Collaborative Research: Dissolved pyrogenic organic matter dynamics in the environment

合作研究：环境中溶解热解有机物动力学

• 批准号: 1451558
• 负责人: Siddhartha Mitra
• 金额: $ 13.07万
• 依托单位: East Carolina University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-06-01 至 2019-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1451558&HistoricalAwards=false
• 关键词: Collaborative; Research; Dissolved; pyrogenic; organic

Pyrogenic organic matter, or black carbon (BC), is derived from the incomplete combustion of biomass and fossil fuels. It is now recognized that this type of organic matter has a great impact on soil chemistry, transport of pollutants, climate and global carbon cycling. Further, its impacts will likely grow due to increased climate change-related wildfires and intentional addition of BC (as biochar) to soils to enhance soil fertility and carbon sequestration. However, while knowledge of the properties of natural and anthropogenic particulate BC has increased in recent years, there has been relatively little study of the properties and cycling of the organic matter that can leach from BC; pyrogenic dissolved organic matter (py-DOM). Although release of py-DOM into the environment may have unrecognized carbon cycling and environmental impacts, py-DOM has been quantified in only a few systems using methods that have not been comprehensively evaluated. This research will examine the fundamental chemical properties and mechanisms associated with py-DOM production and fate and the chemical markers used to quantify it. In addition, in order to broaden general awareness of the importance of fire on climate and the carbon cycle, the investigators will develop an interactive exhibit at a local hands-on science museum that will include touch screen graphics, narrated videos by each of the principal investigators illustrating the scientific process and the research results. To establish the chemical properties and mechanisms associated with py-DOM production and fate and the chemical markers used to quantify it, the project will: 1) produce py-DOM from a logical series of BC solids, both freshly produced and "aged" via microbial and photic treatments, 2) chemically characterize these BC parent solids and their aqueous dissolved products using FTIR, Fourier transform ion cyclotron resonance mass spectrometry (FTICR-MS) and 1- and 2-dimensional NMR, 3) examine py-DOM loss and transformation after microbial and photodegradation treatments, and 4) quantify the yields of putative pyrogenic molecular markers; levoglucosan, benzenepolycarboxylic acids (BPCA) and oxygenated polycyclic aromatic hydrocarbons (O-PAH), from fresh and "aged" BC solids and leachates. Using the same methods and experiments, the leachates and leachate alteration products of potentially interfering non-pyrogenic terrestrial organic materials, some of which the investigators have recently shown to contain "BC-like" compounds will also be examined. This work will test whether py-DOM chemistry can be linked to its parent BC type and "aging" processes, the extent to which py-DOM and its molecular markers undergo major losses and chemical transformation through microbial and photo-oxidation, and whether currently used molecular markers for py-DOM accurately represent actual pyrogenic OM contributions to environmental samples.

热解有机物或黑碳 (BC) 源自生物质和化石燃料的不完全燃烧。现在人们认识到，这类有机物对土壤化学、污染物输送、气候和全球碳循环有很大影响。此外，由于与气候变化相关的野火增加以及有意向土壤中添加BC（作为生物炭）以提高土壤肥力和碳固存，其影响可能会增加。然而，尽管近年来对天然和人为颗粒BC的性质的了解有所增加，但对可从BC中浸出的有机物的性质和循环的研究相对较少；热解溶解有机物 (py-DOM)。尽管将 py-DOM 释放到环境中可能会产生未被认识到的碳循环和环境影响，但仅在少数系统中使用尚未全面评估的方法对 py-DOM 进行了量化。这项研究将研究与 py-DOM 产生和命运相关的基本化学性质和机制，以及用于量化它的化学标记。此外，为了提高人们对火灾对气候和碳循环重要性的认识，研究人员将在当地的实践科学博物馆举办互动展览，其中包括触摸屏图形、每位主要研究人员的解说视频，说明科学过程和研究结果。为了建立与 py-DOM 产生和命运相关的化学性质和机制以及用于量化它的化学标记物，该项目将：1) 从一系列 BC 固体中生产 py-DOM，这些 BC 固体包括新鲜生产的和通过微生物和光处理“老化”的，2) 使用 FTIR、傅里叶变换离子回旋共振质谱法对这些 BC 母体固体及其水溶解产物进行化学表征 (FTICR-MS) 以及一维和二维 NMR，3) 检查微生物和光降解处理后 py-DOM 的损失和转化，以及 4) 量化假定的热解分子标记的产量；来自新鲜和“老化”BC 固体和渗滤液的左旋葡聚糖、苯多羧酸 (BPCA) 和氧化多环芳烃 (O-PAH)。使用相同的方法和实验，还将检查潜在干扰性非热原陆地有机材料的渗滤液和渗滤液蚀变产物，研究人员最近表明其中一些含有“BC 类”化合物。这项工作将测试 py-DOM 化学是否可以与其母体 BC 类型和“老化”过程联系起来，py-DOM 及其分子标记在微生物和光氧化过程中经历重大损失和化学转化的程度，以及目前使用的 py-DOM 分子标记是否准确代表 OM 对环境样品的实际热解贡献。