TU Delft Researchers are slowly solving the puzzle of how newly discovered bacteria can survive in the harsh conditions that reign in highly alkaline springs in Northern California.
Prof. Gijs Kuenen (AS faculty) is one researchers who discovered the new so-called Betaproteobacteria a few years ago in very alkaline springs in an old volcanic region in Northern California. With a pH of almost 12 and water that hardly contains any phosphorus, nitrogen or sulphur – the building blocks of life – the conditions in these springs had long been thought to be too harsh for life. An article about the discovery appeared in Proceedings of the National Academy of Science last year.
Kuenen and colleagues of the J.Craig Venter Institute and the University of Southern California have now isolated the organisms and read their DNA. Their findings, published last month in Nature Communications, give insights in how bacterial life may have looked like on earth a few billions of years ago.
The springs are among the few active terrestrial sites on earth, where serpentinization occurs. They are fed by rainwater that seeps down and reacts with silicates rich in iron such as olivine to produce a new suite of minerals as well as hydrogen, methane and highly alkaline fluids. The living conditions in these springs very much resemble the conditions on Earth more than 3 billion years ago.
The researchers found that the bacteria have very small genomes in comparison with taxonomically similar microbes living in less challenging environments. They believe that these microbes are the ‘precursors’ of other ‘more modern’ microbes, which have achieved their genomes by accretion of new genes later in evolution.
Suzuki S., et al. Physiological and genomic features of highly alkaliphilic hydrogen-utilizing Betaproteobacteria from a continental serpentinizing site, Nature Communications, 21 May 2014, doi:10.1038/ncomms4900.
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