Featured Research

from universities, journals, and other organizations

'Dead Zone' Summer Killed Billions Of Ocean State Mussels

Date:
April 12, 2006
Source:
Brown University
Summary:
A "dead zone" that formed in 2001 in Narragansett Bay left a lethal legacy, Brown University research shows. In a study of nine mussel reefs, published in Ecology, researchers report that oxygen-depleted water killed one reef and nearly wiped out the rest. A year later, only one of the nine reefs was recovering. The result was a sharp reduction in the reefs' ability to filter phytoplankton, a process that helps control "dead zone" formation.

Waves of dead mussels -- researchers estimate the die-off at about 4.5 billion -- washed ashore on Prudence Island, left, and elsewhere in Narragansett Bay during the summer of 2001.
Credit: Image courtesy of Brown University

Fish kills, foul odors and closed beaches hit Rhode Island’s Narragansett Bay during the summer of 2001. The culprit was hypoxia, or oxygen depletion, which literally suffocates sea life. While some evidence of this “dead zone” could be seen on the bay’s surface, Brown University ecologists went underwater and discovered a massive mussel die-off.

In a survey of nine mussel reefs located in the central bay, researchers found one reef completely wiped out. Of the remaining eight, seven were severely depleted. The ecologists estimate that the number of mussels that died was roughly 4.5 billion, or about 80 percent of the reefs’ population.

Just one month before hypoxia hit, researchers surveyed the same reefs and saw acres of healthy, densely packed mussels blanketing the estuary floor.

“What we saw was a local extinction,” said Andrew Altieri, a new Ph.D. graduate from Brown University’s Department of Ecology and Evolutionary Biology. “The mussel population was devastated. If the magnitude of this die-off was visible from the surface, there would’ve been public alarm.”

Altieri conducted the surveys with Jon Witman, a marine ecologist and an associate professor in the Department of Ecology and Evolutionary Biology. In a report on their research, published in Ecology, Altieri and Witman show that mussel die-off had a lasting effect.

In fall 2002, one year after the die-off, the pair found that only one of the nine reefs was recovering. Altieri and Witman wondered how the loss of so many mussels, which filter minute algae called phytoplankton from the water, might affect the bay’s ecosystem.

So Altieri calculated the filtering capacity of mussels in the reefs, before and after the hypoxic event. They found that the healthy mussels could filter the equivalent of the entire volume of Narragansett Bay in just 20 days. But within weeks of the die-off, that filtering capacity dropped by 75 percent.

Altieri said this is an important, and troubling, finding for water quality and sea life in the bay.

Hypoxia can start when fertilizer or sewage spills into coastal waters, carrying nitrogen, phosphorus and other nutrients. Often fueled by warm temperatures and a lack of circulation, this nutrient rush can cause algae blooms. When the algae dies, it sinks to the bottom, where it is consumed by bacteria – along with dissolved oxygen. This is what happened in Narragansett Bay in the summer of 2001 and again in the summer of 2003.

Mussels, however, can help control nutrient overload and hypoxia by consuming phytoplankton, which reduces bottom-dwelling bacteria. “When we lose mussels, we may be losing the ability to prevent future dead zones from forming,” Altieri said. “So these sorts of extinctions may trigger a downward spiral, with coastal zones less able to handle environmental degradation.”

According to a 2004 United Nations Environment Program report, the number of areas hit by hypoxia worldwide has doubled since 1990. “Dead zones” can be found along the east coast of the United States, in the seas of Europe, as well off Australia, Brazil, and Japan. One of the biggest “dead zones” is in the Gulf of Mexico, where it has grown to an area as big as New Jersey.

Altieri and Witman said lessons from Narragansett Bay could be applied to other “dead zones.”

“When you lose a foundation species such as mussels – which filter water and provide food and habitat for other organisms – you see a large and lasting effect on the ecosystem,” Witman said. Added Altieri: “We’ve already seen this in Chesapeake Bay and other coastal estuaries, where loss of filter-feeding oysters has led to runaway effects of pollution and hypoxia and prevented restoration of these shellfish.”

The National Oceanic and Atmospheric Administration, the Andrew Mellon Foundation, and Rhode Island Sea Grant funded the work.


Story Source:

The above story is based on materials provided by Brown University. Note: Materials may be edited for content and length.


Cite This Page:

Brown University. "'Dead Zone' Summer Killed Billions Of Ocean State Mussels." ScienceDaily. ScienceDaily, 12 April 2006. <www.sciencedaily.com/releases/2006/04/060411230140.htm>.
Brown University. (2006, April 12). 'Dead Zone' Summer Killed Billions Of Ocean State Mussels. ScienceDaily. Retrieved July 24, 2014 from www.sciencedaily.com/releases/2006/04/060411230140.htm
Brown University. "'Dead Zone' Summer Killed Billions Of Ocean State Mussels." ScienceDaily. www.sciencedaily.com/releases/2006/04/060411230140.htm (accessed July 24, 2014).

Share This




More Plants & Animals News

Thursday, July 24, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Dogs Appear To Become Jealous Of Owners' Attention

Dogs Appear To Become Jealous Of Owners' Attention

Newsy (July 23, 2014) A U.C. San Diego researcher says jealousy isn't just a human trait, and dogs aren't the best at sharing the attention of humans with other dogs. Video provided by Newsy
Powered by NewsLook.com
Professor Creates Site Revealing Where People's Cats Live

Professor Creates Site Revealing Where People's Cats Live

Newsy (July 23, 2014) ​It's called I Know Where Your Cat Lives, and you can keep hitting the "Random Cat" button to find more real cats all over the world. Video provided by Newsy
Powered by NewsLook.com
Stone Fruit Listeria Scare Causes Sweeping Recall

Stone Fruit Listeria Scare Causes Sweeping Recall

Newsy (July 22, 2014) The Wawona Packing Company has issued a voluntary recall on the stone fruit it distributes due to a possible Listeria outbreak. Video provided by Newsy
Powered by NewsLook.com
Michigan Plant's Goal: Flower and Die

Michigan Plant's Goal: Flower and Die

AP (July 22, 2014) An 80-year-old agave plant, which is blooming for the first and only time at a University of Michigan conservatory, will die when it's done (July 22) Video provided by AP
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:
from the past week

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