Abstract. Decomposition provides a critical mechanism for returning nutrients to the
surrounding environment. In terrestrial systems, animal carcass, or carrion,
decomposition results in a cascade of biogeochemical changes. Soil microbial
communities are stimulated, resulting in transformations of carbon (C) and
nitrogen (N) sourced from the decaying carrion soft tissues, changes to soil
pH, electrical conductivity, and oxygen availability as microbial
communities release CO2 and mineralize organic N. While many of the
rapid changes to soil biogeochemistry observed during carrion decomposition
return to background or starting conditions shortly after soft tissues are
degraded, some biogeochemical parameters, particularly bulk soil stable
δ15N isotopic composition, have the potential to exhibit
prolonged perturbations, extending for several years. The goal of this study
was to evaluate the lateral and vertical changes to soil stable isotopic
composition 1 year after carrion decomposition in a forest ecosystem.
Lateral transects extending 140 cm from three decomposition “hotspots”
were sampled at 20 cm intervals, and subsurface cores were collected beneath
each hotspot to a depth of 50 cm. Bulk soil stable isotopic composition
(δ15N and δ13C) indicated that 1 year after
complete soft tissue removal and decay, soils were significantly
15N enriched by 7.5±1.0 ‰ compared to
control soils up to 60 cm from the hotspot center, and enrichment extended
to a depth of 10 cm. Hotspot soils also contained 10 % more N compared to
control soils, indicating that decomposition perturbs N pools. Our results
demonstrate that carrion decomposition has the potential to result in
long-term changes to soil biogeochemistry, up to at least 1 year after
soft tissue degradation, and to contribute to bulk soil stable isotopic
composition.
Spatial changes in soil stable isotopic composition in response to carrion decomposition
