A green sulfur bacterium from epsomitic Hot Lake, Washington, USA
- Southern Illinois Univ., Carbondale, IL (United States)
- Univ. of Oklahoma, Norman, OK (United States)
- Indiana Wesleyan Univ., Marion, IN (United States)
- Purdue Univ., West Lafayette, IN (United States)
- Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
Hot Lake is a small heliothermal and hypersaline lake in far north–central Washington State (USA) and is limnologically unusual because MgSO4 rather than NaCl is the dominant salt. In late summer, the Hot Lake metalimnion becomes distinctly green from blooms of planktonic phototrophs. In a study undertaken over 60 years ago, these blooms were predicted to include green sulfur bacteria, but no cultures were obtained. We sampled Hot Lake and established enrichment cultures for phototrophic sulfur bacteria in MgSO4-rich sulfidic media. Most enrichments turned green or red within 2 weeks, and from green-colored enrichments, pure cultures of a lobed green sulfur bacterium (phylum Chlorobi) were isolated. Phylogenetic analyses showed the organism to be a species of the prosthecate green sulfur bacterium Prosthecochloris. Cultures of this Hot Lake phototroph were halophilic and tolerated high levels of sulfide and MgSO4. In addition, unlike all recognized species of Prosthecochloris, the Hot Lake isolates grew at temperatures up to 45°C, indicating an adaptation to the warm summer temperatures of the lake. Photoautotrophy by Hot Lake green sulfur bacteria may contribute dissolved organic matter to anoxic zones of the lake, and their diazotrophic capacity may provide a key source of bioavailable nitrogen, as well.
- Research Organization:
- Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC), Biological and Environmental Research (BER)
- Grant/Contract Number:
- AC05-76RL01830
- OSTI ID:
- 1797773
- Report Number(s):
- PNNL-SA-157447
- Journal Information:
- Canadian Journal of Microbiology, Vol. 67, Issue 4; ISSN 0008-4166
- Publisher:
- Canadian Science PublishingCopyright Statement
- Country of Publication:
- United States
- Language:
- English
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