Meiobenthic Communities in Extreme Deep-sea Environment

Abstract

Spatial patterns on the meiobenthic communities in the sediment of variable extreme deep-sea environment were examined. The sediment samples for analysis of meiobenthic comunity structure were collected using ROV, multple corer, TV grab at 20 stations in 5 sites. Totally, 15 meiofauna groups were recorded, Nematodes was the most abundant taxon. Benthic foraminiferans, harpacticoid copepods, polychaetes and nauplius of crustacean were also dominant groups in all site. Total Meiofauna density of study site varied from 49 to 419 ind./10㎠. The maximum density was recorded at the site located in Challenger Deep of Mariana trench, because of flourish of simple benthic foraminifera with organic walls. These distinctive taxa seem to be characteristic of the deepest ocean depths. Active hydrothermal sediments contain up to 150 harpacticoid copepods per 10㎠ of sediment. In th inactive ridge sediments, devoid of macrofaunal organisms, the abundance of harpacticoid copepods never exceeded 15 ind./10㎠. Multivariate analysis (multidimensional scaling) revealed significant differences in community structure among three regions; near the active hydrothermal vent site, the deepest ocean depths site, the other site (common deep-sea bed site).