Ines Dumke

The consequences of warming oceans are manifold and not yet fully understood. One aspect associated with ocean warming is the release of methane gas into the water column, particularly where large amounts of methane are stored in sedimentary gas hydrates. Increased bottom water temperatures affect the sediments and eventually cause hydrate destabilisation and release of free gas into the water column. A high amount of methane may also escape into the atmosphere where, being a stronger greenhouse gas than CO2, it will accelerate global warming. Consequently, it is important to understand the processes involved in gas hydrate destabilisation in areas like the Arctic. To assess the likelihood of triggered hydrate dissociation and large-scale methane release, it is necessary to study other events during which large amounts of methane may have been released. This includes sub-sea magmatism commonly occurring during rifting events. The high temperatures associated with magmatic intrusions alter overlying sediments and may lead to thermogenic methane production. Hydrothermal systems are formed from which large amounts of methane may emanate into the water column and possibly into the atmosphere. Understanding of these hydrothermal systems in terms of fluid migration and their relationship to magmatic intrusions, will give insights into the effects these systems had on oceans and atmosphere, and help to constrain the factors involved in the current global warming period.