Earthworms, litter and soil carbon in a northern hardwood forest

    Authors

    T. J. Fahey; J. B. Yavitt; R. E. Sherman; J. C. Maerz; P. M. Groffman; M. C. Fisk;P. J. Bohlen

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    Abbreviated Journal Title

    Biogeochemistry

    Keywords

    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

    Abstract

    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.

    Journal Title

    Biogeochemistry

    Volume

    114

    Issue/Number

    1-3

    Publication Date

    1-1-2013

    Document Type

    Article

    Language

    English

    First Page

    269

    Last Page

    280

    WOS Identifier

    WOS:000320718200017

    ISSN

    0168-2563

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