The diagram to the right shows where the same stability curve above crosses the temperatures of ocean sedements. Capacity to Trap Gas Hydrate forms as cement in the pore spaces of sediment as well as in layers and nodules of pure hydrate. Hydrates also seem to have the capacity to fill sediment pore space and reduce permeability, so that hydrate-cemented sediments act as seals for gas traps. Gas hydrates are stable at the temperatures and pressures that occur in ocean-floor sediments at water depths greater than about 500 m, and at these pressures they are stable at temperatures above those for ice stability. Gas hydrates also are stable in association with permafrost in the polar regions, both in offshore and onshore sediments.
Gas hydrates bind immense amounts of methane in sea-floor sediments.
This is about twice the amount of carbon held in all fossil fuels on earth .