Earthworms, litter and soil carbon in a northern hardwood forest
Abbreviated Journal Title
Aggregation; Decomposition; Fungal hyphae; Isotope labeling; Microbial; biomass; Sugar maple; CENTRAL NEW-YORK; DISSOLVED ORGANIC-MATTER; MICROBIAL BIOMASS; TEMPERATE; FORESTS; INVASION; SEQUESTRATION; STABILIZATION; PATTERNS; IMPACTS; USA; Environmental Sciences; Geosciences, Multidisciplinary
The important role of soil carbon (C) in the global C cycle has stimulated interest in better understanding the mechanisms regulating soil C storage and its stabilization. Exotic earthworm invasion of northern forest soils in North America can affect soil C pools, and we examined their effects on these mechanisms by adding C-13 labeled leaf litter to adjacent northern hardwood forests with and without earthworms. Two types of labeled litter were produced, one with the C-13 more concentrated in structural (S) components and the other in non-structural (NS) components, to evaluate the role of biochemical differences in soil C stabilization. Earthworm invasions have reduced soil C storage in the upper 20 cm of the soil profile by 37 %, mostly by eliminating surface organic horizons. Despite rapid mixing of litter into mineral soil and its incorporation into aggregates, mineral soil C has not increased in the presence of earthworms. Incorporation of litter C into soil and microbial biomass was not affected by biochemical differences between S versus NS labeled litter although NS litter C was assimilated more readily into earthworm biomass and S litter C into fungal hyphae. Apparently, the net effect of earthworm mixing of litter and forest floor C into mineral soil, plus stabilization of that C in aggregates, is counterbalanced by earthworm bioturbation and possible priming effects. Our results support recent arguments that biochemical recalcitrance is not a major contributor to the stabilization of soil C.
"Earthworms, litter and soil carbon in a northern hardwood forest" (2013). Faculty Bibliography 2010s. 3956.