Collaborative LTREB: Long-Term Ecosystem Response to Chronic Atmospheric Nitrate Deposition

随着下个世纪地球气候变暖，整个北半球的生态系统也将暴露在大气氮沉降速率升高的环境中。理解这种复杂的环境变化，是我们预测森林从大气中吸收人类产生的二氧化碳的程度的能力的核心。一个跨学科的科学家团队将在北美东部以糖枫为主的森林生态系统中进行长期的、基于区域的野外实验，研究气候变暖和模拟大气氮沉降之间的相互作用。在过去的10年里，模拟的大气氮沉降速度预计将在2050年之前发生，促进了树木的生长，减缓了枯叶和枯根的腐烂，增加了这个广泛生态系统中储存的碳量。然而，尚不确定碳储量是否会随着大气氮沉降的增加而长期稳定在更高的平衡状态，或者预期的变暖是否会抵消这种影响。拟议中的研究将量化未来十年在上层树木、森林地面和土壤中储存的碳量，使这组科学家能够测试有关气候变暖和大气氮沉积对生态系统碳封存的相互作用的假设。该项目的成果将通过开发用户友好的基于网络的工具传播给其他全球变化科学家、K-12教师和一般公众。此外，调查小组将继续开展年度全球变化教师研究所。通过讲座和实地学习，初中和高中教师培养了对全球环境变化的原因和生态影响的理解，从而将这些信息纳入科学课程。

As the Earth's climate warms over the next century, ecosystems throughout the northern hemisphere also will be exposed to elevated rates of atmospheric nitrogen (N) deposition. Understanding this complex environmental change lies at the heart of our ability to anticipate the degree to which forests will sequester human-produced carbon dioxide from the atmosphere. An interdisciplinary team of scientists will investigate the interaction between climate warming and simulated atmospheric N deposition using a long-term, regional-based, field experiment located in sugar maple-dominated forest ecosystems common throughout eastern North America. Over the past 10 years, simulated atmospheric nitrogen deposition at rates expected to occur by 2050 have increased tree growth and slowed the decay of dead leaves and roots, increasing the amount of carbon stored in this wide-spread ecosystem. However, it is uncertain whether carbon storage will stabilize at a higher equilibrium over the long-term as atmospheric nitrogen deposition increases, or whether expected warming will counteract this effect. The proposed research will quantify the amounts of carbon stored in overstory trees, forest floor and soil over the next decade, allowing this team of scientists to test hypotheses regarding the interaction of climate warming and atmospheric nitrogen deposition on ecosystem carbon sequestration. The results of this project will be disseminated to other global change scientists, K-12 teachers, and the general public through the development of user-friendly, web-based tools. In addition the team of investigators will continue conducting the annual Global Change Teachers Institute. Through lectures and field-based learning, middle and high school teachers develop an understanding of the causes and ecological impacts of global environmental change, thereby bringing this information into science curricula.