Shanley, James B

12 items:

Comparison of total mercury and methylmercury cycling at five sites using the small watershed approach The small watershed approach is well-suited but underutilized in mercury research. We applied the small watershed approach to investigate total mercury (THg) and methylmercury (MeHg) dynamics in streamwater at the five diverse forested headwater catchments of the US Geological Survey Water, Energy, and Biogeochemical Budgets (WEBB) program. At all sites, baseflow THg was generally less than 1 ng L−1 and MeHg was less than 0.2 ng L−1. THg and MeHg concentrations increased with streamflow, so export was primarily episodic. At three sites, THg and MeHg concentration and export were dominated by the particulate fraction in association with POC at high flows, with maximum THg (MeHg) concentrations of 94 (2.56) ng L−1... Categories: Publication; Types: Citation; Tags: Episodic transport, Methylmercury, Total mercury, Watershed
The stable isotope amount effect: New insights from NEXRAD echo tops, Luquillo Mountains, Puerto Rico The stable isotope amount effect has often been invoked to explain patterns of isotopic composition of rainfall in the tropics. This paper describes a new approach, correlating the isotopic composition of precipitation with cloud height and atmospheric temperature using NEXRAD radar echo tops, which are a measure of the maximum altitude of rainfall within the clouds. The seasonal differences in echo top altitudes and their corresponding temperatures are correlated with the isotopic composition of rainfall. These results offer another factor to consider in interpretation of the seasonal variation in isotopic composition of tropical rainfall, which has previously been linked to amount or rainout effects and not to... Categories: Publication; Types: Citation; Tags: cloud water, precipitation, radar, tropical climate, w
Sources, transformations, and hydrological processes that control stream nitrate and dissolved organic matter concentrations during snowmelt in an upland forest Categories: Publication; Types: Citation
Mercury dynamics in relation to dissolved organic carbon concentration and quality during high flow events in three northeastern U.S. streams Categories: Publication; Types: Citation
A Biogeochemical Comparison of Two Well-Buffered Catchments with Contrasting Histories of Acid Deposition Much of the biogeochemical cycling research in catchments in the past 25 years has been driven by acid deposition research funding. This research has focused on vulnerable base-poor systems; catchments on alkaline lithologies have received little attention. In regions of high acid loadings, however, even well-buffered catchments are susceptible to forest decline and episodes of low alkalinity in streamwater. As part of a collaboration between the Czech and U.S. Geological Surveys, we compared biogeochemical patterns in two well-studied, well-buffered catchments: Pluhuv Bor in the western Czech Republic, which has received high loading of atmospheric acidity, and Sleepers River Research Watershed in Vermont, U.S.A.,... Categories: Publication; Types: Citation; Tags: acidification, alkalinity, base cations, buffering, ca

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