Temporal And Spatial Variation Of Nutrient And Phytoplankton Grain Structure In Jiaozhou Bay

Eutrophication and red tide caused by nitrogen and phosphorus have become an important environment abnormal phenomena in the sea. Especially in the estuary bay and inner bay, the times of red tide increased year by year because of the discharge of domestic sewage,industrial and agricultural wastewater and mariculture wastewater. The occurrence and development of the red tide destroy the local sea area ecological balance, cause the death of the marine organism,damage the fishery resources and human health.Jiaozhou Bay is a semi-closed and shallow bay, the rivers around the bay are polluted seriously. A lot of organic matter and pollutants from domestic sewage,industrial. and agricultural wastewater and mariculture wastewater input Jiaozhou Bay. The ecological function of ecosystem in Jiaozhou Bay decreases year by year, these mainly perform that, the sea area decreases, self-purification capacity decreases, biology community structure is destroyed, and fishery resources decline. Jiaozhou Bay is a good area for studying the structure and function of sea ecosystem and the restoration and reconstruction of damaged ecosystem.This paper discussed the main source,temporal and spatial distribution and the relationship with other environmental factors of nutrients and chlorophyll-a, based on the monthly Omo observations carried out in Jiaozhou Bay from April 2002 to April 2003. The main results are as follows:In Jiaozhou Bay and adjacent waters, the major component of dissolved total phosphorus is dissolved organic phosphorus; while the main part of dissolved inorganic nitrogen is ammonia, followed by nitrate and nitrite.High value of nutrients areas are mainly located in northern and eastern of Jiaozhou Bay, especially the northeastern waters outside Haibo River and Licun River existing high nutrient value area year-round. Exogenous nutrients (including waste discharge and runoff) is the main source of nutrients in Jiaozhou Bay, which is closely related to the frequent affect by human activities. There is a obvious phosphorus limit comparably in Jiaozhou Bay, however, at certain times (such as winter) there is some restriction on silicon at a certain extent, while the nitrogen is sufficient.The surveys about the six cruises from May 2002 to March 2003 suggest that: the concentration of chlorophyll-a in Jiaozhou Bay is in the range of 1.80-6.33μg/L, with an average of 4.07 mg/L. The concentration peak of chlorophyll-a in Jiaozhou Bay appears twice in a yearSize structure of Jiaozhou Bay chlorophyll-a has a large seasonal variation. From the size structure of Chlorophyll-a in a whole year, the contribution of small phytoplankton is higher when there is a high concentration of chlorophyll-a; conversely, the micro-phytoplankton does.