Trophic Cascades and Interacting Control Processes in a Detritus-Based Aquatic Ecosystem

人类活动正在以前所未有的速度改变着当地和全球环境。一些最重大的变化涉及广泛的营养丰富和物种组成的变化，以及全球变暖和海平面上升。预测这些多重压力的影响在沿海盐沼中尤为重要，因为它们是世界上生物生产力最高的地区之一，人类经常将其用于各种目的。沿海地区现在正在经历营养负荷、物种组成和海平面上升的变化，比上个世纪测量的数据高出5-10倍。该项目解决的问题是：从长远来看，营养物质的增加将如何与物种组成的变化相互作用，从而改变沿海生态系统的结构和功能？我们将进行实地实验，通过添加营养物质和移除丰富而重要的鱼类--粘鼠来改变盐沼生态系统。我们将在四年内跟踪这些操作对食物链和营养循环的影响。这些实验将与一个模型联系在一起，该模型可以用来预测几十年来盐沼的反应。这项研究的结果将对那些每天面临着解决人类利用沿海地区多种方式之间的冲突的管理者有用。

Human activity is changing local and global environments at unprecedented rates. Some of the most significant changes involve widespread nutrient enrichment and changes in species composition as well as global warming and sea level rise. Predicting the effects of these multiple stresses is particularly important in coastal salt marshes because they are among the most biologically productive areas in the world and are heavily used by humans for a variety of purposes. Coastal areas are now experiencing changes in nutrient loading, species composition and sea level rise 5-10 fold higher than measured over the last century. This project addresses the question: Over the long run, how will an increase in nutrients interact with changes in species composition to alter coastal ecosystem structure and function? We will conduct field experiments in which salt marsh ecosystems are altered by addition of nutrients and by removal of an abundant and important fish, the mummichog. We will follow the effects of these manipulations on the food web and nutrient cycles for four years. The experiments will be linked to a model that can be used to predict the saltmarsh response over decades. The results of this research will be useful to managers who are faced daily with resolving the conflicts among the many ways that humans use coastal regions.