LAUSR

Abstract The contributions of the microbial loop to the ecosystem in the Bohai Bay, China was studied in this paper. An eco-hydrodynamic model coupled with pelagic and benthic systems was developed, and the comparison between the numerical results and the field survey data shows that the model is able to reproduce the growth curves for ecological variables in the Bohai Bay. The contributions of the microbial loop and new production of nitrogen (new nitrogen) on other ecological variables were investigated using the coupled model. The results demonstrate that the average contributions of the microbial loop to zooplankton growth were 0.0644, 0.134, 0.0873, 0.0590 mmol C m−3 for spring, summer, autumn and winter in pelagic ecosystem of the Bohai Bay, respectively, with the annual mean value being 372.28 mg ⋅ m−3 ⋅ a−1 in the Bohai Bay. The contribution rate of new production of nitrogen through the sediment–water interface ranges from 17.2% to 56.0%, with the average value being 41.1%.