Physical-biological Coupled Diagnositc Model for Cochlodinium polykrikoides

Harmful Algae Blooms (HAB) are anomalous blooms of a specific species, and frequently occur in coastal regions. These excessive blooms of plankton damage marine environments by, for example, consuming dissolved oxygen or introducing toxins to the food web, potentially leading to financial losses for fishing industries. The dynamics causing HABs are complex and poorly understood, particularly the coupling between biological processes and the physical environment. In this work, a coupled physical-biological diagnostic model is developed to simulate HABs focused on Cochlodinium polykrikoides. Hindcasting experiments are conducted for a HAB event off the south coast of Korea in 2013. Simulation results compare favorably with observations, especially the intensity and duration of the bloom are successfully resolved. The diagnostic HAB model shows that growth of the species in the 2013 bloom is mainly limited by the availability of nitrogen nutrients rather than water temperature or light intensity. The simulated HAB is terminated by transport offshore and out of the region, which suggests that advection by local currents plays an important role in the terminal fate of the HAB.