Date of Graduation

12-2017

Document Type

Dissertation

Degree Name

Doctor of Philosophy in Environmental Dynamics (PhD)

Degree Level

Graduate

Department

Graduate School

Advisor

Steven Stephenson

Committee Member

Mark Arnold

Second Committee Member

Steve Boss

Third Committee Member

Malcolm Cleaveland

Fourth Committee Member

Giovanni Petris

Fifth Committee Member

Jason Tullis

Keywords

Biological, Carbon Cycle, Carbon Seqestration, Terrestrial, Arkansas

Abstract

The direct correlation between increasing levels of atmospheric CO2 and global temperatures is now irrefutable. A 50% increase in atmospheric CO2 levels from a pre-industrial level of 270 ppm to a present-day level of 405 ppm, has resulted in documented record temperatures and a concomitant rising of sea levels from melting ice caps.

The ability of biological/terrestrial ecological systems to store atmospheric carbon is a viable option in the effort to mitigate the climate impacts of rising anthropogenically-caused greenhouse gas emissions. Components of the vegetation and soils in the Pea Ridge National Military Park (the Park) were examined for carbon content to assess the carbon storage potential of preserved lands. I collected samples from four distinct study sites in the Park to make quantitative comparisons. These were a gymnosperm (red cedar, Juniperus virginiana) forest, an angiosperm (hardwood) forest, a managed grassland and a semi-native grassland. Mineral and organic soil layers were collected in all four sites along with above-ground biomass samples of coarse woody debris, tree cores, and herbaceous plants in the forests and grasses and associated broadleaf plants in the grassland sites. Samples were dried to constant weight, and 20- and 40-mg samples were analyzed using an Elementar vario El cube for analysis of total C by high temperature combustion.

Soil samples averaged less than 12% carbon, but aboveground biomass ranged from 29% to 46% carbon. The managed grassland had the lowest carbon percentage of all four sites for soil and the lowest carbon percentage for grasses when compared to the semi-native grassland study site. It was only in the tree biomass that the red cedar site had a higher carbon percentage than the angiosperm tree biomass (43.49% for the angiosperm study site and 44.48% for the gymnosperm study site). Therefore, the succession of the species, red cedar, while having negative ecosystem impacts, may benefit carbon sequestration.

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