A28: Do Plant Polyphenols Slow Climate Change?Total Phenolics Quantification using the Folin Assay

Wetlands are established as an extremely important part of the global carbon cycle. Despite covering only 2-3% of the land surface, wetlands store about ⅓ of global soil carbon, giving them a cooling effect on the climate. However, in recent years this effect has gradually decreased. Because of how much of the global soil carbon they contain, these changes in wetland environments could have a significant impact on the global climate, and are therefore important to incorporate into global climate models. To do this, the carbon cycling processes of wetland soils must be understood. This study aims to contribute to this understanding by testing the validity of the enzyme-latch theory. This theory proposes polyphenol buildup in anoxic wetland soils as the cause for their unusually high organic soil carbon content. To do this, we examined the relationship between total polyphenol content and both hydrolase activity and CO2 production in 27 soil samples from three different wetland soil environments: fen, bog, and palsa. Total phenolics quantification was performed using the Folin Assay, a colorimetric method utilizing a redox reaction between the Folin Reagent and polyphenols in soil extracts. The data for these soil samples was combined with CO2 production and hydrolase activity data collected by collaborators at Colorado State University. In doing this, we found that our data did not have the correlations predicted by the enzyme-latch theory. This emphasizes the need for this theory to be more closely examined to ensure our global climate models are as accurate as possible. This could be done with similar methods but different soil sampling strategies. My experience in this project has given me practice optimizing a biochemical assay; gathering, organizing, and interpreting data; and communicating this data with others. These are all skills that will be relevant to a future career as a laboratory technician.

Authors: Eleanor Knutson, Ann Hagerman

Advisor: Ann Hagerman, Chemistry and Biochemistry