Featured Research

from universities, journals, and other organizations

NASA/French Satellite Follows Fish-Feeding Eddies

Date:
February 21, 2000
Source:
NASA/Jet Propulsion Laboratory
Summary:
Some of the largest ocean eddies to form in recent years along the west coast of Alaska and Canada, bringing with them nutrients to feed a dwindling population of salmon and other marine life, are being tracked with satellite data from the joint NASA-French space agency TOPEX/Poseidon.

Some of the largest ocean eddies to form in recent years along the west coast of Alaska and Canada, bringing with them nutrients to feed a dwindling population of salmon and other marine life, are being tracked with satellite data from the joint NASA-French space agency TOPEX/Poseidon.

Related Articles


An eddy is a water current that runs contrary to the main current. The large "Sitka" and "Haida" eddies, named for the town of Sitka, Alaska, and the native name for the Queen Charlotte Islands, British Columbia, Canada, form along the Alaskan Panhandle and Canadian west coast each year and drift into deeper waters to the west. The TOPEX/Poseidon satellite has tracked these and other eddies since the 1992-93 winter. Years with heavy El Niño winds appear to produce particularly large eddies that can last for several years and replenish nutrient-starved regions of the ocean. Observations of the Haida Eddy by the Canadian research vessel J.P. Tully show that the eddies move fresh water, iron and nitrates from land to sea.

"Our concern over the depletion of fish in this region makes altimeter measurements such as TOPEX/Poseidon data particularly important to understanding the formation and movement of these nutrient-rich eddies and how they influence salmon growth and other fisheries," said William Crawford of Fisheries and Oceans Canada at the Institute of Ocean Sciences. He and colleague Frank Whitney have been using TOPEX/Poseidon images produced by the University of Colorado to track large-scale eddies along the Pacific Northwest. They observed unusually high Sitka and Haida eddies in the ocean during the severe El Niño of 1998. Both eddies were 30 centimeters (12 inches) higher than surrounding waters.

"These eddies, which brought higher nutrient levels and a local resurgence of phytoplankton, became two of the largest observed," Crawford said. Phytoplankton is the minute plant life found in bodies of water. "With the subsidence of the Haida Eddy over the next year, we began to observe in the eddy a steady depletion of nutrients that are important to the food chain."

The eddies usually drift westward and disappear within two years in deep waters off the Gulf of Alaska. These rotating masses of water can average up to a few hundred kilometers in diameter, forming along the coast within the northbound coastal current, Crawford said, and a large eddy can contain up to 5,000 cubic kilometers of water, which is about the volume of Lake Michigan.

New measurements taken by TOPEX/Poseidon are available online at http://www-ccar.colorado.edu/~realtime/global-real-time_ssh

Salinity and temperature measurements from the Canadian ship J.P. Tully have indicated that the subsurface water is fresher and warmer in this region than surrounding waters. Plans are under way to augment that data and to combine topographic measurements from space with new data on nutrient levels and fish abundance from ships to help fisheries predict annual food production. Crawford and Whitney will use TOPEX/Poseidon observations in the Gulf of Alaska to determine the average seasonal height of the sea surface and help determine the northward flow of surface currents along the Pacific coasts.

See the Institute of Ocean Sciences web page http://www.ios.bc.ca/ios/osap/projects/eddy.htm for further information.

The U.S./French mission, launched in 1992, is managed by the Jet Propulsion Laboratory for NASA's Earth Sciences Enterprise, Washington, D.C. JPL is a division of the California Institute of Technology in Pasadena.


Story Source:

The above story is based on materials provided by NASA/Jet Propulsion Laboratory. Note: Materials may be edited for content and length.


Cite This Page:

NASA/Jet Propulsion Laboratory. "NASA/French Satellite Follows Fish-Feeding Eddies." ScienceDaily. ScienceDaily, 21 February 2000. <www.sciencedaily.com/releases/2000/02/000218055555.htm>.
NASA/Jet Propulsion Laboratory. (2000, February 21). NASA/French Satellite Follows Fish-Feeding Eddies. ScienceDaily. Retrieved December 19, 2014 from www.sciencedaily.com/releases/2000/02/000218055555.htm
NASA/Jet Propulsion Laboratory. "NASA/French Satellite Follows Fish-Feeding Eddies." ScienceDaily. www.sciencedaily.com/releases/2000/02/000218055555.htm (accessed December 19, 2014).

Share This


More From ScienceDaily



More Plants & Animals News

Friday, December 19, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Navy Unveils Robot Fish

Navy Unveils Robot Fish

Reuters - Light News Video Online (Dec. 18, 2014) — The U.S. Navy unveils an underwater device that mimics the movement of a fish. Tara Cleary reports. Video provided by Reuters
Powered by NewsLook.com
Kids Die While Under Protective Services

Kids Die While Under Protective Services

AP (Dec. 18, 2014) — As part of a six-month investigation of child maltreatment deaths, the AP found that hundreds of deaths from horrific abuse and neglect could have been prevented. AP's Haven Daley reports. (Dec. 18) Video provided by AP
Powered by NewsLook.com
When You Lose Weight, This Is Where The Fat Goes

When You Lose Weight, This Is Where The Fat Goes

Newsy (Dec. 17, 2014) — Can fat disappear into thin air? New research finds that during weight loss, over 80 percent of a person's fat molecules escape through the lungs. Video provided by Newsy
Powered by NewsLook.com
The Hottest Food Trends for 2015

The Hottest Food Trends for 2015

Buzz60 (Dec. 17, 2014) — Urbanspoon predicts whicg food trends will dominate the culinary scene in 2015. Mara Montalbano (@maramontalbano) has the story. Video provided by Buzz60
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
 
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:  

Breaking News:

Strange & Offbeat Stories

 

Plants & Animals

Earth & Climate

Fossils & Ruins

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:  

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile iPhone Android Web
Follow Facebook Twitter Google+
Subscribe RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins