인도양 중앙해령대 열수분출공 수층 동물플랑크톤 분포특성

Abstract

Mesozooplankton from the Indian Ridge hydrothermal vent fields were collected with a 1 m2 multiple opening-closing net and environmental sensing system (MOCNESS) to examine the distribution, taxonomic and species composition. The hydrothermal vents Solitaire(INVENT A), Onnuri Vent Field (OVF), and reference site (ref-site) sampling were conducted with oblique tows from ~100 m above the bottom of the basin (~2,500 m) to the surface. The total abundance of mesozooplankton were26,376 inds. 100 m-3, 82,344 inds. 100 m-3, 97,663 inds. 100 m-3, in INVENT A, OVF and ref-site, respectively. The abundance were higher at the surface mixed layer (0-200 m) (INVENT A: 19,478 inds. 100 m-3 OVF: 72,954 inds. 100 m-3 ref-site: 77,382 inds. 100 m-3). The taxonomic groups foraminiferans, copepods, chaetognaths, radiolarians, ostracods, appendicularians, crustacean larvae, amphipod larvae, polychaete larvae, and mollusc larvae appeared at all survey stations. Copepods (immature and adults) were dominantly distributed (average = 72.7%) in all the stations. The dominant adult copepods were poecilostomatoida Oncaea media (INVENT A: average = 3.5% ref-site: average = 2.4%), and calanoida Paracalanusaculeatus (OVF: average = 2.9%). Gastrodpod larvae, bivalve larvae and amphipod larvae appeared at INVENT A and OVF, and decapod larvae, polychaete larvae and gastropod larvae appeared at ref-site.