Collaborative Research: Biological and mineralogical controls over soil carbon cycling across multiple ecosystems: a focus on the priming effect

合作研究：生物和矿物学对多个生态系统土壤碳循环的控制：关注启动效应

• 批准号: 1123454
• 负责人: Craig Rasmussen
• 金额: $ 11.09万
• 依托单位: University of Arizona
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-09-01 至 2014-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1123454&HistoricalAwards=false
• 关键词: Collaborative; Research; Biological; mineralogical; controls

Carbon dioxide (CO2) is released to the atmosphere when humans burn oil, coal, and gasoline, and is the major cause of global warming. Soils can store carbon (C), helping counteract rising carbon dioxide, but the future of the soil C sink is uncertain. Will it be converted to soil organic C, which can stay put for thousands of years, or will soil microorganisms convert it back to CO2, returning it to the atmosphere? This is a major uncertainty about the future C sink on land. Recent work suggests a surprising response, called the priming effect, in which adding C to soil boosts the metabolism of microorganisms, causing them to produce even more CO2 than expected. Yet, this phenomenon is variable and very poorly understood. Proposed mechanisms fail to explain what conditions modulate the occurrence and magnitude of the priming response. Preliminary data suggest that the soil mineral assemblage, reflecting the chemical and geological properties of soil, interacts strongly with the soil microbial community to influence the priming effect. This research will test the idea that the priming response depends on interactions between the soil mineral assemblage and the soil microbial community. Thus, this research lies at the interface among geology, biology, and chemistry. The research will investigate priming responses in nine soils, spanning a broad range of climatic and environmental conditions. Laboratory experiments will evaluate how priming responds to variation in the mineral assemblage, and samples from the experiments will be tested for carbon cycling and microbial community characteristics. The work will use state-of-the-art techniques, including in-line isotope-ratio measurements using a cavity ring-down instrument, and new stable isotope probing techniques paired with gene microarrays capable of identifying microorganisms performing specific ecological functions. This project emphasizes integrating research and teaching, will provide interdisciplinary training for undergraduate students at institutions with strong histories of minority enrollment. Students will gain experience with the cutting-edge methods, and with a research field with strong implications for policy decisions surrounding global climate change and carbon management.

人类燃烧石油，煤和汽油时，二氧化碳（CO2）被释放到大气中，是全球变暖的主要原因。土壤可以储存碳（C），有助于抵消二氧化碳上升的升高，但土壤c下沉的未来尚不确定。它会转换为土壤有机c，可以保持数千年的时间，还是土壤微生物将其转换回二氧化碳，将其恢复到大气中？这是对未来C上的C下沉的主要不确定性。最近的工作表明，令人惊讶的反应称为启动效应，其中将C添加到土壤中可以增强微生物的代谢，从而导致它们产生的二氧化碳甚至超出预期。然而，这种现象是可变的，并且非常了解。提出的机制无法解释哪种条件调节启动反应的发生和幅度。初步数据表明，土壤矿物质组合反映了土壤的化学和地质特性，与土壤微生物群落相互作用，以影响启动作用。这项研究将测试以下观点：启动反应取决于土壤矿物组合与土壤微生物群落之间的相互作用。因此，这项研究在于地质，生物学和化学之间的界面。该研究将研究九种土壤中的启动反应，涵盖广泛的气候和环境条件。实验室实验将评估启动如何响应矿物组合的变化，并将测试实验中的样本以获取碳循环和微生物群落特征。这项工作将使用最先进的技术，包括使用腔体降压仪器的在线同位素比率测量，以及新的稳定的同位素探测技术与能够识别具有执行特定生态功能的微生物的基因微阵列配对。该项目强调整合研究和教学，将为拥有少数群体入学率的机构的本科生提供跨学科的培训。学生将获得有关尖端方法的经验，并在研究领域具有对全球气候变化和碳管理的政策决策的强烈影响。