钦州湾枯水期富营养化评价及其近5年变化趋势

摘要

利用近5年枯水期现场调查的结果,采用富营养化指数法对该海湾富营养化程度进行评价并探求其变化趋势.结果表明近5年钦州湾枯水期富营养化指数的变化为0.08 ～ 10.2,其空间分布表现为沿着盐度梯度从茅岭江或钦江河口往外富营养化逐渐减轻.从2006年到2010年钦州湾富营养化从贫营养化往中度和重富营养化程度发展,富营养化显逐渐加重的趋势,在近两年河口区达到了重富营养化程度.陆源径流污染源的输入是富营养化空间分布的主要决定因素,而近5年富营养化逐渐加重的趋势主要是由不断增加的磷酸盐导致.海湾富营养化程度的增加并没有引起浮游植物生物量的急剧增加,但却增加了赤潮等生态灾害的风险.%Based on the data obtained from 2006 to 2010, eutrophication was evaluated and its long-term variation during dryrnseason of last five years in Qinzhou bay was studied. The result showed that eutrophication index ranged from 0. 08 to 10. 2. Therndistribution of eutrophication index showed a similar patterns, which decreased from estuary to outer bay as salinity increasing.rnThe trend of eutrophication index from 2006 to 2010 was increased and the eutrophication has become more serious.rnPhytoplankton biomass was not increased as eutrophication index increasing, but the risk of bloom has become large.