Ambient ultraviolet radiation in the Arctic reduces root biomass and alters microbial community composition but has no effects on microbial biomass

TY - JOUR

T1 - Ambient ultraviolet radiation in the Arctic reduces root biomass and alters microbial community composition but has no effects on microbial biomass

AU - Rinnan, R.

AU - Keinänen, M. M.

AU - Kasurinen, A.

AU - Asikainen, J.

AU - Kekki, T. K.

AU - Holopainen, T.

AU - Ro-Poulsen, Helge

AU - Mikkelsen, T. N.

AU - Michelsen, Anders

N1 - KEYWORDS Greenland • heath ecosystem • lipid biomarkers • microbial biomass • mycorrhiza • ozone depletion • root biomass • UV exclusion • Vaccinium uliginosum

PY - 2005

Y1 - 2005

N2 - We assessed the effects of ambient solar ultraviolet (UV) radiation on below-ground parameters in an arctic heath in north-eastern Greenland. We hypothesized that the current UV fluxes would reduce root biomass and mycorrhizal colonization and that these changes would lead to lower soil microbial biomass and altered microbial community composition. These hypotheses were tested on cored soil samples from a UV reduction experiment with three filter treatments (Mylar, 60% UV-B reduction; Lexan, up to 90% UV-B reduction+UV-A reduction; UV transparent Teflon, filter control) and an open control treatment in two study sites after 3 years' manipulation. Reduction of both UV-A and UV-B radiation caused over 30% increase in the root biomass of Vaccinium uliginosum, which was the dominant plant species. UV reduction had contrasting effects on ericoid mycorrhizal colonization of V. uliginosum roots in the two sites, while it had no clear effects on fungal (ergosterol) or microbial biomass (measured both with fumigation-extraction and quantitative lipid biomarker analysis) in soil. However, principal component analysis of lipid biomarkers (phospholipid and glycolipid fatty acid profiles) showed that microbial community composition was altered by UV reduction. Although the UV responses were slight considering the large dose difference between the treatments (from near-ambient to up to 90% UV-B reduction), we cannot rule out the possibility that the recovery of ozone layer would change the below-ground functioning of arctic ecosystems.

AB - We assessed the effects of ambient solar ultraviolet (UV) radiation on below-ground parameters in an arctic heath in north-eastern Greenland. We hypothesized that the current UV fluxes would reduce root biomass and mycorrhizal colonization and that these changes would lead to lower soil microbial biomass and altered microbial community composition. These hypotheses were tested on cored soil samples from a UV reduction experiment with three filter treatments (Mylar, 60% UV-B reduction; Lexan, up to 90% UV-B reduction+UV-A reduction; UV transparent Teflon, filter control) and an open control treatment in two study sites after 3 years' manipulation. Reduction of both UV-A and UV-B radiation caused over 30% increase in the root biomass of Vaccinium uliginosum, which was the dominant plant species. UV reduction had contrasting effects on ericoid mycorrhizal colonization of V. uliginosum roots in the two sites, while it had no clear effects on fungal (ergosterol) or microbial biomass (measured both with fumigation-extraction and quantitative lipid biomarker analysis) in soil. However, principal component analysis of lipid biomarkers (phospholipid and glycolipid fatty acid profiles) showed that microbial community composition was altered by UV reduction. Although the UV responses were slight considering the large dose difference between the treatments (from near-ambient to up to 90% UV-B reduction), we cannot rule out the possibility that the recovery of ozone layer would change the below-ground functioning of arctic ecosystems.

U2 - 10.1111/j.1365-2486.2005.00933.x

DO - 10.1111/j.1365-2486.2005.00933.x

M3 - Journal article

SN - 1354-1013

VL - 11

SP - 564

EP - 574

JO - Global Change Biology

JF - Global Change Biology

IS - 4

ER -