The selection of microbial communities by constant or fluctuating temperatures |
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Authors: | AC Upton DB Nedwell DD Wynn-Williams |
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Institution: | University of Esssex, Department of Biology, Colchester, Essex, U.K.;British Antarctic Survey, Natural Environment Research Council, Cambridge, U.K. |
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Abstract: | Abstract The diversity of bacterial communities isolated from Antarctic lake sediment in chemostats under constant low temperature (8°C) or diurnally fluctuating temperature (1°C to 16°C) was examined. The median optimum temperature for growth of the freshwater bacteria isolated from the fluctuation chemostat was significantly lower ( P < 1%) than that for those from the constant temperature chemostat. The diversity of the enriched bacterial community isolated in the chemostat culture subjected to short-term temperature fluctuations was greater than that enriched under constant temperature. At least 4 different groups of bacteria, that occupied separate 'temperature niches', were isolated from the fluctuating chemostat compared to only one group isolated from the stable chemostat. Furthermore, a pseudomonad from the fluctuating chemostat was shown to out-compete another pseudomonad from the stable chemostat when both were subjected to the fluctuating temperature regime. However, the pseudomonad of constant (8°C) temperature origin out-competed that isolated under fluctuating conditions when subjected to a stable temperature regime. |
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Keywords: | Chemostat Diversity of enriched communities Cardinal growth temperatures |
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