This Major Research Instrumentation grant supports acquisition of an ion chromatograph (IC) to support research and undergraduate education at Wheaton College, a non-Ph.D granting institution. The IC will support PI and student research that will benefit from the ability to measure low concentration (sub ppb) anions and cations in natural water samples. Example research projects that will benefit include studies of CO2 and solute fluxes from hot springs in the Nepal and the Bhutan Himalaya, examination of the impacts of sea-ice cover on biological productivity in the Amundsen Sea, and investigation of the impacts of permafrost degradation on stream and river biogeochemistry across East Siberia. The IC will also support PI high school outreach efforts using the IC through an extant Milton Academy ? Wheaton College high school environmental science summer watershed impact study.
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The new Ion Chromatograph was acquired to enhance and allow for current and future research projects for the PI. These projects represent significant contributions to our understanding of geological environmental and chemical processes, and enhance research at Wheaton College. Acquiring this instrument has also increased our ability to include undergraduate students in all aspects of research, from question generation to operation of instruments, which should significantly improve their intellectual and practical training and will better prepare them to continue their development in graduate school or the workplace. The PI currently has four undergraduate research students. Since installation the IC has been used extensively for two funded projects, Collaborative Research: Quantifying CO2 fluxes along the Himalayan Arc (NSF EAR-0850913) and An interdisciplinary study of recent ice sheet melt, sea ice decline, and enhanced ocean biological productivity along the Amundsen Coast, West Antarctica (NASA # NNX10AP09G). For the NSF project, we have analyzed hot spring and river samples from NW India for major ions (46 total samples). For the NASA project we have analyzed a total of 840 samples since June 2012. In addition, the new IC provides the opportunity to analyze major anions and cations simultaneously from just 3mL of sample. We have re-analyzed ice cores samples that had previously only been analyzed for MSA and Cl for the entire suite of ions now available. Together, this marks a tremendous number and variety of samples from a simple laboratory setting, well over 2000 total analyses including standards. As proposed, and as part of a collaboration with Clark University and the CALON project (NSF ARC-1107596) 45 samples of river and lake samples from the North Slope of Alaska were analyzed for the full suite of ions as well. The IC was used exclusively for a course taught by the PI (Chemistry of Natural Waters) in the Spring of 2012. Students analyzed surface water samples taken as part of a semester-long project resulting in an analysis of weathering fluxes and road-salt impact on local streams (~25 samples). In addition, the IC was used to analyze samples from local vernal pools (10 samples) for a Wheaton colleague. Continuing a multi-year project with Milton Academy, the PI hosted teacher Matthew Bingham and 14 Milton students at Wheaton during the Spring 2012 semester. These students made standards, ran samples, and broke down data from the IC during a full day in-lab experience. While work is still in progress we have some findings to report. From previous work on shallow ice and firn cores, we found that coastal West Antarctic Ice Sheet chemistry (Cl- and MSA) is strongly influenced by Amundsen Sea and Pine Island Bay sea-ice dynamics and polynya variability. Data from the new IC has been found on three new cores, to greater depths than previous work. The figure above shows [MSA] in three cores, along with our previous work (UpT2009) showing good correlation between [MSA] across the region. This work in Antarctica, built upon data produced with our new instrument, has demonstrated an important regional link between sea-ice coverage in polynyas and the chemistry of nearby glaciers. This link should allow us to examine the Pine Island Bay region into the recent past, and better determine how these fast moving glaciers will behave in the future. For our samples from NW India, we have used our major element data to calculate the fraction of total alkalinity that is derived from silicate minerals in both rivers and hot springs there. In rivers, these values range from 5%–17% while a much larger fraction of the solute load in hot springs is derived from the dissolution of silicate minerals (80-100%). In addition, the springs can be characterized as Cl-Na-HCO3- type waters. The attached figure shows the chemical characteristics of both river and hot spring waters. From the plot we see the strong influence of carbonate weathering in the rivers, with high Ca2+ and HCO3- concentrations. The hot springs however are variable, but with stronger Cl- and Na++K+ influences, indicating the high silicate alkalinity in the springs. Our data from river and hot spring samples in India, combined with other data and sample sets, has set about to examine the balance between carbon dioxide uptake from weathering reactions and carbon dioxide release from hot spring systems along the Himalayan front. Mountain building events have traditionally been thought to be a sink for carbon dioxide. The data produced on the newly acquired IC have in part been used to show that the hot springs in both Bhutan and India are bringing significant CO2 to the surface. This is potentially an important paradigm shift in our assessment of the long term carbon cycle.
