Scientists break record by finding northernmost hydrothermal vent field

Jul 24, 2008
The top three feet of a chimney nearly 40 feet tall are visible as the arm of a remotely operated vehicle reaches in to sample fluids. The vent is part of the northernmost hydrothermal vent field yet seen and sampled. Credit: Centre for Geobiology/U. of Bergen

Well inside the Arctic Circle, scientists have found black smoker vents farther north than anyone has ever seen before. The cluster of five vents – one towering nearly four stories in height – are venting water as hot as 570 F.

Dissolved sulfide minerals that solidify when vent water hits the icy cold of the deep sea have, over the years, accumulated around the vent field in what is one of the most massive hydrothermal sulfide deposits ever found on the seafloor, according to Marvin Lilley, a University of Washington oceanographer. He's a member of an expedition led by Rolf Pedersen, a geologist with the University of Bergen's Centre for Geobiology, aboard the research vessel G.O. Sars.

The vents are located at 73 degrees north on the Mid-Atlantic Ridge between Greenland and Norway. That's more than 120 miles from the previous northernmost vents found during a 2005 expedition, also led by Pedersen. Other scientists have detected plumes of water from hydrothermal vents even farther north but have been unable to find the vent fields on the seafloor to image and sample them.

In recent years scientists have been interested in knowing how far north vigorous venting extends. That's because the ridges where such fields form are so stable up north, usually subject only to what scientists term "ultra-slow" spreading. That's where tectonic forces are pulling the seafloor apart at a rate as little as 6/10th of an inch in a year. This compares to lower latitudes where spreading can be up to eight times that amount, and fields of hydrothermal vents are much more common.

"We hadn't expected a lot of active venting on ultra-slow spreading ridges," Lilley said.

The active chimneys in the new field are mostly black and covered with white mats of bacteria feasting on the minerals emitted by the vents. Older chimneys are mottled red as a result of iron oxidization. All are the result of seawater seeping into the seafloor, coming near fiery magma and picking up heat and minerals until the water vents back into the ocean. The same process created the huge mound of sulfide minerals on which the vents sit. That deposit is about 825 feet in diameter at its base and about 300 feet across on the top and might turn out to be the largest such deposit seen on the seafloor, Lilley said. Additional mapping is needed.

"Given the massive sulfide deposit, the vent field must surely have been active for many thousands of years," he said.

The field has been named Loki's Castle partly because the small chimneys at the site looked like a fantasy castle to the scientists. The Loki part refers to a Norwegian god renowned for trickery. A University of Bergen press release about the discovery said Loki "was an appropriate name for a field that was so difficult to locate."

Indeed this summer's expedition and the pinpointing of the location of the vents earlier this month follows nearly a decade of research. Finding the actual field involved extensive mapping. It also meant sampling to detect warm water and using optical sensors lowered in the ocean to determine the chemistry, both parts that involved Lilley. He said a key sensor was one developed by Ko-ichi Nakamura of the National Institute of Advanced Science and Technology, Japan, that detects reduced chemicals that are in the water as a result of having been processed through a hydrothermal vent.

A remotely operated vehicle was used to finally find the vents. The difficulties of the task are described in an expedition Web diary, see "Day 17: And then there were vents" at www.geobio.uib.no/View.aspx?mi… =1093&moduledefid=71 .

The area around the vents was alive with microorganisms and animals. Preliminary observations suggest that the ecosystem around these Arctic vents is diverse and appears to be unique, unlike the vent communities observed elsewhere, the University of Bergen press release said. The expedition included 25 participants from five countries.

Source: University of Washington

Explore further: NASA HS3 mission Global Hawk's bullseye in Hurricane Edouard

add to favorites email to friend print save as pdf

Related Stories

Scientific instruments of Rosetta's Philae lander

Sep 23, 2014

When traveling to far off lands, one packs carefully. What you carry must be comprehensive but not so much that it is a burden. And once you arrive, you must be prepared to do something extraordinary to make ...

Better regulations needed for deep-sea biology

Sep 04, 2014

Although we know relatively little about the deep sea, we do extract raw materials for electronics and medicines from it. Biologist Erik Dücker describes the history of deep-sea biology in his thesis. He ...

Exploring Mars in low Earth orbit

Jul 31, 2014

In their quest to understand life's potential beyond Earth, astrobiologists study how organisms might survive in numerous environments, from the surface of Mars to the ice-covered oceans of Jupiter's moon, ...

Researchers marvel at world's deepest sea vents

Feb 27, 2013

Researchers steering a remote-controlled submarine around the world's deepest known hydrothermal vents have collected numerous samples from sunless depths of the Caribbean Sea where blazing hot, mineral-rich ...

Recommended for you

NASA image: Fires in the southern United States

18 hours ago

In this image taken by the Aqua satellite of the southern United States actively burning areas as detected by MODIS's thermal bands are outlined in red. Each red hot spot is an area where the thermal detectors ...

Software models ocean currents for oil and gas search

19 hours ago

A study involving the use of streamline visualisation has found the technology can help guide electromagnetic transmitter and receiver placements, thereby aiding the search for oil and gas on the seafloor.

User comments : 1

Adjust slider to filter visible comments by rank

Display comments: newest first

bobwinners
5 / 5 (1) Jul 25, 2008
I imagine that the biggest obstacle to finding these vents is the weather. I'm not surprised that the exist up north, given that plate boundaries exist there. It will be interesting to see what the geologists come up with when they actually map the plate boundaries under the Arctic ocean.