 |
|
1 of deep ocean's most turbulent areas has big impact on climate
August 10, 2007TALLAHASSEE, Fla. -- More than a mile beneath the Atlantic's surface, roughly halfway between New York and Portugal, seawater rushing through the narrow gullies of an underwater mountain range much as winds gust between a city's tall buildings is generating one of the most turbulent areas ever observed in the deep ocean.
In fact, the turbulence packs an energy wallop equal to about five million watts -- comparable to output from a small nuclear reactor, according to a landmark study led by Florida State University researcher Louis St. Laurent and described in the August 9 edition of the journal Nature.
The study -- an international collaboration of scientists from the United States and France -- documents for the first time the turbulent conditions in an undersea mountain range known as the Mid-Atlantic Ridge. It provides never-before-seen evidence that deep water turbulence swirling in the small passageways of such mountains is generating much of the mixing of warm and cold waters in the Atlantic Ocean.
Better understanding of the mechanisms of mixing is crucial, says St. Laurent, an assistant professor of physical oceanography at FSU and the study's co-principal investigator, because mixing produces the overall balance of water temperatures that helps control the strength of the Gulf Stream -- the strong, warm ocean current that starts in the Gulf of Mexico, flows along the U.S. east coast to Canada and on to Europe, and plays a crucial climate role.
"Oceanographers are working hard to understand how processes in the ocean help to keep the Earth's climate stable," St. Laurent said. "We are aware that the climate is warming, but we don't yet fully understand how the changes will affect society. Our work will result in better models for predicting how the ocean will affect the climate in the future and a better understanding of sea-level rise, weather patterns such as El Nino, and the impact of these events on fisheries."
St. Laurent compared the flow of seawater through underwater gullies in the Mid-Atlantic Ridge to the wind, so familiar to hikers, that blows through mountain passages on land.
"That wind creates a condition known as turbulence, which can blow the hat from your head," St. Laurent said. "In the ocean, turbulence is produced when water flows quickly though oceanic passages. The turbulence stirs the almost freezing-water near the bottom with warmer water that is closer to the surface much as you would mix cream into coffee by stirring it with a spoon.
"We know that the mixing of warm surface water with very cold deep water is one of several factors that influence the Earth's climate," he said. "The mixing we observed and measured for our study allows the warmth at the surface of the ocean to 'diffuse' deep into the sea. The overall balance between warm and cold water in the Atlantic helps control the strength of the Gulf Stream, which moves heat away from the Earth's equator toward regions that receive much less heating from the sun's rays."
St. Laurent's co-principal investigator and co-author was Andreas M. Thurnherr, a former postdoctoral researcher in the FSU oceanography department and now a scientist at Columbia University. The field study took place in August 2006 during a three-week expedition aboard a French research vessel to a location close to the Azores, volcanic islands 2,000 miles east of the U.S. and west of Europe that comprise an above-sea portion of the mostly submerged Mid-Atlantic Ridge.
To measure the energy generated by the extraordinarily intense turbulence more than a mile below the ocean's surface, St. Laurent and crew used a custom-made instrument called the "turbulence profiler," outfitted with special sensors.
"The turbulence profiler measured the output using 'watts,' the same unit of measurement as printed on light bulbs," St. Laurent said. "In the undersea mountain passage where we intentionally looked, we found turbulence levels as large as one-10th watt per cubic meter of seawater. This is a huge amount of energy when you add all the seawater in the passage, equal to around five million watts, which is comparable to output from a nuclear reactor."
Florida State University
Better understanding of the mechanisms of mixing is crucial, says St. Laurent, an assistant professor of physical oceanography at FSU and the study's co-principal investigator, because mixing produces the overall balance of water temperatures that helps control the strength of the Gulf Stream -- the strong, warm ocean current that starts in the Gulf of Mexico, flows along the U.S. east coast to Canada and on to Europe, and plays a crucial climate role.
"Oceanographers are working hard to understand how processes in the ocean help to keep the Earth's climate stable," St. Laurent said. "We are aware that the climate is warming, but we don't yet fully understand how the changes will affect society. Our work will result in better models for predicting how the ocean will affect the climate in the future and a better understanding of sea-level rise, weather patterns such as El Nino, and the impact of these events on fisheries."
