The Sources, Variation And Degradation Of Particulate Organic Matter And Its Ecological Effect In The Frequent Harmful Algal Blooms Areas Of The East China Sea

Particulate Organic Matter (POM) is not only the important base in the marine ecosystem,but also the mainly form in the carbon fixation, so its source, distribution and transform asmarine biogeochemical process play an important role in carbon circulation in the sea, and TheFrequent Harmful Algal Blooms Areas of the East China Sea have high productivity, so it is ofgreat significance to do research on the distribution of POC in the continental margins and itsimpact on ocean. Based on the data from cruises that carried out in the Frequent Harmful AlgalBlooms Areas of the East China Sea from2010to2011, the seasonal variation, spatial andtemporal distribution of the POM is analyzed in this paper; And the the sources of POM isstudyed at the same time. Besides, the relationship between the POM, the nutrients anddissolved oxygen is discussed by using POC, nutrients and DO of typical sections and station,and using the correlation analysis between POC and many other parameters. From what has beendiscussed above, the main conclusions are drawn as follows:(1) Based on the datas in April, May, July and October of2010, the source and distribution ofPOM is analysed. From the seasonal variation, the concentration of POM is higher in Apriland May than in July and October. From the spatial distribution, in the surface and subsurface,the highest content is in the offshore southeastern of Zhoushan archipelago and the MinZhe seacoast, and the POM is mainly from phytoplankton production in spring (April and May), while inautumn (Octorber) it is mainly from the Yangze River diluted water and MinZhe coastal current;in the bottom, the highest POM content is in the Hangzhou bay and adjacent areas and mainlyfrom the Sediment Resuspension.(2) Based on the data of the typical section ZA from March to May in2011, analyzing theformation and distribution during the HABs occurs. In the surface and subsurface,theconcentration of POC is deeply related with Chla. When the HABs occurs,the concentration ofChla and POC rise while the nutrients reduce,at the same time,the oxygen and C/N become larger, and all of this results is decided by the phytoplankton. Besides, the concentration of Chla,POC, C/N and DO rise from the surface to the bottom,but the concentration of DIP reduce, so itdisplays that the degradation of POC is absorbing the oxygen and releasing the inorganicnutrients.(3) Through the typical sea area and station, the POM is connected with biological bump processand ecoenvironmental variation in ocean. When the HABs occurs, POM is made up with theliving, and they carry out the photosynthesis, absorbing the nutrients and releasing oxygen, soChla and POC have a positive relation, R=0.77, while DO and DIP have a negtive correlation,R=-0.36; In the bottom, the POM will be degrated while absorbing oxygen and releasing thenutrients, then DO and DIP also have a negtive correlation, R=-0.47. Therefore the formation anddegradation of POM has good relationships with nutrients and oxygen.The strong haloclineabove the hypoxic zone, as a result of affluent water from Changjiang, the high concentrations ofPOM are the major factors causing the formation of the hypoxic zone. The halocline started inApril, and ended in Octorber, the August is the strongest month, simultaneously, the HABsoccurred in April and May, so the oxygen deficiency in the bottom will start in May, and discoverthe lowest value in October.