Microbes in Antarctic Lake Divvy Up the Waters


Four microbes, recently sequenced at the U.S. Department of Energy’s Joint Genome Institute, dominate in Antarctica’s Deep Lake, making up 70% of the microbial community. They belong to a group called haloarchaea, which require high salt concentrations to grow and are naturally adapted to extreme conditions that would prove lethally cold to other organisms. In a recent study, researchers found that three of the four haloarchaea are adapted to niche environments within the lake. The most abundant of the four, strain tADL (44% of the lake community), has genes for light harvesting and gas vesicles that help it float near the light-rich surface. The second most abundant haloarchaea, strain DL31 (18% of the community), appears to be adept at metabolizing proteins and peptides. H. lacusprofundi (10% of the lake community)appears to be a more versatile generalist that can feed on a variety of nutrients. The least abundant, strain DL1 (0.3% of the lake community), shows a taste for amino acids and is the only one without genes for using glycerol as a nutrient. The next step is to use metaproteomics (study of proteins in an environmental sample) to investigate whether protein abundance in Deep Lake supports the research team’s hypothesis about niche specialization. Understanding how haloarchaea thrive in extreme polar niches could be used to improve the role of microbes in contaminated site cleanup in permanently or seasonally cold regions. Also, the genes that allow them to adapt to select conditions can be re-tooled for use in industrial or environmental remediation settings.


Williams, T. J., et al. 2014. “Microbial Ecology of an Antarctic Hypersaline Lake: Genomic Assessment of Ecophysiology Among Dominant Haloarchaea,” The ISME Journal 8, 1645-58. DOI:10.1038/ismej.2014.18.