Abstract:Water samples at different depth were collected during 4 cruises nearby the Zhangzidao Island in October 2015 and January, April and July 2016. The spatial-temporal distribution of total particulate matter (TPM), particulate organic matter (POM) and organic content (defined as PCOM, %) in the surface and bottom layers were analyzed. With the results of the regression analysis of POM with Chlorophyll a (Chl-a) and other environmental factors, the potential interaction between the scallop culture and the suspended particulate matter was analyzed, and the major influencing factors of the latter were also discussed. The results were described as follows. Concentration ranges of TPM and POM nearby the Zhangzidao Island were (16.760~97.54) mg/L and (2.20~17.20) mg/L respectively, and their annual averages were (31.65±9.58) and (6.97±2.08) mg/L. The PCOM ranged from 8.69% to 37.09%, with an average of (22.25±4.18)%. The TPM concentration showed a seasonal trend as autumn> spring>summer>winter. The highest TPM concentration was found in the surface layer in autumn. However, the highest and lowest POM concentrations and the organic contents appeared in summer and winter respectively. The concentrations of POM and TPM had a similar pattern of horizontal distribution in most areas. Higher POM concentration was found in the central area compared to the surroundings in spring and summer, and the opposite pattern was found in autumn and winter. The concentrations of POM and TPM in the bottom water were significantly higher (P<0.01) than in the surface water in summer, but there was no difference in the other seasons (P>0.05). In all 4 seasons, there was significantly positive correlation (P<0.01) between POM and Chl-a nearby the Zhangzidao Island. In addition, there was also positive correlation (P<0.01) between POM and Chl-a in the bottom layer in spring and the surface layer in summer. A negative correlation was found between POM and salinity only in the surface water in summer, which indicated that the land sources might affect the concentration of POM in summer.
