Hundreds of deep-sea vents found spewing methane off US coast

Bubbles of methane rising up from the seabed

Nautilus

By Andy Coghlan

Methane is gushing forth from hundreds of newly-discovered deep-sea vents all along the US’s western seaboard.

“It appears that the entire coast off Washington, Oregon and California is a giant methane seep,” says Robert Ballard, founder and director of the Ocean Exploration Trust in Connecticut.

In all, 500 new seeps were discovered by submersibles operated from the trust’s ship, Nautilus (see video below). The discovery will be presented this week in New York at the National Ocean Exploration Forum.

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However, there’s still work to be done to pin down the exact composition of the bubbles coming from the seeps. “Members of our group are analysing the samples taken in June for a wide range of gases,” says Robert Embley, chief scientist on the Nautilus.

Embley says that previous samples from similar sites were mostly methane, but methane hydrate – made from water and methane – can form too.

Methane has the potential to accelerate global warming because it traps heat 40 times as effectively as carbon dioxide. Knowing how much is gushing out of the seeps and what amount makes it into the atmosphere should enable estimates of their impact on global warming in the future.

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“The first step to finding out is getting a baseline of what’s coming out of the seafloor at present,” says Embley.

The team thinks it is likely that they will find yet more seeps on the seafloor off the eastern US. “We hope there will be opportunities for more mapping in the next couple of field seasons to get a more complete baseline of sites,” says Embley.

Strange creatures, like this Dracula squid, roam the deep water where the vents were found

Nautilus

Also being showcased at the National Ocean Exploration Forum this week is the amazing variety of rare and unusual sea creatures. They were filmed this year in the Mariana Trench by submersibles operated from the Okeanos, a deep-sea exploration ship managed by the US National Oceanic and Atmospheric Administration.

Those caught on camera include glowing orb-like creatures (see video below), spectacular Dracula squids,  sea cucumbers that resemble Mary Poppins carrying an umbrella, and a distinctive purple relative of the cuttlefish, so cute it has been dubbed the cuddle fish.

Looks like Mary Poppins

Okeanos Explorer/NOAA

Curiously, many are purple, but no one knows why.

“There may not really be many deep-sea animals that are purple, they just seem to be the ones that get our attention,” says Tara Luke of Stockton University in New Jersey.

Read more: New Arctic __life on barren seabed thrives on methane jets