[Temporal and spatial distribution of particulate organic carbon in the Yellow Sea and East China Sea in spring].

Based on the data from cruises that carried out in the Yellow Sea and East China Sea from April to May, 2009, the temporal and spatial distributions of the particulate organic carbon (POC) were analyzed. And the sources of POC were further discussed according to the chlorophyll a (Chl-a) and C/N. The results showed that the concentration of POC in the Yellow Sea and East China Sea ranged from 24.33 microg/L to 2 817.29 microg/L in spring and the average content was 230.76 microg/L. In horizontal distribution, the highest POC content is in the coastal zones and it tends to decrease toward the far shore on the whole. The highest concentration of POC appears at the northern of Jiangsu Province coastal waters both in surface layer and bottom layer in particular, which is mainly affected by resuspension of sediments. And there is also a second highest concentration in the vicinity of the Yangtze River estuary, indicating the primary influence in the Yangtze River is by diluted water. The concentration of POC in shallow sea area is the highest and distributed uniformly and it is primarily from terrestrial inputs and resuspension. Moreover, the resuspension is relatively stronger than terrestrial inputs. However, the POC concentration in far coast deep water area is under 75 microg/L and it reduces gradually with the increase of water depth, which shows ocean water characteristics. And the POC is mainly from the ocean. The diurnal change of POC concentration in the middle of East Sea shows half-cycle variation, as a whole, the concentration value is high both in the afternoon and midnight, while it is relatively low at dusk, which is mainly under the influence of biological activity at the scene.