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

火在地球生态系统动态中发挥着关键作用，除了对人类和基础设施构成重大威胁外，还对生物地球化学过程、气候和环境质量产生深远影响。今年，巴西亚马逊盆地发生了自2010年以来最多的森林火灾，这为研究火灾对亚马逊河系统碳通量的影响提供了一个令人信服的机会，并提供了一个有利时机，计划于2020年前往Guyanas泥岸，以描述生物质从陆地来源到沉入海洋的整个连续体燃烧的相应特征。该项目利用这一机会，对亚马逊河源头和下游的溶解和颗粒物负荷进行了时间序列采样。这一努力将与在高流量和低流量时对整个河流深度剖面进行有针对性的采样运动相结合，以捕获向大西洋出口的材料。热解碳的浓度和组成将通过将特定的分子功(无水糖左旋葡聚糖和苯多羧酸，简称BPCAs)与斜坡式热解氧化相结合来测量，以表征组成热解碳的化学连续体。放射性碳含量和稳定的碳同位素组成将有助于区分生物物质燃烧产生的热源碳(例如，与土壤或旧沉积物侵蚀的热源碳相反)。与亚马逊盆地火灾活动相对较低的一段时间确定的基线相比，2019年的河流样本提供了一个机会，可以测试海洋的热源碳通量是否对火灾活动的增加做出反应。近海样品将能够描述这种热源碳是如何在沿海海洋中转化和/或保存的。快速反应资金对于充分利用现有基线数据的独特组合、今年火灾活动的显著增加以及计划中的2020年巡航至关重要。该项目的成果将为今后重建过去火灾活动的努力奠定基础，例如，与国际大陆科学钻探方案和国际大洋钻探方案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伙伴关系教育计划相结合，该计划旨在为来自代表性不足的少数族裔的大学生提供在海洋和环境科学方面获得实践经验的机会。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势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.