B076-0007
The Impact of African Aerosol Transport on Biogeochemical Cycles

Monday, 14 December 2020
Poster
Cassandra Gaston1, Anne Barkley1, Haley Royer2, Kathy Panechou3, Kimberly J. Popendorf4, Ali Pourmand5, Amanda M Oehlert6, Natalie M Mahowald7, Douglas S Stephen Hamilton8, Andrew P Ault9, Nicole Olson10, Patricia L Blackwelder11, Joseph M Prospero12, Swarup China13 and Mira L. Pöhlker14, (1)University of Miami, Rosenstiel School of Marine and Atmospheric Science, Miami, FL, United States, (2)University of Miami, Department of Atmospheric Sciences, Miami, FL, United States, (3)ATMO Guyane, Cayenne, French Guiana, (4)University of Miami, Ocean Sciences, Miami, FL, United States, (5)Neptune Isotope Laboratory (NIL), Rosenstiel School of Marine and Atmospheric Science, University of Miami, Department of Marine Geosciences, Miami, FL, United States, (6)Rosenstiel School of Marine and Atmospheric Sciences, University of Miami, Department of Marine Geosciences, Miami, FL, United States, (7)Cornell University, Earth and Atmospheric Sciences, Ithaca, NY, United States, (8)Cornell University, Department of Earth and Atmospheric Sciences, Ithaca, NY, United States, (9)University of Michigan Ann Arbor, Department of Chemistry, Ann Arbor, MI, United States, (10)University of Michigan Ann Arbor, Department of Chemistry, Ann Arbor, United States, (11)University of Miami, Center for Advanced Microscopy, Miami, FL, United States, (12)University of Miami, Miami, FL, United States, (13)Pacific Northwest National Laboratory, Richland, WA, United States, (14)Max Planck Institute for Chemistry, Mainz, Germany
Abstract:
The long-range transport of African dust is of great interest due to its impact on biogeochemical cycles in the Amazon Basin and the Tropical Atlantic Ocean. Despite interest in this topic, few measurements exist to document this phenomenon and quantify its impacts on biogeochemical cycles. Here we will discuss measurements collected at the University of Miami’s Barbados Atmospheric Chemistry Observatory (BACO) and a site in Cayenne, French Guiana located on the coast of the Tropical Atlantic Ocean which receives only long-range transported and sea spray aerosol. Therefore, Cayenne is ideal for determining the impact of long-range transport on the aerosol burden in South America. We will discuss seasonal variations in nutrient loadings and aerosol sources during active and non-active dust transport periods, and single particle measurements of the mixing state of iron (Fe) and phosphorus (P) containing particles. Our measurements reveal that in addition to dust, other particle sources are also important for supplying nutrients to these ecosystems. In particular, we elucidate the underappreciated role of biomass burning transport in supplying nutrients. Overall, our measurements demonstrate the importance of both bulk and single-particle characterization for describing particulate contributions to biogeochemical cycles and for quantifying the deposition of nutrients from different aerosol sources. Further, it is important to continue and expand long-term measurement records to fully quantify the impact of aerosol deposition on ecosystem health and climate.
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