Tidally driven export of dissolved organic carbon, total mercury, and methylmercury from a mangrove-dominated estuary

Brian A. Bergamaschi; D. P. Krabbenhoft; George Aiken; Eduardo Patino; D.G. Rumbold; William H. Orem

doi:10.1021/es2029137

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Tidally driven export of dissolved organic carbon, total mercury, and methylmercury from a mangrove-dominated estuary

Brian A. Bergamaschi·D. P. Krabbenhoft·George Aiken·Eduardo Patino·D.G. Rumbold·William H. Orem

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Abstract

The flux of dissolved organic carbon (DOC) from mangrove swamps accounts for 10% of the global terrestrial flux of DOC to coastal oceans. Recent findings of high concentrations of mercury (Hg) and methylmercury (MeHg) in mangroves, in conjunction with the common co-occurrence of DOC and Hg species, have raised concerns that mercury fluxes may also be large. We used a novel approach to estimate export of DOC, Hg, and MeHg to coastal waters from a mangrove-dominated estuary in Everglades National Park (Florida, USA). Using in situ measurements of fluorescent dissolved organic matter as a proxy for DOC, filtered total Hg, and filtered MeHg, we estimated the DOC yield to be 180 (±12.6) g C m –2 yr –1 , which is in the range of previously reported values. Although Hg and MeHg yields from tidal mangrove swamps have not been previously measured, our estimated yields of Hg species (28 ± 4.5 μg total Hg m –2 yr –1 and 3.1 ± 0.4 μg methyl Hg m –2 yr –1 ) were five times greater than is typically reported for terrestrial wetlands. These results indicate that in addition to the well documented contributions of DOC, tidally driven export from mangroves represents a significant potential source of Hg and MeHg to nearby coastal waters.

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Environmental Science & Technology Article

Source-reported bounding extent: 24.9113494218506° to 26.00248714194576° latitude; -81.5625° to -80.4473876953125° longitude. This indicates report coverage, not an exact sampling location. View area on OpenStreetMap.

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Brian A. Bergamaschi, D. P. Krabbenhoft, George Aiken, Eduardo Patino, D.G. Rumbold, William H. Orem. 2012-01-19. Tidally driven export of dissolved organic carbon, total mercury, and methylmercury from a mangrove-dominated estuary. https://doi.org/10.1021/es2029137

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