Preliminary Data on the Depth Effect on the Nematode Community in the East Siberian Sea

Abstract—

The nematode community was studied at eight stations in the eastern part of the East Siberian Sea shelf (43 m), along the slope, and at a deep-sea site (1350 m). All samples (depth range 43–1350 m) were collected with a MUC corer in the northeastern part of the East Siberian Sea during cruise ARA10C of the R/V Araon in 2019. The taxonomic composition of the nematode community is typical of the Siberian Arctic seas in summer–autumn. The nematode diversity of the East Siberian Sea is poor in comparison with other Russian Arctic seas. Nematode genera typical of the shelf and deep sea were identified. The nematodes density in the uppermost sediment layer increases from the southernmost station along the shelf, amount a maximum on the outer shelf, and decreases downhill with the minimum at the deepest site. It is suggested that the high nematode abundance and diversity on the outer slope was provided by high organic matter fluxes at the boundary of water masses, increasing the oxygen and silt content in sediments.