| Autor: |
Conway TM; College of Marine Science and School of Geosciences, University of South Florida, Tampa, FL, USA. tmconway@usf.edu., Hamilton DS; Department of Earth and Atmospheric Sciences, Atkinson Center for a Sustainable Future, Cornell University, Ithaca, NY, USA., Shelley RU; Department of Earth, Ocean and Atmospheric Science, Florida State University, Tallahassee, FL, USA., Aguilar-Islas AM; College of Fisheries and Ocean Sciences, University of Alaska Fairbanks, Fairbanks, AK, USA., Landing WM; Department of Earth, Ocean and Atmospheric Science, Florida State University, Tallahassee, FL, USA., Mahowald NM; Department of Earth and Atmospheric Sciences, Atkinson Center for a Sustainable Future, Cornell University, Ithaca, NY, USA., John SG; Department of Earth Sciences, University of Southern California, Los Angeles, CA, 90089, USA. |
| Abstrakt: |
Atmospheric dust is an important source of the micronutrient Fe to the oceans. Although relatively insoluble mineral Fe is assumed to be the most important component of dust, a relatively small yet highly soluble anthropogenic component may also be significant. However, quantifying the importance of anthropogenic Fe to the global oceans requires a tracer which can be used to identify and constrain anthropogenic aerosols in situ. Here, we present Fe isotope (δ 56 Fe) data from North Atlantic aerosol samples from the GEOTRACES GA03 section. While soluble aerosol samples collected near the Sahara have near-crustal δ 56 Fe, soluble aerosols from near North America and Europe instead have remarkably fractionated δ 56 Fe values (as light as -1.6‰). Here, we use these observations to fingerprint anthropogenic combustion sources, and to refine aerosol deposition modeling. We show that soluble anthropogenic aerosol Fe flux to the global surface oceans is highly likely to be underestimated, even in the dusty North Atlantic. |
