Project description

The SEAMSTRESS project aims at quantifying the effect of tectonic forcing on the release of greenhouse gasses from the ocean floor in the Arctic.

Greenhouse gasses, such as methane, are a major concern when it comes to climate change. Large amounts of these gasses are released from the sediment on the ocean floor, not only potentially influencing our global climate, but also affecting seabed ecology and increasing the risk of underwater landslides and tsunamis. While we know that this is a widespread phenomenon, we still don’t understand the mechanisms controlling the timing and quantities of this release. SEAMSTRESS puts forward a working hypothesis, this is that methane release is closely related to regional processes such as the separation of tectonic plates at mid-ocean ridges and the crushing weight of solid ice-masses.

Preliminary models from the region offshore west-Svalbard show that most of the gas release in the region occurs where the opening of mid-ocean ridges open cracks in the sediment that allow the gasses to escape. In areas where tectonic forces are compressive, the cracks remain tight and the gas stays trapped within the sediment. During periods of maximum ice mass thickness on Svalbard the outgassing may have been more abundant than at present day, due to additional opening of cracks in the sediment. Final numerical models will tell us what regional mechanism has the strongest influence on the deformation of the sediments and associated gas release. On-site measurements of sediment properties and tectonic forces will validate numerical models explaining the timing and quantities of historical gas release.

The concepts and approaches developed by SEAMSTRESS for Arctic sites also apply to other regions, e.g., along the Atlantic Ocean, where estimating the amount of methane escaping from the ocean floor is crucial to determining its effect on Earth’s hydrological and atmospheric processes.

Illustration by Torger Grytå