggilt. Canonical Correspondence Analyses integrating benthic biota and environmental variables revealed that a higher environmental heterogeneity at Baggilt, related with spatial dimension (unshaded/shaded reaches, wetland reaches), local resources (detritus, bryophytes) and temperature, probably explained the unexpected high richness in benthic assemblages (67 taxa). Environmental conditions imposed by the lake outlet (proglacial) at Torrecillas resulted in a less diverse community (31 taxa). Finally our results suggest that these isolated, small glacier-fed streams typical of the Patagonian landscape appear highly vulnerable to global warming. Endemic elements could disappear at upper segments being replaced by other species common at rhithral environments, which might increase local diversity (alfa diversity) but decrease regional diversity (gamma diversity). From an ecosystem perspective stream functioning can result altered. Glacier retreating or disappearing threatens major ecosystem services for Patagonian inhabitants such as water supply, hydrological regulation, recreation and tourism. [ABSTRACT FROM AUTHOR]

ABSTRACT Peterson, A.; Herkül, K., and Torn, K., 2018. Modeling Coastal Benthic Biodiversity Using Georeferenced Environmental Data: Mapping Present and Predicting Future Changes. In: Shim, J.-S.; Chun, I., and Lim, H.S. (eds.), Proceedings from the International Coastal Symposium (ICS) 2018 (Busan, Republic of Korea). Journal of Coastal Research, Special Issue No. 85, pp. 376–380. Coconut Creek (Florida), ISSN 0749-0208. Biodiversity is critical for maintaining and stabilizing ecosystem processes. There is a need for high resolution biodiversity maps that cover large sea areas in order to address ecological questions related to biodiversity-ecosystem functioning relationships and to provide data for marine environmental protection and management decisions. Climate change can significantly impact patterns of biodiversity with substantial implications for ecosystem functioning and human use of marine biological resources. The Baltic Sea is expected to face serious environmental changes due to climate change during the 21st century mainly manifested as changes in salinity and temperature. Thus, it is important to map the biodiversity now and predict the potential future changes. Boosted regression trees (BRT) modeling method was used to produce maps of benthic biodiversity in the northern Baltic Sea. Environmental layers (such as depth, salinity and temperature) were used as independent variables in the models to predict the spatial distribution of species richness. For future predictions, we had climate scenario-based layers for salinity and temperature. BRT modeling proved to have high predictive ability. Based on the models, depth was the most important environmental variable influencing benthic biodiversity. Future biodiversity was predicted to significantly decrease both in terms of numerical values of species richness and spatial coverage (highly diverse area becoming narrower along coastline) compared to nowadays conditions. Our study showed that predictive modeling of biodiversity patterns can give valuable insights into potential future changes. [ABSTRACT FROM AUTHOR]

Due to its complex hydrological, geomorphological and climatic features, the Chilean fjords region is considered among the most productive areas of the world. The benthic fauna of this region accounts for more than 1600 species showing marked latitudinal biogeographic differences characterizing this as one of the most important hotspot of biodiversity of cold-temperate environments. Despite numerous studies have been conducted to depict the biological characteristics of the fjords, the present situation is strongly unbalanced towards specific taxa. Hence, this study takes into consideration a community approach, highlighting the distribution of six benthic assemblages thriving on vertical walls along the Seno Magdalena fjord (Aysen region). Underwater pictures were used to characterize the trends in abundance and diversity of the main taxa showing distinct responses to salinity and turbidity. Among the less tolerant taxa to high fresh water inputs there are encrusting algae, mainly found in the most external sites lashed by outer currents, far from the estuarine plume. The bathymetric zonation of the assemblages, instead, is characterized by a dense mussel belt in the first 10 m, within a thick layer of low-salinity, nutrient-enriched waters. Rich assemblages of sponges, brachiopods, gorgonians and scleractinians thrive in deeper, marine, clear waters. The evaluation of the ecological role of benthic species leads both to the definition of potential bioindicator taxa responding to anthropic disturbances and to the promotion of protected areas. [ABSTRACT FROM AUTHOR]

