Understanding the effects of terrestrially-derived dissolved organic matter on food web productivity and organismal life histories in lakes

湖泊生态系统及其为人类提供的服务受到陆源溶解有机物（tDOM）输入的深刻影响。湖泊的tDOM输入量因地貌而异;在过去几十年中，许多区域的tDOM输入量也有所增加，并可能继续变化。考虑到这两个观察结果--tDOM输入从根本上塑造湖泊生态系统，而且这些输入在空间和时间上各不相同--对这些系统的生产力以及它们所支持的具有文化和经济价值的渔业有什么影响？ 我们将从两个不同的角度来讨论这个问题。首先，我们将测试一个新的理论框架，描述tDOM对食物网生产力的影响。我们的测试将包括重复实验，比较研究，和整个湖泊的tDOM操作，在其中，我们将评估藻类，无脊椎动物和鱼类的生产力如何响应tDOM输入的差异。第二，我们将问如何在tDOM输入的差异影响的生活史（如增长率，成熟年龄，和繁殖力）的两种不同的生物，蓝鳃太阳鱼和非咬蠓。这些都是分布广泛且广为人知的物种，也是了解tDOM如何影响最佳生活史特征的良好模型系统。 这项工作将为研究领域和加拿大带来重大利益。它将为水生生态系统生态学的前沿理论提供严格的测试，增加我们对这些系统如何工作以及它们如何应对持续环境变化的理解。它将为内陆休闲渔业的当前和未来管理提供信息，这是加拿大人宝贵的文化和经济资源。

Lake ecosystems and the services that they provide to people are profoundly influenced by inputs of terrestrially-derived dissolved organic matter (tDOM). Inputs of tDOM to lakes vary across the landscape; they have also increased over the past several decades in many regions, and are likely to continue to change. Given these two observations - that tDOM inputs fundamentally shape lake ecosystems, and that these inputs vary in space and time - what are the implications for the productivity of these systems and the culturally and economically valuable fisheries that they support? We will address this question from two different perspectives. First, we will test a new theoretical framework describing the effects of tDOM on food web productivity. Our tests will include replicated experiments, comparative studies, and a whole-lake tDOM manipulation, in which we will assess how productivity of algae, invertebrates, and fishes respond to differences in tDOM inputs. Second, we will ask how differences in tDOM inputs affect the life histories (e.g. growth rates, maturation ages, and fecundities) of two different organisms, bluegill sunfish and non-biting midges. These are widespread and well-understood species, and so are good model systems for understanding how tDOM influences optimal life history traits. This work will have major benefits for the research field and for Canada. It will provide rigorous tests of cutting-edge theory in aquatic ecosystem ecology, increasing our understanding of how these systems work and how they may respond to ongoing environmental changes. It will inform current and future management of inland recreational fisheries, which are a valuable cultural and economic resource for Canadians.