N. Ramaiah, SUMMER ABUNDANCE AND ACTIVITIES OF BACTERIA IN THE FRESH-WATER LAKES OF SCHIRMACHER-OASIS, ANTARCTICA, Polar biology, 15(8), 1995, pp. 547-553
Bacterial biomass and heterotrophic potential (using C-14-labeled gluc
ose, glutamic acid and sodium acetate) of water, ice and sediment micr
obial populations were studied from different lakes of the Schirmacher
Oasis, Antarctica. Epifluorescence counts of total bacteria in these
lakes were observed to be lower by a factor when compared to some of t
he ultraoligotrophic Antarctic lakes. Biovolumes of bacteria from diff
erent samples did not show significant variations, suggesting that reg
ulatory factors were oligotrophy and low temperatures rather than micr
ozoan grazing. Microbial uptake rates of glutamic acid were generally
the fastest, followed by glucose and/or sodium acetate in the lakewate
r samples. The mean values of V-max cell(-1) for glutamic acid, sodium
acetate and glucose were 3.81, 0.91 and 0.71 pg C h(-1). Results of t
his study are potentially useful in recognizing the relative abundance
and activity of limnetic microbial populations in the Schirmacher Oas
is during summer - the active period of microbial growth - and for com
paring their activities with other ecosystems elsewhere in continental
Antarctica.