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

学术价值：这项提议旨在研究从地球上最干燥的地区到最潮湿的地区，地球上的S周期如何随着降雨量的变化而变化。硫磺是生命中最重要的常量营养素之一，但人们对它的伴侣？然而，人类对全球S循环的扰动的规模，生态系统对S做出反应的复杂方式，以及生命如何驱动主要元素循环行为的基本问题，使得对S的研究成为一个有趣的科学和社会重要挑战。该项目将大气、地球化学和生态学的专业知识结合在一起，以量化S输入生态系统的来源和速率，探索S在土壤和植物中内部循环的重要途径，并量化S沿~1至~4000 mm降雨梯度的移动路径。工作计划还包括从多组气候梯度测量土壤和植物总量S和S同位素，以了解气候对陆地S储存和循环的影响模式。像N一样，假设在地球潮湿的一端，S循环是由生物中介的氧化还原反应主导的。随着降雨量下降到接近零的水平，植物和微生物达到可以忽略的水平，S循环转向以无机过程为主，整个循环经历了根本性的转变。因此，这种降雨量梯度提供了一个模板，以说明我们的生物控制星球的独特性，并更好地解释我们附近陆地行星火星的地球化学，火星有大量的地表硫酸盐积累。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(水文学和地球化学)的成功至关重要。拟议的工作还将最终为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，加强这一新倡议在地球科学中的作用。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，涉及的广泛科学专业知识将使这一学习环境对参与其中的每个人来说都特别令人兴奋和充满活力。其次，本研究将进一步促进皮亚蒙森、S与智利合作者的合作，助力国际交流。最后，这项建议已经提交给生物地球化学循环中的新兴主题，因为人们认为这个项目包含了气候的广度，最终将使我们能够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？生命在我们星球历史上的作用。硫，以及氮和其他一些元素，带有明显的生命印记。只有通过扫描地球--S(这里提出的)气候，或者从太空(萨根等人，1993)--来审视大的图景。自然365：715-721)，可以传达地球的独特性和脆弱性(阿蒙森)。2008年。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).