Flux of Particulate Elements in the North Atlantic Ocean Constrained by Multiple Radionuclides

Authors

Christopher T. Hayes, University of Southern MississippiFollow
Erin Black, Woods Hole Oceanographic InstitutionFollow
Robert F. Anderson, Lamont-Doherty Earth Observatory of Columbia UniversityFollow
Mark Baskaran, Wayne State UniversityFollow
Ken O. Buesseler, Woods Hole Oceanographic InstitutionFollow
Matthew A. Charette, Woods Hole Oceanographic InstitutionFollow
Hai Cheng, University of MinnesotaFollow
J. Kirk Cochran, Stony Brook UniversityFollow
R. Lawrence Edwards, University of MinnesotaFollow
Patrick Fitzgerald, Stony Brook University
Phoebe J. Lam, University of California, Santa CruzFollow
Yanbin Lu, Earth Observatory of SingaporeFollow
Stephanie O. Morris, Woods Hole Oceanographic Institution
Daniel C. Ohnemus, Bigelow Laboratory for Ocean SciencesFollow
Frank J. Pavia, Lamont-Doherty Earth Observatory of Columbia UniversityFollow
Gillian Stewart, City University of New YorkFollow
Yi Tang, City University of New York

Document Type

Article

Publication Date

12-1-2018

Department

Ocean Science and Technology

Abstract

Sinking particles strongly regulate the distribution of reactive chemical substances in the ocean, including particulate organic carbon (POC) and other elements (e.g. P, Cd, Mn, Cu, Co, Fe, Al and ²³²Th). Yet, the sinking fluxes of trace elements have not been well‐described in the global ocean. The U.S. GEOTRACES campaign in the North Atlantic (GA03) offers the first dataset in which the sinking flux of carbon and trace elements can be derived using 4 different radionuclide pairs (²³⁸U:²³⁴Th, ²¹⁰Pb:²¹⁰Po, ²²⁸Ra:²²⁸Th, and ²³⁴U:²³⁰Th) at stations co‐located with sediment trap fluxes for comparison. POC, particulate P and particulate Cd fluxes all decrease sharply with depth below the euphotic zone. Particulate Mn, Cu and Co flux profiles display mixed behavior, some cases reflecting biotic remineralization and other cases showing increased flux with depth. The latter may be related to either lateral input of lithogenic material or increased scavenging onto particles. Lastly, particulate Fe fluxes resemble fluxes of Al and ²³²Th, which all have increasing flux with depth, indicating a dominance of lithogenic flux at depth by resuspended sediment transported laterally to the study site. In comparing flux estimates derived using different isotope pairs, differences result from different timescales of integration and particle size fractionation effects. The range in flux estimates produced by different methods provides a robust constraint on the true removal fluxes, taking into consideration the independent uncertainties associated with each method. These estimates will be valuable targets for biogeochemical modelling and may also offer insight into particle sinking processes.

Publication Title

Global Biogeochemical Cycles

Volume

32

Issue

12

First Page

1738

Last Page

1758

Recommended Citation

Hayes, C. T., Black, E., Anderson, R. F., Baskaran, M., Buesseler, K. O., Charette, M. A., Cheng, H., Cochran, J. K., Edwards, R., Fitzgerald, P., Lam, P. J., Lu, Y., Morris, S. O., Ohnemus, D. C., Pavia, F. J., Stewart, G., Tang, Y. (2018). Flux of Particulate Elements in the North Atlantic Ocean Constrained by Multiple Radionuclides. Global Biogeochemical Cycles, 32(12), 1738-1758.
Available at: https://aquila.usm.edu/fac_pubs/15684