Coupled Physical-Biological Model for the Pearl River Estuary: A Phosphate Limited Subtropical Ecosystem

The Pearl River, with an annual mean discharge rate of ~ 10,000 ms, has profound dynamic and ecological influences on the northern shelf of the South China Sea. A coastal ocean model is set up to simulate the circulation in the Pearl River Estuary and the neighboring coastal regions. In winter the Guangdong Coastal Current, which flows southwestward and passes the mouth of the estuary, forces the Pearl River plume to the western side of the estuary. Therefore, intrusion occurs mostly in the Da-Yu Channel, which is toward the eastern side of the estuary. As a result, the coastal current has a large impact on the southeastern side of the estuary. A phosphate based biological model with two sizes of phytoplankton and zooplankton is embedded in the circulation model to investigate nutrient and plankton dynamics in the estuary.