Community ecology has broadened considerably with the recognition that it is not only at the species-level data where biological patterns and their determinants should be studied. Rather, also functional and phylogenetic data should be examined, as they may provide important information for both basic ecology and applied fields such as conservation and bioassessment. We thus explored the distance decay of taxonomic, functional, and phylogenetic community compositions along spatial and environmental gradients within a boreal lake metacommunity. We used distance-based methods (i.e., Mantel test, Mantel correlograms and db-RDA) to examine different facets (i.e., taxonomic, functional, and phylogenetic) and components (i.e., total, turnover and nestedness-resultant) in relation to spatial and environmental variables. We found that the species compositions of lake benthic invertebrate communities varied mostly along environmental gradients, but were also weakly related to spatial distances between lakes. We also showed that functional and phylogenetic compositions were solely related to environmental variation across the lakes, but these relationships were generally weak. Our exploration of different facets and components of beta diversity added to the knowledge of lake invertebrate communities by adding functional and phylogenetic views, which has rarely been done in studies of aquatic metacommunities. Such information is also important in valuing lakes for conservation and bioassessment because it is not only at the species-level data where ecological patterns and underlying mechanisms should be explored. [ABSTRACT FROM AUTHOR]

Benthic hydroids are an important component of the Antarctic benthic ecosystem. They have been studied since the first Antarctic expeditions, and in recent years, there has been an important increase in biodiversity studies. In order to analyse the relationship among different areas and validate/dismiss previous biogeographical hypotheses, we have compiled all valid records of the known benthic hydroid species from the Antarctic and Sub-Antarctic regions, and used two previous scheme divisions of the Southern Ocean. In both cases, a hierarchical cluster was performed with the SIMPROF test. Our results suggest the division of the Southern Ocean into three main regions: the first corresponds to the classical Patagonian region; the second consists of the Kerguelen Archipelago, Crozet Island, Prince Edward Islands and Bouvet; the third, here referred to as the Antarctic region, is formed by South Georgia, the Scotia Arc archipelagos and High Antarctica. The results obtained also support the classical division of High Antarctica into two subregions, corresponding to West and East Antarctica. Nevertheless, the limits between both regions are still unclear, mainly because of the scarcity of data from some areas and the complete absence of information from others. [ABSTRACT FROM AUTHOR]

Although the Erfelek Stream is a small stream with a total length of 80 km and a flood discharge of 302.1 m3/sec, from its source to the place where it merges with the sea. It is ecologically very important for its immediate environment in terms of the zonations created by it and the groups of living organisms it contains. The fact that it is the only stream that reaches the sea by forming a delta between the Kızılırmak and Filyos Stream and that it reaches the sea by drawing meanders in the delta after different geological formations it passes through starting from an altitude of 1370 meters allows it to be a stream rich in biodiversity. Karagöl, which is connected with the sea, which is almost destroyed within the delta, and the Aksaz wetlands, which are still continuing their existence increase the importance of the stream in terms of both aquatic products and other groups of living organisms. In the fauna and flora of the Erfelek stream, the presence e few benthic invertebrate, fish, birds, mammals and plant species have been identified up to now. On this study, the importance of biodiversity and ecology of Erfelek Stream is aimed to be revealed as a result of present data and preliminary observations. [ABSTRACT FROM AUTHOR]

In order to reveal the differentiated responses of plankton and zoobenthos to water quality on both annual and seasonal time scales, an ecological study on plankton and zoobenthos community was conducted during 2011 to 2015 in Nansi Lake in northern China. Different dynamics were found among phytoplankton, zooplankton, and zoobenthos in terms of density, biomass, and biodiversity. On an annual time scale and with deterioration of water quality, density and biomass of plankton and zoobenthos showed different variations, while phytoplankton (density, biomass, and biodiversity) changed significantly when water quality improved. On a seasonal time scale, density and biomass of phytoplankton showed significant differences between spring and summer. Results of Pearson's correlation analysis revealed that phytoplankton, zooplankton, and zoobenthos were significantly affected by different environmental factors. Our study demonstrated that phytoplankton was more sensitive to water quality changes than zooplankton and zoobenthos. These results suggest that density and biomass of phytoplankton could rapidly reflect water quality, whereas biodiversity of phytoplankton could indicate long-term status of water quality combined with the physico-chemical parameters of water. The results could contribute to predicting the dynamics of plankton and zoobenthos in freshwater lakes and to selecting effective bio-indicators for ecosystem health assessment of freshwater lakes. [ABSTRACT FROM AUTHOR]

