Community structures and distributional patterns of meiobenthos on the deep seafloor and continental slope of East Sea (Sea of Japan)

Abstract

Meioebtnhic standing stock and community structure were investigated in the on the continental shelf and slope/floor on Ulleung Basin of East Sea (Sea of Japan). The East Sea is a semi-enclosed and mid-latitude marginal sea (total area: 1.01×106 km2, average depth: 1684 m), surrounded by Korea, Japan and Russia. Samples for meiobenthic study were collected at 29 stations (water depth: 74~2155 m) in the continental shelf near the Korea strait and the southern slope area of the Ulleung Basin during the cruise of R/V EARDO. Totally 15 meiobenthos taxa (2-9 taxa at each station) were found. Nematodes were the most abundant taxon (53~80%). Benthic foraminiferans (7~39%) were next dominant groups at the most of allsites. The total meiobenthos density varied from 42 to 3,697 ind./10cm2 (nematodes: 29~3,320 ind./10cm2) and biomass were 11~1,671 &micro g/10cm2 at each station. Distribution of meiobenthic animal in the Ulleung Basin of East Sea showedhigh densities at the stations within the southern slope part of the Ulleung Basin. In several stations in southern slope area of Ulleung Basin, very high standing stocks of meiobenthic animal (over 2000 ind./10cm2, 1000 &micro g/10cm2)werefound. This hot spot is located in the site with high TOC concentration. In such eutrophic environment, high organic food supply may promote meiobenthic abundance and biomass.1×106 km2, average depth: 1684 m), surrounded by Korea, Japan and Russia. Samples for meiobenthic study were collected at 29 stations (water depth: 74~2155 m) in the continental shelf near the Korea strait and the southern slope area of the Ulleung Basin during the cruise of R/V EARDO. Totally 15 meiobenthos taxa (2-9 taxa at each station) were found. Nematodes were the most abundant taxon (53~80%). Benthic foraminiferans (7~39%) were next dominant groups at the most of allsites. The total meiobenthos density varied from 42 to 3,697 ind./10cm2 (nematodes: 29~3,320 ind./10cm2) and biomass were 11~1,671 &micro g/10cm2 at each station. Distribution of meiobenthic animal in the Ulleung Basin of East Sea showedhigh densities at the stations within the southern slope part of the Ulleung Basin. In several stations in southern slope area of Ulleung Basin, very high standing stocks of meiobenthic animal (over 2000 ind./10cm2, 1000 &micro g/10cm2)werefound. This hot spot is located in the site with high TOC concentration. In such eutrophic environment, high organic food supply may promote meiobenthic abundance and biomass.