Hypoxia in a transient estuary caused by summer lake-water discharge from artificial dykes into Chunsu Bay, Korea.
We investigated bottom-water hypoxia induced by freshwater discharge from two artificial dykes into Chunsu Bay (CSB), Korea, during the summer of 2010. Field observations and model results of the dynamic and water-quality parameters indicated that the triggering mechanism of the hypoxia was strong stratification formed by the freshwater discharge from both dykes, which limited the dissolved oxygen (DO) supply in bottom water. Beneath the pycnocline, DO was consumed by sediment oxygen demand (SOD) during the summer. To investigate these processes, model experiments were conducted using a simplified DO budget model coupled with a 3D hydrodynamic model. The DO concentration in the northern part of CSB reached hypoxic conditions very quickly after 3.4days of discharge and lasted 18days until normal conditions resumed. In sum, in the CSB, marked stratification and its maintenance played a critical role in hypoxia in bottom water.
Ocean Research Division, Korea Hydrographic and Oceanographic Administration, Busan 606-806, Republic of Korea. Electronic address: kwangyoung@korea.kr.
Kwang Young
KY
Jung
Department of Ocean Environmental Science, Chungnam National University, Daejeon 305-764, Republic of Korea.
Young Jae
YJ
Ro
Fisheries Resources and Environment Division, Southwest Sea Fisheries Research Institute, NFRDI, Yeosu 556-823, Republic of Korea.
Yang Ho
YH
Choi
Department of Ocean Environmental Science, Chungnam National University, Daejeon 305-764, Republic of Korea.
Baek Jin
BJ
Kim
D061006:Bays; D004784:Environmental Monitoring; D063366:Estuaries; D005068:Eutrophication; D005618:Fresh Water; D057446:Hydrodynamics; D060106:Lakes / Q000737:chemistry*; D008962:Models, Theoretical; D010100:Oxygen / Q000032:analysis; D056910:Republic of Korea; D012621:Seasons; D060753:Water Quality
D010100:Oxygen
Chunsu Bay; DO budget model; Dissolved oxygen; Hypoxia; Sediment oxygen demand; Stratification