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Title: The Effect of Particle Composition and Concentration on the Partitioning Coefficient for Mercury in Three Ocean Basins
The downward flux of sinking particles is a prominent Hg removal and redistribution process in the ocean; however, it is not well-constrained. Using data from three U.S. GEOTRACES cruises including the Pacific, Atlantic, and Arctic Oceans, we examined the mercury partitioning coefficient, K d , in the water column. The data suggest that the K d varies widely over three ocean basins. We also investigated the effect of particle concentration and composition on K d by comparing the concentration of small-sized (1–51 μm) suspended particulate mass (SPM) as well as its compositional fractions in six different phases to the partitioning coefficient. We observed an inverse relationship between K d and suspended particulate mass, as has been observed for other metals and known as the “particle concentration effect,” that explains much of the variation in K d . Particulate organic matter (POM) and calcium carbonate (CaCO 3 ) dominated the Hg partitioning in all three ocean basins while Fe and Mn could make a difference in some places where their concentrations are elevated, such as in hydrothermal plumes. Finally, our estimated Hg residence time has a strong negative correlation with average log bulk K d , indicating that K d has significant effect on Hg residence time.  more » « less
Award ID(s):
2023031
PAR ID:
10355360
Author(s) / Creator(s):
; ; ; ;
Date Published:
Journal Name:
Frontiers in Environmental Chemistry
Volume:
2
ISSN:
2673-4486
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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