A study on the effects of extreme rain events on fungal activity

Abstract

Saprotrophic fungi play a key role in the carbon cycle by breaking down organic carbon in the form of leaf litter or downed wood into inorganic forms with which they perform humification, mineralization, or export as dissolved organic carbon (Boddy, 2008). Human activity has altered Earth’s natural carbon cycle, and one outcome of this in an increase in severity and frequency of extreme precipitation events (O’Neill, 2018). Our study investigates how sensitive fungal communities in varying ecosystems are to an extreme precipitation event in terms of enzymatic activity. We induced an extreme precipitation event on three different landscape ecosystems on the University of Michigan Biological Station property an outwash plain dune, wetland, and moraine. At each site, we analyzed both the conditions of their present fungal community and the community’s enzymatic response to an imposed rain event over time. We found that when comparing the concentrations of phenol oxidase, an enzyme fungus uses to break down phenols, to soil moisture content, the two were inversely correlated in the dune and moraine sites, but positively correlated in the wetland site. From this we derived that in the dune and moraine sites, water is neither limiting nor excessive, therefore additional water will decrease fungal activity by disinsentivising cooperative linking or fungal communities brought about by a common need for a limited resource. However, in the wetland site where water already exists in excess, the addition of water will have no effect on fungal communities.