CAREER: Direct Foliar Uptake of Atmospheric Nitrogen: Molecular to Ecosystem Considerations

【摘要】jed Spark的五年职业生涯奖将建立一个综合研究和教育计划，以调查大气和陆地生态系统之间气态活性氮化合物的交换，这是维持地球生命所固有的平衡。斯帕克斯和他的学生将在多个尺度上研究这些交换的大小，从强调控制交换机制的分子生理学，到强调生态系统氮循环质量平衡的生物地球化学，再到强调反应性和对周转时间控制的大气氮化学。这个项目将培养新一代的跨学科科学家。活性氮化合物来源于自然土壤驱动过程、闪电、肥料施用排放和工业来源，有三个原因特别令人感兴趣。首先，众所周知，高浓度的氧化氮对植物是有毒的，尽管在较低浓度下，这种化合物已被证明是“大气肥料”。其次，生态学家通常不考虑通过叶片直接向植物输入氮，但可以想象，这可能对光合作用、凋落物质量的变化以及植物体内碳氮分配模式的变化产生短期和长期的影响。最后，氮氧化物通过催化臭氧的形成，在控制低层大气的化学成分方面发挥着核心作用。斯帕克斯将研究叶片氮吸收的分子和生理机制，量化一系列生态系统中活性氮的强度和对冠层通量的控制，并支持区域和全球生物地球化学和空气质量模型的发展。此外，他还将实施旨在招募和培养年轻科学家的两阶段教育计划。他将首先开发一个由康奈尔成人大学支持的基于网络的教育平台，旨在招募未来的学生进入该领域。然后，他将通过参与他的研究和参与密歇根大学生物站的生物圈-大气研究培训计划来支持培训年轻科学家。在基因表达和生物地球化学过程之间建立联系是生态系统科学未来的一个非常重要的组成部分，也是这位年轻科学家早期职业发展的一个合适的崇高目标。

ABSTRACTJed Spark's five-year CAREER award will establish an integrated research and education plan to investigate exchanges of gaseous reactive nitrogen compounds between the atmosphere and terrestrial ecosystems, the balances of which are intrinsic to the maintenance of life on earth. Sparks and his students will focus on the magnitudes of these exchanges using studies at multiple scales, from the molecular-physiological with emphasis on mechanisms controlling exchanges, to the biogeochemical with emphasis on the mass balance of nitrogen cycles of ecosystems, to atmospheric nitrogen chemistry with emphasis on the reactivity and control over turnover times. This program will enable a new generation of Interdisciplinary scientists to be trained. Reactive nitrogen compounds derive from natural soil driven processes, lightning, emission from fertilizer application, and industrial sources and are of particular interest for three reasons. First, at high concentrations reactive oxidized nitrogen is known to be toxic to plants, although at lower concentrations such compounds have been shown to act as an "atmospheric fertilizer." Second, direct input of nitrogen through leaves into plants is not normally considered by ecologists, while it is conceivable that this could result in both short and long-term effects on photosynthesis, changes in litter quality, and changes in carbon and nitrogen allocation patterns within plants. Finally, nitrogen oxides play a central role in controlling the chemistry of the lower atmosphere by catalyzing the formation of ozone. Sparks will investigate the molecular and physiological mechanisms of foliar nitrogen uptake, quantify the magnitude and controls over canopy-level flux of reactive nitrogen over a range of ecosystems, and support the development of both regional and global biogeochemistry and air-quality models. Additionally, he will implement a two-phase education plan aimed at recruiting and training young scientists. He will first develop a web-based educational platform supported by the Cornell Adult University aimed at recruiting prospective students to the field. He then will support training of young scientists through participation in his research and participation in the Biosphere-Atmosphere Research Training program at the University of Michigan Biological Station. Making linkages between gene expression and biogeochemical processes, as will occur under this award, is a very important part of the future of ecosystem science and a suitably lofty goal as a theme for the early career development of this young scientist.