Quantity and Quality of Summer Surface Net Zooplankton in the Kuroshio Current-induced Upwelling Northeast of Taiwan

  • Author(s): Houng-Yung Chen and Yuh-Ling Lee Chen
  • DOI: 10.3319/TAO.1992.3.3.321(KEEP)
  • Keywords:
  • Citation: Chen, H.-Y. and Y.-L. Lee Chen, 1992: Quantity and Quality of Summer Surface Net Zooplankton in the Kuroshio Current-induced Upwelling Northeast of Taiwan. Terr. Atmos. Ocean. Sci., 3, 321-334, doi: 10.3319/TAO.1992.3.3.321(KEEP)
Abstract

This study compares the taxa distribution and biochemical composition of zooplankton from stations in a coastal upwelling caused by the intrusion of the Kuroshio Current into the East China Sea shelf. Surface zooplankton samples were taken during a summer cruise of 1989 from 21 stations using a conical net with a mesh size of 330£gm. In addition to zooplankton taxonomical analysis, biochemical compositions of mixed zooplankton hauls including protein, lipid, ash and lipid classes such as phospholipids, free fatty acids, wax or sterol esters, sterols and triacylglycerides were studied. The results indicate that the copepod-dominant zooplankton biomass responded to the upwelling environment. Stations around the upwelling site showed markedly reduced water temperature, increased NO3-N, chlorophyll a and zooplankton concentrations. Zooplankton samples from the upwelled water contained higher proportions of protein and lipid and lower ash content than those from non-upwelling areas. Higher free fatty acid level and lower phospholipid level were also observed in samples from upwelled water. These results suggest an enhancement in upwelling region of zooplankton production in both quantity and quality. Principal component analysis of zooplankton taxa and biochemical composition both indicated the existence of three distinct water masses, that can be related to the Kuroshio Current, the East China Sea continental shelf, and the upwelling. The existence of detritus in the zooplankton samples, which affected the measurement of zooplankton quality and its ecological implications, are discussed.

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