Featured Research

from universities, journals, and other organizations

Large Gulf dead zone, but smaller than predicted

Date:
July 29, 2013
Source:
National Oceanic and Atmospheric Administration
Summary:
Scientists have found a large Gulf of Mexico oxygen-free or hypoxic 'dead' zone, but not as large as had been predicted. Measuring 5,840 square miles, an area the size of Connecticut, the 2013 Gulf dead zone indicates nutrients from the Mississippi River watershed, which drains 40 percent of the lower 48 states, are continuing to affect the nation's commercial and recreational marine resources in the Gulf.

This map shows the hypoxia area on the Louisiana Gulf of Mexico shelf in 2013.
Credit: LUMCON (Rabalais), NOAA

NOAA-supported scientists found a large Gulf of Mexico oxygen-free or hypoxic "dead" zone, but not as large as had been predicted. Measuring 5,840 square miles, an area the size of Connecticut, the 2013 Gulf dead zone indicates nutrients from the Mississippi River watershed are continuing to affect the nation's commercial and recreational marine resources in the Gulf.

Related Articles


"A near-record area was expected because of wet spring conditions in the Mississippi watershed and the resultant high river flows which deliver large amounts of nutrients," said Nancy Rabalais, Ph.D. executive director of the Louisiana Universities Marine Consortium (LUMCON), who led the July 21-28 survey cruise. "But nature's wind-mixing events and winds forcing the mass of low oxygen water towards the east resulted in a slightly above average bottom footprint."

Hypoxia is fueled by nutrient runoff from agricultural and other human activities in the watershed. These nutrients stimulate an overgrowth of algae that sinks, decomposes and consumes most of the oxygen needed to support life. Normally the low or no oxygen area is found closer to the Gulf floor as the decaying algae settle towards the bottom. This year researchers found many areas across the Gulf where oxygen conditions were severely low at the bottom and animals normally found at the seabed were swimming at the surface.

Graph showing historical hypoxia trends.

This is in contrast to 2012, when drought conditions resulted in the fourth smallest dead zones on record, measuring 2,889 square miles, an area slightly larger than Delaware. The largest previous dead zone was in 2002, encompassing 8,481 square miles. The smallest recorded dead zone measured 15 square miles in 1988. The average size of the dead zone over the past five years has been 5,176 square miles, more than twice the 1,900 square mile goal set by the Gulf of Mexico / Mississippi River Watershed Nutrient Task Force in 2001 and reaffirmed in 2008.

On June 18, NOAA-sponsored forecast models developed by Donald Scavia, Ph.D., University of Michigan, and R. Eugene Turner, Ph.D., Louisiana State University, predicted the Gulf hypoxic zone would range in size from 7,286 to 8,561 square miles.

"NOAA's investment in the Gulf of Mexico continues to yield results that confirm the complex dynamics of hypoxia and provide managers and the public with accurate scientific information for managing and restoring the nation's valuable coastal resources," said Robert Magnien, Ph.D., director of NOAA's Center for Sponsored Coastal Ocean Research. "For those who depend upon and enjoy the abundant natural resources of the Gulf of Mexico, it is imperative that we intensify our efforts to reduce nutrient pollution before the ecosystem degrades any further."

This annual measurement provides federal and state agencies working on the 2008 Gulf task force implementation actions with the real consequences of inadequate nutrient pollution management. The task force's actions are set for review this summer.

The hypoxic zone off the coast of Louisiana and Texas forms each summer threatening the ecosystem supporting valuable commercial and recreational Gulf fisheries that in 2011 had a commercial dockside value of $818 million and an estimated 23 million recreational fishing trips. The Gulf task force, in its 2008 report, states that "hypoxia has negative impacts on marine resources." It further states that research on living resources in the Gulf show long term ecological changes in species diversity and a large scale, often rapid change, in the ecosystem's food-web that is both "difficult and impossible to reverse." Additionally, there are numerous annual areas of the Gulf where large scale fish kills occur as a result of hypoxia.

Two surveys conducted in June and early July, one of which was led by a NOAA-supported Texas A&M University team, suggested a large hypoxic zone was forming in the Gulf, though the LUMCON July measurement will be the official one as required of NOAA by the Task Force. NOAA's National Marine Fisheries Service, in conducting its Southeast Monitoring and Assessment Program groundfish surveys, also found large expanses of hypoxia in June-early July. Texas A&M will be conducting a follow-up cruise in mid-August to provide its final seasonal update.

Visit the Gulf Hypoxia web site for additional graphics and information concerning this summer's LUMCON research cruise, and previous cruises.

NOAA's National Ocean Service has been funding monitoring and research for the dead zone in the Gulf of Mexico since 1985 and currently oversees the NGOMEX program, the hypoxia research effort for the northern Gulf which is authorized by the Harmful Algal Bloom and Hypoxia Research and Control Act.

The National Centers for Coastal Ocean Science is the coastal science office for NOAA's National Ocean Service.


Story Source:

The above story is based on materials provided by National Oceanic and Atmospheric Administration. Note: Materials may be edited for content and length.


Cite This Page:

National Oceanic and Atmospheric Administration. "Large Gulf dead zone, but smaller than predicted." ScienceDaily. ScienceDaily, 29 July 2013. <www.sciencedaily.com/releases/2013/07/130729133436.htm>.
National Oceanic and Atmospheric Administration. (2013, July 29). Large Gulf dead zone, but smaller than predicted. ScienceDaily. Retrieved November 22, 2014 from www.sciencedaily.com/releases/2013/07/130729133436.htm
National Oceanic and Atmospheric Administration. "Large Gulf dead zone, but smaller than predicted." ScienceDaily. www.sciencedaily.com/releases/2013/07/130729133436.htm (accessed November 22, 2014).

Share This


More From ScienceDaily



More Earth & Climate News

Saturday, November 22, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Anglerfish Rarely Seen In Its Habitat Will Haunt You

Anglerfish Rarely Seen In Its Habitat Will Haunt You

Newsy (Nov. 22, 2014) For the first time Monterey Bay Aquarium recorded a video of the elusive, creepy and rarely seen anglerfish. Video provided by Newsy
Powered by NewsLook.com
Raw: Buffalo Residents Digging Out, Helping out

Raw: Buffalo Residents Digging Out, Helping out

AP (Nov. 22, 2014) Hundreds of volunteers joined a 'shovel brigade' in Buffalo, New York on Saturday, as the city was living up to its nickname, "The City of Good Neighbors." Video provided by AP
Powered by NewsLook.com
Toyota's Hydrogen Fuel-Cell Green Car Soon Available in the US

Toyota's Hydrogen Fuel-Cell Green Car Soon Available in the US

AFP (Nov. 21, 2014) Toyota presented its hydrogen fuel-cell compact car called "Mirai" to US consumers at the Los Angeles auto show. The car should go on sale in 2015 for around $60.000. It combines stored hydrogen with oxygen to generate its own power. Duration: 01:18 Video provided by AFP
Powered by NewsLook.com
Google Announces Improvements To Balloon-Borne Wi-Fi Project

Google Announces Improvements To Balloon-Borne Wi-Fi Project

Newsy (Nov. 21, 2014) In a blog post, Google said its balloons have traveled 3 million kilometers since the start of Project Loon. Video provided by Newsy
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