Collaborative Research: Dissolved pyrogenic organic matter dynamics in the environment

热源有机物，或称黑碳(BC)，是生物质和化石燃料不完全燃烧的产物。现在人们认识到，这种类型的有机物对土壤化学、污染物迁移、气候和全球碳循环有很大的影响。此外，由于与气候变化相关的野火增加，以及故意在土壤中添加BC(作为生物炭)以提高土壤肥力和固碳，其影响可能会增加。然而，尽管近年来人们对天然和人为颗粒物BC的性质的了解有所增加，但对BC中可浸出的有机物的性质和循环的研究相对较少；热源溶解有机物(Py-DOM)。尽管释放到环境中的Py-DOM可能会有未被认识到的碳循环和环境影响，但仅在少数系统中使用了尚未得到全面评估的方法对Py-DOM进行了量化。这项研究将考察与Py-DOM的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，为了扩大对火对气候和碳循环重要性的普遍认识，调查人员将在当地的一个动手科学博物馆开发一个互动展览，其中将包括触摸屏图形、每个主要调查人员讲述的视频，说明科学过程和研究结果。为了确定与Py-DOM的产生和去向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固体中产生Py-DOM，包括新鲜产生的和通过微生物和光处理“老化”的；2)使用FTIR、傅立叶变换离子回旋共振质谱仪(FTICR-MS)和一维和二维核磁共振对这些BC母体固体及其水溶产物进行化学表征；3)检测微生物和光降解处理后Py-DOM的损失和转化，以及4)量化可能的热源分子标记的产率；左旋葡聚糖、苯多羧酸(BPCA)和含氧多环芳烃(O-PAH)，来自新鲜和陈化的BC固体和渗滤液。使用相同的方法和实验，还将检查潜在干扰的非热源陆地有机物质的渗滤液和渗滤液变化产物，调查人员最近发现其中一些物质含有“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型和“老化”过程相关联，Py-DOM及其分子标记通过微生物和光氧化经历重大损失和化学转化的程度，以及目前使用的Py-DOM分子标记是否准确地代表了环境样品中实际的热源OM贡献。

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.