Effects of sea ice retreat and ocean warming on the Laptev Sea continental slope ecosystem (1993 vs 2012)

• DOI: 10.3389/fmars.2022.1004959
• Publication Date: 2022-12-21T09:01:23Z
• Authors: Christina Bienhold; Vibe Schourup-Kri...; Thomas Krumpen; Eva-Maria Nöthig; Frank Wenzhöfer; Meri Korhonen; Myriel Vredenborg; Laura Hehemann; Antje Boetius
• Keywords: Seafloor Spreading; Phytodetritus

The central Arctic Ocean is rapidly changing due to amplified warming and sea ice retreat. Nonetheless, it remains challenging document decipher impacts on key ecosystem processes such as primary production pelagic-benthic coupling, limited observations in this remote area. Here we investigated environmental changes at the Laptev Sea continental slope (60-3400 m water depth) from surface seafloor, by replicating sample transects two decades apart. Mean break-up of occurred earlier mean freeze-up later 2012 compared 1993, extending ice-free period more than 30 days. On average, model results showed an annual increase 30% study area 2012. In contrast, calculated modelled fluxes particulate organic carbon (POC) seafloor were only slightly higher did not extend far into deep production, possibly a developed retention system. Nevertheless, benthic surveys revealed substantial phytodetritus availability along entire transect shelf edge sea. This calls for input lateral advection shelves, additional ice, and/or late summer bloom. We also composition activity bacterial communities potential linkages observed changes. While abundance, biomass overall community structure no systematic differences between contrasting years all depths, extracellular enzymatic activities had increased result food availability. was partly reflected oxygen uptake, indicating moderate impact remineralization rates time sampling. Our show considerable effects ocean loss Sea, which are likely continue coming decades.