1985～2003年渤海湾水质氮磷生源要素的历史演变趋势分析

Historical Evolvement Trends of Nutrients in Waters of Bohai Bay from 1985 to 2003

通过对渤海湾表层海水生源要素的现场调查以及相应历史数据的收集和分析,对渤海湾生源要素的现状、历史演变趋势以及富营养化状态等进行了分析和研究.结果表明,渤海湾表层海水处于较为严重的氮污染状态.北塘口、大沽口是渤海湾无机氮、磷的2大污染源.DIN、DIP的历史演变趋势与入海径流量息息相关,尤其是大沽口近岸海域,DIN、DIP与入海年径流量呈现显著正相关性,显示了渤海湾无机氮、磷污染的陆源输入性.受渤海湾天津近岸海域无机氮含量持续增长的影响,1985～2003年期间,渤海湾天津近岸海域氮、磷营养盐结构发生了很大变化,从1985年的“氮限制”状态转变为“磷限制”状态,这将对这一海域浮游植物群落结构的变化造成重要影响.

The local condition and the historical evolvement trend of nutrient elements were studied by the collection and analysis of the local investigation and the historical data. The surface seawaters are under the bad nitrogen contaminative conditions. Beitang and Dagu estuary are the main contaminative sources of inorganic nitrogen and phosphorus. The historical evolvement trend of DIN and DIP has close correlation with the yearly runoff, especially in the coastal areas near Dagu estuary. The remarkable positive correlationship between DIN, DIP and the yearly runoff indicates that the main pollution emission source of nutrient elements is the exogenous discharge input. The nutrients structures have changed greatly from 1985 to 2003. Nitrogen limiting in 1985 has changed into phosphorus limiting in 2003, which will influence the structure of phytoplanktons in Bohai Bay.