Vertical distribution of organic constituents in an Antarctic lake: Lake Vanda

Abstract

Vertical distribution of organic constituents, i .e . total organic carbon (TOC), extractable organic carbon with ethyl acetate (EOC), hydrocarbons, phytol, sterols, fatty acids and phenolic acids in Lake Vanda was studied to elucidate their features in relation to the stratification of lake water and the distribution of lake organisms . The concentrations of TOC, EOC and sterols increased with depth and attained the maximum values of 25 and 1 .5 mgC 1 -1 and 1 .4 µg 1-1 in the bottom, respectively, while those of fatty acids showed the maximum value of 61 µg 1-1 at a depth of 55 .4 m, along with the highest value of the ratio of unsaturated (uC16, uC 18 ) to saturated (C 16 , C 18 ) acids (8 .5) and with the highest carbon preference index (35) . Hydrocarbons were only found in the bottom layers (60 .4 and 65 .9 m) and bottom sediment . These results suggest strongly that the vertical distribution of lake organisms and their activity are quite different due to depth . In the bottom warm anoxic layers the degradation of organic materials must have occurred significantly and thus refractory organic materials should be concentrated .

A Halophilic Bacterium Inhabiting the Warm, CaCl 2 -Rich Brine of the Perennially Ice-Covered Lake Vanda, McMurdo Dry Valleys, Antarctica

“…The major carbon and energy sources for the VAN strains were sugars and organic acids. Although the cold Lake Vanda freshwaters contain very low levels of dissolved organic carbon (DOC), DOC levels in the Lake Vanda brine are significantly higher (40). Thus, the organic matter needed to support the growth of the VAN strains should be available in their habitat.…”

Sterols and fatty acids in foams from Antarctic lakes of the Dry Valleys in south Victoria Land.

“…Cholestanol was found only in the L-19 pond sample. These sterols have also been found in lakewaters and sediments from Antarctica, including the Dry Valleys' samples (Matsumoto et al, 1982(Matsumoto et al, , 1983(Matsumoto et al, , 1984a(Matsumoto et al, , 1984b. The most dominant sterol of the Bull Lake samples is 24-e thylch ole sterol.…”

“…The amounts of sterols ranging from 0.57 to 31µg/sample are much smaller than those of fatty acids (54-4600µg/ sample (Table 1). They are, however, con siderably greater than those of lake and river waters from the Dry Valleys (0.1-1.4µg/Q and 2.5-61µg/Q, respectively; Matsumoto and Hanya , 1977;Matsumoto et al, 1979Matsumoto et al, , 1984aMatsumoto et al, , 1984b. Thus our results revealed that sterols and fatty acids are concentrated more than 190 and 730 times in foams as compared with lake and river waters, respectively.…”

“…The analytical methods were described in detail elsewhere (Matsumoto and Hanya, 1977;Matsumoto et al, 1979Matsumoto et al, , 1982Matsumoto et al, , 1984a. Briefly, the ethyl acetate extracts were chromatographed on a silica gel column (180 X 5 mm i.d., 100 mesh, 5% water).…”

Stenols and phytol in lake sediments from Syowa and Vestfold Oases in the Antarctic.

“…Little is known about the kinds and amounts of stenols in Antarctic lake sediments, although some organic compounds have been reported for lakes in the McMurdo Sound region and Syowa Oasis (MATSUMOTO and HANYA, 1977;MATSUMO To et al, 1978, 1981. We have reported the occurrence of six stenols, cholesta-5,22-dien 3j3-ol (2 2-dehydro cholesterol), cholesterol, 24 methylcholesta-5,22-dien-3j3-ol, 24-methylcho lest-5-en-3j3-ol (24-methyl cholesterol), 24-ethyl cholesta-5,22-dien-3j3-ol and 24-ethylcholesterol, the last one predominating, in lake waters and sediments from the Dry Valley areas of south Victoria Land, in addition to three stanols, 5a cholestan-3j3-ol, 24-methyl-5a-cholestan-3j3-ol and 24-ethyl-5a-cholestan-3j3-ol (MATSUMOTO et al, 1982(MATSUMOTO et al, , 1983. We also have reported the presence of phytol in waters and sediments from Lake Vanda in the Dry Valley areas (MATSUMO To et al, 1983 by MURAYAMA (1977).…”