NSFDEB-BSF: Sources, controls, and significance of soil geosmin emissions in dryland ecosystems

NSFDEB-BSF：旱地生态系统中土壤土臭素排放的来源、控制和意义

• 批准号: 2126106
• 负责人: Noah Fierer
• 金额: $ 82.31万
• 依托单位: University of Colorado at Boulder
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-09-01 至 2025-08-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2126106&HistoricalAwards=false
• 关键词: NSFDEB; BSF; Sources; controls; significance

Those who have spent time in deserts are likely familiar with the 'smell of rain' - the earthy scent characteristic of soils moistened by recent precipitation. One of the key compounds contributing to this scent is geosmin, a compound exclusively produced by soil microbes. Geosmin was discovered over fifty years ago. What is its biological function? This is as yet unknown, as are which soil microbes produce geosmin and how its release from soil varies across time and space. These knowledge gaps are unsettling given that geosmin is likely to have critical roles in desert systems, influencing the growth and activity of soil microbes and plants. This project will study soils collected from deserts in Israel and the U.S. to determine how and why rates of geosmin release from soil vary, identify the microbial sources of geosmin, and determine how geosmin can influence the growth of plants and microbes. This work will provide insight into a widely-observed phenomenon that is key to understanding how rain storms influence desert systems and how to best monitor and manage the health of desert landscapes under changing environmental conditions. The study of geosmin also provides a unique opportunity to introduce students to the field of soil ecology. This project will leverage research activities to enhance educational opportunities for groups typically under-represented in scientific disciplines (high school-aged Bedouin students in Israel and Native American undergraduates in the U.S.) with activities focused on desert soil ecology. In addition, as a collaboration between U.S. and Israeli researchers, this project presents a unique opportunity to foster international research and educational training efforts.Although volatile organic compounds (VOCs) are increasingly recognized as being important in belowground systems, the specific nature of these emissions and the associated consequences for soil biota remain poorly understood. This project focuses on one such VOC, geosmin - a microbially-produced metabolite often emitted in high concentrations from desert soils following rain events. This project will examine geosmin emissions across aridity gradients in southern Israel and the southwestern U.S., pairing gas chromatography/mass spectrometry analyses with DNA and RNA-based approaches to identify the specific taxa responsible for the production of this VOC and the controls on its emission rates. This project will also use a series of experimental assays to test the hypothesis that geosmin acts as a signaling molecule with wide-ranging effects on the germination, growth, and activities of microbes and plants in desert ecosystems. Together, this work will advance our understanding of a poorly understood, phenomenon in desert systems that is likely to have important consequences for understanding biotic responses to rewetting events in arid environments. As such, this work will be relevant to researchers in disciplines ranging from ecosystem ecology to microbiology to soil science, and is very relevant to understanding the impacts of climate change. Training opportunities that broaden participation in science will be incorporated into different aspects of the project, and information will be disseminated to K-12 students and the public via science-based graphic novels.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

那些在沙漠里待过的人可能对“雨的味道”很熟悉——这是最近降水湿润的土壤特有的泥土气味。产生这种气味的关键化合物之一是土臭素，一种仅由土壤微生物产生的化合物。土臭素是50多年前发现的。它的生物学功能是什么？这一点目前尚不清楚，也不清楚哪些土壤微生物会产生土臭素，以及土臭素从土壤中释放出来是如何随时间和空间变化的。考虑到土臭素可能在沙漠系统中发挥关键作用，影响土壤微生物和植物的生长和活动，这些知识缺口令人不安。该项目将研究从以色列和美国的沙漠中收集的土壤，以确定土臭素从土壤中释放的速率如何以及为何变化，确定土臭素的微生物来源，并确定土臭素如何影响植物和微生物的生长。这项工作将为了解暴雨如何影响沙漠系统以及如何在不断变化的环境条件下最好地监测和管理沙漠景观健康提供一个广泛观察到的现象的关键。土臭素的研究也为学生介绍土壤生态学领域提供了一个独特的机会。该项目将利用研究活动，通过以沙漠土壤生态学为重点的活动，为在科学学科中代表性不足的群体（以色列的高中贝都因学生和美国的土著美国大学生）增加教育机会。此外，作为美国和以色列研究人员之间的合作，该项目为促进国际研究和教育培训工作提供了一个独特的机会。尽管人们越来越认识到挥发性有机化合物（VOCs）在地下系统中的重要性，但人们对这些排放物的具体性质及其对土壤生物群的相关后果仍然知之甚少。本项目主要研究一种挥发性有机化合物，土臭素——一种微生物产生的代谢物，通常在降雨事件后从沙漠土壤中高浓度排放。该项目将研究土臭素在以色列南部和美国西南部干旱梯度上的排放，将气相色谱/质谱分析与DNA和rna为基础的方法相结合，以确定产生这种VOC的特定分类群及其排放率的控制。该项目还将使用一系列实验分析来验证土臭素作为一种信号分子对沙漠生态系统中微生物和植物的萌发、生长和活动具有广泛影响的假设。总之，这项工作将促进我们对沙漠系统中一个知之甚少的现象的理解，这可能对理解干旱环境中生物对再湿润事件的反应产生重要影响。因此，这项工作将与从生态系统生态学到微生物学到土壤科学等学科的研究人员相关，并且与了解气候变化的影响非常相关。扩大科学参与的培训机会将被纳入项目的不同方面，信息将通过以科学为基础的图画小说传播给K-12学生和公众。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。