Collaborative Research: Headwater stream networks in a warming world: predicting heterotrophic ecosystem function using theory, multi-scale temperature manipulations and modeling

合作研究：变暖世界中的源头河流网络：利用理论、多尺度温度操纵和建模预测异养生态系统功能

• 批准号: 1655996
• 负责人: Erin Hotchkiss
• 金额: $ 9.86万
• 依托单位: Virginia Polytechnic Institute and State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-07-01 至 2022-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1655996&HistoricalAwards=false
• 关键词: Collaborative; Research; Headwater; stream; networks

Earth's river systems receive, transport, store, and break down a substantial proportion of the dead plant material produced in terrestrial ecosystems. Many of the steps in the breakdown of this organic matter are greatly affected by water temperature, which is increasing along with air temperature globally. While the effects of temperature on some of these steps are understood relatively well at small scales, it remains an open question how they interact as a complex, integrated ecosystem-level process to drive the effects of rising temperatures at the large spatial and temporal scales over which Earth's river systems operate. Consequently, research is needed that tests the effects of temperature on organic matter breakdown in whole ecosystems, with the explicit goal of scaling up these results to understand how entire river reaches and networks process organic matter. This project will use data from temperature manipulations at multiple spatial and temporal scales to: 1) inform ecological theory that uses basic principles to understand how the effects of temperature scale from individual organisms to entire ecosystems; and 2) build a model that simulates the effects of temperature on organic matter processing in an entire forest stream network. This research is important because rising temperatures may alter the global biogeochemical role of streams and rivers in currently unpredictable ways, making the results useful in the future management of river health. An education program will be an integral part of this project and will include the development of a citizen science project, as well as training of undergraduates, graduate students and research technicians. Fieldwork for this project will take place at the Coweeta Hydrologic Laboratory, North Carolina, U.S.A., a site with a decades-long history of research on organic matter processing in stream ecosystems. The first objective is to understand how warming affects the organisms (fungi and invertebrates) that are critically important in organic matter breakdown in streams. This component of the project will combine detailed laboratory-based studies of fungi, experiments in heated streamside channels and the warming of an entire reach of a small forest stream to understand how higher temperatures change community structure of fungal and animal decomposers. The second objective is to use the various temperature manipulations to understand how temperature changes pathways and rates of organic matter processing in streams and rivers. The fates of organic matter will be studied using laboratory investigations, streamside channels, and field experiments combined with organic matter budgets and food web descriptions in the experimentally warmed stream and a matching reference stream. The results of these first two objectives will be combined with extensive existing datasets available at the Coweeta site to inform the final objective: construction of an ecological model that predicts the effects of warming on organic matter processing in an entire stream network. This model will also allow incorporation of other important factors that could potentially change in the future, such as precipitation and the relative quality of organic matter that enters stream ecosystems. Together, this research will provide much needed information about how warming influences the important biogeochemical role of streams and rivers.

地球的河流系统接收、运输、储存和分解陆地生态系统中产生的大量死亡植物物质。这种有机物分解的许多步骤都受到水温的极大影响，水温沿着全球气温的上升。虽然温度对其中一些步骤的影响在小尺度上得到了相对较好的理解，但它们如何作为一个复杂的综合生态系统级过程相互作用，在地球河流系统运行的大空间和时间尺度上推动温度上升的影响，仍然是一个悬而未决的问题。因此，需要进行研究，测试温度对整个生态系统中有机物分解的影响，明确的目标是扩大这些结果，以了解整个河流河段和网络如何处理有机物。该项目将使用多个空间和时间尺度的温度操纵数据：1）告知生态理论，该理论使用基本原理来了解温度如何从单个生物体到整个生态系统的影响; 2）建立一个模型，模拟温度对整个森林溪流网络中有机物处理的影响。这项研究很重要，因为气温上升可能会以目前不可预测的方式改变溪流和河流的全球生物地球化学作用，使其结果在未来的河流健康管理中非常有用。一个教育方案将是该项目的一个组成部分，将包括制定一个公民科学项目，以及培训本科生、研究生和研究技术人员。该项目的实地工作将在美国北卡罗来纳州的考维塔水文实验室进行，一个有着数十年河流生态系统中有机物处理研究历史的网站。第一个目标是了解变暖如何影响生物（真菌和无脊椎动物），这些生物在溪流中的有机物分解中至关重要。该项目的这一组成部分将结合联合收割机详细的实验室真菌研究，在加热的河边通道和一个小森林流的整个范围的变暖的实验，以了解更高的温度如何改变真菌和动物分解者的群落结构。第二个目标是使用各种温度操纵来了解温度如何改变溪流和河流中有机物处理的途径和速率。有机物的命运将使用实验室调查，河边渠道，并结合有机物预算和食物网的描述，在实验变暖流和匹配的参考流的现场实验进行研究。这前两个目标的结果将结合广泛的现有数据集可在Coweeta网站通知的最终目标：构建一个生态模型，预测在整个流网络的有机物处理变暖的影响。这一模式还将允许纳入未来可能发生变化的其他重要因素，如降水和进入河流生态系统的有机物的相对质量。总之，这项研究将提供有关变暖如何影响溪流和河流的重要地球化学作用的急需信息。

项目成果

Integrating Ecosystem Patch Contributions to Stream Corridor Carbon Dioxide and Methane Fluxes

整合生态系统斑块对河流廊道二氧化碳和甲烷通量的贡献

• DOI: 10.1029/2021jg006313
• 发表时间: 2021
• 期刊: Journal of Geophysical Research: Biogeosciences
• 作者: Bretz, Kristen A.;Jackson, Alexis R.;Rahman, Sumaiya;Monroe, Jonathon M.;Hotchkiss, Erin R.
• 通讯作者: Hotchkiss, Erin R.