Tidally Driven Export of Dissolved Organic Carbon, Total Mercury, and Methylmercury from a Mangrove-Dominated Estuary

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• 作者：Brian A. Bergamaschi ; David P. Krabbenhoft ; George R. Aiken ; Eduardo Patino ; Darren G. Rumbold ; William H. Orem
• 刊名：Environmental Science & Technology (ES&T)
• 出版年：2012
• 出版时间：February 7, 2012
• 年：2012
• 卷：46
• 期：3
• 页码：1371-1378
• 全文大小：334K
• 年卷期：v.46,no.3(February 7, 2012)
• ISSN：1520-5851

文摘

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 (卤12.6) g C m^鈥? yr^鈥?, 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 卤 4.5 渭g total Hg m^鈥? yr^鈥? and 3.1 卤 0.4 渭g methyl Hg m^鈥? yr^鈥?) 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.