赤潮多发区深圳湾叶绿素a的时空分布及其影响因素

于2008年2月至2008年11月分四个季度调查了赤潮多发区深圳湾叶绿素a的时空分布,并分析了叶绿素a与主要环境因子之间的关系.结果表明,深圳湾叶绿素a质量浓度范围为3.07～309.94 mg·m~(-3),年平均值为42.29 mg·m~(-3).四季叶绿素a平均质量浓度由高到低排列分别为:春季(108.33 mg·m~(-3))>夏季(35.2 mg·m~(-3))>秋季(16.68 mg·m~(-3))>冬季(8.96 mg·m~(-3)).叶绿素a的质量浓度在冬季和春季呈现由湾内向湾外递减的分布特征,而夏季和秋季呈现由西岸向东岸递减的分布特征,整体则呈现由湾内向湾外递减的分布特征.相关分析显示深圳湾叶绿素a与水温、COD、TOC、PO_4~(3-)-P和浮游植物密度因子显著正相关,与DIN因子极显著正相关,说明叶绿素a与水温、DIN、PO_4~(3-)-P、COD、TOC和浮游植物密度之间有着比其它因子更为密切的关系.以叶绿素a作为富营养化评价标准,发现深圳湾海域富营养化严重,存在随时爆发赤潮的潜在风险.

The spatial and temporal distribution of chlorophyll a and the influencing factors in Shenzhen Bay with frequent occurrence of red tide

From Feb. To Nov. 2008, spatial and temporal distribution of concentration of chlorophyll a were surveyed in four seasons in Shenzhen Bay, and the relationship was analyzed between Chlorophyll-a and main environmental factors. In Shenzhen Bay, the concentration of chlorophyll-a ranged from 3.07 mg·m~(-3) to 309.94 mg·m~(-3), with an annual average of 42.29 mg·m~(-3). The highest av-erage concentration of chlorophyll-a was found in spring (108.33 mg·m~(-3)), followed by that in summer (35.2 mg·m~(-3)), autumn (16.68 mg·m~(-3)) and winter (8.96 mg·m~(-3)) in turn. The concentration of Chlorophyll-a decreased from inner bay to outside bay in winter and spring, while in summer and autumn it decreased from west coast to east coast. The average concentration of Chlorophyll-a declined from inner bay to outside bay throughout the year in this investigation. Correlation analysis showed significant positive correlation between the concentration of Chlorophyll-a and water temperature, COD, TOC, PO_4~(3-)-P, phytoplankton abundance and DIN in Shenzhen Bay, indicating there was close relationship between Chlorophyll-a and these environmental factors. The water body was in serious eutrophication in Shenzhen Bay with the chlorophyll a as assessment criteria implying potential risks of outbreak of red tide at any moment.