Terrestrial carbon in aquatic ecosystems: experimental tests of the subsidy-stability hypothesis

水生生态系统中的陆地碳：补贴稳定性假说的实验检验

• 批准号: 1303720
• 负责人: Jay Lennon
• 金额: $ 27.23万
• 依托单位: Indiana University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-08-01 至 2013-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1303720&HistoricalAwards=false
• 关键词: Terrestrial; carbon; aquatic; ecosystems; experimental

Ecosystems are spatially linked by the flux of materials and energy. Over the past decade there has been growing appreciation that the movement of resources across the landscape can act to subsidize populations in local habitats. In addition, theory suggests that resource subsidies may act to stabilize food webs and ecosystems, but these predictions remain largely untested. This study will examine the effects of terrestrial-derived dissolved organic carbon (DOC) on the stability of aquatic ecosystem metabolism. Traditionally been viewed as a low quality resource, it is now recognized that terrestrial DOC inputs are a resource subsidy for bacteria that can determine whether recipient aquatic ecosystems function as sources or sinks of atmospheric carbon dioxide. The first goal of this project is to describe the shape, magnitude, and direction of subsidy-stability relationships using a set of whole-pond experiments that manipulate the supply rate of terrestrial DOC. The second goal of this project is to identify the mechanisms by which terrestrial DOC influences aquatic ecosystem stability. Specifically, the project will assess whether DOC affects ecosystem stability by modifying nutrient cycling, altering temperature dynamics, or by altering interaction strengths among different groups of microorganisms. The objectives of this project will be assessed using a combination of autonomous sensor technology to quantify ecosystem metabolism and temperature variability, radioisotope assays to measure nutrient cycling, and molecular techniques to evaluate changes in the metabolic activity of microbial communities. At a global scale, the export of terrestrial DOC to aquatic ecosystems is increasing due to a combination of factors, including atmospheric deposition, climate variability, and shifting land use. The tools and approaches developed in this proposal will address this phenomenon and help scientists and managers predict how changes in DOC loading affect ecosystem functioning and water quality under existing and future climate scenarios. This project has a significant education and outreach component that will foster interactions among the Kellogg Biological Station (KBS), Michigan State University (MSU), and rural Michigan K-12 school districts. Specifically, the project will continue an ongoing collaboration that will introduce concepts of ecological stability, microbial diversity, and biogeochemical cycling into the high-school classroom. The project will also provide interdisciplinary research training in the fields of ecosystem science, quantitative ecology, and molecular biology for undergraduate students, a graduate student, a high school teacher, and postdoctoral researcher.

生态系统在空间上通过物质和能量的流动联系在一起。 在过去的十年里，人们越来越认识到，资源在整个景观中的移动可以起到补贴当地栖息地人口的作用。 此外，理论表明，资源补贴可能会起到稳定食物网和生态系统的作用，但这些预测基本上尚未得到验证。 本研究将探讨陆源溶解有机碳（DOC）对水生生态系统代谢稳定性的影响。 传统上被视为一种低质量的资源，它是现在认识到，陆地DOC输入是一种资源补贴的细菌，可以决定是否接收水生生态系统作为源或汇的大气二氧化碳。 该项目的第一个目标是描述的形状，大小和方向的沉降稳定性关系，使用一组全池实验，操纵陆地DOC的供应率。 本项目的第二个目标是确定陆地DOC影响水生生态系统稳定性的机制。 具体而言，该项目将评估DOC是否通过改变营养循环、改变温度动态或改变不同微生物群体之间的相互作用强度来影响生态系统稳定性。 该项目的目标将使用自主传感器技术来量化生态系统代谢和温度变化，放射性同位素测定来测量营养循环，以及分子技术来评估微生物群落代谢活动的变化。在全球范围内，由于大气沉积、气候变化和土地利用变化等因素的综合作用，陆地DOC向水生生态系统的输出正在增加。 本提案中开发的工具和方法将解决这一现象，并帮助科学家和管理人员预测DOC负荷的变化如何影响现有和未来气候情景下的生态系统功能和水质。 该项目有一个重要的教育和推广组成部分，将促进凯洛格生物站（KBS），密歇根州立大学（MSU）和密歇根州农村K-12学区之间的互动。 具体而言，该项目将继续进行合作，将生态稳定性，微生物多样性和生物地球化学循环的概念引入高中课堂。 该项目还将为本科生、研究生、高中教师和博士后研究人员提供生态系统科学、数量生态学和分子生物学领域的跨学科研究培训。