Columbia Scientists Take
First Geological Samples Ever
From the Arctic Gakkel Ridge
by Abigail Beshkin
For the first time, a team of scientists, including six from Columbia University's Lamont-Doherty Earth Observatory, will enter the Arctic Ocean with two scientific ice breakers to collect rock and sediment samples from the seafloor along the Gakkel Ridge, the earth's slowest-moving mid-ocean ridge system.
This is the first time systematic geological sampling of this area has been undertaken. The Arctic Basin is one of the last of Earth's oceanic frontiers to be explored. The expedition departed from Tromso, Norway on July 31 into a raging north Atlantic storm and will return to Tromso October 3.
Last March, Columbia's scientists and others published an article in Nature on findings of volcanic activity on the eastern portions of the Gakkel Ridge. This discovery was based on bathymetric (sonar mapping) data and sidescan images taken in 1999 by a Navy submarine. Before that expedition, only vague topography was available due to the continuous ice cover of the region. In addition, because of the difficulties of Arctic logistics, systematic sampling of the Gakkel Ridge has never before been undertaken.
The Gakkel Ridge poses unique scientific opportunities as the slowest-moving ridge on earth, and as a result scientists expect this expedition to yield discoveries of rocks that have never been seen before. In addition, the isolation of the arctic basin could allow discoveries of species of animals that have never been seen before.
Ridges are the elevated boundaries—like underwater mountain ranges — between the Earth's tectonic plates. As the plates spread apart, they create gaps. Magma, which turns into the volcanic rock basalt, fills in these gaps, thus creating the ocean floor. The fastest-moving ridge moves at a speed of one foot each year. The Gakkel Ridge moves less than one half inch each year.
"Ridges that spread at the slowest end have not been able to be investigated," said Charles Langmuir, Arthur Storke Professor of Earth and Environmental Sciences at Columbia's Lamont-Doherty Earth Observatory. "As the spreading slows, everything gets much slower, and there's a whole different range of processes that occur." Langmuir said the mission of the expedition is to learn more about how the ocean floor is formed, how the mantle is melting and how the Gakkel Ridge differs from other mid-ocean ridges.
But Langmuir and the other scientists are also hoping they'll discover whether the Gakkel Ridge delivers enough heat to support "black smokers," hot springs on active volcanoes on the sea floor. At these sites, where chimneys emitting 400-degree centigrade water can reach eight or more stories high, anaerobic bacteria support complex ecosystems and exotic animals that can exist without sunlight.
"Since the Gakkel Ridge is at the end of the ridge system and is so isolated," said Langmuir, "if we do find such hydrothermal activity, we would expect to find many new species we have never seen before."
Langmuir said the researchers expect many challenges during the expedition. For one thing, this is the maiden voyage for the U.S. icebreaker, the US Coast Guard Cutter Healy; U.S. icebreakers have not yet been effective in reaching this region of the world. Aboard the Healy will be 20 scientists from Columbia, the Woods Hole Oceanographic Institution and the University of Tulsa. Also aboard will be 40 coast guard members and a middle school science teacher.
The Healy will travel with the German icebreaker, Polarstern. The ice breakers must travel together, so if one becomes lodged in the ice, the other can free it. As the two research vessels travel, they will take turns breaking the ice to form lanes in which the other vessel can travel close behind and do the sampling. Langmuir said each research team has a slightly different research mission, and so part of the challenge will be sharing and presenting the data in a way that fulfills the needs of both research parties.
The team will post information about the trip daily, communication permitting, to a special website, http://www.arcticvolcanoes.com/. The group will transmit their findings, journals, travelogues and pictures to the Internet via a NASA satellite. The site is being hosted by Columbia's Earthscape, at http://www.earthscape.org/, an online multi-media resource of earth science information for scientists and laypeople alike.
Langmuir said he hopes the findings from this expedition will pave the way for a greater understanding of the origins of planetary life.
"Understanding the whole process of ocean ridges reveals the Earth as a single, unified machine," said Langmuir. "The hydrothermal vents on mid-ocean ridges provide an incubation site for life, and these ridges may be where life originated. The Arctic region provides a unique window into understanding these phenomena and how they relate to ocean ridge volcanic activity."
About The Earth Institute
The Earth Institute at Columbia University is the world's leading academic center for the integrated study of Earth, its environment and society. The Earth Institute builds upon excellence in the core disciplines earth sciences, biological sciences, engineering sciences, social sciences and health sciences and stresses cross-disciplinary approaches to complex problems. Through research, training and global partnerships, it mobilizes science and technology to advance sustainable development, while placing special emphasis on the needs of the world's poor. For more information, visit www.earth.columbia.edu.