서인도양 유광층 내 중형동물플랑크톤의 위도별 분포특성

Abstract

We investigated latitudinal distribution of the mesozooplankton biomass and the related environmental characteristics in the euphotic zone of the western Indian Ocean, in order to understand the spatial characteristics in the mesozooplankton associated with the environmental parameters. Samples for analysis of mesozooplankton biomass were collected from the upper 200 m between 5°N and 16°S at 1° latitudinal intervals along 67°E transect in the Indian Ocean during July 2017. Multiple opening/closing net and environmental sensing system (MOCNESS 1 m2 opening, 200 &micro m mesh, haul in speed of 20 m min-1) were towed behind the research vessel ISABU. Sampling depth strata were determined by the vertical structures of thermocline and divided into 3 - 4 layers (i.e. surface mixed layer, middle, and bottom) for the euphotic zone (0 &#8211 200 m). The total abundance and composition of mesozooplankton community is yet to be analyzed. The surface mixed layer (SML) was at an average depth of 50 m from 5°N to 10°S, and the layer deepened towards 16°S. Warmer water (>29°C) was observed at northern latitudes and the temperature gradually decreased towards the southern latitudes (average 27 °C). The upwelling zone was located between 2°N - 4°N, and 7°S &#8211 9°S, which caused a shoaling of the thermocline depth (~50 m). The thermocline (2°N - 4°N) coincided with high concentrations of nitrate and chlorophyll-on associated with the environmental parameters. Samples for analysis of mesozooplankton biomass were collected from the upper 200 m between 5°N and 16°S at 1° latitudinal intervals along 67°E transect in the Indian Ocean during July 2017. Multiple opening/closing net and environmental sensing system (MOCNESS 1 m2 opening, 200 &micro m mesh, haul in speed of 20 m min-1) were towed behind the research vessel ISABU. Sampling depth strata were determined by the vertical structures of thermocline and divided into 3 - 4 layers (i.e. surface mixed layer, middle, and bottom) for the euphotic zone (0 &#8211 200 m). The total abundance and composition of mesozooplankton community is yet to be analyzed. The surface mixed layer (SML) was at an average depth of 50 m from 5°N to 10°S, and the layer deepened towards 16°S. Warmer water (>29°C) was observed at northern latitudes and the temperature gradually decreased towards the southern latitudes (average 27 °C). The upwelling zone was located between 2°N - 4°N, and 7°S &#8211 9°S, which caused a shoaling of the thermocline depth (~50 m). The thermocline (2°N - 4°N) coincided with high concentrations of nitrate and chlorophyll-