Collaborative research: Interactive effects of temperature and nutrient supply on the structure and function of stream ecosystems

合作研究：温度和养分供应对河流生态系统结构和功能的交互影响

• 批准号: 1354411
• 负责人: Wyatt Cross
• 金额: $ 61.38万
• 依托单位: Montana State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-08-01 至 2019-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1354411&HistoricalAwards=false
• 关键词: Collaborative; research; Interactive; effects; temperature

A lot of scientific effort is now being focused on how plants and animals will respond to a warming climate. This is critically important, but very difficult because there are many other global changes occurring at the same time. For example, humans have widely spread large amounts of nitrogen and phosphorus, which are important fertilizers. But what effects excess nutrients that are deposited mainly on land but then wash into aquatic ecosystems will have as the world warms is not clear. So studies are needed that examine how multiple global changes like these interact at the same time. The goal of this research project is to explore how freshwater ecosystems respond to warming and nutrient enrichment simultaneously. The research is important because nutrient enrichment may drastically alter the effects of warming on streams and rivers and so the results should be useful as society tries to adapt to warmer conditions. Results will also inform ecological theory that attempts to use basic principles for understanding how species and ecosystems may respond to global change. An education program will be an integral part of this project and will include the development of film documentaries, student podcasts, and the more traditional training of undergraduate and graduate students, as well as research technicians. This project will be conducted in a geothermally active region of southwestern Iceland, where streams exhibit a wide range in ambient temperature without significant differences in background chemistry that would otherwise influence results. The research team will use the differences in natural temperature between streams to examine how nutrient supply and temperature together influence the ecology of streams and rivers. The first objective is to quantify effects of warming and nutrients on the origin and fate of carbon and nitrogen (e.g., ecosystem productivity, nutrient uptake, and nitrogen-fixation). The team will then combine ecosystem-scale nitrogen and phosphorus additions with controlled streamside channel experiments to examine how the influence of warming on the ecology of streams and rivers is affected by nutrient supply, and whether short-term responses to warming differ from those observed in natural ecosystems over longer periods. Responses of these ecosystem-level processes should also shape how energy and materials flow through food webs from algae to trout. The second objective is to quantify the interactive effects of temperature and nutrients on the routes of energy and materials through river and stream food webs. Food web responses to nutrients between streams of varying temperatures will be tracked using a combination of stable (i.e., non-radioactive) isotope tracer additions, secondary production measurements, and flow food web analyses. This research will provide much needed information about how two dominant global change drivers, warming and nutrient enrichment, interact to influence biodiversity and ecosystem function in an important freshwater habitat.

现在，许多科学努力都集中在动植物如何应对温暖气候上。这非常重要，但非常困难，因为同时还有许多其他全球变化。例如，人类广泛传播了大量氮和磷，这是重要的肥料。 但是，什么会影响主要沉积在陆地上的多余营养，然后将其洗涤成水生生态系统，因为世界温暖不清楚。 因此，需要研究研究类似的多个全球变化如何同时相互作用。 该研究项目的目的是探索淡水生态系统如何同时对变暖和营养富集的反应。 这项研究很重要，因为养分富集可能会大大改变变暖对溪流和河流的影响，因此由于社会试图适应温暖的状况，结果应该很有用。 结果还将为生态学理论提供信息，即尝试使用基本原理来了解物种和生态系统如何应对全球变化。 教育计划将是该项目不可或缺的一部分，包括电影纪录片，学生播客以及对本科生和研究生的传统培训以及研究技术人员的发展。该项目将在冰岛西南部的地热区域进行，在该区域中，溪流在环境温度的范围很广，而背景化学的差异很大，否则会影响结果。研究小组将利用溪流之间自然温度的差异来检查养分供应和温度如何共同影响溪流和河流的生态。第一个目标是量化变暖和养分对碳和氮的起源（例如生态系统生产力，养分摄取和氮固定）的作用。然后，该团队将将生态系统规模的氮和磷添加与受控的流侧通道实验相结合，以检查变暖对养分和河流生态学的影响如何受到养分供应的影响，以及对变暖的短期反应与在自然生态系统中观察到的短期变暖是否有所不同。 这些生态系统级过程的反应还应影响能量和材料如何从藻类流到鳟鱼的食物网。第二个目标是量化温度和养分对通过河流和溪流食品网的能量和材料途径的交互作用。将使用稳定（即非放射性）同位素示踪剂，二级生产测量和流食品网络分析的组合来跟踪食物网络对养分的反应。这项研究将提供急需的信息，以了解如何在重要的淡水栖息地中影响生物多样性和生态系统功能，以影响生物多样性和生态系统功能。