钦州湾叶绿素a和初级生产力时空变化及其影响因素

于2009年1—11月对广西钦州典型养殖海湾——钦州湾海域水体中叶绿素a(Chl-a)浓度和初级生产力进行了4个季节航次的调查,分析了该海湾Chl-a和初级生产力的时空变化特征并探讨其影响因素.结果表明,钦州湾表层海水Chl-a浓度周年变化在0.83~32.5 mg·m-3之间,平均为5.39 mg·m-3;Chl-a浓度季节性变化表现为夏季春季冬季秋季.初级生产力变化范围是92.3~1494.5 mg·m-2·d-1(以C计,下同),平均为425.1 mg·m-2·d-1;初级生产力季节变化特征呈现夏季冬季秋季春季.钦州湾Chl-a浓度和初级生产力在春、夏、冬季呈现内湾和三娘湾海区高、钦州港海区低的分布特征,秋季出现相反的特征.相关分析显示,钦州湾Chl-a与水温、盐度和氨氮之间存在密切的相关关系.总体来看,陆源输入的营养盐及贝类养殖活动是影响Chl-a和初级生产力时空变化的重要因素.

Spatio-temporal variations of chlorophyll a and primary productivity and its influence factors in Qinzhou Bay

Chlorophyll a (Chl-a) concentration and primary productivity were investigated during four cruises from January 2009 to November 2009 in a typical mariculture bay (Qinzhou Bay, Guangxi). The spatio-temporal variations as well as influencing factors of Chl-a were investigated. The concentrations of Chl-a in the surface seawater ranged from 0.83 to 32.5 mg · m^-3, with a mean of 5.39 mg · m^-3. The seasonal variations of Chl-a concentration ranked in the order of summer >spring >winter >autumn. The primary productivity varied from 92.3 to 1494.5 mg(C) · m^-2 · d^-1 with an average of 425.1 mg(C) · m^-2 · d^-1, and exhibited an obvious seasonal variation in the order of summer >winter >autumn >spring. In spring, summer and winter, the Chl-a concentration and primary productivity were higher in the inner bay and Sanniang Bay and lower in the Qinzhou Port area, but an opposite distribution pattern was observed in autumn. Correlation analysis indicated that the Chl-a concentrations were closely related to water temperature, salinity and ammonium levels. In summary, terrestrial input of nutrients and shellfish cultures might be the main factors influencing the variations of Chl-a concentration and primary productivity.