2005년 여름의 울릉분지의 하위영양 생태계의 생산력과 구조

Abstract

The Ulleung Basin, located in the southwestern part of JES, is a complex environment which is characterized by different types of waters: the North Korean Cold Water from north; the Tsushima Current, a branch of the Kuroshio, which carries diluted water from the Changjiang River; and the coastal current flowing northward along the eastern Korean Peninsula which carries freshwater as well as up-welled intermediate water from depths. Frequently eddies also formed from the Tsushima Current reflecting the bottom topography of the Ulleung basin. In July 2005, a cruise conducted surveys of hydrography, structure and productivity of lower trophic communities, and flux of carbon in a region between 35.5~37.5N and 129.5~ 132E. A strip of high chlorophyll concentration was formed in the entrained coastal waters along the west side of an anti-cyclonic eddy in the center of the Ulleung basin. Community structure of the lower trophic level components in the area was different from other areas. Partial pressure of carbon dioxide in the surface water was also lower than that in the air while in other areas the reverse was true. Primary production ranged 281~772 mg C m-2 d-1 over the whole study area. The export production at 100m depth based on sediment traps was estimated 36~44 mg m-2 d-1 inside the eddy, while estimates based on POC/Th methods gave lower values. We discuss how the different structure in the lower trophic level communities might influence the carbon flux in the region.