Microbial community at the front of Ecology Glacier (King George Island, Antarctica): initial observations.
2009; De Gruyter Open; Volume: 30; Issue: 1 Linguagem: Inglês
ISSN
2081-8262
AutoresJakub Grzesiak, Magdalena J. Żmuda-Baranowska, Piotr Borsuk, Marek K. Zdanowski,
Tópico(s)Biocrusts and Microbial Ecology
ResumoSince 1978 the retreat of Ecology Glacier in the vicinity of Henryk Arctowski Sta− tion has opened new ice−free areas for colonization by terrestrial organisms initiated by pio− neer microbes. Samples were collected from the soil surface, at 0, 5 and 20 cm below surface close to glacier front, then stored at below −20C. Total bacterial count (TC), estimated by epifluorescence microscopy, reached high values, of 10 10 g −1 dry wt. Healthy looking bacte− rial cells of mean volume 0.0209 μm 3 at 0 cm to 0.0292 μm 3 at 20 cm made up from 7% at 0 cm, to 30% at 20 cm of total bacterial population. The number of colony forming units (CFU) accounted for only 0.02% of TC. Taxonomically they belonged to the,, subdivi− sions of the proteobacteria and to the Cytophaga−Flavobacterium−Bacteroides (CFB) group. Morphophysiologically CFU bacteria were diverse, from Gram variable short coccal forms to very long rods or filaments. Randomly selected CFU colonies were characterized by low sugar assimilation and high esterase/lipase activity. Spore forming bacteria - absent from 0 and 5 cm, formed a small fraction of 175 cells g −1 dry wt at the 20 cm depth. Filamentous fungi were relatively abundant and represented mainly by oligotrophs. Key wor ds: Antarctica, glacial retreat, ice−free areas, microbial communities.
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