Collaborative Research: Hydrologic-Nutrient Cycle Interaction in Small Undisturbed and Man-Manipulated Ecosystems

这项研究将继续研究北方阔叶林生态系统中不断加重和受到干扰的空气-土地-植物-水-人类相互作用。从历史上看，哈伯德·布鲁克生态系统研究将生态系统生物地球化学和森林生长的长期调查与详细的实验相结合，包括实验室和地块水平的研究、整个生态系统的操纵以及计算机模型的开发和应用。将继续对降水输入、生态系统池和河流流出进行研究。这项长期的生物地球化学研究将通过制定质子预算和分析元素循环相互作用，与正在进行的和拟议的过程一级研究相结合。这项研究包括两项新举措。首次使用(NH4)2SO4、H2SO4、Na2SO4和CaSO4的地块和分水岭级别的化学操作将研究当今人类诱导的氢离子、硫、氮和金属阳离子循环的变化。其次，这项研究将测试一个新的假说，该假说将植物生长和生理过程的时间与水文和养分输出的调节联系起来。对哈伯德布鲁克北部阔叶林生态系统的研究是一项多研究者/多机构的努力。大多数工作将在NH的哈伯德·布鲁克实验森林进行，但要调查的概念和过程通常适用于许多类型的生态系统。同以往一样，这项研究将有助于从根本上了解森林生态系统，并提供有助于更好地管理其宝贵自然资源的信息。项目团队非常优秀，由久经考验的合作表演者组成。美国农业部/林务局的合作是相当积极的。机构住宿是一流的。生态系统研究计划自信地建议颁发这个协作性的、为期四年的持续奖项。

This research will continue investigations of air-land-plant- water-human interactions in aggrading and disturbed northern hardwood forest ecosystems. Historically, the Hubbard Brook Ecosystem Study has coupled long-term investigation of ecosystem biogeochemistry and forest growth with detailed experimentation, including laboratory and plot-level studies, whole ecosystem manipulations, as well as the development and application of computer models. Studies of precipitation inputs, ecosystem pools and stream outflow will be continued. This long-term biogeochemical research will be integrated with ongoing and proposed process-level studies through the development of proton budgets and analysis of element cycle interactions. The research includes two new initiatives. First plot- and watershed-level chemical manipulations using (NH4)2SO4, H2SO4, Na2SO4 and CaSO4 will investigate present-day, anthropogenically-induced changes in hydrogen ion, sulfur, nitrogen and metallic cation cycles. Second, the research will test a new hypothesis relating the timing of plant growth and physiological processes to regulation of hydrological and nutrient export. Research on northern hardwood forest ecosystems at Hubbard Brook is a multi- investigator-/multi-institutional effort. Most work will be conducted at the Hubbard Brook Experimental Forest, NH, yet the concepts and processes to be investigated are generally applicable to many types of ecosystems. This research will, as in the past, contribute to the fundamental understanding of forest ecosystems and yield information useful to the better management of their valuable natural resources. The project team is excellent and comprises proven collaborative performers. USDA/Forest Service collaboration is quite positive. Institutional accommodations are first-rate. The Ecosystem Studies Program confidently recommends that this collaborative, four-year continuing award be made.