Seagrass meadows occupy less than 0.2% of the area of the world’s oceans but are estimated to contribute 10% of the yearly estimated organic carbon burial.Globally,seagrass ecosystems could store as much as 19.9 Pg organic carbon. The high carbon storage capacity in seagrass meadows may result from the high primary production of seagrass meadows and their capacity to filter out particles from the water column and store them in soils. Eelgrass, Zostera marina is one of the common seagrass species in the northern hemisphere.Investigation in Sanggou Bay showed that the biomass of eelgrass varied between 313.5 and 769.3 g DW/m2 from 2011 to 2012, with the maximum of 738.1 g DW/m2 in summer. Primary production was about 2.0~6.4 g DW/m2•d and tissue carbon content was 35.5% in the plant. Stored carbon in the eelgrass meadow from primary production was about 543.5 gC/m2•yr. Biomass of algal epiphyte was small, with a wet weight of 21.2 g/m2 and contributed 30 g C/m2•yr carbon storage. As a Ruditapes philippinarum stock enhancement area, the carbon sink contribution from the clam was 63.15g C/m2•yr.In addition, when other carbon source, such as stripped particles was considered, the carbon pool capacity was 1 180 g C/m2•yr and the whole of the bed can reach 290 Mg C/yr.