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: 0819706
• 负责人: Andrew Zimmerman
• 金额: --
• 依托单位: University of Florida
• 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 2012-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0819706&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.

知识分子的优点：直到最近才意识到，热源碳或黑碳（BC）可以占土壤和沉积物中有机碳的很大一部分。因此，BC是全球碳循环中重要但知之甚少的部分，它用作地质时间尺度上的碳汇和氧气来源。此外，BC可能是土壤生育能力的重要成分，控制有机污染物的命运，并且作为木炭，通常用于14C约会和古环境和考古学研究中，以重建频率和人类的占用记录，通常被视为生物学上和化学上的结构和longe con。但是，考虑到其通过生物质燃烧的估计生产率，它也必须以相当大的速度（100-1000年？）流动。尽管最近的研究记录了短期微生物孵育的可测量降解速率，但几乎不知道与不同BC形式发生的降解率范围，或控制微生物利用率的化学和物理变量。此外，尽管一些研究表明，存在不稳定的有机物（OM）可能会增强BC降解，但其他研究则可以保护OM免受微生物分解。拟议的研究研究了BC，OM和微生物之间的关系，重点是研究化学和物理因素对土壤中BC降解的相对重要性。Science计划：一系列综合实验室BC-Microbial孵育，OM吸附实验和基于现场的土壤研究提出，将为理解BC的环境提供强有力的理论基础。这些实验的材料将包括由国际卑诗省指导委员会推荐的BC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生产的BC。通过13C-NMR（官能团）和电位计量滴定（表面电荷）（表面电荷），以及通过CO2辅助测量法（对常用N2 Sorptemetry的改进），将表征这些材料的表面化学在实验室和实地孵育之前和之后进行表征。这些参数中的每一个都将与通过实验室中的CO2进化测量的微生物降解速率以及在巴西热带土壤中测量的BC损失和骨料形成有关。另外，将使用孵育/吸附实验来确定不稳定的OM启动的潜力？为了增强BC的降解和OM吸附，以隔离并保留BC的影响力。Boader的影响：生成的数据对努力确定BC的组成和结构的科学家社区将具有巨大的价值，并建立了最合适的分析方法，并将在这种可怜的习惯上提供对贫困型习惯的重要信息。对于那些将BC作为土壤修复，改善和大气碳固存的工具的人来说，结果也将具有实际价值。对于传统科学文献之外的广泛散布，发现将发布在积极讨论卑诗省应用程序的网站和列表服务上。 PI还将与使用或考虑BC Technologies的商业部门与商业部门进行交往。该提案代表了PI的新方向，PI的新方向，一位没有先前的NSF资金的早期职业科学家，以及PI和PI和Co-Pi的新合作，以及四个其他合作者，包括巴西在巴西。它包括向三个毕业生（UF的2名，FSU的1名）和两名本科生提供全部或部分支持的请求。该项目的结果将纳入教师培训研讨会和公开演讲中。