Oasis Garcia, & Dr. Caryl Ann Becerra
Decomposition in soil is a major component of the carbon cycle. The breakdown of organic matter releases carbon emissions, which are ultimately released into the atmosphere. Extracellular enzymes are considered to be largely responsible for the decomposition of organic matter; however, little research has been conducted on the functional lifespan of these enzymes. In this study, we measured the persistence of enzyme function in soil with varied water holding capacities (15%; 35%; 55%). Soil was collected from a chaparral terrestrial ecosystem. Soils were kept under constant chloroform fumigation to prevent additional production of enzymes from microorganisms. Six hydrolytic enzymes were selected (α 1,4-Glucosidase, β-1,4-Glucosidase, β-D-1,4-Cellobiosidase, β-1,4-Xylosidase, β-1,4-N-acetyl-glucosaminidase, and Acid Phosphatase) and measured for potential function activities biweekly over a course of 12 weeks. Decay rate constants were calculated and fitted to first-order and zero-order models. Generally, the greater the water holding capacity, the longer persistence of activity was observed. Alpha-glucosidase had less persistence than the other enzymes with beta-glucosidase activities persisting the longest. This information can be utilized to better understand the constraints on enzyme stability in soil