2009-2011年渤海湾赤潮监控区营养盐概况分析

根据2009--2011年的5—10月在渤海湾赤潮监控区6个监测站点进行的连续监测结果，分析、探讨渤海湾赤潮监控区营养盐的变化特征及富营养化概况．结果表明：近3年来，渤海湾赤潮监控区海域受到了无机氮和活性磷酸盐的污染，水体处于严重的富营养化状态，且无机氮的污染程度明显高于活性磷酸盐；从空间分布上看，渤海湾赤潮监控区海域活性磷酸盐的空间变异系数在0．14～0．39之间，高于其他项目的空间变异系数，说明活性磷酸盐在空间分布上的差异明显大于无机氮和硅酸盐；在时间分布上，表层海水营养盐质量浓度存在明显的月变化特征，出现先增高后降低的趋势，在8月份其质量浓度达到最高值；从营养盐的结构特征上看，NO3--N占无机氮质量浓度的57％～70％，是该海域无机氮的主要存在形式；从赤潮监控区的富营养化等级划分来看，赤潮监控区由2009--2010年的磷限制状态转为2011年的富营养化状态．

Nutrient Conditions of the Red Tide Monitoring Area in the Bohai Bay from 2009 to 2011

On the basis of the monitoring data of nutrients （N, P and Si）in the surface seawater from May to October （2009- 2011）in the red tide monitoring area at six monitoring stations of the Bohai Bay, nutrient conditions in the red tide monitoring area were analyzed and discussed. The results showed that the water quality in the red tide monitoring area was still seri- ously over-nutritious and polluted with high N and P contents obviously in recent three years and N pollution was more seri- ous than that of P; DIP content had the biggest change in that three years at the six stations. The spatial variation coefficient of DIP was 0.14 ~ 0.39, which was higher than inorganic nitrogen and silicate. As for the time distribution, the surface sea- water nutrient contents had significant monthly variation characteristics of first increasing and then decreasing, which reached maximum values in August. As for the nutrient structure characteristics, NO3- -N accounts for 57% to 70% of the inorganic nitrogen content, which was the main form of inorganic nitrogen. As for the red tide-monitoring area eutrophication classification, the red tide-monitoring area had been transformed from phosphorus limitation in 2009-2010 into the eutrophic state in 2011.