Soil water oxygen and hydrogen isotopes, Toolik Lake, Alaska, 2016

In this study we examine the ecophysiological consequences of different snow depth regimes in moist acidic tundra in the Alaskan Arctic, with a particular focus on the role of snowmelt water in plant ecophysiological processes. We paired regular measurements of leaf-level performance and tissue chemistry with an isotopic characterization of active layer water and xylem water to address the question: does snowmelt water play a critical role in driving tundra plant ecophysiology? We sampled soil water from the active layer throughout the growing season using Rhizon Soil Moisture Samplers (Eijkelkamp Agrisearch Equipment, Giesbeek, Netherlands). Samples were pulled from the full depth of the active layer in increments of 10cm, including the uppermost 10cm of the soil profile in tussocks , and analyzed for d18O and d2H with a Picarro L2130-i cavity ring down-spectrometer at the University of Alaska-Anchorage.