Generally, environments with a great habitat complexity (HC) can support a great number of species and large abundances of organisms. However, the mechanisms behind this effect are not entirely clear and some studies did not observe positive effects of complexity on diversity and abundance of biological assemblages. Here, HC was considered as an integrative perspective, specifically as different characteristics of physical structure and; it was tested whether abundance and diversity of macrobenthic assemblages of soft bottom are influenced by variation of two characteristics of habitat complexity, the number and evenness of sediment fractions. The hypothesized positive relationships between HC and richness, Shannon-Wiener diversity index and abundance of benthic macrofauna were not observed. The different response variables (richness, Shannon-Wiener, abundance) which consider different dimensions of biodiversity, can show distinct results when the same habitat is compared. For both structural characteristics of the sediment, a large amount of specimens of Bispira sp. (Polychaeta: Sabellidae) and Terebellides sp. (Polychaeta: Trichobranchidae) were observed in the most complex treatments. These taxa were favored by the presence of gravels where their larvae, likely originated from adult populations at nearby habitats, can settle. The multidimensional structure of the benthic macrofauna was significantly influenced by habitat complexity; and considering high taxonomical and functional diversity, multivariate analyses were more appropriated to investigate such complex effects. In this context, it is clear that careful thought must be given to choose appropriated habitat complexity characteristics and biological measurements. Therefore, studies addressing different combinations of structural characteristics of habitat and mechanisms behind the effects on biological communities are still of great need in ecological science. [ABSTRACT FROM AUTHOR]

Rigorous documentation of spatial heterogeneity (β-diversity) in present-day and preindustrial ecosystems is required to assess how marine communities respond to environmental and anthropogenic drivers. However, the overwhelming majority of contemporary and palaeontological assessments have centred on single higher taxa. To evaluate the validity of single taxa as community surrogates and palaeontological proxies, we compared macrobenthic communities and sympatric death assemblages at 52 localities in Onslow Bay (NC, USA). Compositional heterogeneity did not differ significantly across datasets based on live molluscs, live non-molluscs, and all live organisms. Death assemblages were less heterogeneous spatially, likely reflecting homogenization by time-averaging. Nevertheless, live and dead datasets were greater than 80% congruent in pairwise comparisons to the literature estimates of β-diversity in other marine ecosystems, yielded concordant bathymetric gradients, and produced nearly identical ordinations consistently delineating habitats. Congruent estimates from molluscs and non-molluscs suggest that single groups can serve as reliable community proxies. High spatial fidelity of death assemblages supports the emerging paradigm of Conservation Palaeobiology. Integrated analyses of ecological and palaeontological data based on surrogate taxa can quantify anthropogenic changes in marine ecosystems and advance our understanding of spatial and temporal aspects of biodiversity. [ABSTRACT FROM AUTHOR]

Predation within the marine environment has been well-studied and shown to be of major importance in shaping patterns of biodiversity. Typically larger predators, such as fishes, are examined because of the ease of manipulation and strong detectable results, whereas effects of smaller micro-predators are much more difficult to evaluate. Here, we examined the distribution and prey consumption of the polyclad flatworm, Euplana gracilis, in the Chesapeake Bay. Euplana gracilis is a common, micro-predator, but no data exist on its ecological function. Flatworms were found to actively prey upon a single species, the tube-building amphipod Apocorophium lacustre, in lab trials when tested against several other commonly encountered species. To examine natural population densities of flatworms, large-scale field sampling was conducted via benthic grabs and E. gracilis abundances were found to be significantly correlated with A. lacustre particularly in areas close to the shoreline. Some predator-prey interactions were examined including timed observations of consumption, predator size, and tube protection. Flatworm body size was found to correlate strongly with the number of prey consumed over time. Tubes constructed by amphipods were examined as a means of refuge when in the presence of E. gracilis, but provided very little protection as flatworms could easily penetrate tubes in search of prey. Our results are the first to show predation of an estuarine/marine polyclad flatworm on amphipods as well as provide some insight into the dynamics of this previously unknown predator-prey relationship. [ABSTRACT FROM AUTHOR]

The aim of this study was to attempt to fill current knowledge gaps on midlittoral Mediterranean biodiversity at local and regional scales, by using benthic polychaetes as a model taxon. Two different data sets were analysed: (i) a quantitative data set from the two Natural Geography in Shore Areas (Na GISA) study sites in Crete and (ii) a qualitative data set from multiple sites across the Mediterranean. At the local scale, the results provide evidence that (i) discrete species communities are formed in midlittoral Mediterranean habitats, which vary by geographical location and year, depending on the scale of observation; (ii) macrophyte coverage and Chl- a are the only environmental variables associated, albeit weakly, with the above pattern; (iii) although naturally disturbed, the Cretan Na GISA sites do not seem to experience any anthropogenic stress; (iv) environmental heterogeneity and history seem to be much less important in shaping the polychaete communities than inter-specific interactions; however, it is not possible to specify at this stage whether local or regional processes or even their interactions may shape the polychaete communities. At the regional scale, the results indicate that (i) the only factor that seems to be involved in the regional pattern is the identity of the study providing the data sets, which implies variability and bias in how research projects are carried out, from the sampling design through to data collection and analysis; (ii) the Cretan Na GISA sites may be considered as representative of the habitat in the Mediterranean, under certain conditions. [ABSTRACT FROM AUTHOR]

