胶州湾海水中无机氮的分布与富营养化研究

Study on Dissolved Inorganic Nitrogen Distributions and Eutrophication in the Jiaozhou Bay

根据2003年1—12月胶州湾海区12个航次海水无机氮等的调查资料,分析了该海域生态环境中无机氮的分布特征及时空变化,评价了水质的富营养化状况。结果表明,测区全年溶解无机氮的平均含量为17.70μmol/dm3。在4个季节中,溶解无机氮以NO3-N的含量为最大,占58.2%,是氮主要存在形态,其中秋季含量最高,占溶解无机氮的64.74%。无机氮分布从东北部高含量区域向湾内及湾口方向呈逐步递减趋势。溶解无机磷的年平均含量为0.49μmol/dm3,表层海水4个季节中N/P比平均为39.41,胶州湾海水中的磷相对于氮是匮乏的。据营养状态指数划分,胶州湾的东、北岸海域属富营养化区,夏、秋两季可能受到赤潮的严重威胁。

Based on the monthly observed hydrochemical data in the Jiaozhou Bay in the period from January to December, 2003, the distributional characteristics and space-time variations of dissolved inorganic nitrofrom the analysis results that the annual mean DIN concentration in the area is 17. 70 μmol/dm^3, and NO3-N is the main component of DIN with a concentration accounting for 58. 2 % of DIN concentration on an average. In autumn, the NO3-N concentration is the highest, and accounts for 64.74 % of DIN concentration. The DIN concentration is the highest in the northeastern Jiaozhou Bay and decreases gradually towards the inner bay and bay mouth. The annual mean dissolved inorganic phosphorus （DIP） concentration in the area is only 0.49 μmol/dm^3, and the annual mean ratio of DIN to DIP in the surface seawater is 39.41, so DIP in the area is deficient relative to DIN. It is shown from the nutritional condition index distributions that the northeast coastal area belongs to eutrophic area, and the red tide may constitute a serious threat to the sea area in summer and autumn.