동중국해의 여름철 식물플랑크톤 증식

Abstract

The East China Sea is a marginal sea which connects to the open ocean, and its physical, chemical and biological environments are influenced by the Kuroshio Current The discharge of Changjiang River also severely affects the water properties in summer time. We conducted a cruise in the region circumscribed by 32 ~ 34°S and 124 ~ 127.5°E which is northeastern from the estuary of Changjiang River. We measured temperature, salinity, chlorophyll a, and bio-optic parameters.Sea-viewing Wide Field-of-view Sensor (SeaWiFS ) and MODIS (Moderate Resolution Imaging Spectrometer) chlorophyll data were obtained from NASA Data Active Archive Center (DAAC), and the data consist of level-2 (approximate 1 km resolution) and level-3 (spatially, approximate 4.5 and 9 km resolution; temporally, daily, 8-days, and monthly, respectively). To verify that the satellite chlorophyll is actual chlorophyll, we compared Rrs (remote sensing reflectance) spectra in the four regions and two representative regions which are sediment laden water and chlorophyll dominant water, respectively. A large scale (circa. 200 × 200 km) bloom in the south of Jeju Island appeared and continued for about twenty days. If the large bloom remains twenty days, primary production will be increased by about 330 kilo-ton Carbon. The fate of this additional production in the ecosystem is of interest. Such large scale blooms were also observed in summertime in 1998, 1999, 2003, and 2004. Here, we address two questions. Firstly, what may control phytoplankton bloom pattern in this region? Especially, we focus on the year-to-year variation of bloom positions. Secondly, what could induce the phytoplankton bloom in this region? The results and uncertainties are discussed.