SGER: Amount, Rate and C-isotope value of Soil Organic Matter Production by Armadillidium vulgare

Johns Hopkins University, Baltimore MD

Investigators

Abstract

Feeding activities of soil macrofauna exert critical influence upon the chemical and physical transformation of soil organic matter. In mesic and xeric habitats where earthworms are absent (e.g., parts of the Southwestern U.S.), soil isopods can be the primary detritivores. It is therefore likely that soil isopods play a pivotal role in organic matter processing, carbon and nitrogen cycling, and soil development in these regions. This research represents preliminary work on the influence of terrestrial isopods on the organic horizons of the soil profile through feeding and excretion. The research will utilize natural abundance 13C/12C ratios to investigate the source and fate of organic matter utilized by soil isopods. In feeding experiments to Armadillidium vulgare, a model organism for terrestrial isopod research due to its ubiquity, the investigators will determine feeding amount and rate across a gradient of soil organic substrates: green leaves, litter layer, and soil humus. They will also assess changes in C:N, %C and *13C composition of organic matter during feces production. The research has widespread implications to ecosystem processes in mesic and xeric habitats, due to the global distribution of Armadillidium vulgare.