Researchers surveying the Arctic Ocean's seafloor have discovered something particularly unsettling for many climatologists. Plumes of methane, a particularly potent greenhouse gas, are rising in tiny ominous bubbles from the ocean floor. Why exactly this is happening remains unclear, but initial speculation is tying it to warning temperatures and ice melt.

Researchers from Stokholm University have recently been plowing through the Laptev Sea in the icebreaker ship Oden, closely measuring the air and water around the East Siberian Arctic Ocean.

"The SWERUS-C3 expedition is really well equipped to detect the release of methane," chief scientist Örjan Gustafsson wrote a week into his expedition.

"For 72 hours now, we have been in the thick of extensive investigations of methane releases from the outer Laptev Sea system," he wrote on July 20.

According to Stokholm University, the discovery of these releases came as a bit of a surprise, not because the plumes were unexpected, but because of their concentration. An increased concentration of methane release, Gustafsson suspects, may be coming from collapsing "methane hydrates" - pockets of the gas that were once trapped in frozen water on the ocean floor.

"It has recently been documented that a tongue of relatively warm Atlantic water, with a core at depths of 200-600 [meters] may have warmed up some in recent years," Gustafsson explained. "As this Atlantic water, the last remnants of the Gulf Stream, propagates eastward along the upper slope of the East Siberian margin, our SWERUS-C3 program is hypothesizing that this heating may lead to destabilization of upper portion of the slope methane hydrates. This may be what we now for the first time are observing."

The researchers are quick to point out that they are just a few weeks into their work, and this is a very much speculation. However, the very fact that these plumes are there is worrying enough.

[Credit: SWERUS-C3/Pete Hill]

Methane (CH4), while not often mentioned in climate talks, is the far more threatening of the world's two carbon-based greenhouse gases.

"Pound for pound, the comparative impact of CH4 on climate change is over 20 times greater than carbon dioxide (CO2) over a 100-year period," the Environmental Protection Agency (EPA) reported.

What's worse, the EPA has found that methane has increased in average world volume by an estimated 50 percent compared to pre-industrial levels.

Jason Box, a widely published climatologist, has been closely following the SWERUS-C3 expedition, and is concerned - based on observations - that some of these methane bubbles are not being dissolved or consumed by microorganisms before reaching the surface.

"If even a small fraction of Arctic sea floor carbon is released to the atmosphere, we're f'd," he tweeted last week.

Now he and others of like-mind wait with bated breath for more conclusive observations from the ongoing expedition.