Stansell, Nathan D.
M.S. (Master of Science)
Department of Geology and Environmental Geosciences
This study examines records of past climate variability and the controls affecting carbon accumulation rates at Teringi Bog, Estonia (57°58'31.26", 25°33'34.80"E). Analyses of [delta]¹³C, [delta] ²H, [delta]¹⁸O, and d-excess from Sphagnum fuscum moss cellulose, [delta]¹³C and [delta]¹⁵N from bulk peat, and [delta]18O and [delta]²H from surface waters indicate that carbon accumulation rates are influenced by changes the overall amount of precipitation and its seasonality throughout the Late Holocene. Changes in the depth to the water table were recorded from August, 2014, to May, 2016, and it was observed that the hydrologic balance is principally driven by fall, winter and spring precipitation. The summer hydrologic budget is affected by regional draining. Bulk peat isotopes indicate that high carbon accumulation rates correspond to high [delta]¹³C and [delta]¹⁵N values signifying periods of overall increased wetness. Low [delta]¹⁸Ocellulose values indicate periods of increased relative winter/summer precipitation and also correspond to periods of high carbon accumulation rates. D-excess has been utilized in few peat-based paleoclimate studies, but shows potential to be an indicator of precipitation source. Periods of high d-excess and low [delta]¹⁸O values (from 4200 to 3800 cal yr BP and from 2500 to 2200 cal yr BP) indicate times of greater relative winter to summer precipitation, but conditions at the source can also be inferred. The interval beginning at 4200 cal yr BP show low [delta]²H values, and the interval beginning at 2500 cal yr BP shows high [delta]²H values indicating that the source vapor originated under cooler and more arid conditions. Comparisons of this study with NAO reconstructions show a relationship between periods of increased [delta]¹³C and positive phases of the NAO, but studies from nearby lakes show that the NAO has had variable effects on the region during the Late Holocene. The results of this study show that periods of increased wetness and increased winter precipitation are related to increased carbon accumulation rates, and that those periods correspond to positive phases of the NAO.
Hill, Kristyn, "Late Holocene climate controls on carbon dynamics at Teringi Bog, Estonia" (2016). Graduate Research Theses & Dissertations. 3762.
v, 49 pages
Northern Illinois University
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