What is an extreme environment?
Extreme environments are found across the Earth. They are places where humans would not survive – for example, environments that have very high temperatures or pressure. They could be very acidic or alkaline or extremely cold with very little nutrients. For scientists like Dr Adele Williamson from The University of Waikato, studying these living organisms’ unique enzymes and DNA repair processes provides new and challenging science that may unlock useful methods and knowledge to help us in our quest for medical advancements.
Find out more about Dr Adele Williamson’s research in these articles:
Transcript
Dr Adele Williamson
If it’s living in an environment where we would not be able to survive, so extreme to us – say a very, very high pressure or a very high temperature – we will call it an extremophile.
There are microorganisms that are living pretty much anywhere that you can think of. They’ve adapted and evolved to survive in conditions which we ourselves would be utterly unable to survive in. This would be organisms that are living really deep down under the ocean – say in the subsurface sediments with the physical pressure of the water and the sediment pushing down on them.
The most common things that we think of when we think of extreme environments are things like the geothermal features here in Aotearoa New Zealand. You see some of these bubbling mud pools with very high or very low pH.
Then you also have extreme environments that may be a little bit less obvious – say the upper levels of the open ocean where you have very low nutrient content but very, very high UV bombardment because sunlight is hitting the top of that water all the time – that you could also classify as an extreme environment because the organisms living up there are unable to get away from that really high UV radiation, and they haven’t got an awful lot of food to live off to repair themselves either.
Another extreme environment that I’m personally very interested in are very low temperature environments. So this would be the Arctic in the northern hemisphere and the Antarctic in the southern hemisphere. I’m working on samples that come from an area called the Dry Valleys of the Antarctic. These are dry because they don’t have any snow cover – the snow has been sublimed away by the winds that blow there – and the reason that this is such an extreme environment is that the sediment, which is where the microbes are living here, is subjected to multiple freeze/thaw cycles in the summertime.
If you imagine what happens when you’ve got below 20° with cloud cover over, and then that cloud goes, the Sun is shining and suddenly that temperature’s going to spike as the Sun hits that sediment. What little water is there is going to thaw out. Clouds come back over, that’s going to freeze again, and so this is very, very damaging to the biological molecules inside those microbes. If they’re above the sediment or sitting on the surface of the sediment, they’re going to be absolutely nailed by that UV light coming down. And finally, there’s not a lot of nutrients in this environment, so these bacteria and archaea have very little resources to be able to live and to repair themselves and divide.
Acknowledgements
Dr Adele Williamson, The University of Waikato Arctic exteriors, Climate Central Mud pools, LEARNZ CC BY-NC 3.0 Sea floor with bubbles, ocean surface from boat and Antarctic ice shelf and sea ice, NIWA Black smoker on seafloor, Ocean Sci TV. CC BY 3.0 White Island volcanic activity, filmed by Bradley Scott. GNS Science Underwater view of diver, Samuel Nowack. CC BY 3.0 Time-lapses from the McMurdo Dry Valleys in Antarctica, Keith Heyward and Jennifer Berglund, Prehensile Productions
