| Generally speaking, nutrients like nitrogen, phosphate, silicate are the fundamental elements of energy flow and material flow in the eco-system. By using field investigation, indoor analysis and simulation methods, the distribution and key processesses of nutrients in the typical waters of western pacific, continental shelf waters of East China Sea, coastal waters of Qingdao were investigated with the considerations of both anthropogenic impacts and natural influences.The primary results were as follows:In the typical waters of western pacific, the PIW(Pacific Intermediate Waters) which was temperature low, nutrients rich, could be upwelled from the middle layer to the subsurface layer by Ekmam pumping. In ME(Mindanao Eddy) controlled area, such pumping process was enhanced. Consequently, the distribution and structure of nutrients in the euphotic layer of such waters were much preferable for phytoplankton proliferation rather than unupwelled region. The strength and influenced area scale of ME varied in an inter-annual pace which was influenced by ENSO(El Nino and South Osciliation) principally. Such results could be supportable for the transportation mechanism of nutrients with natural influences in the typical oligotrophic euphotic waters.In the Continental Shelf waters of East China Sea(ECS), the HSW(High Salinity waters) locating at the bottom of the outside part of the target area, were argued to be a potential P resources of the Continental Shelf waters of ECS. In this research, HSW was proved originating from the KSSW(Kuroshio Subsurface Water), and could be moved to the subsurface layer along 50 m isobaths off the Zhejiang coast in spring. Furthermore, a hydrodynamic based box model was built to calculate the flux of N and P nutrients by HSW along the moving path towards the coast. As a result, the flux of P could be over 4 times than territorial inputs by such transportation. Therefore, P in ECS was influenced mainly by natural processes. Meanwhile, N in such waters was primarily from the territorial inputs, and from Changjiang river discharge mainly, which was believed with a strong relationship with anthropogenic impacts. Moreover, the HSW could be supportable for Prorocentrum donghaiense proliferation in the spring time due to the influence on both P nutrients supply and suitable temperature in the subsurface waters along Zhejiang coast where such species always be dominating during that time. As a whole, both anthropogenic impacts and natural influences were important when considering the distribution of the nutrients and related processes in the Continental Shelf waters of ECS. Meanwhile, such results could be supportable for a better understanding of development of the ecosystem structure and function in the coastal waters of China.In the coastal waters of Qingdao, the N, P nutrients in the area OJB(Out part of Jiaozhou Bay) was proved to be a much rapid increasing than the average level over 2000. Consequently, the N/P ratio in such area became much imbalanced with the normal redfield ratio than before. The OJB became potentially P limited. By the fluctuations of amounts and structure of nutrients, the HABs(Harmful Algal Blooms) became much serious after 2000 in such area, either. The frequency of HABs became higher, the scale of influenced area became larger, the dominating species became much diversified and frequently toxic than before in the OJB. Provided by GIS(Geographic Information System) analysis of HAB occurrences in the coastal waters of Qingdao, the Fushan bay and related shallow bays along OJB became the most crucial area suffering frequently HAB occurrences after 2003, while JB(Jiaozhou Bay) was believed as the main area of HAB occurrences before. According to the results of this research, several suggestions on HABs mitigation in Qingdao coastal waters were presented. Therefore, the results and related methods in this research could be used by the government for a better controlling of ecosystem disasters than before. |
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