Collaborative Research: RAPID: Mechanisms and fate of fire-induced carbonate formation in a cold desert ecosystem

旱地一直与野火有关，但气候变化和植被的变化改变了这些敏感生态系统的火灾状况和碳平衡。野火消耗植被，将储存的有机碳以温室气体二氧化碳（CO2）的形式释放出来。然而，最近，盐以土壤碳酸盐的形式积累（即，无机碳）的影响。火诱导碳酸盐积累（FICA）的机制及其对长期碳储存的重要性仍然未知。这项研究开始解决我们对火灾引起的土壤碳酸盐的起源，命运和影响的知识空白，因为野火活动在旱地处于历史最高水平。在这里，研究人员使用预定于2023年9月在美国农业部西北流域研究中心（NWRC）和临界区观测站（CZO）的一个已经密集仪器化的集水区中进行的规定牧场火灾来描述火灾引起的碳酸盐积累的环境控制。该研究是研究人员和土地管理人员合作的跨学科小组的一部分，旨在加强对野火的了解，以产生更大的区域影响。本研究将使用2023年9月的实验性火灾来表征非生物因素对火灾诱导的碳酸盐积累（FICA）的影响，该实验性火灾位于爱达荷州南部及周边地区的寒冷沙漠，山艾树草原生态系统特征内。包括土壤pH值，钙的可用性，土壤二氧化碳（CO2）浓度和胞外酶活性的因素的组合似乎导致FICA，但所涉及的确切机制，以及这种碳的来源和命运仍然没有解决。在牧场野火研究中不常见，该项目将1）在火灾前收集土壤样本，并将其与火灾后的条件进行对比，以促进未来对FICA控制的调查，2）测量土壤CO2，水分和温度条件之前，期间和火灾后9个月-一个独特的易腐烂的数据集，以及从未有人研究过的由火灾引起的碳酸盐形成机制。样本收集和传感器测量将在面向北和面向南的方面分层，并且烧伤严重程度治疗（即，植被类型），以了解FICA的景观控制。土壤样品也被认为是易腐的，将被存档，以供未来调查超出初始pH值，EC和碳酸盐测定。该奖项反映了NSF的法定使命，并已被认为是值得通过使用基金会的智力价值和更广泛的影响审查标准进行评估的支持。

Drylands have always been linked with wildfires, but climate change and shifts in vegetation have altered the fire regime and carbon balance of these sensitive ecosystems. Wildfires consume vegetation, releasing stored organic carbon as carbon dioxide (CO2), a greenhouse gas. Recently, however, the accumulation of salts in the form of soil carbonates (i.e., inorganic carbon) have been observed after dryland wildfires. The mechanisms of fire-induced carbonate accumulation (FICA) and its importance to long-term carbon storage remain unknown. This research begins to address a gap in our knowledge about the origin, fate, and impact of fire-induced soil carbonates as wildfire activity is at its historic highest levels in drylands. Here, researchers characterize the environmental controls on fire-induced carbonate accumulation using a prescribed rangeland fire slated for September 2023 in an already intensively instrumented catchment of the US Department of Agriculture’s Northwest Watershed Research Center (NWRC) and Critical Zone Observatory (CZO). The research is part of an interdisciplinary group of researchers and land managers collaborating to enhance understanding of wildland fires to create greater regional impact. This research will characterize the abiotic factors contributing to fire-induced carbonate accumulation (FICA) using an experimental fire in September 2023, located within the cold desert, sagebrush steppe ecosystem characteristic of southern Idaho and the surrounding region. A combination of factors including soil pH, calcium availability, soil carbon dioxide (CO2) concentration, and extracellular enzymatic activity appear to lead to FICA, but the exact mechanisms involved, and the source and fate of this carbon remain unresolved. Uncommon in rangeland wildfire studies, the project will 1) collect soil samples just before the fire, and contrast these with post-fire conditions to facilitate future investigation of controls on FICA, and 2) measure soil CO2, moisture, and temperature conditions before, during, and for 9 months after the fire – a unique and perishable dataset, and something that has never been done to study the mechanisms driving carbonate formation caused by fires. Sample collection and sensor measurements will be stratified across north- and south-facing aspects, and burn severity treatments (i.e., vegetation types) to understand landscape controls on FICA. Soil samples are also considered perishable and will be archived for future investigation beyond initial pH, EC, and carbonate determination.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.