RAPID: Collaborative Research: Tracking Amazon Forest Fires from Source to Sink

火灾在地球生态系统动力学中起着关键作用，对生物地球化学过程、气候和环境质量产生深远影响，对人类和基础设施构成重大威胁。自2010年以来，今年是巴西亚马逊流域发生森林火灾最多的一年，这为研究火灾对亚马逊河系统碳通量的影响提供了一个极好的机会，同时计划在2020年前往圭亚那泥滩进行一次吉祥的巡航，以表征从陆地源头到海洋沉降的整个连续体中生物质燃烧的相应特征。该项目利用这一机会，对亚马逊河上游和下游的溶解物和微粒负荷进行时间序列采样。这项工作将与有针对性的采样活动相结合，在高流量和低流量的整个河流深度剖面上进行采样，以捕获向大西洋出口的物质。将通过结合特定的分子功（无水糖左旋葡聚糖和苯多羧酸，或BPCAs）和梯度热解氧化来测量热原碳的浓度和组成，以表征组成热原碳的化学连续体。放射性碳含量和稳定的碳同位素组成将有助于区分来自活生物质燃烧的热原碳（与来自土壤或旧沉积物侵蚀的热原碳相反）。与亚马逊盆地火灾活动相对较低时期建立的基线相比，2019年的河流样本提供了一个机会，可以测试海洋的热原碳通量是否对火灾活动的增加做出反应。离岸样品将允许表征这种热原碳是如何转化和/或保存在沿海海洋。快速响应资金对于利用现有基线数据、今年火灾活动的显著增加以及计划的2020年巡航的独特组合至关重要。该项目的结果将为未来重建过去的火灾活动奠定基础，例如，与国际大陆科学钻探计划和国际海洋钻探计划支持的亚马逊系统即将开展的钻探项目相结合。最后，该项目将与伍兹霍尔合作伙伴教育计划对接，该计划旨在为来自代表性不足的少数民族的大学生提供获得海洋和环境科学实践经验的机会。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Fire plays a key role in Earth's ecosystem dynamics with profound effects on biogeochemical processes, climate, and environmental quality beyond the significant threat to people and infrastructures. This year has seen the most forest fires in the Amazon Basin of Brazil since 2010, providing a compelling opportunity to study the impact of fires on carbon fluxes in the Amazon River system, and, together with an auspiciously-timed cruise planned to the Guyanas mudbanks in 2020, to characterize the corresponding signature of biomass burning along the entire continuum from source on land to sink in the oceans. This project takes advantage of this opportunity through time series sampling of the dissolved and particulate load in the headwaters and the lower reaches of the Amazon River. This effort will be combined with targeted sampling campaigns across the full river depth profile at high and low discharge to capture the export of material to the Atlantic Ocean. Pyrogenic carbon concentration and composition will be measured by combining specific molecular work (anhydrous sugar levoglucosan and benzene polycarboxylic acids, or BPCAs) with ramped pyrolysis oxidation to characterize the chemical continuum that makes up pyrogenic carbon. Radiocarbon content and stable carbon isotope composition will help to distinguish pyrogenic carbon derived from combustion of living biomass (as opposed to that eroded from soils or old sediments, for example). Compared to a baseline established during a period of time when fire activity in the Amazon basin was relatively low, river samples from 2019 offer a chance to test whether pyrogenic carbon fluxes to the ocean respond to an increase in fire activity. The offshore samples will allow for characterizing how this pyrogenic carbon is transformed and/or preserved in the coastal ocean. Rapid-response funding will be essential to capitalizing on the unique combination of existing baseline data, the pronounced increase in fire activity this year, and the planned 2020 cruise. The outcome of this project will lay the groundwork for future efforts at reconstructing past fire activity, e.g., in association with upcoming drilling projects in the Amazon system supported by International Continental Scientific Drilling Program and the International Ocean Drilling Program. Finally, the project will interface with the Woods Hole Partnership Educational Program, which is designed to provide college students from underrepresented minorities opportunities to gain practical experience in marine and environmental sciences.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.