DISSERTATION RESEARCH: INCREASED SOIL CARBON WITH NITROGEN ADDITIONS IN NITROGEN-RICH TROPICAL FORESTS: SEARCHING FOR MECHANISMS

论文研究：富氮热带森林中添加氮增加土壤碳：寻找机制

• 批准号: 0709903
• 负责人: Whendee Silver
• 金额: $ 1.2万
• 依托单位: University of California-Berkeley
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-05-15 至 2009-04-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0709903&HistoricalAwards=false
• 关键词: DISSERTATION; RESEARCH; INCREASED; SOIL; CARBON; DISSERTATION; RESEARCH; INCREASED; SOIL; CARBON

Human activity has greatly increased the availability of nitrogen on Earth, with nitrogen deposition rates in tropical regions predicted to be the highest globally in coming decades. Because plant growth is not commonly stimulated by nitrogen in tropical forests, the effects of increased nitrogen availability on carbon accumulation are likely to be largest in soils. An increase in soil carbon after 3.5 years of nitrogen fertilization has been observed in two tropical forest types. The proposed study will focus on the biological mechanisms related to this increase. Specifically, microbial enzyme assays and measurements of microbial community composition over the course of a decomposition experiment will be used to determine effects of nitrogen on carbon loss. A fractionation scheme to separate soils into labile and recalcitrant pools will be applied to explore links between microbial activity and changes in soil carbon. This study will help illuminate mechanisms by which human alteration of the global nitrogen cycle might affect, positively or negatively, carbon dioxide releases from the large soil carbon pools that exist in tropical forests. Information from this project also will be used in education and training programs for undergraduate and secondary school students in California and Puerto Rico, and will form the basis for a science experiment conducted with students (grades 6-12) enrolled in an after-school program for under-served students in Berkeley, California.

人类活动大大提高了地球上氮的可用性，在未来几十年中，热带地区的氮沉积速率被预计是全球最高的。 由于在热带森林中氮通常不会受到植物的生长的刺激，因此氮的可用性增加对碳积累的影响可能最大。 在两种热带森林类型中，已经观察到了3。5年的氮肥后，土壤碳的增加。 拟议的研究将重点介绍与此增长有关的生物学机制。 具体而言，在分解实验过程中微生物群落组成的微生物酶测定和测量将用于确定氮对碳损失的影响。 将土壤分解为不稳定和顽固池的分级方案将应用于探索微生物活性与土壤碳变化之间的联系。 这项研究将有助于阐明人类对全球氮周期的改变可能影响的机制，从而积极或负面影响二氧化碳从热带森林中存在的大土壤碳池中释放。 该项目的信息还将用于加利福尼亚州和波多黎各的本科和中学生的教育和培训计划，并将为参加加利福尼亚州伯克利人服务不足的学生的学生（6至12年级）进行科学实验的基础。