Bryozoan communities off Franz Josef Land (northern Barents Sea, Russia): Distribution patterns and environmental control

Franz Josef Land is located in the northern region of the Barents Sea and is subjected to the constant influx of cold Arctic water. Although this area is difficult to access, several benthic surveys have been conducted to evaluate the spatial patterns and community structure of the local fauna. However, there is a lack of information regarding the structure of bryozoan communities in this region during the ongoing climate change period. Therefore, we studied the species composition and spatial distribution of bryozoan diversity and biomass at 17 stations sampled by a 0.1 m² Van Veen grab in the southern region of the archipelago between 2006 and 2008. We found 151 bryozoan species, with Turbicellepora incrassata, Celleporina ventricosa, Leieschara subgracilis, Porella compressa, and Escharopsis lobata being the most prevalent. The proportions of Boreo-Arctic, Arctic, and boreal taxa were 55.6%, 35.8%, and 8.6%, respectively. Twenty-two species were recorded for the first time in this region, including seven boreal species (31.7% of their total number) probably as a result of climate change in the Arctic. Alpha-diversity ranged from 3 to 76, with a mean value of 26 species. Bryozoan biomass ranged from 0.1 to 742 g m⁻², averaging 139.4 g m⁻². Cluster analysis revealed three groups of stations following the depth gradient and sediment composition in shallow and deep waters. The primary environmental drivers of bryozoan communities were depth and temperature (negative association) and contents of stones and shells (positive link). Our research addresses crucial knowledge gaps, such as benthic diversity shifts during the climate change period and the impact of ecological factors on community structure.