A study of anthropogenic and climatic disturbance of the New River Estuary using a Bayesian belief network

The present paper utilizes a Bayesian Belief Network (BBN) approach to intuitively present and quantify our current understanding of the complex physical, chemical, and biological processes that lead to eutrophication in an estuarine ecosystem (New River Estuary, North Carolina, USA). The model is further used to explore the effects of plausible future climatic and nutrient pollution management scenarios on water quality indicators. The BBN, through visualizing the structure of the network, facilitates knowledge communication with managers/stakeholders who might not be experts in the underlying scientific disciplines. Moreover, the developed structure of the BBN is transferable to other comparable estuaries. The BBN nodes are discretized exploring a new approach called moment matching method. The conditional probability tables of the variables are driven by a large dataset (four years). Our results show interaction among various predictors and their impact on water quality indicators. The synergistic effects caution future management actions.     

不同生态修复措施下太湖西五里湖沉积物氮磷形态的时空分布

以太湖西五里湖为研究对象,研究了生态修复工程实施两年后,疏浚区、疏浚并水生植被重建示范区、退渔还湖区及对照区沉积物中氮、磷形态的季节变化及垂直分布特征,同时分析了各区上覆水的氮磷含量.结果表明:生态修复措施的实施对沉积物中氮磷形态分布及上覆水的氮磷含量影响显著.示范区和退渔还湖区水体中氮磷含量较低;沉积物中不同磷形态的垂直分布变化较复杂;疏浚基础上进行的水生植被重建对Lab-P、Al-P、Fe-P的吸收作用显著,对Ca-P、Org-P的影响较小;退渔还湖区沉积物磷形态以Ca-P、Org-P为主,Fe-P所占比例较低,与疏浚区不同.生态修复措施对沉积物中TN的影响较小;示范区NH 4 -N含量在秋季突增,可能与植物残体形成的有机质的分解有关.疏浚区水体中氮磷含量与对照区差别不大,沉积物中TN的平均含量还略高于对照区,因此单一的疏浚措施对水环境改善的长期作用需要进一步研究.而示范区水体及沉积物中的TN、TP含量均比较低,水生植被恢复较好,可见在减少外来污染的前提下,对湖区底泥进行疏浚并开展水生植被恢复工程应该是控制湖泊富营养化的有效途径.