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.

那些在沙漠中呆过的人可能对“雨的味道”很熟悉--这是土壤被最近的降水湿润后特有的泥土气味。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。土臭素是五十多年前发现的。它的生物学功能是什么？这一点还不清楚，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的释放如何随时间和空间而变化。这些知识空白令人不安，因为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。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什么不同，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。这项工作将深入了解一种广泛观察到的现象，这是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的关键。土臭素的研究也提供了一个独特的机会，向学生介绍土壤生态学领域。该项目将利用研究活动，为科学学科中代表性不足的群体（以色列的贝都因高中生和美国的美洲原住民本科生）增加教育机会。活动的重点是沙漠土壤生态。此外，作为美国和以色列研究人员之间的合作，该项目提供了一个独特的机会，以促进国际研究和教育培训的努力。虽然挥发性有机化合物（VOCs）越来越被认为是重要的地下系统，这些排放的具体性质和土壤生物群的相关后果仍然知之甚少。该项目的重点是一种挥发性有机化合物，土臭素-一种微生物产生的代谢物，通常在降雨后从沙漠土壤中以高浓度排放。该项目将研究以色列南部和美国西南部干旱梯度下的土臭素排放，将气相色谱/质谱分析与基于DNA和RNA的方法相结合，以确定负责产生这种VOC的特定类群及其排放率的控制。该项目还将使用一系列实验测定来验证土臭素作为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种知之甚少的现象的理解，这种现象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，并且与理解气候变化的影响非常相关。该项目的不同方面将纳入扩大科学参与的培训机会，并将通过基于科学的图画小说向K-12学生和公众传播信息。该奖项反映了NSF的法定使命，并通过使用基金会的智力价值和更广泛的影响审查标准进行评估，被认为值得支持。