Collaborative Research: Dissolved pyrogenic organic matter dynamics in the environment

热生有机物或黑碳（BC）来自生物质和化石燃料的不完全燃烧。目前已认识到这类有机质对土壤化学、污染物运移、气候和全球碳循环具有重要影响。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BC中可浸出的有机物的性质和循环的研究相对较少；热原溶解有机质（py-DOM）。虽然释放到环境中的py-DOM可能会产生无法识别的碳循环和环境影响，但py-DOM仅在少数系统中进行了量化，使用的方法尚未得到全面评估。本研究将研究与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，为了扩大公众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动手科学博物馆举办一个互动展览，其中包括触摸屏图形，每位主要研究人员讲解科学过程和研究结果的视频。为了确定与py-DOM产生和命运有关的化学性质和机制以及用于量化它的化学标记，该项目将：1)通过微生物和光处理从新鲜生产和“老化”的BC固体中产生py-DOM， 2)使用FTIR，傅立叶变换离子回旋共振质谱（FTICR-MS）和一维和二维核磁共振对这些BC母固体及其水溶产物进行化学表征，3)检查微生物和光降解处理后py-DOM的损失和转化，4)量化假定的热原分子标记的产量；左旋葡聚糖，苯聚羧酸（BPCA）和氧合多环芳烃（O-PAH），来自新鲜和“老化”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生陆生有机物质的渗滤液和渗滤液改造产物，其中一些研究人员最近发现含有“类bc”化合物。这项工作将测试py-DOM的化学性质是否与其母体BC类型和“老化”过程有关，py-DOM及其分子标记在多大程度上通过微生物和光氧化经历了重大损失和化学转化，以及目前使用的py-DOM分子标记是否准确地代表了对环境样品的实际热原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.