St. Laurent compared the flow of seawater through underwater gullies in the Mid-Atlantic Ridge to the wind, so familiar to hikers, that blows through mountain passages on land.
"That wind creates a condition known as turbulence, which can blow the hat from your head," St. Laurent said. "In the ocean, turbulence is produced when water flows quickly though oceanic passages. The turbulence stirs the almost freezing-water near the bottom with warmer water that is closer to the surface much as you would mix cream into coffee by stirring it with a spoon.
"We know that the mixing of warm surface water with very cold deep water is one of several factors that influence the Earth's climate," he said. "The mixing we observed and measured for our study allows the warmth at the surface of the ocean to 'diffuse' deep into the sea. The overall balance between warm and cold water in the Atlantic helps control the strength of the Gulf Stream, which moves heat away from the Earth's equator toward regions that receive much less heating from the sun's rays."
St. Laurent's co-principal investigator and co-author was Andreas M. Thurnherr, a former postdoctoral researcher in the FSU oceanography department and now a scientist at Columbia University. The field study took place in August 2006 during a three-week expedition aboard a French research vessel to a location close to the Azores, volcanic islands 2,000 miles east of the U.S. and west of Europe that comprise an above-sea portion of the mostly submerged Mid-Atlantic Ridge.
To measure the energy generated by the extraordinarily intense turbulence more than a mile below the ocean's surface, St. Laurent and crew used a custom-made instrument called the "turbulence profiler," outfitted with special sensors.
"The turbulence profiler measured the output using 'watts,' the same unit of measurement as printed on light bulbs," St. Laurent said. "In the undersea mountain passage where we intentionally looked, we found turbulence levels as large as one-10th watt per cubic meter of seawater. This is a huge amount of energy when you add all the seawater in the passage, equal to around five million watts, which is comparable to output from a nuclear reactor."
Florida State University
Ocean Current Events and Ocean News RSSFitness in a Changing World
The stickleback fish, Gasterosteus aculeatus, is one of the most thoroughly studied organisms in the wild, and has been a particularly useful model for understanding variation in physiology, behavior, life history and morphology caused by different ecological situations in the wild.
Team led by Livermore scientists helps to resolve long-standing puzzle in climate science
A team led by Livermore scientists has helped reconcile the differences between simulated and observed temperature trends in the tropics.
Researchers Turning Freshwater Farm Ponds into Crab Farms
Work by researchers at North Carolina State University is leading to a new kind of crab harvest - blue crabs grown and harvested from freshwater ponds, instead of from the sea.
Wildfires Cause Ozone Pollution to Violate Health Standards, New Study Shows
Wildfires can boost ozone pollution to levels that violate U.S. health standards, a new study concludes.
Diversity of plant-eating fishes may be key to recovery of coral reefs
For endangered coral reefs, not all plant-eating fish are created equal. A report scheduled to be published this week in the early edition of the journal Proceedings of the National Academy of Sciences suggests that maintaining the proper balance of herbivorous fishes may be critical to restoring coral reefs, which are declining dramatically worldwide.
Deep biosphere research points to new methods for recovering petroleum
Miles below us, deep within Earth's crust, life is astir. Organisms there are not the large creatures typically envisioned when thinking of life.
Brookhaven Scientists Take Off for Southeastern Pacific Climate Study
During October and November 2008, some 150 scientists from 40 institutions in eight nations - including scientists from the U.S. Department of Energy's (DOE) Brookhaven National Laboratory - will take part in an international field experiment designed to make observations of critical components of the climate system of the southeastern Pacific.
NASA spacecraft ready to explore outer solar system
The first NASA spacecraft to image and map the dynamic interactions taking place where the hot solar wind slams into the cold expanse of space is ready for launch Oct. 19. The two-year mission will begin from the Kwajalein Atoll, a part of the Marshall Islands in the Pacific Ocean.
NASA study finds rising Arctic storm activity sways sea ice, climate
A new NASA study shows that the rising frequency and intensity of arctic storms over the last half century, attributed to progressively warmer waters, directly provoked acceleration of the rate of arctic sea ice drift, long considered by scientists as a bellwether of climate change.
