太湖水体氮、磷赋存量的逐月变化规律研究

基于中国科学院太湖湖泊生态系统研究站2005~2009年对太湖逐月叶绿素a、氮、磷各形态因子及水深的监测,结合太湖大浦水文站的逐日水位数据,估算出2005~2009年太湖的逐日水量,并运用泰森多边形法,估算出太湖水体总氮（TN）、总磷（TP）、溶解性总氮（TDN）、溶解性总磷（TDP）、硝态氮（NO3）、铵态氮（NH4）、亚硝态氮（NO2）、反应性活性磷（PO₄）、颗粒态总氮（TPN）、颗粒态总磷（TPP）、浮游藻类叶绿素a（Chla）的逐月动态变化过程。结果表明:（1）太湖2005~2009年TN、TDN、NO₂、NO₃、NH₄、TP、TDP、PO₄、TPN、TPP、Chla的平均赋存量分别为1.36×104t、1.02×104t、0.02×104t、0.37×104t、0.25×104t、514.34 t、147.30 t、51.44 t、0.34×104t、367.04 t、7.92 t,不同月份、年际之间变化剧烈,变幅分别为106%、142%、657%、252%、233%、95%、196%、276%、236%、131%、276%;（2）2007年6月无锡贡湖水厂"饮用水危机"事件之后,截止到2009年12月,太湖水体各形态氮及总磷赋存量的下降趋势不明显,溶解性总磷、反应性活性磷的赋存量反而增高,反映出营养盐控制任务的艰巨性。本研究表明,对于年水量变幅巨大的大型湖泊,全湖水体营养盐赋存量在评估水体营养盐污染状况中是一个有价值的指标;对于太湖流域的污染控制效果,仅从浓度角度评价具有一定的缺陷,有必要从水体营养盐赋存量的变化规律上探讨其治理效果。

Monthly Variation of Nitrogen and Phosphorus Volume in Taihu Lake, China

Based on the monthly data of chlorophyll-a, nitrogen forms, phosphorus forms and water depth observed by the TaihuLake Ecosystem Research Station under Chinese Academy of Sciences from 2005 to 2009, and the daily water level data from theDapu Station, the daily water quantity of the Taihu Lake from 2005 to 2009 was estimated, and the Tyson polygon method wasused to estimate the monthly variation of total nitrogen (TN), total phosphorus (TP), total dissolved nitrogen (TDN), total dissolvedphosphorus (TDP), nitrate nitrogen (NO3), ammonium nitrogen (NH4), nitrite nitrogen (NO2), reactive phosphorus(PO4), total particulatenitrogen (TPN), total particulate phosphorus (TPP), planktonic algae chlorophyll-a (Chl-a) in the Taihu Lake. The results show that:(1) The average volumes of TN, TDN, NO2, NO3, NH4, TP, TDP, PO4, TPN, TPP, Chl -a are respectively 1.36×104t,, 1.02 ×104t,0.02×104t, 0.37×104t, 0.25×104t, 514.34t, 147.30t, 51.44t, 0.34 ×104t, 367.04t, 7.92t in the Taihu Lake during 2005 -2009. Themonthly and annual change are violent. The relative amplitude are respectively 106%, 142%, 657%, 252%, 233%, 95%, 196%,276%, 236%, 131%, 276%. (2) Since the Wuxi water crisis in June 2007 untill the end of 2009, the decline trend of variousnitrogen forms and total phosphorus in the Taihu Lake is not obvious, and the volume of dissolved phosphorus and reaction activityof phosphate increased. This study shows that as for large lakes with great change amplitude of water quantity, the volume of lakenutrient is a valuable indicator in the assessment of nutrient pollution. In the view of pollution control, it is not perfect only toevaluate the concentration, and it is necessary to pay attention to nutrient volume changes.