Effect of Collembola on mineralization of litter and soil organic matter

Abstract

Although soil Collembola are known to contribute to soil carbon (C) cycling, their contribution to the mineralization of C sources that differ in bioavailability, such as soil organic C (SOC) and leaf litter, is unknown. Stable C isotopes are often used to quantify the effects of both soil C and litter C on C mineralization. Here, 13C-labeled litter was used to investigate the effects of Collembola (Folsomia candida) on the mineralization of both SOC and litter C in laboratory microcosms. The three microcosm treatments were soil alone (S); soil treated with δ13C-labeled litter (SL); and soil treated with δ13C-labeled litter and Collembola (SLC). The presence of Collembola did not significantly affect soil microbial biomass or litter mass loss and only had a small effect on CO2 release during the first week of the experiment, when most of the CO2 was derived from litter rather than from SOC. Later, during the experiment (days 21 and 63), when litter-derived labile C had been depleted and when numbers of Collembola had greatly increased, Collembola substantially increased the emission of SOC-derived CO2. These results suggest that the effect of Collembola on soil organic C mineralization is negatively related to C availability.