淀山湖浮游植物初级生产力及其影响因子

Phytoplankton Productivity and Its Influencing Factors in Dianshan Lake

为了解淀山湖浮游植物初级生产力时空变化及与环境因子的相关关系,于2009年4月～2010年3月采用黑白瓶法对其进行逐月采样调查.结果表明,初级生产力(以C计)四季变化规律为夏季[0.95 g.(m3.d)-1]>冬季[0.83 g.(m3.d)-1]>春季[0.77 g.(m3.d)-1]>秋季[0.62 g.(m3.d)-1].水平分布上,南北部生产力值较高,东西部相对较低,各样点差别不显著(p>0.05).垂直分布上,浮游植物光能可得性是制约初级生产力的一个重要因素,初级生产力以水下0.3 m处较0.5 m处高约12.7%,而夏季水体表层由于光抑制作用初级生产力较低.初级生产力四季变化可能跟浮游植物群落结构和优势种更替有较大关系,与叶绿素a、浮游植物密度均呈极显著正相关(p<0.01),前者相关性更好.浮游植物的生物量(或现存量)与其生产量之间存在正相关,生产量可为浮游植物数量变化提供一定的参考.

To understand the relationship between the spatial-temporal variations of phytoplankton primary productivity and its environmental factors in Dianshan Lake,monthly survey was carried out from April,2009 to March,2010,with the method of white and black bottles.The result shows that seasonal variation of primary productivity（calculated according to carbon,following the same） is summer [0.95 g.（m3.d）-1 ] winter [0.83 g.（m3.d）-1 ] spring [0.77 g.（m3.d）-1 ] autumn [0.62 g.（m3.d）-1 ].From the flat distribution,primary productivity is higher in northern and southern parts than that in east and west,with no significant differences in each point（p 0.05）.From the vertical distribution,phytoplankton light availability is an important limiting factor.Primary production of 0.3 m underwater is higher than that of 0.5 m.However,primary production of 0.3 m level in summer is lower because of light inhibition.Seasonal changes in primary productivity may be due to phytoplankton community structure and replacement of the dominant species.There are significantly positive correlation between Chlorophyll a（Chl-a） and phytoplankton density with primary productivity（p 0.01）,and Chl-a has better correlation with primary productivity.Phytoplankton biomass shows a positive reaction to its productivity and may preliminary provide a reference for the number of phytoplankton.