Kaylee Brennan

Project title: Investigations of root biomass as an indicator of the contribution of respiration to the CO2 flux in vernal pools

Mentors: Bianca Ross and Dr. Mark Stolt

Abstract: There is some debate in the scientific community as to whether vernal pools are a source or sink for the greenhouse gas carbon dioxide. Soil respiration, which consists of both autotrophic and heterotrophic respiration, was analyzed to determine their contribution to CO2 flux in four vernal pools in Rhode Island. Gas was sampled, roots collected, and soil temperature monitored from the upper 10 cm of the soil at basin, transition, and upland zones in the vernal pools. There was a strong linear correlation between soil temperature and CO2 flux during the summer and fall suggesting these are the optimal temperatures for respiration. There was no direct correlation between root biomass and CO2 flux. This may have been due to abnormally low precipitation rates or too small of a sample size (just the upper 10 cm). Future studies should explore a larger sample area and roots deeper in the profile which may provide a clearer understanding of the contributions of roots to soil respiration.