A discovery that microbes in Antarctica can scavenge hydrogen, carbon monoxide and carbon dioxide from the air to stay alive in such extreme conditions has implications for the search for life on other planets.
Robinson Ridge, one of the two sites in Antarctica where microbes were collected.
UNSW-Sydney led scientists have discovered that microbes in Antarctica have a previously unknown ability to scavenge hydrogen, carbon monoxide and carbon dioxide from the air to stay alive in the extreme conditions.
The find has implications for the search for life on other planets, suggesting extra-terrestrial microbes could also rely on trace atmospheric gases for survival.
“Antarctica is one of the most extreme environments on Earth. Yet the cold, dark and dry desert regions are home to a surprisingly rich diversity of microbial communities,” says study senior author and UNSW scientist Associate Professor Belinda Ferrari.
“The big question has been how the microbes can survive when there is little water, the soils are very low in organic carbon and there is very little capacity to produce energy from the sun via photosynthesis during the winter darkness.
“We found that the Antarctic microbes have evolved mechanisms to live on air instead, and they can get most of the energy and carbon they need by scavenging trace atmospheric gases, including hydrogen and carbon monoxide,” she says.
The Australasian-based study, by researchers at UNSW, Monash University, the Australian Centre for Ecogenomics at the University of Queensland, GNS Science in New Zealand, and the Australian Antarctic Division, is published in the journal Nature.
Soil samples were collected from two coastal ice-free sites in different regions of eastern Antarctica. One was Robinson Ridge, 10 kilometres from Casey Station, in Wilkes Land. The other was Adams Flat, 242 kilometres from Davis Station in Princes Elizabeth Land.
Adams Flat, one of two sites in Antarctica where microbes were collected. Photo: Phil O'Brien
“Both areas are pristine polar deserts devoid of any vascular plants,” says Associate Professor Ferrari, of the UNSW School of Biotechnology and Biomolecular Sciences.
The researchers studied the microbial DNA in the surface soil from both sites and reconstructed the genomes of 23 of the microbes that lived there, including some of the first genomes of two groups of previously unknown bacteria called WPS-2 and AD3.
They found the dominant species in the soils had genes which gave them a high affinity for hydrogen and carbon monoxide, allowing them to remove the trace gases from the air at a high enough rate to sustain their predicted energy needs and support primary production.
“This new understanding about how life can still exist in physically extreme and nutrient-starved environments like Antarctica opens up the possibility of atmospheric gases supporting life on other planets,” says Associate Professor Ferrari.
Most organisms use energy from the sun or the earth to grow. More research is needed to see if this novel use of atmospheric gases as an alternative energy source is more widespread in Antarctica and elsewhere, the scientists say.
exitpursuedbybear on December 24th, 2017 at 06:46 UTC »
Problem with extremophiles is did they form in these constantly hostile environments or are they emigres from mild life giving environments exploiting niches. Can a environment that's only extreme produce these without suitable mild environments in the same biosphere?
kerovon on December 24th, 2017 at 06:26 UTC »
Link to the full article
Abstract for convenience:
DanHeidel on December 24th, 2017 at 05:56 UTC »
Edit: since this post got surprising traction, I've added a little more info. Thanks for the gold, too!
I'm not surprised at all. When you work in microbiology, you find microbes growing and thriving in the most ridiculous environments. Oligotrophs are microbes adapted to extremely resource poor environments. Some examples:
it's been found that there are species of bacteria commonly found to be growing in ultra-high purity lab water reservoirs. These are 18.2 mega-ohm/sub ppb TOC water purifier outputs. (edit: lab-speak for extremely high purity water) The bacteria in them are presumably surviving on the materials coming through the air being breathed out by the people in the lab. Edit: Since folks were asking about more info - I don't have citations as it's not something I ever personally researched or read up on. I did talk to another researcher that had done some reading on the subject and I know there has been some sporadic looks at these organisms. They represent a potential issue since their presence can contaminate PCR and other sensitive techniques that use the water. However, I think it's been one of those research topics that never got much traction and very few biologists are even aware of it.
As an addendum, I've talked to maintenance techs that have found microbes growing in Millipore lab water supply 180nm UV chambers. Those are the chambers used to eliminate organic contaminants by applying UV radiation sufficiently energetic to directly dissociate C-C bonds. And stuff grows in there. edit: no citations here. I'm not sure if there has even been published research on the subject. I simply heard about this from a water purification system tech once. For all I know, he was pulling my leg, but he seemed genuine about this. Of all the examples, it's the one I consider the most far fetched.
The Black Sea deep biomes are extremely low light. There are photosynthetic organisms that grow down there that intercept a photon every few hours or days. These typically have cell division times measured in centuries rather than the usual < 1 hour. edit: I can't remember the original references since I read them 10+ years back but this is the organism or something similar to it.
edit: Extra bonus - There is a similar biome deep in the Earth. Numerous researchers have found bacteria miles down in the crust living in porous rock. Apparently they feed on hydrogen generated as a byproduct of nuclear decay. (not sure how that works, I thought only helium got generated that way) They also have insanely slow growth rates. Some estimates were in the millenia per division, but that's extremely unlikely. If they were that energy poor, they wouldn't have enough energy to repair DNA damage, much less do other stuff.
A couple bonus, non-oligotroph examples:
I once found a giant fuzzball of fungus growing in a 100 mM pH 1 dissolved calcium phosphate solution.
A lab tech from an old lab once found fungus growing in a 10,000x stock solution of acridine orange. edit: for reference, acridine orange is a very old dye that was banned because it is fantastically carcinogenic. Turns out the dye is perfectly sized to slip in between DNA base pairs and fuck up DNA replication. It's now used as a mutagen in genetics research to create mutant organisms. This fungus in question was living in a stock solution 10,000 more concentrated than the usual amount that was enough to nearly kill E. coli from DNA damage.
edit: Extra bonus - as a few folks mentioned, there's a fungus that's been found growing in nuclear reactors that literally feeds on radiation. That's something that I had assumed was completely impossible. Basically, a bacterium trying to use ionizing radiation for a power source is like you trying to catch a cannonball - not a good idea. But this fungus secretes a melanin-like substance all around it. This stuff gets hit by the radiation (the fungus does too, which can kill it, but there's a lot of it) and takes radiation damage. The delocalized bonds found in melanin can capture a lot of the radiation energy in the form of high-energy bonds and stabilized free radicals. The fungal cells then go around eating those high-energy bonds. Blew my mind when I first heard about it.