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

Environmental Science & Technology
By: , and 

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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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Publication type Article
Publication Subtype Journal Article
Title Tidally driven export of dissolved organic carbon, total mercury, and methylmercury from a mangrove-dominated estuary
Series title Environmental Science & Technology
DOI 10.1021/es2029137
Volume 46
Issue 3
Year Published 2012
Language English
Publisher American Chemical Society
Contributing office(s) California Water Science Center, FLWSC-Tampa, Wisconsin Water Science Center
Description 8 p.
First page 1371
Last page 1378
Country United States
State Florida
Other Geospatial Gunboat Island
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