Author

Kiele Goins

Date of Award

Summer 2021

Document Type

Open Access Thesis

Department

Geography

First Advisor

Lori Ziolkowski

Abstract

Soil is an important but often poorly understood portion of the carbon cycle. Soil can store more carbon than twice today’s atmosphere, but the factors that control carbon storage are often unclear. Carbon enters the soil through input of organic matter, erosion, and aerosol deposition and is lost mostly via microbial decomposition. Carbon loss in soil is impacted by the chemical composition of organic compounds, environmental factors, and human activities. Furthermore, as climate changes soil, carbon storage may be vulnerable. Although carbon can be stored throughout soil, carbon storage varies with depth. In topsoil, carbon is stored for short periods of time through aggregation of organic compounds with soil minerals, roots, and fungus. Subsoil can store carbon for long periods because of mineral bonding; the process of organic compounds attaching to the surface of minerals and becoming inaccessible to microbes. Organic compounds bind to mineral surfaces in a layered, or zonal, manner based on the polarity and binding strength of the compounds. In addition to the zonal model, mineral bound organic compounds are impacted by mineral structure and cation exchange, which can alter the attachment of organic compounds. The interaction of organic compounds with soil minerals changes with moisture and chemical inputs from plant roots. Recently, the increasing threat of climate change has encouraged attempts to prevent soil carbon loss and increase storage. In order to increase carbon storage and prevent loss, soil mineralogy, soil moisture, and plant roots are important to understand as processes working together to control carbon storage. As such, better systems of soil sampling and routine soil carbon monitoring that take into account soil mineralogy, plant root depth, and soil moisture must be developed to determine how soil carbon loss can be prevented and carbon amounts increased.

Included in

Geology Commons

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