Interaction between natural planktonic ecosystem and cultured animals in the coastal aquaculture environment.

本研究的目的是评估养殖、养殖和河流排放可能造成的环境影响。1996年和2000年，通过大量的数据采集和观测，研究了珠母湾和松屋湾两个典型的珍珠牡蛎和牡蛎养殖场的自然浮游生物生态系统的物理化学参数变化及其对生态系统的影响。大小分级的叶绿素a测量和显微镜观察表明，微浮游植物和纳米浮游植物是全年碳生物量的主要组成部分。从包括细菌在内的微微浮游生物到微型浮游生物的潜在碳流计算表明，有机物质的管道主要通过微生物食物网驱动，例如微微浮游生物-异养纳米鞭毛虫-微型浮游动物，…一年中更多的时间。在松屋湾，以叶绿素a为基础的浮游植物生物量在夏秋两季有所增加。湾内NO_3-N主要来自来水河流，且在夏季和秋季浓度升高。PO4-P和NO2-N的补给主要来自湾内底层的再生，PO4-P的再生活跃在夏季和秋季。湾内SiO_2-Si的主要来源为来水河流，但在夏秋季也受到湾内底部再生的影响。红场比和半饱和常数表明，海湾浮游植物的生物量通常受氮的限制，有时在夏秋季河流流量较大时受磷的限制。因此，在夏季和秋季，内湾流入河流的氮素负荷和底层PO4-P的活跃再生引发了浮游植物生物量的增加。较少

The aim of the present study is to assess the possible environmental impact caused by culture farming and river discharge. Intensive data collection and observations were carried out during 1996 and 2000 to determined the variations of physical and chemical parameters and their impacts on the natural plankton ecosystem in Ago Bay and Matoya Bay, which are both typical embayments with pearl oyster and/or oyster culture grounds, respectively.In Ago Bay, nutrients were continuously supplied from the bottom sediment during summer. The size-fractionated chlorophyll a measurements and the microscopic observations revealed that the picoplankton and nanoplankton were major components in term of carbon biomass throughout the year. The calculated potential carbon flow from pico-sized plankton including bacteria to micro-sized plankton indicate that the conduit for organic materials is driven inainly through the microbial food web, e.g. picoplankton-heterotrophic nanoflagellates-microzooplankton, … More througout the year. It is also suggested that the microbial food chain affect the mesozooplankton biomass.In Matoya Bay, the phytoplankton biomass based on chlorophyll a increased in summer and autumn. NO_3-N was mainly supplied from the inflow rivers and the concentration increased in summer and autumn in the bay. PO_4-P and NO_2-N were mainly supplied through regeneration from the bottom at the interior bay, and the active regeneration of PO_4-P occurred in summer and autumn. The main source of SiO_2-Si in the bay was the inflow rivers, but it also influenced by regeneration from the bottom at the interior bay in summer and autumn. Redfield-ratio and half saturation constants were indicated that phytoplankton biomass in the bay was usually limited by nitrogen, and occasionally, by phosphorus when river flow was higher in summer and autumn. Therefore, it was suggested that loading nitrogen from the inflow rivers and active regeneration of PO_4-P from the bottom at the interior bay triggered the increase of phytoplankton biomass in summer and autumn. Less