EAGER SitS: Studying soil biotic and abiotic processes through continuous, high-precision monitoring of soil CO2 an O2 concentrations

EAGER SitS：通过连续、高精度监测土壤二氧化碳和氧气浓度来研究土壤生物和非生物过程

基本信息

批准号：
1841641
负责人：
Daniel Breecker
金额：
$ 29.63万
依托单位：
University of Texas at Austin
依托单位国家：
美国
项目类别：
Standard Grant
财政年份：
2018
资助国家：
美国
起止时间：
2018-09-15 至 2022-08-31
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=1841641&HistoricalAwards=false
关键词：
EAGER SitS Studying soil biotic

项目摘要

Soils are a vital natural resource, the successful management of which depends on the ability to monitor and understand numerous belowground biotic and abiotic processes. These processes, such as mineral weathering and carbon and nitrogen cycling, directly affect soil health. In order to advance our understanding of these soil processes, this research project will combine continuous, high precision monitoring of soil pore space oxygen, carbon dioxide, and ammonia gas concentrations, each of which are affected by these processes, with the development of a computer model. Undergraduate students who identify with underrepresented groups will be recruited to participate in this research project. The research results will help to quantify soils as a carbon source/sink and inform sustainable land management practices aimed at feeding the expanding global population while managing environmental contamination from fertilizers. These results will be disseminated through courses that the PI teaches, in addition to peer-reviewed publications.The respiratory quotient (RQ, moles of CO2 produced per mole of O2 consumed during respiration) is a fundamental indicator of metabolism that we currently cannot monitor in-situ in soils. Learning about soil community RQ and the factors that affect its variability will help to understand microbial metabolisms, controls on autotrophic and heterotrophic respiration rates, and ultimately soil carbon cycling. Therefore, the goal of this research project is to isolate continuously and monitor in-situ the RQ of the soil community. The first step of this research project will be to expand existing soil physics and chemistry models to quantify the effects of diffusion and gas-water exchange on soil gas composition. The effectiveness of these adapted models will be tested using controlled laboratory experiments. The next step will be to calibrate pore space NH3 and O2 concentrations as a measure of nitrification, using laboratory incubations of soils selected for later field-monitoring. This information is required for accurate determination of RQ, because nitrification consumes O2 in addition to that consumed by respiration. The final step will be to measure continuously and in-situ CO2, O2, and NH3 concentrations in natural soils using commercially-available flow-through sensors coupled to a custom-built autosampler. Simultaneous measurement of soil moisture, soil temperature, and relevant meteorological variables will accompany the soil gas monitoring. The expanded soil physics model and the laboratory soil core calibrations will be used to account for diffusion, water-gas exchange and nitrification in order to determine soil community RQ. Variation in soil community RQ through time and space in grassland and forest soils will be investigated. An improved understanding of natural variability in soil RQ will advance 1) understanding of soil biotic processes, such as how metabolisms in soil change temporally and spatially, and 2) the interaction between biotic and abiotic processes, such as those that drive chemical weathering and calcium carbonate dissolution/precipitation.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

土壤是重要的自然资源，成功的管理取决于监测和理解许多地下生物和非生物过程的能力。这些过程，例如矿物风化，碳和氮循环，直接影响土壤健康。为了促进我们对这些土壤过程的理解，该研究项目将结合对土壤孔隙空间氧，二氧化碳和氨气浓度的连续高精度监测，每个氧化物都受这些过程的影响，以及开发计算机模型。认同人数不足的小组的本科生将被招募参加该研究项目。该研究结果将有助于将土壤作为碳源/下沉量进行量化，并为旨在供养不断扩大的全球人群的可持续土地管理实践，同时管理肥料的环境污染。除了经过同行评审的出版物外，PI教学的机构还将传播这些结果。呼吸商（RQ，呼吸过程中消耗的O2摩尔产生的CO2的摩尔）是代谢性的基本指标，我们目前无法监测土壤中的含量。了解土壤社区RQ及其影响变异性的因素将有助于了解微生物代谢，对自养和异养的呼吸率的控制以及最终的土壤碳循环。因此，该研究项目的目标是连续隔离并在原位土壤社区的RQ位置。该研究项目的第一步是扩展现有的土壤物理和化学模型，以量化扩散和气水交换对土壤气体成分的影响。这些改编模型的有效性将使用受控实验室实验进行测试。下一步将使用选择用于以后的现场监测的土壤的实验室孵育，将孔隙空间NH3和O2浓度作为硝化量。精确确定RQ所需的信息是必需的，因为硝化除了呼吸消耗的含量外消耗了O2。最后一步是使用与定制的自动进样器耦合的市售流通传感器，在天然土壤中连续和原位二氧化碳，O2和NH3浓度进行测量。土壤水分，土壤温度和相关气象变量的同时测量将伴随土壤气体监测。扩大的土壤物理模型和实验室土壤核心校准将用于解释扩散，水电交换和硝化，以确定土壤社区RQ。将研究土壤社区RQ在草原和森林土壤中的时间和空间的变化。对土壤RQ中自然变异性的深入了解将提高1）对土壤生物过程的理解，例如土壤中的代谢在时间和空间上如何变化，以及2）生物和非生物过程之间的相互作用，例如那些化学风化和驱动碳酸盐的碳酸盐溶解/降水的人，这些奖项反映了NSF的智力传统和质量的构建，这是碳酸盐的溶解和降水的范围。审查标准。