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Organic matter flow in the food web at a temperate heath under multifactorial climate change
Author(s) -
Andresen Louise C.,
Konestabo Heidi S.,
Maraldo Kristine,
Holmstrup Martin,
Ambus Per,
Beier Claus,
Michelsen Anders
Publication year - 2011
Publication title -
rapid communications in mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.528
H-Index - 136
eISSN - 1097-0231
pISSN - 0951-4198
DOI - 10.1002/rcm.4907
Subject(s) - detritivore , chemistry , biomass (ecology) , abiotic component , food web , ecosystem , decomposer , temperate climate , organic matter , nutrient cycle , ecology , environmental chemistry , agronomy , biology , organic chemistry
The rising atmospheric CO 2 concentration, increasing temperature and changed patterns of precipitation currently expose terrestrial ecosystems to altered environmental conditions. This may affect belowground nutrient cycling through its intimate relationship with the belowground decomposers. Three climate change factors (elevated CO 2 , increased temperature and drought) were investigated in a full factorial field experiment at a temperate heathland location. The combined effect of biotic and abiotic factors on nitrogen and carbon flows was traced in plant root → litter → microbe → detritivore/omnivore → predator food‐web for one year after amendment with 15 N 13 C 2 ‐glycine. Isotope ratio mass spectrometry (IRMS) measurement of 15 N/ 14 N and 13 C/ 12 C in soil extracts and functional ecosystem compartments revealed that the recovery of 15 N sometimes decreased through the chain of consumption, with the largest amount of bioactive 15 N label pool accumulated in the microbial biomass. The elevated CO 2 concentration at the site for 2 years increased the biomass, the 15 N enrichment and the 15 N recovery in detritivores. This suggests that detritivore consumption was controlled by both the availability of the microbial biomass, a likely major food source, and the climatic factors. Furthermore, the natural abundance δ 13 C of enchytraeids was significantly altered in CO 2 ‐fumigated plots, showing that even small changes in δ 13 C‐CO 2 can be used to detect transfer of carbon from primary producers to detritivores. We conclude that, in the short term, the climate change treatments affected soil organism activity, possibly with labile carbohydrate production controlling the microbial and detritivore biomass, with potential consequences for the decomposition of detritus and nutrient cycling. Hence, there appears to be a strong coupling of responses in carbon and nitrogen cycling at this temperate heath. Copyright © 2011 John Wiley & Sons, Ltd.