An accumulation of natural gazes, emerging from an icy matrix situated on the seabed to the west of Greenland, potentially represents the deepest known gas hydrate cold seep, a site also discovered to be flourishing with diverse fauna.
The Freya gas hydrate formations were identified during the Ocean Census Arctic Deep EXTREME24 expedition, an undertaking spearheaded by investigators from UiT The Arctic University of Norway, in collaboration with several other entities. An anomalous gas plume detected in the water column alerted the research team to significant activity far beneath their vessel, prompting the deployment of a remotely operated vehicle (ROV) for closer examination.
Upon investigation, exposed geological structures composed of a crystalline substance identified as gas hydrate were observed. The scientific team skillfully maneuvered the ROV to procure samples of both the methane-rich seepage and crude oil, alongside sediment samples that harbored a rich array of marine organisms.
“This finding fundamentally alters our understanding of Arctic deep-sea ecosystems and the intricate processes of carbon cycling,” remarked the expedition’s co-chief scientist, Giuliana Panieri, as documented in a related report.
“Our discovery reveals an ultrasdeep system characterized by significant geological dynamism and abundant biological activity, bearing profound implications for biodiversity, climatic processes, and the future management of the High North region.”
The inhabitants of the Freya gas hydrate formations subsist on chemosynthetic microorganisms. These microbes possess the remarkable ability to convert chemical compounds such as methane, sulfides, and various hydrocarbons into essential biological energy sources.
This precise chemical milieu is what emanates from the seafloor at the recently charted Freya mounds, situated considerably beneath the surface of the Greenland Sea. The effusions consist primarily of methane, with a lesser proportion of heavier hydrocarbon compounds.
Sustained by a continuous influx of these chemical nutrients originating from the Earth’s crust, the denizens of the Freya mounds remain unaffected by the immense pressure exerted by the 3,640 meters (approximately 11,940 feet) of ocean water overhead. The necessity for solar illumination is obviated by the presence of gas hydrates, which constitute a frozen amalgamation of methane and water, maintained in a stable crystalline state by the extreme pressures and frigid temperatures characteristic of the abyssal ocean.
Approximately one-fifth of the global methane reserves exist in the form of gas hydrates, sequestered within deep marine sediments.
The discovery of the Freya mounds at an elevation exceeding 3.5 kilometers below the sea’s surface presents an exceptionally profound depth for such a seep, as most previously documented seeps occur at depths less than 2,000 meters.
The fauna cataloged encompasses siboglinid and maldanid tubeworms, skeneid and rissoid gastropods, and melitid amphipods. The ecological community shares a striking similarity in its family-level composition with Arctic hydrothermal vent ecosystems found at comparable depths.
Analysis of chemical compounds within the sediment samples indicates that the oil, and potentially the gases, have their origin in terrestrial flora that once flourished in a verdant, temperate Greenland during the Miocene epoch, a geological period spanning from 23 to 5.3 million years ago.
These carbon-rich deposits are instrumental in rendering the Freya mounds a highly habitable environment for organisms such as maldanid tubeworms and melitid amphipods. Furthermore, this resource is a primary factor drawing the attention of global mining interests and certain governmental bodies towards the remote Arctic seabed.
“Despite considerable advancements in comprehending the geographical distribution and concentration of gas hydrates, a substantial impediment persists in accurately assessing their potential as an energy source and their influence on global climatic shifts,” the authors state.
Currently, deep-sea extractive operations have predominantly focused on polymetallic nodules—concretionary masses the size of potatoes found on the ocean floor, containing critical rare earth elements vital for the manufacture of devices like smartphones. However, the repercussions of such anthropogenic disturbance of the deep-sea environment on marine ecosystems within our already precarious global biosphere remain largely undetermined.
“It is highly probable that additional ultra-deep gas hydrate cold seeps akin to the Freya mounds await discovery within this region, and the marine life congregating around them could play a crucial role in bolstering the biodiversity of the deep Arctic,” observed marine ecologist Jon Copley of the University of Southampton, a participant in the expedition, according to information from a related source.
“The observed interconnections between life at this seep and Arctic hydrothermal vents underscore the imperative to safeguard these isolated oceanic habitats from any prospective impacts stemming from deep-sea mining activities in the area.”
