In the chapter on water accumulation I will describe how methanogens are possibly
responsible for the abundance of water on Earth. I will now discuss the methanogen’s
other bi-product of metabolism - methane gas.
Methane is also abundant in our oceans in the form of a hydrate. Under certain conditions
of pressure and temperature methane forms a solid structure with water.
These conditions exist in the bottom of oceans - or within the sediment/rock itself.
On land hydrates can exist in perma-frost areas like Siberia.
See ScienceDirect.com - confirms gas hydrates are associated with methanogen communities.
Much methane enters the atmosphere where it is broken down to carbon dioxide and
water vapour by OH radicals and ultra-violet light.
The Distribution and Abundance of Methanogens
Population densities of methanogen communities vary considerably - depending upon
temperature, the supply of hydrogen, and anaerobic substrate.
D Y Liu et al, 2010 indicate around 1 billion microbes per gram of their samples
from wetland areas. In peatland areas, Ding et al (2004) estimated that methanogens
produce 2.87 mg/m2/hour of methane. However, they also estimated that six times this
amount of methane was being produced at the Sanjiang marsh.
See Biogeosciences for their research on methanogen populations.
D’Hont, Jorgensen, Miller et al (2003) suggest populations of methanogens on slopes
of the Peru Trench as being in the order of 10^8 cells per cm3