Earth Science News  





.
WATER WORLD
Eddies found to be powerful modes of ocean transport

Eddies appear to form repeatedly, and the high-speed, long-distance transport can last for months.
by Staff Writers
Woods Hole MA (SPX) Apr 29, 2011
Researchers from Woods Hole Oceanographic Institution (WHOI) and their colleagues have discovered that massive, swirling ocean eddies-known to be up to 500 kilometers across at the surface-can reach all the way to the ocean bottom at mid-ocean ridges, some 2,500 meters deep, transporting tiny sea creatures, chemicals, and heat from hydrothermal vents over large distances.

The previously unknown deep-sea phenomenon, reported in the journal Science, helps explain how some larvae travel huge distances from one vent area to another, said Diane K. Adams, lead author at WHOI and now at the National Institutes of Health.

"We knew these eddies existed," said Adams, a biologist. "But nobody realized they can affect processes on the bottom of the ocean. Previous studies had looked at the upper ocean."

Using deep-sea moorings, current meters and sediment traps over a six-month period, along with computer models, Adams and her colleagues studied the eddies at the underwater mountain range known as the East Pacific Rise.

That site experienced a well-documented eruption in 2006 that led to a discovery reported last year that larvae from as far away as 350 km somehow traveled that distance to settle in the aftermath of the eruption.

The newly discovered depth of the powerful eddies helps explain that phenomenon but also opens up a host of other scientific possibilities in oceans around the world.

"This atmospherically generated mechanism is affecting the deep sea and how larvae, chemical and heat are transported over large distances," Adams said.

The eddies are generated at the surface by atmospheric events, such as wind jets, which can be strengthened during an El Nino, and "are known to have a strong influence on surface ocean dynamics and production," say Adams and Dennis J. McGillicuddy from WHOI, along with colleagues from Florida State University, Lamont Doherty Earth Observatory, and the University of Brest in France. But this "atmospheric forcing...is typically not considered in studies of the deep sea," they report.

Moreover, the eddies appear to form seasonally, suggesting repeated interactions with undersea ridges such as the Eastern Pacific Rise. The models "predict a train of eddies across the ocean," Adams said.

"There may be two to three eddies per year at this location," Adams said. Each one, she says, "could connect the site of the eruption to other sites hundreds of miles away." Elsewhere, she adds, "there are numerous places around the globe where they could be interacting with the deep sea."

In her 2010 report on larvae traveling great distances to settle at the eruption site, WHOI Senior Scientist Lauren S. Mullineaux , along with Adams and others, suggested the larvae traveled along something like an undersea superhighway, ocean-bottom "jets" travelling up to 10 centimeters a second.

But conceding that even those would not be enough to carry the larvae all that distance in such a short time, the researchers speculated that large eddies may be propelling the migrating larvae even faster.

Adams's current work follows up on that possibility. "The mechanism we found helps explain what we saw in the first paper," Adams said.

It is the larger picture, over longer periods of time, however, that Adams and her colleagues find particularly intriguing. "Transport [of ocean products] could occur wherever...eddies interact with ridges-including the Mid-Atlantic Ridge, the Southwest Indian Ridge, and the East Scotia Ridge-and the surrounding deep ocean," the researchers say.

And because the eddies appear to form repeatedly, the high-speed, long-distance transport can last for months. "Although the deep sea and hydrothermal vents in particular are often naively thought of as being isolated from the surface ocean and atmosphere, the interaction of the surface-generated eddies with the deep sea offers a conduit for seasonality and longer-period atmospheric phenomena to influence the 'seasonless' deep sea," Adams and her colleagues write.

"Thus, although hydrothermal sources of heat, chemical and larval fluxes do not exhibit seasonality there is potential for long-distance transport and dispersal to have seasonal to interannual variability."




Share This Article With Planet Earth
del.icio.usdel.icio.us DiggDigg RedditReddit
YahooMyWebYahooMyWeb GoogleGoogle FacebookFacebook



Related Links
Water News - Science, Technology and Politics



Tempur-Pedic Mattress Comparison

Newsletters :: SpaceDaily Express :: SpaceWar Express :: TerraDaily Express :: Energy Daily
XML Feeds :: Space News :: Earth News :: War News :: Solar Energy News
WATER WORLD
Conservation of coastal dunes is threatened by poorly designed infrastructure
Madrid, Spain (SPX) Apr 28, 2011
Although the dune ecosystem is unusual, fragile and is protected by the "habitats" directive of the network Natura 2000, its conservation is very vulnerable to the proliferation of car parks, nearby buildings and inadequate boardwalks installed for protection or beach access. Researchers at the University of Seville (UoS) have published a study in the Journal of Coastal Research of human i ... read more

.
Get Our Free Newsletters Via Email
  


WATER WORLD
Japan PM on defensive over disaster leadership

Dalai Lama tells Japan to look to future

Quake-hit Japan open for business: foreign minister

Second woman exposed to radiation at Japan plant

WATER WORLD
Thousands queue for iPad 2 across Asia

New polymer structures for use as plastic electronics

Chinese pay price for world's rare earths addiction

NIST nanomagnets offer food for thought about computer memories

WATER WORLD
Venice turns to floating barriers to ward off flood threats

U.S. land mass is shrinking

Miner Vale invests in mega dam

Eddies found to be powerful modes of ocean transport

WATER WORLD
Calling all candidates for Concordia

Melting ice on Arctic islands a major player in sea level rise

ESA-NASA Collaboration Furthers Sea-Ice Research

Melting ice on Arctic islands boosts sea levels: study

WATER WORLD
Scorpion venom bad for bugs but good for pesticides

China food scandals spark new safety fears

Stressed out crop impede higher agriculture yields

Lima to declare itself a GMO-free zone

WATER WORLD
Japan mulls tsunami lessons for reconstruction

Ecuador on alert after volcano erupts

Forecasters predict multiple US hurricane landfalls

Rain is Colombia's 'worst' natural disaster: Santos

WATER WORLD
Diehard pro-Gbagbo militia begin to disarm

Darfur rebels reject draft Doha accord

Nigeria holds final polls despite violence

Burkina Faso president assumes defence post

WATER WORLD
Chinese population ageing, moving to the cities

Evolution of human 'super-brain' tied to development of bipedalism, tool-making

Berlusconi, Sarkozy meet over migrants

Pope urges 'solidarity' with refugees from conflict


The content herein, unless otherwise known to be public domain, are Copyright 1995-2010 - SpaceDaily. AFP and UPI Wire Stories are copyright Agence France-Presse and United Press International. ESA Portal Reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. Advertising does not imply endorsement,agreement or approval of any opinions, statements or information provided by SpaceDaily on any Web page published or hosted by SpaceDaily. Privacy Statement