| The Yellow Sea Cold Water Mass (YSCWM), as an important oceanic phenomenon in the marginal sea of China, is always the focus of oceanographers. Though great achievements have been made in bioactive elements in YSCWM, we still know less about the numerical studies from the aspect of ecosystem. The main purpose of our paper is to build the coupling pelagic-benthic one-dimensional box model for YSCWM, and use it to study the seasonal variability of the vertical structure of each variables, energy flow characteristics, the contribution of microbial loop and the income and expenses of nutrient elements of the ecosystem in this region.First, based on in situ observation in the Yellow Sea and East China Sea during 2000-2001 and other former research results, the basic characteristics of the pelagic-benthic ecosystem in this region are well understood. The biomass of phytoplankton and zooplankton show a bi-peak variation trend. The stratification is very obvious in the vertical profiles of chlorophyll and dissolved oxygen, with high content in the subsurface layer when thermocline exists. Nutrients are with the lowest content in the upper layer and the highest content in the lower layer during the stratified period in the YSCMW. And the benthos ecosystem also shows a seasonal cycle. The biomass of macrobenthos is higher in Autumn while that of meiobenthos tends to be higher in both Spring and Autumn.By synthesis and reanalysis of recent research results on dry and wet deposition of nutrient elements in the southern Yellow Sea and the East China Sea, the results suggest that the concentrations of nutrient elements in aerosol and precipitation show an apparent seasonal cycle with the maximum values in winter and the minimum values in summer, which is close related with the seasonal variations in prevailing winds and precipitation. Depositions of nitrate are dominated by wet deposition, while the deposition for phosphate is mainly dry deposition. The dry and wet deposition fluxes in the East China Sea are both smaller than those in the southern Yellow Sea, but for its large area, the annual atmospheric input is greater than that to the southern Yellow Sea. The atmospheric inputs of atmospheric of ammonium and phosphate aregreater than that from rivers. The nutrient elements inputs via atmosphere play an important role in controlling new productivity in the southern Yellow Sea and the East China Sea.In this paper, the pelagic-benthic copling one-dimension box model in the YSCMW is built on the basis of Jiaozhou Bay model. The model is divided into three boxes according to the depths of thermocline and eupthotic layer. All the three boxes contain pelagic submodel which includes seven state variables such as phytoplankton (P), zooplankton (Z), particle organic carbon (POC), dissolved organic carbon (DOC), dissolved oxygen (DO), total inorganic nitrogen (TIN) and total inorganic phosphate (TIP). The lower box contains the benthic submodel which includes six variables such as macrobenthos (MacroB), meiobenthos (MeioB), benthic bacteria (Bbac), detritus (Det), total benthic inorganic nitrogen (Btin) and total benthic inorganic phosphate (Btip). The pelagic-benthic coupling is realized by the deposition of phytoplankton and POC into the detritus and the transportation of nutrient elements from the bottom to the pelagic. In this model, the effect of microbial loop is considered by a parameterization way. The vertical flux between compartments of the model system is also taken into account.Basic characteristics of the seasonal variations of the pelagic-benthic coupling ecosystem in the YSCMW are simulated. Compared with the observations and the related studies in this region, it is found that the seasonal cycle of ecosystem is well represented and the relationships between variations and different layers are acceptable. Generally, the model is competent for the simulation of energy flow characteristics of the ecosystem in the YSCMW.The analysis of the sensitive tests suggests that the phytoplankton biomass is c...
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