Biology subjects

Vedenin, A.

Publications and source records attributed to Vedenin, A..

3 recordsLinked to original sources

bioRxiv2022

Habitat types and megabenthos composition from three sponge-dominated high-Arctic seamounts

Seamounts are isolated underwater mountains often stretching >1,000 m above the seafloor. They are usually identified as biodiversity hotspots of marine life, and host benthos assemblages that may vary on regional (among seamounts) and local (within seamounts) scales. Here, we collected seafloor imagery of three seamounts at the Langseth Ridge in the central Arctic Ocean to assess habitats and megabenthos community composition at the Central Mount (CM), the Karasik Seamount (KS), and the Northern Mount (NM). The majority of seafloor across these seamounts comprised bare rock, covered with a mixed layer consisting of sponge spicule mat intermixed with detrital debris composed primarily of polychaete tubes as well as sand, gravel, and/ or rocks. The megabenthos assemblages consisted of in total 15 invertebrate epibenthos taxa and four fish taxa, contributing to mean megabenthos densities of 55,745 ind. ha-1 at CM, 110,442 ind. ha-1 at KS, and 65,849 ind. ha-1 at NM. The faunal assemblages at all three seamounts were dominated by demosponges of the order Tetractinellida that contributed between 66% (KS) and 85% (CM) to all megabenthos. Megabenthos assemblages living on bare rock or on mixed substrate differed among seamounts and across individual seamounts.

ecology↗

bioRxiv2019

Deep-sea megabenthos communities of the Eurasian Central Arctic are influenced by ice-cover and sea-ice algal falls

Quantitative camera surveys of benthic megafauna were carried out during the expedition ARK-XXVII/3 to the Eastern Central Arctic basins with the research icebreaker Polarstern in summer 2012 (2 August-29 September). Nine transects were performed for the first time in deep-sea areas previously fully covered by ice, four of them in the Nansen Basin (3571-4066m) and five in the Amundsen Basin (4041-4384m). At seven of these stations benthic Agassiz trawls were taken near the camera tracks for species identification. The observed Arctic deep-sea megafauna was largely endemic. Several taxa showed a substantially greater depth or geographical range than previously assumed. Variations in the composition and structure of megabenthic communities were analysed and linked to several environmental variables, including state of the sea ice and phytodetritus supply to the seafloor. Three different types of communities were identified based on species dominating the biomass. Among these species were the actiniarian Bathyphellia margaritacea and the holothurians Elpidia heckeri and Kolga hyalina. Variations in megafaunal abundance were first of all related to the proximity to the marginal ice zone. Stations located closer to this zone were characterized by relatively high densities and biomass of B. margaritacea (mean 0.2-1.7 ind m-2; 0.2-1.5 g ww.m-2). The food supply was higher at these stations, as suggested by enhanced concentrations of pigments, organic carbon, bacterial cell abundances and porewater nutrients in the sediments. The fully ice-covered stations closer to the North Pole and partially under multi-year ice were characterized by lower concentrations of the same biogeochemical indicators for food supply. These stations nevertheless hosted relatively high density and biomass of the holothurians E. heckeri (mean 0.9-1.5 ind m-2; 0.3-0.4 g ww.m-2) or K. hyalina (mean 0.004-1.7 ind m-2; 0.01-3.5 g ww.m-2), which were observed to feed on large food falls of the sea-ice colonial diatom Melosira arctica. The link between the community structure of megafauna and the extent and condition of the Central Arctic sea-ice cover suggests that future climate changes may substantially affect deep ocean biodiversity.

ecology↗

bioRxiv2018

Spatial distribution of benthic macrofauna in the Central Arctic Ocean

Permanent ice coverage and the low primary production in the mostly ice-covered Central Arctic ocean basins result in significantly lower biomass and density of macrobenthos in the abyssal plains compared to the continental slopes. However, little is known on bathymetric and regional effects on macrobenthos diversity. This study synthesizes new and available macrobenthos data to provide a baseline for future studies of the effects of Arctic change on macrofauna community composition in the Arctic basins. Samples taken during three expeditions (in 1993, 2012 and 2015) at 37 stations on the slope of the Barents and Laptev Seas and in the abyssal of the Nansen and Amundsen Basins in the depth range from 38 m to 4381 m were used for a quantitative analysis of species composition, abundance and biomass. Benthic communities clustered in five depth ranges across the slope and basin. A parabolic pattern of species diversity change with depth was found, with the diversity maximum for macrofauna at the shelf edge at depths of 100-300 m. This deviates from the typical species richness peak at mid-slope depths of 1500-3000 m in temperate oceans. Due to the limited availability of standardized benthos data, it remains difficult to assess the massive sea ice retreat observed in the past decade has affected benthic community composition. The polychaete Ymerana pteropoda and the bryozoan Nolella sp. were found for the first time in the deep Nansen and Amundsen Basins, as a potential first sign of increasing productivity and carbon flux with the thinning ice.

ecology↗