AUTHOR=Meyer Heidi K. , Roberts Emyr M. , Mienis Furu , Rapp Hans T. TITLE=Drivers of Megabenthic Community Structure in One of the World’s Deepest Silled-Fjords, Sognefjord (Western Norway) JOURNAL=Frontiers in Marine Science VOLUME=7 YEAR=2020 URL=https://www.frontiersin.org/journals/marine-science/articles/10.3389/fmars.2020.00393 DOI=10.3389/fmars.2020.00393 ISSN=2296-7745 ABSTRACT=
The Sognefjord is the longest (205 km) and deepest (1308 m) fjord in Norway, and the second-longest in the world. Coast-fjord exchange in Sognefjord is limited by a seaward sill at 170 m water depth, which causes a clear stratification between water masses as the dense oxygen-poor basin water mixes slowly with the well-oxygenated water directly above from the coastal ocean. Due to the homogeneity and limited variability in the deep-water, the deep slopes of Sognefjord represent the ideal setting to study how abiotic factors influence the deep-water benthic community structure. During the summer of 2017, two remotely operated vehicle (ROV) video transects were performed to compare the megabenthic community behind the sill (water depth: 1230 to 55 m; transect length: 1.39 km; distance from sill: ∼17 km) and within the central fjord (water depth: 1155–85 m; transect length: 2.43 km; distance from sill: ∼79 km). Accompanying conductivity–temperature–depth (CTD) deployments were made to measure the