MSU Undergraduate Intern Analyzes Stable Water Isotopes To Better Understand Water Flow Path Dynamics

Hi there.

This is Sam Leuthold, and this summer I worked on a project using stable water isotopes to think about water flow path dynamics in the Gallatin Valley. The isotopes we were interested in measuring this summer were 18O and 2H, also known as deuterium (D). We had study sites all over the Gallatin Valley, and in Hyalite Canyon (fig. 1), and ended up with a pretty sizeable sample set to analyze at the end of the summer!

Water isotopes can tell us a lot about the processes water goes through before ending up in a sample bottle. Because the isotopes we were interested in are heavier than the more common isotopes, they tend to rain out of clouds first, and evaporate from streams last. With that in mind, we established two precipitation collectors to provide a baseline for our stream sites. One of these sites is at the Lick Creek SNOTEL site in Hyalite Canyon, placed there with permission from the NRCS. The other is in my former backyard, near the Montana State Campus. These precipitation collectors were primed with a small amount of mineral oil, such that no rain water would be subjected to any evaporation between collections. To date, 6 months’ worth of precipitation data have been collected, as well as snow samples from Hyalite Canton. These data provide valuable insights about the character of water in the valley, and the seasonal dynamics of this water. They also plot super well (fig. 2)!

All the samples are being analyzed in the Montana State University Environmental Analytical Lab. The lab recently purchased a new water isotope analyzer, and the first half of my summer was spent in apprehensive purgatory, hoping that no shipping delays would hinder the arrival of the instrument. Finally, in August, it arrived! Now we are learning the best ways to bracket standards into runs, as well as the methodology behind the processing of the raw data into a more robust and viable data set.

This summer has been busy, and super fun! It’s great to be able to work in such a positive and challenging lab group, as well as having the ability to become better acquainted with analytical environmental sciences. The data is still preliminary, but I think we’re going to have some really exciting results, so stay tuned!

  • Sam


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