Date of Award

2014

Document Type

Thesis

Degree Name

Bachelors

Department

Natural Sciences

First Advisor

McDonald, Patrick

Keywords

Microbes, Soil Organic Matter, Mathematical Models

Area of Concentration

Applied Mathematics

Abstract

Soil organic matter (SOM) decomposition releases the nutrients and minerals stored long-term in soil, so they can be consumed by a variety of soil biota via direct assimilation or trophic interactions. It is involved in both carbon and nitrogen cycling and also has relevance to climate change research due to its effect on net CO2 respired and N2O emitted via denitrication. K strategist microbes only con- sume SOM-derived substrate and are primarily responsible for SOM decomposition, so their population dynamics influence and are affected by SOM decomposition rates. On the other hand, r strategist microbes take advantage of soluble substrate that already exists in the system and cannot decompose insoluble materials. A mathematical model is developed to study the relationship between SOM decomposition and the community dynamics of microbes. The model is tested for different factors that change carbon and nitrogen availability in a soil ecosystem, including addition of root exudates, plant litter, and ammonia. In particular, root exudates, represented by the parameter (phi)r, are shown to increase steady states for r and K strategist biomass.

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