Collaborative research: Controls over decomposition by microbial communities under climate change

合作研究：气候变化下微生物群落分解的控制

• 批准号: 1457160
• 负责人: Steven Allison
• 金额: $ 83.98万
• 依托单位: University of California-Irvine
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-08-15 至 2019-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1457160&HistoricalAwards=false
• 关键词: Collaborative; research; Controls; over; decomposition

One way that microbes, including bacteria and fungi, play a critical role in the global carbon cycle is by recycling dead plant matter into nutrients and carbon dioxide. Although necessary for plant growth, carbon dioxide is also a greenhouse gas, so changes in activities of the Earth's tiniest life forms could have affects on a global scale. Warming temperatures, in turn, could affect microbial activities. If warming increases microbial activities and carbon dioxide production, there could be a positive feedback that compounds the severity of environmental changes. The goal of this project is to study the effects of temperature warming on natural communities of microorganisms in soil. The research team will use cutting-edge experimental and computational tools to analyze the importance of microbial diversity. The project investigators have designed an experiment to test how well microbes from one climate do in another. For example, they will transplant microbes from a cool, wet mountaintop and measure how fast they can recycle dead plant matter in a desert. It's plausable that the mountaintop microbes will lack essential genes for survival in a desert - genes that desert microbes already have. To test this possibility, the investigators will use DNA sequencing to identify the genes present in nearly all of the microbes from each climate condition. The study will also test whether all microbes are equivalent and speed up their metabolism when the temperature rises. The investigators will apply a sophisticated computer model to extend their experimental findings. The broad societal impacts of this project include training for a postdoctoral researcher and four graduate students, new computational infrastructure, and an outreach-education program for visitors to a California state park. Student and postdoctoral training will focus on interdisciplinary research that links microbial diversity with environmental change. The investigators will make their computer models available on the Web so that they are easily accessible to the scientific community. This project will train a postdoctoral scientist and four graduate students, develop computational infrastructure, and establish an outreach-education program for visitors to a California state park. Training will focus on interdisciplinary research that links microbial ecology and genomics with ecosystem function. A specific aim of this project is to develop a web-based version of the microbial community model for dissemination to the scientific community. On the local scale, the PIs will partner with a University of California-Irvine outreach internship program and the non-profit Crystal Cove Alliance to develop an interactive research education station for visitors to Crystal Cove State Park, CA. Park visitors will have the opportunity to learn about the ecosystem process of litter decomposition and the consequences of microbial diversity in the context of climate change.Conventional ecosystem models assume that biogeochemical rates are independent of microbial community composition, yet emerging empirical evidence contradicts this assumption. In light of this new evidence, the investigators hypothesize that litter decomposition rates and responses to climate change depend on microbial community composition. They will test this hypothesis by manipulating microbial community composition and transplanting communities across a climate gradient in southern California. The hypothesis would be supported if different communities transplanted into the same location decompose litter at different rates. Similarly, the response of litter decomposition rate to climate variation across the gradient should vary for different microbial communities. This project will also analyze the microbial traits underlying differences (or similarities) in microbial community function. The investigators hypothesize that variation in decomposition rates across different microbial communities will be driven by extracellular enzyme traits. Likewise, variation in the microbial community response to climate change should relate to differences in 'response traits' such as drought and temperature tolerance. These hypotheses will be tested by sequencing the metagenomes of litter microbial communities and extracting functional traits using bioinformatics analyses. The taxonomic composition of the microbial communities will be quantified with high-throughput sequencing of 16S and ITS markers for bacteria and fungi. Finally, the investigators aim to examine the consequences of their experimental results under future climate change predictions. Molecular and ecosystem data will be incorporated into a simulation model that accounts for microbial community composition. The transplant manipulation results will be compared to model simulations with and without diverse microbial communities to test the importance of composition for function. Following a model selection procedure, the investigators will simulate litter decomposition under climate change scenarios in southern California. These efforts will reveal the consequences of microbial community composition for ecosystem responses to future climate change.

包括细菌和真菌在内的微生物在全球碳循环中发挥关键作用的一种方式是将枯死的植物物质回收成养分和二氧化碳。尽管二氧化碳是植物生长所必需的，但它也是一种温室气体，因此地球上最微小的生命形式活动的变化可能会在全球范围内产生影响。变暖的温度反过来可能会影响微生物的活动。如果变暖增加了微生物的活动和二氧化碳的产生，那么可能会有一个积极的反馈，从而加剧环境变化的严重性。该项目的目标是研究气温变暖对土壤中微生物自然群落的影响。研究小组将使用尖端的实验和计算工具来分析微生物多样性的重要性。项目调查人员设计了一项实验，以测试来自一种气候的微生物在另一种气候下的表现如何。例如，他们将从凉爽潮湿的山顶移植微生物，并测量他们在沙漠中回收死亡植物物质的速度。有可能的是，山顶微生物将缺乏在沙漠中生存所必需的基因--沙漠微生物已经拥有的基因。为了测试这种可能性，研究人员将使用DNA测序来识别来自每种气候条件的几乎所有微生物中存在的基因。这项研究还将测试是否所有微生物都是等价的，并在温度上升时加快它们的新陈代谢。研究人员将应用一个复杂的计算机模型来扩展他们的实验结果。该项目的广泛社会影响包括对一名博士后研究员和四名研究生的培训，新的计算基础设施，以及为加州州立公园的游客提供的外展教育计划。学生和博士后培训将侧重于将微生物多样性与环境变化联系起来的跨学科研究。研究人员将在网上提供他们的计算机模型，这样科学界就可以很容易地访问它们。该项目将培养一名博士后科学家和四名研究生，开发计算基础设施，并为加州州立公园的游客建立一个外展教育计划。培训将侧重于将微生物生态学和基因组学与生态系统功能联系起来的跨学科研究。该项目的一个具体目标是开发微生物群落模型的网络版本，以便向科学界传播。在当地规模上，私人投资机构将与加州大学欧文分校的外展实习项目和非营利组织水晶湾联盟合作，为加州水晶湾州立公园的游客开发一个互动研究教育站。公园游客将有机会了解凋落物分解的生态系统过程和气候变化背景下微生物多样性的后果。传统的生态系统模型假设生物地球化学速率与微生物群落组成无关，但新兴的经验证据与这一假设相矛盾。根据这一新证据，研究人员假设，垃圾的分解速度和对气候变化的反应取决于微生物群落的组成。他们将通过操纵微生物群落组成并将群落移植到南加州的气候梯度来检验这一假设。如果移植到同一地点的不同群落分解凋落物的速度不同，这一假说将得到支持。同样，对于不同的微生物群落，凋落物分解速率对梯度上气候变化的响应也应该有所不同。该项目还将分析微生物群落功能中潜在的不同(或相似)微生物特征。研究人员假设，不同微生物群落之间的分解率差异将由胞外酶特性驱动。同样，微生物群落对气候变化反应的差异应该与干旱和耐温等“反应特征”的差异有关。这些假说将通过对凋落物微生物群落的元基因组进行测序并利用生物信息学分析提取功能特征来验证。微生物群落的分类组成将通过细菌和真菌的16S及其标记的高通量测序来量化。最后，研究人员的目标是检查他们的实验结果在未来气候变化预测下的后果。分子和生态系统数据将被纳入到一个模拟模型中，该模型解释了微生物群落的组成。移植操作的结果将与有和没有不同微生物群落的模型模拟进行比较，以测试成分对功能的重要性。在模型选择过程之后，研究人员将模拟南加州气候变化情景下的凋落物分解。这些努力将揭示微生物群落组成对生态系统应对未来气候变化的影响。