ETBC: Collaborative Research: "The Effect of Climate on the Terrestial Sulfur Cycle"

智力价值：本提案旨在研究地球上从最干燥到最潮湿地区的陆地S循环随降雨变化的方式。硫是生命中最重要的常量营养素之一，人们对它的了解远不如它的“伴侣”硫。然而，人类对全球S循环的扰动程度，生态系统对S的复杂反应方式，以及生命如何驱动主要元素循环行为的基本问题，使S研究成为一项有趣的科学和重要的社会挑战。该项目将大气、地球化学和生态方面的专业知识结合起来，量化生态系统中S输入的来源和速率，探索土壤和植物内部S循环的重要途径，并量化从~1到~4000 mm MAP -1的降雨梯度中的S去除途径。该工作计划还包括测量来自多组气候梯度的土壤和植物S和S同位素总量，以了解气候对陆地S储存和循环的影响模式。与氮一样，假设在地球的湿端，S循环由生物介导的氧化还原反应主导。当降雨量下降到接近0，植物和微生物达到可以忽略不计的水平时，S循环转向以无机过程为主，整个循环发生根本性的转变。因此，这个降雨梯度提供了一个模板来说明我们这个生物控制的星球的独特性，并更好地解释我们附近的类地行星火星的地球化学，火星表面有大量的硫酸盐积累。更广泛的影响：要使用的降雨梯度由一系列站点组成，这些站点是NSF资助的CZEN网络（关键区域勘探网络）的一部分。该项目将受益于以前在这些地点所做的工作，其中一些工作对该项目的成功至关重要（水文学和地球化学）。拟议的工作最终还将为CZEN网络数据库提供新的数据和信息。此外，CZEN的研究人员将成为该项目的合作者，加强这一新的地球科学倡议的功能。该项目将主要涉及研究生，因此将为年轻学者提供培训和机会。然而，所涉及的广泛的科学专业知识将使它成为一个特别令人兴奋和充满活力的学习环境。其次，这项研究将进一步推动PI阿蒙森？与智利合作者合作，并协助国际交流。最后，该提案已提交给生物地球化学循环新兴主题，因为人们认为该项目涵盖了气候的广度，最终将允许我们通过一般的科学和教育渠道来说明真正独特的？但是可以改变吗？生命在地球历史上的角色。硫和氮以及其他一些元素，都具有生命的明显特征。它只能通过地球的扫描来检查大局吗？美国的气候（此处建议），或从太空（Sagan et al.1993）。自然365:715-721)，这是可能传达地球的独特性和脆弱性(阿蒙森，2008。自然地球科学1:5-6)。

Intellectual Merit: This proposal intends to examine the manner in which the terrestrial S cycle varies with rainfall from the driest to the wettest parts of the planet. Sulfur, one of the most important macronutrients for life, is far less understood that its ?companion? element N. However, the magnitude of the human perturbation of the global S cycle, the complex ways in which ecosystems respond to S, and the basic question of how life drives the behavior of major elemental cycles makes a study of S an interesting scientific and societally important challenge. The project brings atmospheric, geochemical, and ecological expertise together to quantify the sources and rates of S inputs to ecosystems, to explore important avenues of internal S cycling within soils and plants, and quantify S removal pathways along a rainfall gradient from ~1 to ~4000 mm MAP y-1. The work plan also includes the measurement of total soil and plant S and S isotopes from multiple sets of climate gradients to learn about the patterns that climate imparts on terrestrial S storage and cycling. Like N, it is hypothesized that at the wet end of Earth the S cycle is dominated by biologically mediated redox reactions. As rainfall declines to near 0, and as plants and microbes reach negligible levels, the S cycle shifts to dominantly inorganic processes, and the entire cycle undergoes a fundamental transformation. This rainfall gradient therefore provides a template to illustrate the uniqueness of our biotically-controlled planet, and to better interpret the geochemistry of our nearby terrestrial planet Mars, which has large surficial sulfate accumulations. Broader Impacts: The rainfall gradient to be used is comprised of a series of sites that are part of the NSF funded CZEN network (Critical Zone Exploration Network). The project will benefit from the previous work done at these sites, some of which is critical to the success of this project (hydrology and geochemistry). The proposed work will also ultimately provide new data and information to the CZEN network database. Additionally, CZEN researchers will be collaborators on the project, strengthening the functioning of this novel initiative in geosciences. The project will largely involve graduate students, and will therefore provide training and opportunities for young scholars. However, the broad range of scientific expertise involved will make this an especially exciting and dynamic learning environment for everyone involved. Secondly, this research will further PI Amundson?s collaboration with Chilean collaborators and aid in international exchange. Finally, this proposal has been submitted to Emerging Topics in Biogeochemical Cycles because it is perceived that this project encompasses a climatic breadth that will allow us, in the end, to illustrate via general science and education outlets, the truly unique ? but alterable ? role of life on the history of our planet. Sulfur, along with N and some other elements, bears the unmistakable stamp of life. It is only by examining the big picture, via the sweep of Earth?s climate (proposed here), or from space (Sagan et al.1993. Nature 365:715-721), that it is possible to convey the uniqueness and fragility of Earth (Amundson. 2008. Nature Geoscience 1:5-6).