Organism Survival

[ScienceDike]

Hell SF, I have a question that google searching has not been able to help me with.

Are there organisms that can survive in the abscence of organic matter. For instance, could any organisms survive and reporduce purely off of sunlight, water, and some mix of the elements?

[John Cuthber]

Using just the elements isn't going to work. Carbon is far to unreactive and nitrogen isn't much better.

But you can grow organisms on just "simple" compounds.

For example, you can grow algae on a diet of water, minerals, CO2, and sunlight.

[CharonY]

Yes there are, if you replace elements with inorganic compounds. Sunlight is not even necessary as the light reaction is but one of the means to generate energy without oxidation of organic sources. Generally the role of organic substrates are to provide a) building blocks for biomass (mostly C and depending on organism also N) and b) provide energy by either reducing equivalents which are necessary to generate energy or direct generation of ATP via substrate level phosphorylation.

Litotrophic bacteria can generate the reducing equivalents by oxidizing diverse inorganicconmpounds including ferrous iron, ammonia, nitrite, sulfur, hydrogen etc, In other words, for energy generation in some cases elemental forms can be utilized. This is not the case for the generation of biomass, however. While some bacteria (the nitrogen fixers) can utilize elemental nitrogen, this is not possible with carbon. In this case they have to use CO2 via the Kalvin cycle.

 

Edit: crossposted with John

Edited March 30, 2014 by CharonY

[ScienceDike]

Thanks for the help!