Cassini flyby of Saturn moon offers insight into solar system history
NASA's Cassini spacecraft is scheduled to fly within 16 miles of Saturn's moon Enceladus on Oct. 9 and measure molecules in its space environment that could give insight into the history of the solar system.
More Ocean Current Events and Ocean News Articles
 | Blue Ocean Strategy: How to Create Uncontested Market Space and Make Competition Irrelevant by W. Chan Kim, Renée Mauborgne Winning by Not Competing: A Fresh Approach to Strategy Since the dawn of the industrial age, companies have engaged in head-to-head competition in search of sustained, profitable growth. They have fought for competitive advantage, battled over market share, and struggled for differentiation. Yet these hallmarks of competitive strategy are not the way to create profitable growth in the future.... |
 | Ocean (American Museum of Natural History) Breathtaking, powerful, and all-encompassing in its sheer scope and visual impact, Ocean sweeps you away on an incredible journey into the depths of our astonishing marine world. As the site where life first formed on Earth, a key element of the climate, and a fragile resource, oceans are of vital importance to our planet. This definitive visual guide to the world's oceans - including the... |
 | Olive's Ocean (rpkg) (HarperClassics) by Kevin Henkes Sometimes life can change in an instant Martha Boyle and Olive Barstow could have been friends, but they weren't. Weeks after a tragic accident, all that is left are eerie connections between the two girls, former classmates who both kept the same secret without knowing it. Now, even while on vacation at the ocean, Martha can't stop thinking about Olive. Things only get more complicated when... |
 | An Ocean of Air: Why the Wind Blows and Other Mysteries of the Atmosphere by Gabrielle Walker We don’t just live in the air; we live because of it. It’s the most miraculous substance on earth, responsible for our food, our weather, our water, and our ability to hear. In this exuberant book, gifted science writer Gabrielle Walker peels back the layers of our atmosphere with the stories of the people who uncovered its secrets:• A flamboyant Renaissance Italian discovers how heavy our... |
 | Europe Between the Oceans: 9000 BC-AD 1000 by Barry Cunliffe Europe is, in world terms, a relatively minor peninsula attached to the Eurasian land mass. Yet it became one of the most innovative regions on the planet, generating restless adventurers who traversed the globe to trade, to explore, and often to settle. By the fifteenth century Europe was a driving world force, but the origins of its success have until now remained obscured in prehistory. In... |
 | The Emperor of Ocean Park by Stephen L. Carter In his triumphant fictional debut, Stephen Carter combines a large-scale, riveting novel of suspense with the saga of a unique family. The Emperor of Ocean Park is set in two privileged worlds: the upper crust African American society of the Eastern seabord—families who summer at Martha’s Vineyard—and the inner circle of an Ivy League law school. Talcott Garland is a successful law... |
 | I'm The Biggest Thing in the Ocean by Kevin Sherry When a giant squid takes inventory of all of the creatures in the ocean, he realizes that he’s way bigger than most of them! Of course, there are bigger things lurking around . . . but maybe this giant squid with a giant touch of hubris doesn’t really care? First-time author-illustrator Kevin Sherry is sure to garner fans of all sizes for his perfect-for-preschool read-aloud with simple text,... |
 | Hello Ocean by Pam Munoz Ryan Spend a day at the beach, and take in the ocean through the senses of sight, hearing, feeling, taste, and smell in this lively romp through sand and waves. Glorious illustrations of water, sun, and sky accompany brief, evocative verses, making this a perfect keepsake of a seaside vacation or a striking introduction to the pleasures of a day by the... |
 | Over in the Ocean: In a Coral Reef by Marianne Berkes This coral reef is a marine nursery, teeming with mamas and babies! In the age-old way of kids and fish, children will count and clap to the rhythm of Over in the Meadow while puffer fish "puff," gruntfish "grunt" and seahorses "flutter." The colorful art is fresh and fun - constructed entirely from clay-like material - and invites young fingers to fashion fishy... |
 | The Pop-Up Commotion in the Ocean by Giles Andreae This Pop-up adaptation of the best-selling picture book, Commotion in the Ocean brings to life everyone’s favorite ocean and sea creatures. In this pop-up edition see the angelfish, whale, penguins and octopus pop right off the... |
| © 2008 BrightSurf.com |