When terrestrial and marine ecologists meet: Using complementary methods (X-ray tomography and luminophores) to study earthworms bioturbation in an organic matter compartmented soil
Résumé
Earthworm bioturbation (both biogenic structure constructing and particle reworking) was studied using X-ray tomography combined with luminophores (colored particulate tracer), a method widely used in sediment ecology. Within laboratory repacked soils (upper half filled with a top soil containing 4% organic matter and lower half-filled with a deep soil at 2% organic matter), anecic and endogeic earthworms had contrasting reactions with only endogeic species burrowing more intensively in the upper part. More precisely, endogeic species and especially Aporrectodea caliginosa bioturbated the most soil close to the surface (3 cm depth) while the two anecic species influenced the luminophore distribution differentially with Lumbricus terrestris displacing significantly more luminophores than Aporrectodea nocturna due to intense surface activity. Results showed that luminophore displacements also provided qualitative information to complement the tomography. Beyond methodological developments, our study found that endogeic earthworms burrow more in zones with higher organic matter contents and this explains why they are mainly found close to the soil surface in non-tilled soils.
Origine : Fichiers produits par l'(les) auteur(s)
Licence : Domaine public
Licence : Domaine public