Question

Why are methanogens autotrophs?

Answer 1

Autotrophs are referred to as primary producers at the "bottom of the food chain" because they convert carbon to a form required by heterotrophs. ... Themethanogens play a dual role in the carbon cycle. These archaea are inhabitants of virtually all anaerobic environments in nature where CO2 and H2 (hydrogen gas) occur.

Answer 2

Methanogens are autotrophic archebacteria that use anaerobic respiration for ATP synthesis. Methanogens use CO2 taken up from their growth environment as the carbon substrate for growth. ... It is a waste of feed carbon because the rumen does not have methanotrophic bacteria and the host ruminant can not utilize this gas.