June 25 (UPI) -- Scientists have discovered a volcanic heat source underneath Antarctica's Pine Island Glacier.
Already threatened by rising atmospheric temperatures and warming ocean currents, the West Antarctic Ice Sheet's enemy list continues to grow.
Scientists discovered the heat source while analyzing trace gases from water samples collected near the glacier's coastal shelf.
"I was sampling the water for five different noble gases, including helium and xenon," Brice Loose, a chemical oceanographer at the University of Rhode Island's Graduate School of Oceanography, said in a news release. "I use these noble gases to trace ice melt as well as heat transport. Helium-3, the gas that indicates volcanism, is one of the suite of gases that we obtain from this tracing method."
Loose and his colleagues weren't looking for volcanism. When they measured the elevated levels of helium-3, they assumed it was an anomaly or a mistake.
But followup measurements confirmed the helium isotope spike wasn't an aberration.
"When you find helium-3, it's like a fingerprint for volcanism. We found that it is relatively abundant in the seawater at the Pine Island shelf," Loose said.
Pine Island Glacier is losing ice mass faster than any other glacier in Western Antarctica, but researchers don't believe the volcanic heat source is the main driver of the glacier's melting.
"There are several decades of research documenting the heat from ocean currents is destabilizing Pine Island Glacier, which in turn appears to be related to a change in the climatological winds around Antarctica," Loose said.
The volcanic heat source is, however, one more factor to account for when modeling the stability of the West Antarctic Ice Shelf. The ice shelf's stability has serious implications for the future of sea level rise.
The analysis of trace gases -- published in the journal Nature Communications -- suggests the volcanic heat source is putting off as much as 25 times more thermal energy than a dormant volcano. And while climate change explains the bulk of the glacier's melting, the new heat source is most likely accelerating the glacier's ice loss.
"The discovery of volcanoes beneath the Antarctic ice sheet means that there is an additional source of heat to melt the ice, lubricate its passage toward the sea, and add to the melting from warm ocean waters," said Karen Heywood, a professor at the University of East Anglia. "It will be important to include this in our efforts to estimate whether the Antarctic ice sheet might become unstable and further increase sea level rise."