Combining light and arsenic, these bacteria make their food and multiply using a chemical that is toxic to most other life forms. The researchers think using arsenic as an energy source was a process used by ancient bacteria. Their findings are reported in the journal Science.
Ronald Oremland of the US Geological Survey explained that these bacteria are photosynthetic, using sunlight - like plants - to turn carbon dioxide into food. What is different about them is that instead of using water in this process, they use arsenic. The US-based researchers isolated the bacterium from the lake, which lies at the foot of the Sierra Nevada.
"We suspected that these bacteria were using arsenic to make a living, so we scraped the biofilms off the rock and studied them under laboratory conditions." By first withholding light, then arsenic, the team showed that the bacteria required both to grow. This the first time an organism has been found that can use arsenic to photosynthesise under anaerobic conditions, Dr Oremland believes. He suspects that this is an ancient ability in bacteria. "We think that bacteria were photosynthesising before oxygen was present in the atmosphere," he said.
Source: BBC News
Aporte: Guillermo Figueroa