Measuring the Periodicity of Droughts Using Soluble Sugar Stable Carbon Isotopes Extracted from Sphagnum Soluble Sugars
Date of Award
Bachelor of Science
Steven K. Rice
As the climate changes due to human activity, precipitation patterns are changing and leading to increasing severity of droughts in some areas. To understand if intraseasonal weather patterns are being altered, the periodicity of droughts needs to be measured. This study explores the use of stable carbon isotopes (13C) in soluble sugars from Sphagnum moss to record bioavailable water over a timescale of days to weeks. Two species, S. magellanicum and S. fallax, were exposed to wet and dry conditions over three months, harvested periodically and the stable isotope composition (d13C) of bulk tissue and soluble sugars was measured. Plants grown under the wet treatment were significantly isotopically heavier (p13C of all the plants over time (p13C. In the wet treatment, neither species showed stable d13C values after three months indicating a longer time before equilibrium is established. The d13C in the soluble sugars also changed significantly through time (p=0.02) and was significantly isotopically heavier than the bulk tissue (p13C in sugars did not differ significantly between the two water treatments. There was much variation in the data and the d13C value of the sugars did not change more rapidly in response to hydrologic conditions as expected. Based on the findings of this study, soluble sugars are likely not an efficient and accurate measurement of intraseasonal hydrologic patterns.
Charest, Julia, "Measuring the Periodicity of Droughts Using Soluble Sugar Stable Carbon Isotopes Extracted from Sphagnum Soluble Sugars" (2022). Honors Theses. 2667.
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