Original paper

Indirect effects of elevated atmospheric CO2 and solar radiation on the growth of culturable bacteria

Langó, Z.; Leech, D.M.; Wetzel, R.G.

Abstract

Previous studies indicate that leachates derived from plants grown under elevated CO2 are more recalcitrant and consequently reduce bacterial productivity. Here bacteria were cultured on organic leachates derived from trembling aspen (Populus tremuloides) and white willow (Salix alba) grown under ambient (360 ppm) and elevated (720 ppm) CO2 concentrations and exposed and unexposed to simulated solar radiation. In treatments not exposed to light, determined numbers of colony forming units (CFU mL−1) were higher on ambient CO2 than elevated CO2 leachates in both plant species. After exposure to simulated sunlight, the number of CFU mL−1decreased on the ambient CO2 leachates and increased on the elevated leachates, particularly the aspen. These results demonstrate that environmental parameters, mediated by climate change, may have both positive and negative effects on the growth of bacteria.

Keywords

dissolved organic matterbacterial utilizationelevated atmospheric co2ultraviolet radiationpar