An ecosystem modeling study of spatio-temporal variations of phytoplankton distribution in the Okhotsk Sea

A three-dimensional ecosystem–physical-coupled model is applied to the Okhotsk Sea. Factors that determine the spatial distribution of phytoplankton in the Okhotsk Sea in autumn and spring are analyzed, and the effects of sea ice on the spring bloom are also discussed. One of the most important factors determining the spatial distribution of phytoplankton in autumn is regional variation in mixed layer depth. The model can explain the spatio-temporal variation of chlorophyll-a concentration in the Okhotsk Sea during the spring blooms in 1997 and 2001. The start of the spring bloom in the Okhotsk Sea depends on the light environment. By controlling the light intensity in sea surface water, sea ice controls the timing of the spring bloom.