MRI: Acquisition of Instrumentation for Measurement of Trace Gas Fluxes in the Arizona Highlands

普雷斯科特学院的杰克·海岭博士和蒂姆·克鲁斯博士获得了一笔赠款。这笔赠款提供的精密研究仪器将允许测量大气和陆地表面之间各种痕量气体的交换。 这项研究的主要目标是更好地了解亚利桑那州中部高地的氮循环。 第二个目标是研究这些生态系统中氮和碳循环之间的关系。 此外，这些仪器将在普雷斯科特学院的学生培训这些分析技术中发挥核心作用。 最初，仪器将被安装在查帕拉尔，在美国西南部的一个重要的植物群落，有很少的信息氮循环的动态。 查帕拉尔很有趣，因为它是美国密度最高的固氮木本植物之一。 由于潜在的高输入氮通过生物固定，和一年的降水制度，有利于极端干燥和湿润的事件，它被怀疑，内部查帕拉尔生态系统可能支持至少定期高到非常高的氮氧化物排放率。 具体而言，该设备将用于使用基于激光的技术对NO2、NO + NO2（NOx）和N2O的交换进行连续、长期的测量。 仪器塔还将配备一个测量垂直风的特殊装置和一个测量CO2和H2O浓度的装置。 除了这些气体交换测量外，还将通过气相色谱法对N2O排放量进行支持性短期室内研究，并对NO排放量进行室内测量。这些室内研究将在查帕拉尔和其他生态系统中进行，这些生态系统的特点是人类改变的N循环，其中包括火处理黄松林地，干旱的农业用地和牲畜放牧的干旱草原。当查帕拉尔研究完成时，结果将指导仪器的使用。随着来自许多学科的科学家努力更好地了解全球变化的基本过程，越来越清楚的是，需要改进生物体与大气之间相互作用的知识。 氮循环与全球变化之间的联系既有直接的（由于N2O排放的温室效应），也有间接的（由于氮的供应对主要温室气体CO2和CH4的净吸收或释放的影响）。 对这些生态系统动力学的良好理解是理解生物圈吸收目前由化石燃料燃烧释放的二氧化碳的潜力以及理解生态系统将如何应对它们现在所面临的许多环境变化的关键。 这些信息对于目前正在努力解决全球气候变化等问题的决策者至关重要。 这些问题的答案只能来自广泛的仪器网络，这将需要培训大量的科学家在这些测量所涉及的专业技术。

A grant has been awarded to Dr. Jack Herring and Dr. Tim Crews at Prescott College. The sophisticated research instrumentation provided by this grant will allow measurement of the exchange of variety of trace gases between the atmosphere and the land surface. The primary goal of the research is to better understand the cycling of nitrogen in the highlands of central Arizona. A secondary goal is to study the relationship between the cycling of nitrogen and carbon in these ecosystems. Additionally, the instruments will play a central role in training students at Prescott College in these analytical techniques. Initially, the instrumentation will be installed in chaparral, an important plant community in the southwestern U.S. for which there is little information on the dynamics of nitrogen cycling. Chaparral is interesting because it has among the highest, if not the highest, density of nitrogen-fixing woody plants in the United States. Due to the potentially high inputs of nitrogen via biological fixation, and an annual precipitation regime that favors extreme drying and wetting events, it is suspected that the interior chaparral ecosystem may support at least periodically high to very high rates of nitrogen oxide emissions. Specifically, this equipment will be used to make continuous, long-term measurements of exchanges of NO2, NO + NO2 (NOx), and N2O using a laser-based technique. The instrument tower will also be equipped with a special device for measuring vertical winds and a device for measuring CO2 and H2O concentrations. In addition to these measurements of gas exchange,supporting short-term chamber studies of N2O emissions by gas chromatography and chamber measurements of NO emissions will be conducted. These chamber studies will be conducted both in chaparral and in other ecosystems that are characterized by human alteration of the N cycle; these include fire-treated ponderosa woodlands, arid agricultural land and livestock-grazed arid grasslands. The results will guide the use of the instrumentation when the chaparral study is completed. As scientists from many disciplines work toward a better understanding of the processes underlying global change, it becomes increasingly clear that the knowledge of the interactions between living organisms and the atmosphere needs to be improved. The linkage between nitrogen cycling and global change is both direct (due to the greenhouse effect of N2O emissions) and indirect (due to the effects of nitrogen availability on the net absorption or release of key greenhouse gases CO2 and CH4). A good understanding of these ecosystem dynamics is key tounderstanding the potential for the biosphere to absorb the CO2 currently being released by fossil fuel combustion as well as to understanding how ecosystems will respond to the many environmental changes they are now being exposed to. Such information is vital to policymakers who are currently wrestling with issues such as that of global climate change. The answers tothese questions will only come from extensive networks of such instrumentation; this will necessitate the training of large numbers of scientists in the specialized techniques involved in these measurements.