July 15 Polar Mail
Question:
Is it thought possible that these volcanoes contribute to the recent Arctic melt?
Thank you in advance for your response.
Laurie K. McClure
Answer:
Thanks for your question. Although Greenland does not have volcanoes, we discovered evidence of volcanoes during Expedition 2 to the Gakkel Ridge in the Arctic Ocean.
Volcanic eruptions do not contribute to the melting of the Arctic ice cap. The Arctic Ocean is a huge reservoir of water that can readily absorb and disperse the heat and volatile gases from the volcanic eruptions at the seafloor.
To get a sense of how readily and easily the ocean disperses heat from the Earth’s crust, look at underwater volcanoes and hydrothermal vents in other regions of the ocean. At hydrothermal vents, scientists have found mineral-rich fluids with temperatures approaching 400°C (750°F) spewing out of the Earth. But if you measure temperatures just a few meters above or to the side of a vent, water temperatures return to just 2° to 3°C (35° to 37°F). And if you are floating on the ocean surface and a deep-sea volcano or vent erupts thousands of meters below, you wouldn’t detect a change in ocean temperatures.
The water in the Arctic Ocean is stratified—layered like a cake—with lighter layers lying atop denser layers of water, like oil atop water. (Colder and/or saltier seawater is denser than warmer and/or less salty seawater.) Waters in the Arctic depths remain trapped near the bottom. They do not mix much with surface waters. Almost no heat is transmitted all the way up to the underside of the ice.
During many Arctic expeditions, scientists have studied the movement of water, heat, and chemicals in the depths of the Arctic Ocean. They have found that heat and other emissions from the Arctic seafloor do not rise much higher than 500 to 1000 meters up from the ocean bottom. The volcanoes under the Arctic sea ice are 3,000 to 4,000 meters (approximately 2.5 miles) below.
Comment:
Just wanted to say that I am enjoying the site and expedition immensely. With the amazing photography and story telling you really get the feeling that you are right there with you minus the sounds and cool temps of course. The Polar Discovery Expeditions keep getting better and better. Congratulations. Keep up the awesome work and be safe.
Warm (from sunny Woods Hole) regards,
Dina Pandya
Reply:
Hi Dina,
Thanks for your email--it's kind comments like these that keep me feeling warm even though my toes may be cold!
