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

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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.