Long-term effects of the elevated atmospheric CO 2 on biosphere have been in focus of research since the last few decades. In this experiment undisturbed soil monoliths of loess grassland were exposed to an elevated CO 2 environment (twotimes the ambient CO 2 level) for a period of six years with the aid of the open top chamber method. Control without a chamber and CO 2 elevation was applied as well. Elevated CO 2 level had very little impact on soil food web. It did not influence either root and microbial biomass or microbial and nematode community structure. The only significant response was that density of the bacterial feeder genus Heterocephalobus increased in the chamber with elevated CO 2 concentration. Application of the open top chambers initiated more changes on nematodes than the elevated CO 2 level. Open top chamber (OTC) method decreased nematode density (total and plant feeder as well) to less than half of the original level. Negative effect was found on the genus level in the case of fungal feeder Aphelenchoides, plant feeder Helicotylenchus and Paratylenchus. It is very likely that the significantly lower belowground root biomass and partly its decreased quality reflected by the increased C/N ratio are the main responsible factors for the lower density of the plant feeder nematodes in the plots of chambers. According to diversity profiles, MI and MI(2-5) parameters, nematode communities in the open top chambers (both on ambient and elevated CO 2 level) seem to be more structured than those under normal circumstances six years after start of the experiment.
ASJC Scopus subject areas
- Ecology, Evolution, Behavior and Systematics