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

Abstract

Vertical distribution of bacteria in Lake Vanda, an Antarctic meromictic lake, was examined by the acridine orange epifluorescence direct count method. Total bacteria were 10"-lo5 cells. ml-I in the water at 55 m depth and above, and increased drastically to lo7 ~e l l s -m l -~ in the bottom water. Filamentous or long rodshaped bacteria occurred at a high frequency in the upper layers, but in the bottom layers most bacteria were coccoidal or short rods. Mean bacterial cell volume in water of between 10 m and 60 m deep was fairly large compared with common bacterial populations in seawater and lake water. Aerobic heterotrophic bacteria were recovered from the water of a depth of 30 m and above, and were assumed to belong to Caulobacter. Viable heterotrophic bacteria were not recovered from the high salinity deep water by media prepared with the same deep water. Phototrophic purple non-sulphur bacteria were isolated by enrichment cultures from water at 55 m depth.

Biogeochemical study of organic substances in Antarctic lakes

“…The proportion of branched (iso and antefio) fatty acids in the top and bottom waters of the lake was somewhat greater than that in the middle waters. This is consistent with the pattern of vertical distribution of bacteria (Takii et al, 1986;Konda et al, 1987). Vertical profiles of the total fatty acid contents in Lake Fryxell must reflect phytoplankton abundance with the maximum value occurring at a depth of around 10 m, just above the anoxic layer.…”

Vertical stratification and stability of biogeochemical processes in the deep saline waters of Lake Vanda, Antarctica

“…Reduced metals diffusing upward from 70 m are reoxidized and sink again, while those diffusing downward precipitate with sulfide and are buried in the sediment. Indeed, much of the upward diffusing sulfide flux was apparently consumed in the anoxic bottom waters of Lake Vanda (Table ), probably by metal precipitation, with possible additional contributions by phototrophic sulfur bacteria (Kriss et al ; Takii et al ), though only 0.2% (2.4 μ mol photons m −2 s −1 ) of incident PAR penetrated to 70 m depth (Fig. ).…”

Cold-Active, Heterotrophic Bacteria from the Highly Oligotrophic Waters of Lake Vanda, Antarctica

“…Although several studies have focused on the enrichment and isolation of bacteria from lakes in the Dry Valleys [ 16 , 17 , 18 , 19 , 20 , 21 , 22 ], few descriptions of bacterial isolates from Lake Vanda exist. Decades-old studies on the microbial communities of Lake Vanda reported the successful culture of some bacteria and even yeasts from Lake Vanda [ 23 , 24 , 25 , 26 ]; however, phylogenetic analyses were not included in these descriptions. More recently, Bratina et al [ 27 ] described cultures of manganese-reducing bacteria, mostly of the genus Carnobacterium , from oxic portions of the Lake Vanda water column, and Tregoning et al [ 28 ] described CaCl 2 -tolerant, halophilic bacteria isolated from the comparatively warm Lake Vanda brines of 60–72 m. In the latter study, the 15 mesophilic strains obtained comprised a single species most closely related to the aerobic marine γ-proteobacterium Halomonas zincidurans .…”