Coastal Ocean and Shelf-Sea Biogeochemical Cycling of Trace Elements and Isotopes: Lessons Learned From GEOTRACES

Authors

Matthew A. Charette, Woods Hole Oceanographic InstitutionFollow
Phoebe J. Lam, University of California, Santa CruzFollow
Maeve C. Lohan, University of SouthamptonFollow
Eun Young Kwan, Seoul National University
Vanessa Hatje, Universidade Federal da Bahia
Catherine Jeandel, University of ToulouseFollow
Alan M. Shiller, University of Southern MississippiFollow
Gregory A. Cutter, Old Dominion UniversityFollow
Alex Thomas, University of EdinburghFollow
Philip W. Boyd, University of Tasmania
William B. Homoky, University of Oxford
Angela Milne, Plymouth University
Helmuth Thomas, Dalhousie UniversityFollow
Per S. Andersson, Swedish Museum of Natual History
Don Porcelli, University of Oxford
Takahiro Tanaka, University of Tokyo
Walter Geibert, Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research
Frank Dehairs, Vrije Universiteit BrusselFollow
Jordi Garcia-Orellana, Universitat Autònoma de Barcelona

Document Type

Article

Publication Date

11-1-2016

Department

Marine Science

School

Ocean Science and Engineering

Abstract

Continental shelves and shelf seas play a central role in the global carbon cycle. However, their importance with respect to trace element and isotope (TEI) inputs to ocean basins is less well understood. Here, we present major findings on shelf TEI biogeochemistry from the GEOTRACES programme as well as a proof of concept for a new method to estimate shelf TEI fluxes. The case studies focus on advances in our understanding of TEI cycling in the Arctic, transformations within a major river estuary (Amazon), shelf sediment micronutrient fluxes and basin-scale estimates of submarine groundwater discharge. The proposed shelf flux tracer is 228-radium (T_1/2 = 5.75 yr), which is continuously supplied to the shelf from coastal aquifers, sediment porewater exchange and rivers. Model-derived shelf ²²⁸Ra fluxes are combined with TEI/ ²²⁸Ra ratios to quantify ocean TEI fluxes from the western North Atlantic margin. The results from this new approach agree well with previous estimates for shelf Co, Fe, Mn and Zn inputs and exceed published estimates of atmospheric deposition by factors of approximately 3-23. Lastly, recommendations are made for additional GEOTRACES process studies and coastal margin-focused section cruises that will help refine the model and provide better insight on the mechanisms driving shelf-derived TEI fluxes to the ocean.

Publication Title

Philosophical Transactions A

First Page

1

Last Page

19

Recommended Citation

Charette, M. A., Lam, P. J., Lohan, M. C., Kwan, E. Y., Hatje, V., Jeandel, C., Shiller, A. M., Cutter, G. A., Thomas, A., Boyd, P. W., Homoky, W. B., Milne, A., Thomas, H., Andersson, P. S., Porcelli, D., Tanaka, T., Geibert, W., Dehairs, F., Garcia-Orellana, J. (2016). Coastal Ocean and Shelf-Sea Biogeochemical Cycling of Trace Elements and Isotopes: Lessons Learned From GEOTRACES. Philosophical Transactions A, 1-19.
Available at: https://aquila.usm.edu/fac_pubs/16728