A swirling oasis of life

Feb 14, 2012 by Jason Major, Universe Today
A 150-km (93-mile) - wide eddy in the southern Indian Ocean. Credit: NASA/Terra-MODIS

A serpentine eddy swirls in the southern Indian Ocean several hundred kilometers off the coast of South Africa in this natural-color image, acquired by NASA’s Terra satellite on December 26, 2011.

The blue color is created by blooms of phytoplankton, fertilized by the nutrient-rich deep water drawn up by the 150-km-wide eddy.

The counter-clockwise anticyclonic structure of the eddy may resemble a hurricane or typhoon, but unlike those violent storms eddies bring nourishment rather than destruction.

“Eddies are the internal weather of the sea,” said Dennis McGillicuddy, an oceanographer at the Woods Hole Oceanographic Institution in Massachusetts.

And also unlike atmospheric storms, ocean eddies can last for months, even up to a year. The largest ones can contain up to 1,200 cubic miles (5,000 cubic kilometers) of water.

The nutrient-drawing power of eddies can supply the relatively barren waters of the open ocean with nutrients, creating “oases in the oceanic desert,” according to McGillicuddy.

Read more about the WHOI study of eddies here.

The eddy imaged here likely peeled off from the Agulhas Current, which flows along the southeastern coast of Africa and around the tip of . Agulhas eddies tend to be among the largest in the world.

The image below shows the eddy in context with the surrounding area:

Eddy off the coast of South Africa. December 26, 2011. Credit: NASA/Terra-MODIS

MODIS (or Moderate Resolution Imaging Spectroradiometer) is a key instrument aboard ’s Terra (EOS AM) satellite. Terra MODIS views the entire Earth’s surface every 1 to 2 days, acquiring data in 36 spectral bands. These data improve our understanding of global dynamics and processes occurring on the land, in the , and in the lower atmosphere.

Explore further: Strong quake hits east Indonesia; no tsunami threat

add to favorites email to friend print save as pdf

Related Stories

East Coast gliders yield valuable marine life data

Feb 28, 2011

The influence ocean eddies have on marine life in the oceans surrounding Australia’s south-east is expected to become clearer after scientists examine data from new deep-diving research ‘gliders’ ...

NASA Satellites Keep Watch on Gulf Current Near Spill

May 25, 2010

(PhysOrg.com) -- Scientists and agencies monitoring the oil spill in the Gulf of Mexico are keeping a wary eye on changes in the nearby Loop Current, a warm ocean current that is part of the Gulf Stream.

Image: Phytoplankton Bloom in the North Atlantic

May 26, 2010

(PhysOrg.com) -- Late May 2010 brought peacock-hued swirls of blue and green to the North Atlantic. The iridescent waters formed a giant arc hundreds of kilometers across, extending from west of Ireland to ...

Recommended for you

Strong quake hits east Indonesia; no tsunami threat

10 hours ago

A strong earthquake struck off the coast of eastern Indonesia on Sunday evening, but there were no immediate reports of injuries or damage, and authorities said there was no threat of a tsunami.

Scientists make strides in tsunami warning since 2004

Dec 19, 2014

The 2004 tsunami led to greater global cooperation and improved techniques for detecting waves that could reach faraway shores, even though scientists still cannot predict when an earthquake will strike.

Trade winds ventilate the tropical oceans

Dec 19, 2014

Long-term observations indicate that the oxygen minimum zones in the tropical oceans have expanded in recent decades. The reason is still unknown. Now scientists at the GEOMAR Helmholtz Centre for Ocean Research ...

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.