Light, Phosphorus, and Ecological Stoichiometry in Pelagic Communities

ELSER 9725878生态学家已经越来越意识到组成生态系统食物网的有机体元素组成的差异的根本重要性。埃尔瑟，这项提议的PI，一直是发展这一被称为生态化学计量学的领域的领导者之一。该项目支持的工作将把模拟调查与实地实验和人工围栏相结合，以研究光照和营养供应对远洋栖息地水生群落组织的联合影响。具体地说，它将测试不同的光照和营养条件是否可以通过改变主导相互作用的生态化学计量学来将远洋生物群落转变为根本不同的状态。模拟研究将评估交替状态的可能性，其中一种状态以数量效应为主，例如低藻类生物量限制了食草动物的生长，而另一种状态由营养效应驱动，在这种情况下，藻类食物质量差可能会限制食草动物的生长。模拟结果将在加拿大实验湖地区进行的现场操作中进行测试，并在日本京都大学新的最先进的设施中进行人工中观系统的测试。实验将涉及对光线和开始放牧条件的操纵，以测试该模型对这些交替生态系统状态的预测。这项工作将有助于理解种群动态和生态系统功能之间的界面。具有重要的理论意义和实践意义。

Elser 9725878 Ecologists have been increasingly aware of the fundamental importance of differences in the elemental composition of organisms that comprise the food webs of ecosystems. Elser, the PI on this proposal, has been one of the leaders in developing this field termed ecological stoichiometry. The work supported by this project will combine modeling investigations with experiments in field and artificial enclosures to examine the joint effects of light and nutrient availability on the organization of aquatic communities in pelagic habitats. Specifically it will test whether different light and nutrient conditions can shift pelagic communities into fundamentally different states by altering the ecological stoichiometry of dominant interactions. Modeling studies will evaluate the potential for alternate states in which one is dominated by quantity effects such as where low algal biomass limits growth by grazers and the alternate is driven by nutritional effects where poor algal food quality can limit grazer growth. Modeling results will be tested in field manipulations conducted at the Experimental Lakes Area in Canada and in artificial mesocosms at new, state-of-the-art facility at Kyoto University in Japan. Experiments will involve manipulations of light and starting grazer conditions to test predictions from the model on these alternate ecosystem states. This work will contribute to the understanding of the interface between population dynamics and ecosystem function. It has substantial theoretical and practical implications.