An Ecosystem of One Species
Ecosystems, as the name suggests, normally have several or many different species interacting and each contributing in their own way to the whole system of life in their environment.
Some might be producer organisms, often plants, while others are animals eating the plants, returning the nutrients of the plant bodies to the ecosystem. Yet others will decompose both the animals and plants, again returning the nutrients. There are very many other niches within most ecosystems.
So, could one species do everything? In a goldmine in South Africa some water was sampled from nearly 3 kilometres (about 2 miles) deep. Only one species was found. This was a bacterium called Candidatus Desulforudis audaxviator.
Candidatus Desulforudis audaxviator is a chemoautotrophic Sulphate reducing bacterium. This means that it gets its energy from mineral sources, not from light or from organic matter produced by other organisms.
Not all bacteria can move by themselves, but this versatile one can, using a whip like appendage called a flagellum.
Although Candidatus Desulforudis audaxviator Can use fixed forms of Nitrogen like Ammonia, it can also fix nitrogen from the gaseous form to forms it can use.
This bacterium does not need Oxygen, and in fact, Oxygen is poisonous to its active form. Some deep living organisms do need small amounts of the Oxygen made by plants, but this one is totally independent of surface life.
Candidatus Desulforudis audaxviator likes high temperatures, and 60 degrees C (140 degrees F) is fine.
This organism produces resistant spores that can survive many things including exposure to Oxygen and the vacuum of outer space.
In considering what organisms could be spread from the Earth to other planets, one of the problems is that most cannot form an ecosystem by themselves. Lichen may be able to survive for very long periods growing on Mars, but if it was the only organism, it would not be a complete ecosystem, and eventually might not survive.
Candidatus Desulforudis audaxviator could live deep inside Mars and several other bodies of our Solar system, and live on minerals just as it does deep inside the Earth.
Source by Steve Challis