Microbial community structure across depth gradients on the West Greenland shelf: ECOTIP Arctic metagenome study

The ECOTIP1 study characterizes microbial communities along depth gradients across the West Greenland shelf in southern Baffin Bay. Between 18–28 July 2021, seawater was collected aboard the RV Dana from 25 stations distributed across five transects spanning approximately 64.7–70.6° N, 53–58° W. The sampling campaign covered diverse oceanographic zones from the Nuuk region in the south to beyond Disko Bay in the north, capturing inshore waters near major fjord systems (Kangerlussuaq, Nassuttooq, and Ilulissat), mid-shelf stations, and offshore regions extending to the shelf edge. For metagenomic analysis, five representative stations (6, 10, 15, 17, 21) at 65.98–69.29° N, 52.91–56.96° W were selected to capture the full environmental gradient from surface waters to >550 m depth across inshore, mid-shelf, and offshore locations. At these stations, water was sequentially filtered through 3.0 µm, 0.8 µm, and 0.2 µm membranes, defining large particle-associated (3.0 µm), small particle-associated (0.8 µm), and free-living (0.2 µm) size fractions across depth profiles. DNA was extracted and prepared for shotgun metagenomic sequencing (WGS) to compare taxonomic composition and functional potential across depth categories (surface 0-20m, shallow 20-60m, midwater 60-200m, deep >200m), size fractions, and spatial gradients influenced by Arctic water masses, sea ice meltwater, and glacial freshwater input. This study will include raw sequence reads linked to sample records with comprehensive environmental metadata, and downstream submissions of metagenome-assembled genomes (MAGs) derived from these samples. Funding provided by the European Union Horizon 2020 research and innovation program ECOTIP (grant agreement no. 869383). The ECOTIP project investigated ecological tipping points and cascading effects in Arctic marine ecosystems, with a focus on understanding biodiversity responses to climate change and implications for fisheries production and carbon sequestration.