Nitrogen Enrichment during Soil Organic Matter Burning and Molecular Evidence of Maillard Reactions
Nitrogen Enrichment during Soil Organic Matter Burning and Molecular Evidence of Maillard Reactions
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DOI：
10.1021/acs.est.1c06745
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发表时间：
2022-04-05
影响因子：
11.4
通讯作者：
Borch, Thomas
中科院分区：
文献类型：
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作者：
Bahureksa, William;Young, Robert B.;Borch, Thomas
森林流域的野火极大地改变了储存和不稳定的土壤有机质 (SOM) 库以及溶解有机质 (DOM) 的输出。野火后的生态系统恢复取决于土壤微生物群落和植被恢复，因此受到营养物质（例如含氮和不稳定的水溶性化合物）可用性的限制。然而，人们对不同野火强度下产生的 SOM 副产品知之甚少，导致评估野火严重程度和预测生态系统恢复困难。在这项工作中，通过质谱分析对在离散温度下燃烧的实验室微观世界中的可水提取有机物 (WEOM) 进行表征，以研究火灾温度对 SOM 和 DOM 组成的影响。不同燃烧温度的分子组成表明，含氮副产物随着加热而富集，并由多种芳香族特征和氧化态组成。基于质量差异的分析还表明，可以使用沿着美拉德反应途径的转化来模拟加热过程中形成的产物。不同土壤燃烧强度下含氮SOM和DOM的富集对生态系统恢复和下游水质具有重要意义。
Wildfires in forested watersheds dramatically alter stored and labile soil organic matter (SOM) pools and the export of dissolved organic matter (DOM). Ecosystem recovery after wildfires depends on soil microbial communities and revegetation and therefore is limited by the availability of nutrients, such as nitrogen-containing and labile, water-soluble compounds. However, SOM byproducts produced at different wildfire intensities are poorly understood, leading to difficulties in assessing wildfire severity and predicting ecosystem recovery. In this work, waterextractable organic matter (WEOM) from laboratory microcosms of soil burned at discrete temperatures was characterized by mass spectrometry to study the impacts of fire temperature on SOM and DOM composition. The molecular composition derived from different burn temperatures indicated that nitrogencontaining byproducts were enriched with heating and composed of a wide range of aromatic features and oxidation states. Mass difference-based analysis also suggested that products formed during heating could be modeled using transformations along the Maillard reaction pathway. The enrichment of N-containing SOM and DOM at different soil burning intensities has important implications for ecosystem recovery and downstream water quality.