Diversity, structure and environmental drivers of benthic epifaunal communities on one Arctic cold seep site based on seafloor image analysis

Cold seeps are hotspots of biodiversity throughout the oceans and one of the agents for changing surrounding sediments (e.g., authigenic carbonate crusts). Decades of seepages studies have revealed the structure of correlated ecology especially chemosynthetic communities. In this study, a shallow water area offshore northern Svalbard, where evidence of methane emission has been observed, is investigated, with the aim of characterising benthic epifaunal communities and seafloor substrates using high-resolution seafloor imagery, and finding the correlation between them. Visual data consists of 2 photomosaics assembled from videos collected using ROV Ægir6000 equipped with an HD video camera. This photo-referenced data was annotated using ArcMap software. All visible epibenthic fauna, more than 30,000 individuals, and this does not even include the thousands of small sponges, was annotated and identified to the lowest possible taxonomic level based on discernible external morphological characteristics. In addition, the seafloor covering the study area was classified into 6 categories based on geomorphology and named according to SOSI standards (a Norwegian national standard for geographical data). All these outcomes are reported in a catalogue which can be used for future surveys. Furthermore, Annotation data will be used to quantify patterns of community diversity, abundance, and structure in relation to seafloor characteristics in a community analysis framework. This work comprises data collected during the CAGE 20-7 cruise conducted in November 2020 as part of the Centre of Excellence for Arctic Gas Hydrate, Environment and Climate (CAGE) at UiT – The Arctic University of Norway and within the framework of the INTPART-AKMA “Advancing Knowledge on Methane in the Arctic (AKMA)”