여름철 東中國海의 海洋構造와 植物色素量 分布特性

A thermohaline structure and distribution of chlorophyll a in the east China sea in summer

Field observation were carried out on oceanographic conditions and phytoplankton biomass, such as chlorophyll a in the East China Sea along the 31˚30 N latitude in August 1992. As a result of water mass on T-S diagram, two characteristic water mass were identified. We can divide them into coastal water mass and oceanic water mass. The former are characterized by high temperature and low salinity originated China territory, while the latter are low temperature and high salinity originated from kuroshio warm current, between them internal discontinuous layer was formed at the intermediate depth (between 10m and 20m layer). In the coastal water regions, dissolved oxygen(DO) were supersaturation in the chlorophyll a rich water which indicated active photosynthesis. And not only nutrient concentration but also chlorophyll a concentration were higher than oceanic water regions. On the other hand, in the oceanic water regions from Kuroshio warm current, DO were unsaturation which indicated active mineralization. And not only nutrients but chlorophyll a concentrations were lower than coastal water regions. Phytoplankton biomass, such as concentration of chlorophyll a in the East China Sea were controlled by nutrient concentrations, especially they were limited by nitrogen source.