Collaborative Research on Nitrogen Cycling in Ecosystems under Elevated CO2 and O3 is Regulated by Soil Microbial Communities at the Microscale

CO2和O3升高下生态系统氮循环受微尺度土壤微生物群落调控的合作研究

• 批准号: 0543238
• 负责人: Michael Sadowsky
• 金额: $ 22万
• 依托单位: University of Minnesota-Twin Cities
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-09-01 至 2009-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0543238&HistoricalAwards=false
• 关键词: Collaborative; Research; Nitrogen; Cycling; Ecosystems

Atmsopheric carbon dioxide (CO2) concentration has increased by 31% during the past century, and atmospheric ozone (O3) concentration has risen about 1 percent per year over the past four decades. The combined influence of elevated CO2 and O3 on agriculture is direct but often unpredictable. Consequently, the goal is to investigate the relationships between changes in soybean productivity, microbial community composition and nitrogen cycling in response to elevated CO2 and O3. The focus will be on biological nitrogen fixation, a major nitrogen input process, and nitrification and denitrification, processes inducing nitrogen losses. These nitrogen cycling processes will be determined with stable isotope techniques and will be linked to the microbial community structure, which will be measured by molecular techniques. Although soil nitrogen availability is crucial for plant growth, the long-term effects of elevated CO2 and O3 on the capacity of the soil to sustain plant productivity is largely unknown. This project will bridge this knowledge gap by linking the structure and function of soil microbes to the flow of nitrogen. The results from this research will improve our overall understanding of the role soil processes play in maintaining sustainable ecosystem functioning under elevated CO2 and O3. This area of inquiry and education is important as increased human population and atmospheric pollution increasingly stress ecosystems.

过去一个世纪，大气二氧化碳（CO2）浓度增加了31%，过去四十年，大气臭氧（O3）浓度每年增加约1%。二氧化碳和氧气升高对农业的综合影响是直接的，但往往是不可预测的。因此，我们的目标是研究二氧化碳和氧气升高导致的大豆生产力、微生物群落组成和氮循环变化之间的关系。重点将放在生物固氮（主要的氮输入过程）以及硝化和反硝化（导致氮损失的过程）上。这些氮循环过程将通过稳定同位素技术来确定，并将与微生物群落结构联系起来，而微生物群落结构将通过分子技术进行测量。尽管土壤氮的有效性对于植物生长至关重要，但二氧化碳和氧气升高对土壤维持植物生产力的能力的长期影响在很大程度上尚不清楚。该项目将通过将土壤微生物的结构和功能与氮的流动联系起来，弥补这一知识差距。这项研究的结果将提高我们对土壤过程在二氧化碳和氧气升高的情况下维持可持续生态系统功能所发挥的作用的整体理解。随着人口的增加和大气污染对生态系统的压力越来越大，这一领域的探究和教育非常重要。