%0 Journal Article %J Geology %D 2018 %T Barium and barite dynamics in Antarctic streams %A Saelens, Elsa D. %A Christopher B. Gardner %A Kathleen A. Welch %A Sue Welch %A W. Berry Lyons %X

Most natural waters are undersaturated with respect to barite (BaSO4), and while much work has focused on the processes of microbially mediated barite precipitation in undersaturated solutions, particularly in marine environments, little documentation exists on the changes in barite saturation in stream waters. We examined ephemeral glacial meltwater streams in the McMurdo Dry Valleys, Antarctica, that undergo large variations in streamflow and temperature on both a diel and seasonal basis. We measured dissolved Ba in stream water in downstream transects and on a diel cycle, total Ba in stream sediments, algal mats, and lake sediments. Ba concentrations decreased downstream in all four transects, and mineral saturation modeling indicates these waters go from supersaturated to undersaturated with respect to barite in very short distances. Ba is concentrated in stream benthic algal mats at a factor less than observed in marine systems. Both seasonal and diel changes in stream water temperature affect the solubility of barite near glacial sources. Our work shows that both changing stream temperature and the presence of algal materials likely play significant roles in controlling Ba concentrations in polar streams.

%B Geology %V 46 %P 811 - 814 %8 08/2018 %G eng %U https://pubs.geoscienceworld.org/gsa/geology/article/545184/Barium-and-barite-dynamics-in-Antarctic-streams %N 9 %R 10.1130/G45048.1 %0 Journal Article %J Elementa: Science of the Anthropocene %D 2018 %T The impact of fossil fuel burning related to scientific activities in the McMurdo Dry Valleys, Antarctica: Revisited %A W. Berry Lyons %A Saelens, Elsa D. %A Kathleen A. Welch %K carbon dynamics %K emissions %K fossil fuels %K helicopter %K management %K McMurdo Dry Valleys %K nitrogen %K science activites %X

 

Fossil fuel use associated with scienti c activities in the Taylor Valley, Antarctic has been examined to determine the fluxes of particulate organic and elemental carbon and nitrogen as well as NOx for the 2015–2016 austral summer field season. These carbon and nitrogen fluxes are compared to our previously published calculations for the 1997–1998 austral summer. In addition, we compile fossil fuel usage and resulting C and N fluxes from the major field camp in Taylor Valley, Lake Hoare Camp (LHC) from the late 1990’s through 2017. In general, the annual fluxes do vary from year to year, but there is no significant trend, at least during the primary summer field season. There is indication that increasing the length of scientific operations does increase the C and N inputs via fossil fuel burning. This works supports our original results demonstrating that over long periods of time the anthropogenic flux of N from local fossil fuel burning could become quantitatively important in the region. Although the particulate C fluxes remain very low, the recent finding of black carbon in the Taylor Valley landscape indicates more on-going monitoring of the source of this material is merited.

 

%B Elementa: Science of the Anthropocene %V 6 %8 04/2018 %G eng %U https://www.elementascience.org/article/10.1525/elementa.288/ %! Elem Sci Anth %R 10.1525/elementa.288 %0 Thesis %B School of Earth Sciences %D 2017 %T The geochemistry of minor cations within Antarctic stream water: Determining the role of the hyporheic zone %A Saelens, Elsa D. %E W. Berry Lyons %B School of Earth Sciences %I The Ohio State University %C Columbus, OH %V B.A. %G eng %U http://library.ohio-state.edu/record=b8218699~S7 %9 bachelors