Collaborative Research: Predicting Effects of Climate Warming on Stream Ecosystems Using Metabolic Theory and Iceland's Unique Geothermal Environment

气候变暖已被认为是全球淡水生态系统面临的最重要威胁之一。由于温度是几乎所有生物过程的根本驱动因素，气候变暖可能会对淡水生态系统及其为人类提供的生态系统服务产生强烈影响。尽管最近的理论进展为生物体应如何应对变暖提供了明确的预测，但我们目前的理解受到以下因素的阻碍：(A)以前大多数研究的短期和小规模性质，以及(B)与生态系统规模淡水实验变暖相关的非同小可的实际挑战。这项研究将利用冰岛独特的地热活跃分水岭，该分水岭包含陡峭的水流温度梯度和非常小的溶质化学差异。通过对“温度适应”溪流的景观梯度研究、溪边操纵和生态系统规模实验，这项研究将量化气候变暖对关键生态系统过程(生态系统新陈代谢和营养循环)以及通过溪流食物网的能量和元素流动的影响。拟议的多尺度设计将产生关于河流生态系统对温度变化的反应的迫切需要的数据，通过增加对气候变暖将如何影响淡水生态系统及其为人类提供的关键服务的了解，使社会受益。该项目将通过对本科生、研究生和博士后助理的培训和指导，将研究和教育结合起来。除了通过传统渠道(出版物、国家/国际会议)交流成果外，还将通过演讲、互动研究博客和与冰岛同事的半年度会议向当地小学、高中和广大社区介绍调查结果。

Climate warming has been identified as one of the most important threats to freshwater ecosystems globally. Because temperature is the fundamental driver of nearly all biological processes, climate warming will likely have strong effects on freshwater ecosystems and the ecosystem services they provide for humans. Despite recent theoretical advances that provide clear predictions about how organisms should respond to warming, our current understanding is hindered by (a) the short-term and small-scale nature of most previous studies and (b) the non-trivial practical challenges associated with experimental warming of freshwaters at the ecosystem scale. This study will take advantage of a unique geothermally-active watershed in Iceland that contains a steep gradient of stream temperatures and very little difference in solute chemistry. Using a landscape gradient study of "temperature-acclimated" streams, streamside manipulations, and an ecosystem-scale experiment, this study will quantify the effects of warming on critical ecosystem processes (ecosystem metabolism and nutrient cycling) and the flow of energy and elements through stream food webs. The proposed multi-scale design will produce much-needed data concerning the response of stream ecosystems to changes in temperature regime, benefitting society through increased understanding of how climate warming will influence freshwater ecosystems and the critical services they provide to humanity. The project will integrate research and education through training and mentoring of undergraduates, graduate students and a post-doctoral associate. In addition to communicating results through traditional outlets (publications, national/international meetings), findings will be presented to local grade schools, high schools, and the community at large with presentations, an interactive research blog, and semi-annual meetings with Icelandic colleagues.