Macrocosm experiments at various scales have been applied in lake eutrophication management worldwide. This study investigated how artificially created macrocosms affect the physicochemical characteristics of lake water, as well as the density, community structure, and biodiversity of benthic diatoms. First, we found that macrocosms were mesotrophic compared to the eutrophic control lake water from March 2012 to February 2013. Second, 148 diatom taxa were recorded across all study sites; both species richness and the number of dominant diatom taxa were higher in the macrocosms, compared with the control lake water. Mean diatom densities in the macrocosms and the control were 8.4 and 21 × 109cells/m2, respectively. Across all sites and seasons,Achnanthidium minutissimumwas the most abundant species and dominant contributor to total abundance (14%). In the macrocosms, other abundant diatom taxa wereCymbella gracilis,Cymbellaaffinis,Gomphonema truncatum, andGomphoneis olivaceum, all of which are associated with high water quality. Canonical correspondence analysis indicated that the variation in benthic diatom communities was strongly related to phosphorus and nitrogen concentrations in macrocosms, but related to pH and total nitrogen in the control. This study suggests that macrocosms created to alter water characteristics have a positive effect on ecosystem biodiversity and function. [ABSTRACT FROM PUBLISHER]

Spatial heterogeneity of biodiversity has been extensively researched, but its spatial homogeneity is virtually unstudied. An intertidal seagrass system at Knysna (South Africa) known to display spatially homogeneous macrobenthic species density at scales ≥0.0275 m 2 was re-investigated at four smaller spatial grains (0.0015 m 2 - 0.0095 m 2 ) via a lattice of 8 × 8 stations within a 0.2 ha area. The aim was to investigate the null hypothesis that spatial homogeneity of species density is not a fixed emergent assemblage property but breaks down at small spatial grains within given spatial extents. Although assemblage abundance was significantly heterogeneous at all spatial grains investigated, both species density and functional-group density were significantly homogeneous across those same scales; observed densities not departing from those expected on the basis of independent assortment. Spatial homogeneity is therefore an emergent assemblage property within given spatial extents at Knysna and probably at equivalent sites elsewhere. Equivalent species density in South Africa, Australia and the UK at spatial grains <0.03 m 2 , however, is a scale-related sampling artefact, as may be temporal homogeneity of species density at Knysna over a 3 year period, but close similarity in shape of their species occupancy distributions remains unexplained. [ABSTRACT FROM AUTHOR]

The seaboard extending from northern Svalbard to Scotland is the only region of the world where fjords have been comprehensively studied for their live (stained) benthic foraminiferal faunas. These modern faunas provide essential baseline data for the interpretation of the postglacial and continuing environmental changes in those fjords and this is the first biogeographic synthesis. The data come from the surface sediment assemblages (mainly sampled in the 1990's) from all the available literature. Due to limited information of shallow water assemblages in the north, only the species occurrences in deeper water from below the halocline are considered. Amongst these, only “common species” species occurring in more than one fjord are included. There is a clear pattern of distribution with five groups of taxa: 5 widespread species found throughout the region; 53 species reaching their northern limit; 13 species reaching their southern limit; 11 deep-sea species; 1 recently introduced species. Although there is an abrupt change in temperature from Tanafjorden in northern Norway to Hornsund in southern Svalbard, the faunal change from N to S is progressive throughout the investigated region. The area of overlap of the northern and southern species corresponds with the previously recognised boundary between the Barents Sea Province and the Norwegian Coast Province based on shelf and upper slope invertebrate macrofaunal benthos and plankton. Temperature is the main abiotic control on the distributions. For the fjords which have shallow sills separating them from the open shelf it is likely that most of the foraminiferal colonisers of the deeper fjord basins are sourced from the shelf or slope via propagules. One species has recently been introduced from further south into the southern region probably through the discharge of ballast water from ships. The biodiversity of the pristine Svalbard fjords extends below what is considered to reflect acceptable ecological status for mainland Norway, illustrating the need to introduce new methods to determine possible deviations from the reference conditions as defined in the EU's Water Framework Directive (WFD; 2000/60/EC). Altogether 347 species have so far been recorded in Norwegian waters: 214 in fjords (60 above and 180 below the halocline of which 26 occur both above and below the halocline) and 266 on the shelf and slope (133 of which also occur in fjords). [ABSTRACT FROM AUTHOR]