Spatiotemporal Behavior of Hypoxic Zones in Jinhae Bay Determined with Delft3D Model
박성은·조창우1*·조준모·김청숙·김종홍·임월애
국립수산과학원 해양환경연구과, 1(주)지오시스템리서치
Coastal hypoxia is driven by nutrient loading, organic matter accumulation, and limited water circulation, causing problems in semi enclosed bays, such as Jinhae Bay, on the southeastern Korea coast. This hypoxia is affecting aquaculture and fisheries. Three-dimensional hydrodynamic and water quality Delft3D modules were used to simulate the seasonal dynamics of hypoxia in Jinhae Bay. The model captured the stratification and bottom water behavior in the bay. The 2021 data on tides, currents, temperature, salinity, and dissolved oxygen (DO), content were used for model calibration and validation, the model results strongly agreed with observations. Hypoxia initiated in late spring, intensified in summer due to stratification and elevated sediment oxygen demand (SOD), and dissipates in autumn with increased water mixing. Organic matter consumption contributed to DO depletion; however, the main drivers of hypoxia were the responses of SOD to temperature and DO levels. Including DO-threshold dynamics in SOD modeling produced deeper and more persistent hypoxia. These findings highlight the need to incorporate dynamic benthic processes and stratification into regional hypoxia models. Specifically, the Delft3D framework effectively simulates these processes, offering a scientific basis for developing accurate hypoxia forecasting and effective mitigation strategies for coastal ecosystems.
Hypoxia, Delft3D, Jinhae Bay, SOD, Stratification