Mercury dynamics in a San Francisco Estuary tidal wetland: Assessing dynamics using in situ measurements

Primary tabs

Bergamaschi, B. A., Fleck, J. A., Downing, B. D., Boss, E., Pellerin, B. A., Ganju, N. K., … Fujii, R. (2012). Mercury dynamics in a San Francisco Estuary tidal wetland: Assessing dynamics using in situ measurements. Estuaries and Coasts, 35(4), 1036-1048. doi:10.1007/s12237-012-9501-3
Metadata
TitleMercury dynamics in a San Francisco Estuary tidal wetland: Assessing dynamics using in situ measurements
AuthorsB. Bergamaschi, J. Fleck, B. Downing, E. Boss, B. Pellerin, N. Ganju, D. Schoellhamer, A. Byington, W. Heim, M. Stephenson, R. Fujii
AbstractWe used high-resolution in situ measurements of turbidity and fluorescent dissolved organic matter (FDOM) to quantitatively estimate the tidally driven exchange of mercury (Hg) between the waters of the San Francisco estuary and Browns Island, a tidal wetland. Turbidity and FDOM-representative of particle-associated and filter-passing Hg, respectively-together predicted 94 % of the observed variability in measured total mercury concentration in unfiltered water samples (UTHg) collected during a single tidal cycle in spring, fall, and winter, 2005-2006. Continuous in situ turbidity and FDOM data spanning at least a full spring-neap period were used to generate UTHg concentration time series using this relationship, and then combined with water discharge measurements to calculate Hg fluxes in each season. Wetlands are generally considered to be sinks for sediment and associated mercury. However, during the three periods of monitoring, Browns Island wetland did not appreciably accumulate Hg. Instead, gradual tidally driven export of UTHg from the wetland offset the large episodic on-island fluxes associated with high wind events. Exports were highest during large spring tides, when ebbing waters relatively enriched in FDOM, dissolved organic carbon (DOC), and filter-passing mercury drained from the marsh into the open waters of the estuary. On-island flux of UTHg, which was largely particle-associated, was highest during strong winds coincident with flood tides. Our results demonstrate that processes driving UTHg fluxes in tidal wetlands encompass both the dissolved and particulate phases and multiple timescales, necessitating longer term monitoring to adequately quantify fluxes. © 2012 The Author(s).
JournalEstuaries and Coasts
Date2012
Volume35
Issue4
Start page1036
End page1048
ISSN15592723
Subjectsassessment method, concentration (composition), dissolved organic matter, environmental monitoring, in situ measurement, intertidal environment, mercury (element), resolution, time series, turbidity, wetland management, California, San Francisco Estuary, United States
NoteCited By (since 1996):1

Bookmark

Bookmarks: