Ecological Modelling
Physical control of phytoplankton bloom development in the coastal
waters of Jiangsu (China)
A large amount of phytoplankton blooms have occurred in the Jiangsu coastal waters since 2000. The
trigger of the phytoplankton blooms responds to environmental factors. The present study aims to investigate
the phytoplankton bloom development from the physical properties. To stress the significance of
the phytoplankton, a vertical phytoplankton model is developed, coupling the characteristics of phytoplankton
dynamics with a physical model. Combining with the analyses ofthe Delft3D model,the vertical
phytoplankton model is well applied to the Jiangsu coastal waters. Significant correlations are established
between chlorophyll a and phytoplankton biomass. The vertical stability threshold is strongly related to
the specific growth rate, the loss rate and the euphotic depth, and critical depth is closely linked with
light availability. The vertical stability provides a favourable living condition for the phytoplankton, while
the shallower mixed layer depth promotes the accumulation of phytoplankton density in the water volume.
All the observed blooms falling within the predictions demonstrate that the physical limitation can
produce reliable blooms. The findings of this study contribute much to the understanding of the coastal
ecosystem and the coastal management.