Distributions of Dissolved Inorganic Nutrients in the Southwestern East Sea in Summer |
하계 동해 남서해역에서 영양염류 분포 특성 |
김태훈 |
제주대학교 |
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Abstract |
Vertical and horizontal distributions of nutrients in the southwestern East Sea (ES) were investigated in the summer of 2006 (12-15 July). The ratio of dissolved inorganic nitrogen (DIN) to dissolved inorganic phosphate (DIP) (12.1) was much lower than the Redfield ratio (16) over the entire depth of the East Sea. The concentrations of DIN relative to those of DIP and dissolved inorganic silicate (DSi) decreased exponentially as the intensities of fluorescence, an index of chlorophyll a, increased in the surface layer (0-200 m). This result indicates that the ES is in a significantly DIN-deleted condition. The fluorescence intensity recorded the highest in the mixed layer (<10 m). Although the concentrations of nutrients in the mixed layer were much lower, a supply of nutrients for the growth of phytoplankton in the southwestern ES seems to be associated with physical processes, such as coastal upwelling and the mixed surface water between Changjiang Diluted Water (CDW) and Tsushima Surface Water. Relatively higher nutrient concentrations were observed in lower salinity waters in the range of 30.31~30.50. The intensities of fluorescence showed a negative correlation with salinity.
These results suggested that nutrient inputs derived from CDW into the southwestern ES may play an important source for the growth of phytoplankton in summer. |
Key Words:
East sea, Nutrient, Upwelling, Changjiang diluted water, Mixed layer |
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