IT’S LIFE Jim, but not as we know it. Scientists have scooped a unique life form from the sludge at the bottom of a lake that is so unique it could have come from outer space.
The organism, a bacteria, is noteworthy in that it can grow by consuming the deadly poison arsenic. Realising how varied life can be on Earth should help astrobiologists to be more “creative” when searching for extraterrestrial life.
The bug is a member of the Halomonadaceae family of gammaproteobacteria. It is, however, a perfect example of what scientist and author Paul Davies refers to as “weird life”.
He has written before about the possibility that a “shadow biosphere” may exist side by side with our own but remains invisible because we cannot even imagine how to spot it.
Now research scientist Dr Felisa Wolfe-Simon has managed to find some weird life at the bottom of Mono Lake in California. She is lead author in a study published this morning in Science Express.
All of life on Earth requires phosphorus to support the chemistry in cells. Arsenic on the other hand is so dangerous mainly because it is chemically related to phosphorus.
Lake Mono is naturally polluted with high levels of arsenic but is low on phosphorus. The bug has been able to switch, using phosphorus when available but substituting arsenic when necessary.
The bug is weird but is not strictly alien given it can use phosphorus, said Mr Davies, commenting on the study of which he is a co-author.
“The holy grail would be a microbe that contained no phosphorus at all.”
