Earthworm effects on the use of C sources by microorganisms: Non-linear response to temperature alteration |
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| Authors: | Volkmar Wolters Klemens Ekschmitt |
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| Institution: | (1) Institut für allgemeine und spezielle Zoologie der Justus-Liebig Universität, Stephanstrasse 24, D-35390 Giessen, Germany |
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| Abstract: | A microcosm was used to study the effect of the endogeic earthworm Aporrectodea caliginosa (Savigny) on the use of C by microorganisms in a calcareous beech forest soil and its dependence on temperature (5–25%C). Inclusion of 14C-labelled beech leaf litter made it possible to differentiate between C use by litter-colonizing microflora and by autochthonous soil microflora. The effect of temperature on the soil microbial biomass 12C was confined to a significant increase at 15 and 20°C. The size of the 14C-labelled microbial biomass, in contrast, was positively correlated with temperature. The 12C mineralization increased exponentially with temperature. The relationship between 14C mineralization and temperature, in contrast, followed a logistic curve. Significant main effects of A. caliginosa were confined to 12C mineralization, reflecting an increase in 12CO2–C production in the earthworm treatments. The earthworm effects on 12CO2–C production and on 14C incorporation of the microflora were not linear. The effect of A. caliginosa on 12CO2–C production was most pronouned at intermediate temperatures. It is concluded that temperature alterations affect the microbial use of different C sources in different ways and that the temperature effects can be significantly modified by endogeic earthworms. |
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| Keywords: | Aporrectodea caliginosa Soil microflora C mineralization Beech litter Temperature Climate change |
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