Authors

Christopher T. Hayes, School of Ocean Science and Engineering, University of Southern Mississippi Stennis Space Center, MS
Erin E. Black, Woods Hole Oceanographic Institution, Woods Hole, MA
Robert F. Anderson, Department of Earth and Environmental Sciences, Columbia University, New York, NY
Mark Baskaran, Department of Geology, Wayne State University, Detroit, MIFollow
Ken O. Buesseler, Woods Hole Oceanographic Institution, Woods Hole, MA
Matthew A. Charette, Woods Hole Oceanographic Institution, Woods Hole, MA
Hai Cheng, Institute of Global Environmental Change, Xi’an Jiaotong University, Xi’an, China
J. Kirk Cochran, School of Marine and Atmospheric Science, Stony Brook University, Stony Brook, NY
R. Lawrence Edwards, Department of Earth Sciences, University of Minnesota, Minneapolis, MN
Patrick Fitzgerald, School of Marine and Atmospheric Science, Stony Brook University, Stony Brook, NY
Phoebe J. Lam, Ocean Sciences Department, University of California, Santa Cruz, CA
Yanbin Lu, Earth Observatory of Singapore, Nanyang Technical University, Singapore
Stephanie O. Morris, Woods Hole Oceanographic Institution, Woods Hole, MA
Daniel C. Ohnemus, Bigelow Laboratory for Ocean Sciences, East Boothbay, ME
Frank J. Pavia, Department of Earth and Environmental Sciences, Columbia University, New York, NY
Gillian Stewart, School of Earth and Environmental Sciences, Queens College, City University of New York, Flushing, NY
Yi Tang, School of Earth and Environmental Sciences, Queens College, City University of New York, Flushing, NY

Document Type

Article

Abstract

Sinking particles strongly regulate the distribution of reactive chemical substances in the ocean, including particulate organic carbon 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 data set in which the sinking flux of carbon and trace elements can be derived using four different radionuclide pairs (238U:234Th ;210Pb:210Po; 228Ra:228Th; and 234U:230Th) at stations co-located with sediment trap fluxes for comparison. Particulate organic carbon, 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 modeling and may also offer insight into particle sinking processes.

Disciplines

Environmental Sciences | Geology | Oceanography

Comments

Copyright © 2018 American Geophysical Union, originally published in Global Biogeochemical Cycles (https://doi.org/10.1029/ 2018GB005994), deposited here in compliance with publisher policy.

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