Antarctica: The Microbiology of an Unfrozen Saline Pond

Abstract

A saline pond in a region in Antarctia where other lakes and ponds are frozen remains unfrozen at the prevailing low temperatures. The ecology of the pond is unique. A distinctive aerobic microbial population, though restricted to this natural habitat, adapts to growth in artificial culture. The growth habit of these organisms, as seen in nature and in laboratory culture, indicates a possible relationship between growth at high salt concentration, at low temperatures, and in media of low organic content.

Vertical distribution in and isolation of bacteria from Lake Vanda: an Antarctic lake

“…The failure to detect bacterial colonies in deeper water may be a result of the death of bacteria during storage or from use of unsuitable media containing high salt concentrations. Studies of Lake Vanda and other Antarctic saline lakes and ponds reported the absence of recovery of bacteria on agar media prepared with in situ lake water of high salinity or seawater (Meyer et al, 1962;Benoit et a/., 1971;Cameron et al, 1972;Kriss et al, 1976;Waguri, 1976;Hand, 1980). Bacteria from Deep Lake could also not be cultured on media in which salinity was more than half that of the lake itself (Hand, 1980).…”

“…but information on its bacterial population, especially bacterial biomass, is as limited as in other Antarctic lakes and ponds (Wright & Burton, 1981). Meyer et al (1962), Benoit et al (1971) and Kriss et al (1976) enumerated bacteria and tried to isolate some bacteria, and Vincent et al (1981) estimated microbial activity in Lake Vanda.…”

Halophilic Prokaryotes

“…This is well below the lowest limit known to support any kind of microbial life. Viable organisms have been isolated from the Don Juan Pond, but their presence was evidently adventitious since they could not grow in saturated calcium chloride media (MEYER et al 1962;HOROWITZ et al 1972). HOROWITZ et al (1972) describe the Don Juan Pond as "abiotic", implying that it may contain adventitious viable organisms but will not support the growth of any of them.…”

8. Occurrence of benthic microbial mats in saline lakes

“…hot springs (Bauld & Brock 1973), Solar Lake (Jorgensen et al 1979), Lake Bonney . Don Juan Pond (Table 8.2) is a hypersaline body of water approximately 700 m X 200 m in extent with an average depth of about 11 cm, varying between 10 and 20 cm (Meyer, Morrow, Wyss, Berg & Littlepage 1962). The saturated calcium chloride brine remains unfrozen for most of the year in a region where the mean annual air temperature is ca.…”