| 摘要: |
| 于2009 年5 月和11 月, 在长江口邻近海域通过现场营养盐加富实验, 研究了浮游植物对营养盐添加的响应。应用高效液相色谱技术分析培养样品中的特征色素组成, 通过CHEMTAX 软件估算了硅藻、甲藻、隐藻、定鞭藻、金藻、绿藻、青绿藻和蓝藻8 个浮游植物类群对叶绿素a 生物量的贡献(μg/L)。加富实验结果显示: 不同海区或同一海区不同季节的浮游植物生长对营养盐响应不尽相同, 这与培养实验水样采集时浮游植物所处的N、P 限制状态有着密切的关系。营养盐的加富不仅能够促进浮游植物生物量的增加, 也可能引起浮游植物的群落结构的变化。不同浮游植物类群对营养盐添加的敏感性不同, 培养实验开始后营养盐的输入使得硅藻在竞争中取得了优势, 硅藻所占比重明显上升;但随着培养的进行, 营养盐逐渐消耗, 一些在低营养条件下竞争能力强的浮游植物类群比如甲藻、蓝藻、隐藻等对生物量的贡献逐渐上升; 同时, 培养海水中初始浮游植物群落组成对营养盐加富后群落结构的变化有着重要的影响。 |
| 关键词: 光合色素 浮游植物 营养盐加富 长江口 |
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| 基金项目:国家重点基础研究发展计划“973 项目”(2010CB428706);国家自然科学基金创新研究团体项目(40821004); 国家863 计划专题项目(2008AA09Z107) |
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| Pigment-based assessment of the response of phytoplankton to nutrient addition at the Changjiang Estuary |
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| Abstract: |
| In situ nutrient enrichment experiments were conducted in May and November, 2009 in the Changjiang River Estuary and adjacent areas to investigate phytoplankton growth and composition response to nutrient addition. Phytoplankton samples from the field experiments were analyzed by RP-HPLC to determine pigments composition, and CHEMTAX was used to estimate the contribution of eight algal groups to total chlorophyll a. Results showed that the responses of phytoplankton to nutrients were closely related to the nutrient limitation status of phytoplankton at sampling. Nutrient additions to natural water not only stimulated phytoplankton growth but also potentially altered the phytoplankton community structure. Due to the fact rapid growth depleted nutrients, diatom had more sensitivity response to nutrient input than other phytoplankton groups, shifting the community composition toward higher relative abundance of diatoms during the early stage of incubation. However, with the nutrient consumed by phytoplankton, algal groups growing better under the condition with lower nutrients concentrations comprised more portion of the total community biomass (μg/ L) at the end of incubation. The results suggested that the effect of changing concentrations of nitrate and phosphate depends on the initial phytoplankton community present at the time of nutrient addition. |
| Key words: Photopigments phytoplankton nutrient enrichments Changjiang Estuary |
