摘要
在南海北部、大亚湾及珠江口3个不同水体生物-光学数据的基础上,研究了浮游植物粒径结构的变化特征,建立了基于浮游植物吸收光谱提取的浮游植物粒径参数(S<f>)的混合光谱模型。南海海区不同的水体环境下浮游植物的粒级结构有着很大的差异:在河口和沿岸水体小型浮游植物占优势,在外海水体微微型浮游植物占优势。浮游植物粒径参数随小型浮游植物增多而减少,随微微型浮游植物增多而增大。叶绿素a浓度从外海到沿岸逐渐增大,浮游植物粒径参数随叶绿素a浓度的增大而减小,它们之间呈幂函数关系。结果表明,利用混合光谱模型得到的浮游植物粒径参数与南海海区不同水体的生物-光学特征(粒级结构Rpico和Rmicro、粒级指数SI、叶绿素a浓度)有一定的相关性。具体的相关性表示为:S<f>与粒级结构(Rpico和Rmicro)存在一定的关系,与小型浮游植物和微微型浮游植物之间的线性相关系数分别是0.55和0.65;S<f>与浮游植物粒级指数(SI)有较好的线性关系,相关系数是0.57;S<f>与叶绿素a浓度呈幂函数关系,相关系数是0.64。这个混合光谱模型为从光学参数反演浮游植物种群的生态学信息提供了有效的手段,同时又可用于分析浮游植物优势粒径结构对光学特性的影响。
Data from three cruises conducted in the northern South China Sea （SCS）, the Daya Bay and the Pearl River Estuary respectively, were examined to access the variations of phytoplankton size structure. A spectral mixing model was established to retrieve phytoplankton size parameter from phytoplankton absorption spectra, with S〈f〉 as a proxy of the size parameter. There were significant similarities in phytoplankton size structure in the estuarine and coastal waters; however, it is very different in the open ocean. In the estuarine and coastal waters, the micro-phytoplankton plays a dominant role, while in the open ocean the pico-phytoplankton was the dominant species. Phytoplankton size parameter tended to decrease with increasing micro-phytoplankton, and to increase with increasing pico-phytoplankton. There was an increasing trend for chlorophyll a concentration from the open ocean to the coastal sea. Phytoplankton size parameter showed a power function relation with chlorophyll a concentration and decreased with increasing chlorophyll a concentration. The results showed that there was a relationship between phytoplankton size parameter retrieved from the spectral mixing model and the bio-optical characteristics in different circumstances of the SCS. This spectral mixing model provided a simple tool for extracting ecological information of phytoplankton species from optical measurements, and can be used to analyze the influence of dominant phytoplankton size structure on optical characteristics.
出处
《热带海洋学报》
CAS
CSCD
北大核心
2010年第2期59-64,共6页
Journal of Tropical Oceanography
基金
中国科学院知识创新工程重要方向项目(KZCX2-YW-215)
国家自然科学基金青年项目(40906021)
关键词
浮游植物吸收光谱
混合光谱模型
粒径参数
phytoplankton absorption spectrum
spectral mixing model
size parameter
