广西近岸海域营养盐时空分布及潜在性富营养化程度评价

Temporal and Spatial Distribution of Guangxi Inshore Nutrients and Evaluation of Its Potential Eutrophication

根据广西近岸海域2015年3、5、8、11月4个航次的海水中营养盐监测数据,分析了广西近岸海域海水中营养盐的时空分布特征,应用潜在性富营养化评价模式对整个海域水质富营养化程度进行了评价。结果表明:广西近岸海域富营养化状态总体良好,时空分布受陆源污染的影响,营养盐质量浓度呈湾内-湾口-湾外递减趋势。多数站位点氮磷比常年大于Redfield比值,处于磷限制状态。钦州湾内和大风江口是富营养化最为严重的水域,其次是防城港湾内、廉州湾内和铁山港湾,呈磷限制状态,容易在磷污染增高时,爆发富营养化,应特别加以监测与控制。

The temporal and spatial distribution of nutrients in Guangxi inshore was analyzed based on the monitoring data from the four cruises in March,May,August and November,2015.The mode of potential eutrophication was also applied to evaluating the eutrophic state of the whole sea area.The results showed that the overall eutrophication status was good.Effect of temporal and spatial distribution affected by terrestrial pollution.Nutrient concentration decreased from the inner gulf to the outer gulf. The nitrogen to phosphorus ratio was higher than the red field value (16)in most years when monitoring was conducted,thereby indicating that the water was in a phosphorus-limited state.The Qinzhou inner bay and Dafeng River were the most eutrophic sites,which was followed by Fangcheng inner bay, Lianzhou inner Bay and Tieshan harbour.Eutrophication control should be conducted in these sites,especially,the phosphorus level should be reduced.This is due to the high risk of eutrophication when the amounts of nitrogen pollutants is large and phosphorus conditions are limiting.