Southern Hydrate Ridge

It extends 25 km in length and 15 km across, trending north-northeast-south-southwest at the depth of approximately 800 m.[1] Southern Hydrate Ridge has been the site of numerous submersible dives with the human occupied Alvin submarine, extensive visits by numerous robotic vehicles including the Canadian ROV ROPOS, Jason (US National Deep Submersible Facility), and Tiburon (MBARI), and time-series geophysical studies that document changes in the subsurface distribution of methane.

[2][3] It is also a key site of the National Science Foundations Regional Cabled Array that is part of the Ocean Observatories Initiative (OOI), which includes eight types of cabled instruments streaming live data back to shore 24/7/365 at the speed of light, as well as uncabled instruments.The geologic history of the Southern Hydrate Ridge has been reconstructed through seismic imaging,[4] which provides constraints on the origin of methane ice deposits found in this region.

Methane ice at Southern Hydrate Ridge has been found within the shallow sediments, and more rarely exposed on the seafloor.

[9] Migration and egress of methane-rich fluids and microbial interactions can lead to the formation of chemoherms through anaerobic oxidation of methane.

[7] Methane venting at Southern Hydrate Ridge has been observed to be transient and episodic[8] with temporal variations of hours to days.

[3][12] New instrumentation at this site, including cabled multibeam sonar systems developed by the University of Bremen, now image the entire seep area of Southern Hydrate Ridge, scanning for plumes every two hours.

Release of methane from marine seep sites into the atmosphere may have been a factor for past climate warming events, such as the Paleocene-Eocene Thermal Maximum (PETM).