长江口及邻近海域浮游动物生物量分布及季节变化

2006年7月—2007年12月,在长江口及邻近海域(29°30′N~32°30′N,120°00′E~127°30′E)布设150个观测站位,进行了4个季节生物、化学和物理海洋学综合调查。根据采集的浮游动物样品的分析鉴定结果及现场环境参数的测定数据,对浮游动物群落生物量分布及季节变化进行了研究。结果表明:长江口及邻近海域浮游动物生物量有明显的季节变化,主要表现为:春季>夏季>秋季>冬季。中华哲水蚤(Calanussinicus)、双生水母(Diphyeschamissonis)、百陶带箭虫(Zonosagittabedoti)和中华假磷虾(Pseudeuphausiasinica)是长江口及邻近海域浮游动物生物量的主要贡献者。化学营养盐是影响长江口及邻近海域浮游动物生物量分布的主要环境因素,除此以外,其它环境因子在不同季节对浮游动物生物量的影响存在差异。春季,温度和盐度是影响浮游动物生物量的主要因素;夏季,温度、溶解氧和叶绿素a是影响浮游动物生物量的主要因素;秋季,盐度、溶解氧和悬浮颗粒物是影响浮游动物生物量的主要因素。冬季,环境因子对浮游动物生物量影响不明显。

Biomass distribution and seasonal variation of zooplankton in the Changjiang Estuary and its adjacent waters

A comprehensive investigation involving biological, chemical and physical parameters was conducted in the Changjiang Estuary and its adjacent waters (29°30′N~32°30′N,120°00′E~127°30′E) in four seasons (from July 2006 to December 2007). The biomass of zooplankton, the key species affecting the biomass and their seasonal variation were studied based on the identification result of zooplankton samples and field measurement of environmental parameters. The results showed that there was a significant seasonal change in zooplankton biomass in the Changjiang Estuary and its adjacent waters. A significant decreasing trend was observed from spring to winter. The main contributors to zooplankton biomass included Calanussinicus, Diphyeschamissonis, Zonosagittabedoti and Pseudeuphausiasinica. The characteristics of this area were closely related to the influence of Changjiang River Plume, Taiwan Warm Current, Zhejiang Coastal Current and Kuroshio Current, thus formed an unique physical and chemical environment. Nutrient were the main environmental factor influencing the zooplankton biomass distribution in this area. Besides, other environmental factors also influenced the biomass of zooplankton, and there was seasonal difference. In spring, water temperature and salinity were the main influence factors. The zooplankton biomass had a significant positive correlation with water temperature and salinity. In summer, temperature, dissolved oxygen and chlorophyll a concentration were the main factors affecting the biomass of zooplankton. The zooplankton biomass was significantly negatively related to water temperature, and significantly positively related to dissolved oxygen and chlorophyll a concentration. In autumn, salinity, dissolved oxygen and suspended particles were the main factors affecting the biomass of zooplankton. The zooplankton biomass was significantly positively related to salinity, and significantly negatively related to dissolved oxygen and suspended particles. In winter, the water temperature in the Changjiang Estuary and its adjacent waters decreased significantly under the influence of cold front and current. Lower temperature depressed the growth and metabolism of zooplankton community. In addition, the community structure was simpler and the zooplankton biomass decreased. Therefore, no significant correlation between zooplankton biomass and environmental factors was found.