九龙江河口水体叶绿素a含量和初级生产力的时空变化

Temporal and spatial variations of chlorophyll a concentration and primary production in Jiulongjiang Estuary waters

根据2009年春(5月)、夏(8月)、秋(11月)在九龙江河口水域进行的生态安全示范区综合外业调查资料,研究了九龙江河口水体叶绿素a含量和初级生产力的时空变化.结果表明,九龙江河口水体叶绿素a含量变化范围为0.77～15.89 mg/m3,平均含量为3.11 mg/m3;初级生产力变化范围为19.05～332.91 mg/(m2.d),平均值为103.51 mg/(m2.d).叶绿素a含量均值以夏季的为最高(4.01 mg/m3),其季节变化呈夏季>春季>秋季;初级生产力均值以春季的为最高[112.16mg/(m2.d)],季节变化呈春季>夏季>秋季的趋势.与本研究区上世纪90年代的调查结果比较,本次调查的表层水叶绿素a含量均值(3.11 mg/m3)为1990年均值(2.24 mg/m3)的1.3～1.6倍,而初级生产力均值[103.5 mg/(m2.d)]则比1990年的[151.6 mg/(m2.d)]降低了约32%.叶绿素a含量与初级生产力、可溶性硅酸盐含量、水温在这3个季节均显著正相关,与浮游植物密度的分布并不一致,二者的相关性并不显著.在高无机氮和高可溶性硅酸盐含量状态下,水温与活性磷酸盐含量对九龙江河口水体叶绿素a含量和初级生产力的时空变化起调控作用.

A comprehensive survey of hydrological, chemical and biological resources was conducted in Jiulongjiang Estuary waters in spring, summer and autumn of 2009, for the ecological management of the estuarine safety. This paper studied the seasonal and spatial variation of chlorophyll a concentration and primary production, with their re- lation to environmental factors. The results showed that the chlorophyll a concentration varied from 0.77 to 15.89 mg/m3 with a mean of 3.11 mg/m3. The primary production varied from 19.05 to 332.91 mg/（m2 ~ d） with a mean of 103.51 mg/（m2 ~ d）. Chlorophyll a concentration was the highest in summer and the lowest in autumn. Primary production was the highest in spring and the lowest in autumn. Compared with literature data chlorophyll a concentration in surface water increased 1.3 to 1.6 times higher than that in 1990. While the primary production in surface water dropped 32% less than that in 1990. Pearson correlate analysis of chlorophyll a concentration with theprimary production and environmental factors indicated that the chlorophyll a concentration correlateo posmvety to the primary production, SiO3-Si concentration and temperature, while correlated insignificantly to phytoplankton density. When the concentrations of DIN and Si03-Si were high, the water temperature and POa-P concentration became important in controlling the chlorophyll a concentration and primary production in Jiulongjiang Estuary wa- ters.