紫外线（UV）对热带珊瑚礁海区浮游藻类光合作用的生态效应

项目名称： 紫外线（UV）对热带珊瑚礁海区浮游藻类光合作用的生态效应

项目编号： No.40806050

项目类型： 青年科学基金项目

立项/批准年度： 2009

项目学科： 生物科学

项目作者： 周伟华

作者单位： 中国科学院南海海洋研究所

项目金额： 20万元

中文摘要： 本项目涉及由臭氧损失引起的海洋生态环境问题，属海洋环境研究的热点和前沿。项目的主要研究成果为：1）进行了三亚湾浮游植物和浮游细菌生物量时空变异特征与调控因素研究。生物量从近岸的三亚河口往外海逐渐降低，三亚河的陆源输送和入海扩散是造成此分布特征的主要原因，初级生产是影响水域浮游细菌分布的重要因素。2）开展了UV强度季节变化差异及在水柱中的通量研究。UVB在三亚湾穿透深度为2-10 m，同我们在珠江口－南海北部的结果相比，UVB在三亚湾的穿透深度较高，对珊瑚礁生态系有潜在的威胁。3）调研了干季珊瑚礁海区营养盐限制情况，发现冬季N和P同时都成为三亚湾的限制性营养盐。4）UV对三亚湾珊瑚礁海区浮游植物光合作用碳吸收的抑制率及与其他纬度海区的对比研究，发现UVB抑制率在温带的东海＞亚热带的南海北部珠江口和大亚湾＞热带的三亚湾＞热带的南沙群岛海区。5）发现浮游植物对UV的敏感性要比低于浮游细菌和病毒，强UVR可能导致亚热带的南海北部更趋向于自养的生态系统。本项目可为政府管理部门采取正确有效的污水处理手段，为合理保护和恢复脆弱的珊瑚礁生态系的科学管理提供可靠依据，可望在珊瑚白化机理研究提出新的思路。

中文关键词： 紫外线（UV）；珊瑚礁；浮游藻类；光合作用速率；白化

英文摘要： The proposal involves the marine ecological issues caused by ozone loss, which was induced by global warming and environmental deterioration. It belongs to the hot spot of marine environmental science. The main conclusions of the project include: 1) The distribution of phytoplankton and bactrioplankton biomass and their regulation processes. The biomass decreased from estuary to offshore waters, primarily due to the terrestrial input from the Sanya River and influx of oceanic water. Phytoplankton primary production was one of the most important factors in controlling the distribution of bacterioplankton. 2) Spatial and seasonal changes UV intensity and its flux in the water column were studied. UVB can penetrated 2-10 m deep, and is a threate to the health of coral reef. 3) During dry season, nutrients limitation on phytoplankton were studied. We found that N and P were co-limited in Sanya Bay in winter. 4) Inhibition of UV to phytoplankton caron assimilation in coral reef ecosystem were conducted. The results showed that UVB inhibition rates were increased with latitude, i.e., East China Sea (Temperate Zone) > northern South China Sea and Daya Bay (Subtropical Zone) > Sanya Bay (Tropical Zone) > Nansha Islands waters (Tropical Zone). 5) Phytoplankton are more tolerant to UV than bacteria and viruses, and hence strong UVR likely results in a more autotrophic ecosystem in the sub-tropical northern South China Sea. This project may propose effective references of the proper sewage treatment for the local government, provide background information for reasonable protection and restoration of the frail coral reef ecosystem, and put forward some new ideas on the studies of coral bleaching mechanism.

英文关键词： Ultraviolet Radiation; Coral Reef;　Phytoplankton; Photosynthetic efficiency; Bleaching