An Observation of Primary Production Enhanced by Coastal Upwelling in the Southwest East/Japan Sea

Doshik Hahm, Pusan National University, Department of Oceanography, Busan, Korea, Republic of (South), Tae Siek Rhee, KOPRI Korea Polar Research Institute, Incheon, South Korea, Hyun Cheol Kim, Korea Polar Research Institute, Incheon, Korea, Republic of (South), Chan Joo Jang, KIOST Korea Institute of Ocean Science and Technology, Ansan, Korea, Republic of (South), Yong Sun Kim, Korea Institute of Ocean Science and Technology, Ocean Circulation & Climate Research Department, Busan, South Korea and Jae-Hun Park, Inha University, Ocean Sciences, Incheon, South Korea
Abstract:
Coastal upwelling (CU) is an important process that causes changes in physical and chemical properties, resulting in variation of biological processes in a coastal area. In the southwestern part of the East/Japan Sea (SWES), CU has been alleged as one of the mechanisms responsible for higher net primary production (NPP) than the rest of the East/Japan Sea. We provide, for the first time, high spatial resolution underway observations of sea surface temperature, salinity, chlorophyll-a fluorescence and Δ(O2/Ar), revealing the physical and biological characteristics of the upwelled waters in the SWES. The cold, upwelled waters retained high fluorescence and Δ(O2/Ar), consistent with enhanced phytoplankton biomass and biological O2 production by CU. The net community production (NCP) in the ambient and upwelled waters were 33 ± 19 and 77 ± 41 mmol O2 m−2 d−1, respectively. The latter should be considered as a lower bound, containing a significant fraction of low O2 waters from subsurface. Satellite observation indicated that NPP in the upwelled waters were higher than the ambient waters by 51%. This implies that up to half of higher NPP in the SWES than the rest of the East/Japan Sea can be ascribed to CU events.
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