Collaborative Research: Black Carbon Remineralization in the Environment: Physical and Chemical Controls

合作研究：环境中的黑碳再矿化：物理和化学控制

• 批准号: 0819811
• 负责人: William Cooper
• 金额: $ 5.92万
• 依托单位: Florida State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-08-15 至 2011-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0819811&HistoricalAwards=false
• 关键词: Collaborative; Research; Black; Carbon; Remineralization

Intellectual Merit: It has only recently been realized that pyrogenic carbon, or black carbon (BC), can make up a significant fraction of the organic carbon in soils and sediments. As such, BC is an important but poorly understood portion of the global carbon cycle that serves as a carbon sink and oxygen source over geological time-scales. Further, BC may be an important ingredient for soil fertility, controls the fate of organic contaminants, and, as charcoal, is commonly used for 14C dating and in paleoenvironmental and archeological studies to reconstruct fire-frequency and human occupation records.Black Carbon has generally been regarded as biologically and chemically inert due to its chemical structure and longevity in the geosphere. However, considering its estimated production rate by biomass combustion, it must also turnover at considerable rates (100-1000 years?). While recent studies have recorded measurable degradation rates in short-term microbial incubations, little is known as to the range of degradation rates that occur with different BC forms, or the chemical and physical variables that control rates of microbial utilization. Further, while some studies suggest that the presence of labile organic matter (OM) may enhance BC degradation, others would have BC serve to protect OM from microbial decomposition. The proposed study examines the relationships between BC, OM, and microbes with a focus on examining the relative importance of chemical and physical factors on BC degradation in soils.Science Plan: The series of integrated laboratory BC-microbial incubations, OM adsorption experiments and field-based soil studies proposed will provide a strong theoretical foundation for understanding the cycling of BC in the environment. Materials for these experiments will include both BC reference materials recommended by the International BC Steering Committee and BC produced by the PI by combustion of a variety of wood and grasses under a range of controlled temperature and oxygenation conditions. The surface chemistry of these materials will be characterized before and after lab and field incubations by 13C-NMR (functional groups) and potentiometric titration (surface charge), and the surface morphology (external and internal surface area and pore size distribution and volume) by CO2 sorptometry (an improvement over commonly used N2 sorptometry). Each of these parameters will be related to rates of microbial degradation measured via CO2 evolution in the laboratory, and BC loss and aggregate formation measured in tropical soils in Brazil. In addition, incubation/adsorption experiments will be used to determine the potential for labile OM ?priming? to enhance BC degradation and for OM adsorption to sequester and preserve labile organic carbon within BC.Broader Impacts: The data generated will be of great value to the community of scientists struggling to identify the composition and structure of BC, establish the most appropriate methods of analysis, and will also provide critical information on the biogeochemical cycling of this poorly understood component of the global carbon cycle. The results will also be of practical value to those considering BC as a tool for soil remediation, amelioration, and atmospheric carbon sequestration. For wide dispersal beyond the conventional scientific literature, findings will be posted on websites and list-serves that are actively discussing BC applications. The PI will also interface with the commercial sector employing or considering BC technologies.This proposal represents a new direction for the PI, an early career scientist with no prior NSF funding, and a new collaboration for the PI and co-PI as well as for four additional collaborators including one in Brazil. It includes a request for full or partial support of three graduate (2 at UF, 1 at FSU) and two undergraduate students. Results of this project will be incorporated into a teacher training workshop and public lectures.

智力优势：直到最近才意识到热解碳或黑碳（BC）可以构成土壤和沉积物中有机碳的重要部分。因此，BC是全球碳循环的一个重要但知之甚少的部分，在地质时间尺度上充当碳汇和氧源。此外，BC可能是土壤肥力的重要成分，控制有机污染物的命运，并且，作为木炭，通常用于14 C测年和古环境和考古研究，以重建火灾频率和人类居住记录。由于其化学结构和在地球圈中的寿命，黑碳通常被认为是生物和化学惰性的。然而，考虑到生物质燃烧的估计生产率，它也必须以相当大的速度周转（100-1000年？）。虽然最近的研究记录了短期微生物培养中可测量的降解率，但对不同BC形式的降解率范围或控制微生物利用率的化学和物理变量知之甚少。此外，虽然一些研究表明，不稳定的有机物（OM）的存在可能会促进BC的降解，但其他研究则认为BC可以保护OM免受微生物分解。拟议的研究探讨了BC、OM和微生物之间的关系，重点考察化学和物理因素对土壤中BC降解的相对重要性。科学计划：拟议的一系列综合实验室BC微生物培养、OM吸附实验和现场土壤研究将为了解BC在环境中的循环提供强有力的理论基础。这些实验的材料将包括国际生物质指导委员会推荐的生物质参考材料和PI通过在一系列受控温度和氧合条件下燃烧各种木材和草产生的生物质。在实验室和现场孵育前后，将通过13 C-NMR（官能团）和电位滴定（表面电荷）表征这些材料的表面化学，并通过CO2吸附测定法（对常用N2吸附测定法的改进）表征表面形态（外部和内部表面积以及孔径分布和体积）。这些参数中的每一个都将与通过实验室中的CO2释放测量的微生物降解率以及在巴西热带土壤中测量的BC损失和聚集体形成有关。此外，孵育/吸附实验将用于确定不稳定OM？启动？更广泛的影响：所产生的数据将对努力确定BC的组成和结构的科学家社区具有重要价值，建立最适当的分析方法，并将提供关于全球碳循环中这一知之甚少的组成部分的生物地球化学循环的关键信息。研究结果也将具有实用价值的那些考虑BC作为一种工具，土壤修复，改良，和大气固碳。为了广泛传播传统的科学文献，研究结果将被张贴在网站和列表服务，正在积极讨论BC应用。该项目也将与采用或考虑采用生物连续性技术的商业部门进行对接，该项目代表了该项目的一个新方向，该项目是一名早期职业科学家，此前没有国家科学基金的资助，该项目代表了该项目的一个新合作，该项目代表了该项目的主要研究者和共同主要研究者以及另外四名合作者的新合作，其中一名合作者在巴西。它包括三个研究生（2在UF，1在FSU）和两个本科生的全部或部分支持的请求。该项目的成果将纳入教师培训讲习班和公开讲座。