Enzyme Activities Down the Soil Profile: A Meta-Analysis
Résumé
Soil enzymes are major contributors the decomposition of soil organic matter. They are believed to reflect microbial nutrient and energy acquisition strategies and limitations. Whilst enzyme activities in surface soil layers have been widely studied, activities down the soil profile have received far less attention. Here, we present the results of a meta-analysis of hydrolase and oxidoreductase activities involved in the C, N and P cycles as a function of soil depth. The aim of the analysis was to understand how the relationship between microbial communities and their nutritional environment changes with depth. We assembled a database of 210 soil profiles published in 40 studies from diverse locations, soil types, land uses and climates. In order to compare activity profiles, we used Gaussian process regression, followed by hierarchical clustering. Our results show that, when expressed per soil mass, the majority of hydrolase activities decrease with increasing soil depth. However, this is not the case for a majority of oxidoreductase activities, possibly indicative of changes in microbial community resource acquisition strategies with depth. Microbial biomass specific enzyme activities tended to increase with soil depth, suggesting an increase in microbial allocation to resource acquisition in response to decreased resource (C, N and P) availability and/or an increased enzyme stabilization on mineral and organic surfaces.
Auteurs, date et publication :
Auteurs Fatima El Mekdad , Naoise Nunan , Samuel Abiven , Xavier Raynaud
Date : 2022