Nutrient availability and stoichiometry mediate microbial effects on soil carbon sequestration in tropical forests

A one-year <em>in situ</em> soil incubation experiment using mesh bags (mesh size of 38 µm, allowing colonization of bacteria and penetration of fungal hyphal but precluding root penetration) with fertile sugarcane soil and infertile sand along an elevational gradient characterized by varied climatic and biotic conditions in a tropical forest. Biomarkers, including phospholipid fatty acids, carbon-nitrogen-phosphorus acquiring hydrolases, glomalin-related proteins and amino sugars were measured to characterize the production and accumulation of microbial living biomass, exo-enzymes, extracellular glycoprotein and microbial necromass, and to elucidate their contributions to SOC sequestration.