富营养化对白洋淀底栖-浮游耦合食物网结构和功能的影响

国际湖沼学的长期研究发现,一个完整的湖泊生态系统应包括底栖食物网和浮游食物网,而营养条件变化会显著改变浅水湖泊中底栖-浮游食物网的结构和功能。为了明晰富营养化对浅水湖泊底栖-浮游耦合食物网结构和功能的影响,以浅水草型湖泊——白洋淀为研究区,运用野外监测和ECOSIM与ECOPATH(Ew E)模型相结合方法,构建白洋淀底栖-浮游耦合食物网的概念模型,模拟1982—2011年间富营养化对白洋淀底栖路径和浮游路径的结构和功能影响:(1)野外监测的结果表明,从1999年至今白洋淀一直处于富营养化状态;(2)Ew E模型模拟结果表明1982—2006年,总生物量呈下降趋势,下降比例达66.38%;能流路径从以底栖路径为主转变为以浮游路径为主;(3)运用Pearson相关分析,结果表明:浮游植物与TN(r=0.67,P0.01)和TP(r=0.37,P0.05)呈显著正相关,而底栖藻类和大型沉水植物与TN(r=0.77,P0.01;r=0.67,P0.01)和TP(r=0.54,P0.01;r=0.36,P0.05)呈显著负相关。富营养化是白洋淀底栖初级和次级生产力向浮游初级和次级生产力转变的主要驱动力。采用科学的方法准确评估富营养化对湖泊底栖-浮游耦合食物网结构和功能的影响,可为湖泊生态系统管理提供技术和方法支持。

Effects of eutrophication on the benthic-pelagic coupling food web in Baiyangdian Lake

According to the research finding for the limnology, in the whole lake ecosystem it should be including benthic pathway and pelagic pathway, while the variation of nutrition conditions can significantly change the structure and function of the bethic-pelagic coupling foodweb. In order to certain the effects of eutrophication on the benthic-pelagic coupling foodweb in shallow lake ecosystem, Baiyangdian Lake as the study area. Field samping and ECOSIM with ECOPATH(EwE) model method were applied in this study, the conceptual model for benthic-pelagic coupling foodweb in Baiyangdian Lake was established, the effects of eutrophication on the benthic-pelagic coupling foodweb was monitored during the period of 1982-2011. The research finding was:(1) the result for the filed sampling was showed that the nutrition condition for Baiyangdian Lake was belonged to eutrophication from 1999 to 2011; (2) the result for the EwE model was showed that the total biomass of Baiyangdian Lake was decreased for 66.38%, and the main energy pathway was changed from benthic pathway to pelagic pathway; (3) through Pearson correlation analysis, the phytoplankton was showed significantly positive correlation with TN (r=0.67, P < 0.01) and TP(r=0.37, P < 0.05) while the periphyton and macrophyte were showed significantly negative correlation with TN (r=0.77, P < 0.01; r=0.67, P < 0.01) and TP (r=0.54, P < 0.01; r=0.36, P < 0.05). Therefore, eutrophication is the main driving force for the change from benthic primary and secondary productivity to pelagic primary and secondary productivity. Applying scientific method to evaluate the effects of eutrophication on the pelagic-benthic coupling foodweb is very important, it also can help to provide technology and method to the lake ecosystem management.