COLLABORATIVE RESEARCH: Ecosystem Response to N and Organic C Deposition from the Urban Atmosphere

未来30年，大部分人口增长将发生在城市地区。虽然人类活动对城市环境的影响最为强烈，但我们缺乏对城市生态系统中人类活动引起的变化的生态响应的机械理解。这个项目研究了大凤凰城陆地和大气之间的化学元素交换，并提出问题：城市元素循环在生态系统中是独一无二的吗？生态系统科学家、大气化学家和生物地球化学家正在验证这一假设，即不同的生物地球化学途径是从大气到陆地的无机氮和有机碳沉积增加的结果。研究人员将研究养分沉积增加在生态系统层面上的后果，测试解释生态系统反应的替代假说，并评估他们的发现是否可以推广到西南部和墨西哥的沙漠生态系统。该项目将一系列复杂的方法应用于一个离家很近的常见问题--大多数人生活的城市环境。这项工作与一个现有的长期生态研究项目正在进行的对快速增长的凤凰城的环境调查密切相关。除了进行研究外，科学家还与包括部落首领在内的当地决策者合作，解决快速扩张的城市边界日益恶化的环境质量问题。该项目还通过暑期实习计划为少数族裔本科生提供培训，并通过独立研究为研究生和博士后学者提供培训。

Most population growth during the next 30 years will occur in urban areas. Although human activities affect the environment most intensely in cities, we lack a mechanistic understanding of ecological response to human-wrought changes in urban ecosystems. This project studies the exchange of chemical elements between land and atmosphere in Greater Phoenix and asks: Are urban elemental cycles unique among ecosystems? Ecosystem scientists, atmospheric chemists, and biogeochemists are testing the hypothesis that distinct biogeochemical pathways result from elevated inorganic nitrogen and organic carbon deposition from atmosphere to land. Researchers will examine ecosystem-level consequences of elevated nutrient deposition, test alternative hypotheses to explain ecosystem response, and evaluate whether their findings can be generalized to desert ecosystems in the Southwest and Mexico.The project applies a range of sophisticated methods to a common problem that is close to home-the urban environment in which most humans live. The work is closely coupled with ongoing environmental investigations of rapidly growing Phoenix by an existing Long-Term Ecological Research project. In addition to conducting research, scientists are working with local decision makers, including tribal leaders, to address worsening environmental quality on the borders of rapidly expanding cities. The project also provides training for minority undergraduate students through a summer internship program, and for graduate students and a post-doctoral scholar through independent research.