岱山赤潮监控区氮磷营养盐变化特征及其潜在性富营养化程度评价

摘要

The status of nutrients pollution and variation and its structural charicteristic in red tide monitoring area of Daishan were analyzed as well as potential eutrophication assessment based on the monitoring data of nutrient from April to October,2007--2009. The results indicate that the water quality is on the state of severe eutrophication.which turns out that inorganic--nitrogen（DIN） is the main driving factor ot eutrophication.Due to the effection of the reproduction of marine phytoplankton us well as land--sourced pollutants,the content ot nutrients displays with a significant time variation ,which is high in spring and low in summer（lowest on August） and rise again on September..The content ot Station 1 is the highest among 8 stations while S8 is the lowest,and NO3- N is the main exsistence in the form of DIN which account for 94.79% showing that DIN is on a state of thermodynamic--equilibrium in the whole area.The result of potential eutrophication assessment shows that the levels of potential eutrophication in red tide monitoring area of Daishan is between moderate level and eutrophic level （Ⅱ--Ⅲ） with a tendency towards eutrophic level（Ⅲ）.%根据2007年至2009年4～10月岱山赤潮监控区水质监测资料,对N、P营养盐的污染现状、变化规律、结构特征进行分析,并进行潜在性富营养化程度评价。结果表明,监控区水体处于严重的富营养化状态,无机氮（DIN）是富营养化的主要驱动因子;受海洋浮游植物生长繁殖规律以及陆源污染物排放的影响,监控区营养盐含量呈明显的时间变化特征：即春季高,夏季低（8月最低）,至9月有所回升;在8个监测站位中,S1站点营养盐含量最高,S8站点最低。赤潮监控区DIN处于热力学平衡状态,NO3-N占DIN的94.79%,是岱山赤潮监控区无机氮的主要存在形式。潜在性富营养化评价结果显示：监控区的营养水平等级介于中度营养与富营养之间（Ⅱ～Ⅲ）,并逐渐趋于富营养等级（Ⅲ）。