Marsh gas

Marsh gas, also known as swamp gas or bog gas, is a mixture primarily of methane and smaller amounts of hydrogen sulfide, carbon dioxide, and trace phosphine that is produced naturally within some geographical marshes, swamps, and bogs.

The surface of marshes, swamps, and bogs is initially porous vegetation that rots to form a crust that prevents oxygen from reaching the organic material trapped below. That is the condition that allows anaerobic digestion and fermentation of any plant or animal matter, which then produces methane.

The trapped methane can escape through any of three main pathways: by the diffusion of methane molecules across an air–water interface, by bubbling out of water in a process known as ebullition, or through plant-mediated transport.

Methane formation

Methane is the primary gas that makes up the product colloquially known as "marsh gas". Much of the biogenic methane produced in nature is derived from either acetate cleavage or by the hydrogen reduction of carbon dioxide. Methane can also be produced by methanogens, archaea that produce methane under anoxic conditions, in a process known as methanogenesis. Methanogens generate Methanosarcina which are common in marsh environments. They are both known for stimulating methane production in aquatic muds and using acetate, methanol, and trimethylamine as substrates for methane production.

Escape routes

Global wetlands are one of the largest sources of atmospheric methane.