ETBC: Plant-microbe-mineral interaction as a driver for rock weathering and chemical denudation

ETBC：植物-微生物-矿物相互作用是岩石风化和化学剥蚀的驱动因素

• 批准号: 1023215
• 负责人: Katerina Dontsova
• 金额: $ 42.46万
• 依托单位: University of Arizona
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-09-01 至 2014-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1023215&HistoricalAwards=false
• 关键词: ETBC; Plant; microbe; mineral; interaction

Plants and microorganisms modify the local weathering environment by exuding organic compounds, CO2 and protons, altering the composition of geomedia surfaces, redirecting soilwater and solute fluxes, and immobilizing lithogenic nutrients. The goal of this study is to better understand the effects of plants on weathering and denudation. The PIs propose to measure how plant-microbe interactions affect the initial weathering of four distinct rock types (basalt, granite, schist, and rhyolite) and the extent to which this weathering results in chemical denudation versus biomass accumulation or re-precipitation of dissolution products. Two types of higher plants will be used in a replicated plant-microbe-rock mesocosms experiment: a grass species (with vesicular arbuscular mycorrhizal association) and a tree species (with ectomycorrhizal association). The experiments will also include plant-free (but microbially-colonized) and abiotic (sterile) controls.One hypothesis is that the presence of plants will increase weathering but decrease denudation (i.e., we will see more mineral transformation but less element loss from system in the presence versus absence of plants). This implies important feedbacks to soil fertility and C sequestration. A series of environmentally-controlled, greenhouse experiments will be conducted that involve measuring plant uptake, mineral transformation and chemical denudation in basalt, granite, rhyolite, and schist, as affected by presence and growth of microbiota and vascular plants. Weathering will be estimated based on denudation, bio-uptake, sorption, and secondary mineral precipitation, each of which will be quantified by detailed characterization of biomass, aqueous solution and effluxes, and solid phase changes. Experimental results will be used to parameterize a biogeochemical model.Broader Impacts: This project will enable the training of two collaborating Ph.D. students whose thesis research will focus on the vibrant interface between biogeochemistry, microbial ecology, and plant physiological ecology. Research will be closely coordinated with broader efforts associated with the National Critical Zone Observatory (CZO) system, and also with Biosphere2 (B2), a unique research instrument now managed by the University of Arizona. Conceptual and practical linkages with B2 and CZO will place the well-controlled experiments into a broader context of parallel field and "macrocosm" studies that are unable to address these questions unambiguously. Interaction with B2 and CZO will also create a collaborative environment where the Ph.D. students will be required to integrate their mechanistic findings into an evolving understanding manifested at larger (pedon to hillslope to catchment) scales. B2, which has fifty thousand visitors a year, will provide a compelling environment and powerful venue for research translation to the general public.

植物和微生物通过渗出有机化合物、二氧化碳和质子、改变地介质表面的成分、改变土壤水和溶质通量以及固定成岩养分来改变当地的风化环境。这项研究的目的是更好地了解植物对风化和剥蚀的影响。 PI建议测量植物-微生物相互作用如何影响四种不同岩石类型（玄武岩、花岗岩、片岩和流纹岩）的初始风化，以及这种风化导致化学剥蚀与生物量积累或溶解产物再沉淀的程度。复制植物-微生物-岩石中生态系统实验将使用两种高等植物：草种（具有囊泡丛枝菌根关联）和树种（具有外生菌根关联）。实验还将包括无植物（但有微生物定殖）和非生物（无菌）对照。一种假设是，植物的存在会增加风化但减少剥蚀（即，我们将看到更多的矿物转化，但系统中的元素损失更少在有植物的情况下与没有植物的情况下）。这意味着对土壤肥力和碳固存的重要反馈。将进行一系列环境控制的温室实验，包括测量玄武岩、花岗岩、流纹岩和片岩中植物的吸收、矿物转化和化学剥蚀，这些实验受微生物群和维管植物的存在和生长的影响。风化作用将根据剥蚀、生物吸收、吸附和二次矿物沉淀进行估计，其中每一项都将通过生物质、水溶液和流出物以及固相变化的详细表征来量化。实验结果将用于参数化生物地球化学模型。更广泛的影响：该项目将培训两名合作博士。论文研究将重点关注生物地球化学、微生物生态学和植物生理生态学之间充满活力的界面的学生。研究将与国家关键区域天文台（CZO）系统以及生物圈2（B2）（目前由亚利桑那大学管理的独特研究仪器）相关的更广泛的努力密切协调。与 B2 和 CZO 的概念和实践联系将把良好控制的实验置于更广泛的平行场和“宏观世界”研究的背景中，而这些研究无法明确地解决这些问题。与 B2 和 CZO 的互动还将创建一个协作环境，让博士可以在其中进行协作。学生将被要求将他们的机械发现融入到更大范围（从山坡到流域）表现出来的不断发展的理解中。 B2 每年有 5 万名参观者，将为公众提供令人信服的环境和强大的研究翻译场所。