作 者 ：宋星宇,刘华雪,黄良民*,谭烨辉,柯志新,周林滨
期 刊 ：生态学报 2010年 30卷 23期 页码：6409~6417
Keywords:South China Sea, bacterial production, primary production, microbial loop,
摘 要 ：2008年夏季对南海北部不同海区的基础生物生产力（初级生产力及细菌生产力）进行了调查。结果表明，表层初级生产力(C)和真光层水柱初级生产力平均值(C)分别为（0.83±1.15） mg?m-3?h-1和（225.39±136.64） mg?m-2?d-1；表层细菌生产力(C)和真光层水柱细菌生产力平均值(C)分别为（0.14±0.19） mg?m-3?h-1和（128.14±74.86） mg?m-2?d-1。基础生产力的平面分布整体呈由近岸向深海降低的趋势，同时在西沙群岛邻近水域存在一个基础生物生产力的高值区。与环境因子的相关分析表明，温度、营养盐不是影响南海细菌生产力的主要因素，细菌生产力与浮游植物生物量及初级生产过程密切相关。IBP∶IPP比平均值为（67.55±37.13）%。与细菌生产力的分布规律不同，IBP∶IPP比值在深海海域明显高于近岸水域，在吕宋海峡附近水域发现了IBP∶IPP＞100%的高比值区，说明异养细菌在南海寡营养海域碳循环体系中的重要生态作用。
Abstract:Both primary production (PP) and bacterial production (BP) are key basic biological productions in marine ecosystems. In this study, the basic biological productions in different zones in the northern South China Sea were investigated in summer in 2008, in order to evaluate the spatial distribution characteristics of the basic biological productions, their influencing factors and their contributions to the carbon flux in the ecosystems of the South China Sea. The investigation covered the estuarine and Yuedong coastal area, the adjacent area of Taiwan Strait and Luzon Strait, the southeast waters of Hainan Island, and the open waters in the northern South China Sea. The results showed that the surface PP (C) and the integrated PP in the euphotic zone (IPP) (C) were (0.83±1.15) mg?m-3?h-1 and (225.39±136.64) mg?m-2?d-1 respectively; the average surface bacterial production (C) and the integrated bacterial production (IBP) (C) in the euphotic zone were (0.14±0.19) mg?m-3?h-1 and (128.14±74.86) mg?m-2?d-1 respectively. The basic biological production generally declined from the nearshore waters to the deep sea. Besides the general distribution of high production in coastal and estuarine waters, high PP area could also be found near the Xisha Islands. The high PP value usually appeared in the deep water other than in the surface layer with two vertical peaks in the euphotic zone, one at the depth of 0-20 m and another at the depth of 50-75 m in most stations in the open water of the northern South China Sea. According to the vertical distribution of BP, maximum BP values appeared mostly near bottom layers of the euphotic zone (50-75 m). The correspondence analysis between BP and environmental parameters indicated that temperature and nutrients are not key controlling factors of BP in the northern South China Sea; BP was significantly correlated with phytoplankton biomass and PP. The IBP: IPP ratio averaged 67.55 37.13% and had a significant negative correlation with PP, which indicated that in the northern South China Sea, phytoplankton photosynthesis could afford enough carbon resource to the ecosystem in the high PP area in the euphotic zone, while in the area with low PP, the bacterial production process appeared to be more active. Microphytoplankton and nanophytoplakton was often the primary contributor to PP in the coastal area accompanying with the distribution of low BP∶PP and IBP∶IPP, which indicated that the classic food chain was the main approach for the basic carbon flux in the coastal waters of the northern South China Sea. However, in the oligotrophic open waters that cover most area of the northern South China Sea, IBP: IPP was evidently higher than that in the nearshore waters; the area with extreme high IBP: IPP ratio (>100%) was found in part of the deep sea area. Meanwhile, picophytoplakton was the dominant primary producer in the oligotrophic waters in the South China Sea, which suggested that heterotrophic bacteria and picophytoplakton play important roles in the ecosystem carbon cycle transporting carbon flux via the microbial loop to higher nutrition levels in the oligotrophic waters of the South China Sea.
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