Dissimilatory and Assimilatory Controls on Nitrogen Retention and Loss: Oxygen and Nitrate Dynamics in Tropical Forest Soils

对氮保留和损失的异化和同化控制：热带森林土壤中的氧和硝酸盐动态

• 批准号: 0089783
• 负责人: Whendee Silver
• 金额: $ 37.5万
• 依托单位: University of California-Berkeley
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2001
• 资助国家: 美国
• 起止时间: 2001-04-15 至 2005-03-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0089783&HistoricalAwards=false
• 关键词: Dissimilatory; Assimilatory; Controls; Nitrogen; Retention

Abstract00-89783SilverDissimilatory and assimilatory controls on nitrogen retention and loss: Oxygen and nitrate dynamics in tropical forest soilsIn humid tropical forests, the combination of abundant rainfall, soils with high water-holding capacity, and high metabolic activity can lead to conditions where oxygen is rapidly and completely consumed in the soil. These conditions also increase the potential for nitrogen trace gas loss and leaching. In a global context, tropical forests currently have the highest N2O emissions, and can exhibit large nitrogen losses to groundwater relative to temperate forests. Despite this high potential for nitrogen loss, tropical forest plant productivity is not generally nitrogen limited. Dr. Silver and colleagues propose to combine field and laboratory experiments to study nitrogen retention (via dissimilatory nitrate reduction to ammonium, and plant and microbial uptake) and nitrogen loss (via leaching and denitrification) in forests of Puerto Rico. This research will contribute to our understanding of the mechanisms controlling nitrogen dynamics in humid tropical forests, and improve our ability to predict the effects of anthropogenic nitrogen deposition and global change on nitrogen cycling

异化和同化作用对氮保持和损失的控制：热带森林土壤中的氧和硝酸盐动态在潮湿的热带森林中，充足的降雨、具有高持水能力的土壤和高代谢活性的结合可以导致土壤中的氧迅速而完全消耗的条件。 这些条件也增加了氮痕量气体损失和沥滤的可能性。在全球范围内，热带森林目前的N2 O排放量最高，并且与温带森林相比，地下水中的氮流失量很大。尽管氮损失的可能性很高，但热带森林植物的生产力一般不受氮的限制。银博士和同事建议将现场和实验室实验联合收割机结合起来，研究波多黎各森林中的氮保留（通过异化硝酸盐还原为铵以及植物和微生物吸收）和氮损失（通过淋溶和反硝化）。本研究将有助于我们理解热带湿润森林中氮素动态的控制机制，提高我们预测人为氮沉降和全球变化对氮循环影响的能力