Influence of solar UV-B radiation on peatland microbial communities of southern Argentina

SEARLES PS; KROPP BR; FLINT SD; CALDWELL MM

NEW PHYTOLOGIST

WILEY-BLACKWELL PUBLISHING, INC

Año: 2001 vol. 152 p. 213 - 221

0028-646X

Stratospheric ozone depletion occurs over Tierra del Fuego, Argentina, in the austral spring and summer due to the Antarctic ´ozone hole´ and the general erosion of the ozone layer. Thus, we investigated the responses of microbial communities to manipulations of solar UV-B radiation. Results reported here are for field plots receiving either near-ambient or reduced solar UV-B using plastic filters in a Sphagnum peatland and a Carex fen during the second and third years of UV-B manipulations. The total number of testate amoebae (Protozoa, Rhizopoda) inhabiting the upper centimeter of Sphagnum magellanicum was greater under near-ambient solar UV-B than under reduced UV-B. No response to UV-B manipulation was apparent for rotifers, nematodes, bacteria, microfungi, and a common microalga (Euglena mutabilis) inhabiting the S. magellanicum. On leaves of small Nothofagus antarctica trees, the ratio of upper: lower leaf-surface fungal populations for the genus Aureobasidium and for total fungi indicated lower populations on the upper, relative to the lower, surface under near-ambient solar UV-B. When responses to modifications of the solar UV-B flux were detected, these involved both direct UV-B inhibition and indirect consequences of UV-B manipulation.