Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

“Dead Zone” Summer Killed Billions of Ocean State Mussels

12.04.2006


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.


Dead Zone
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.



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.

The Ecology paper is available online.

Wendy Lawton | EurekAlert!
Further information:
http://www.brown.edu

More articles from Ecology, The Environment and Conservation:

nachricht When corals eat plastics
24.05.2018 | Justus-Liebig-Universität Gießen

nachricht Dispersal of Fish Eggs by Water Birds – Just a Myth?
19.02.2018 | Universität Basel

All articles from Ecology, The Environment and Conservation >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Powerful IT security for the car of the future – research alliance develops new approaches

The more electronics steer, accelerate and brake cars, the more important it is to protect them against cyber-attacks. That is why 15 partners from industry and academia will work together over the next three years on new approaches to IT security in self-driving cars. The joint project goes by the name Security For Connected, Autonomous Cars (SecForCARs) and has funding of €7.2 million from the German Federal Ministry of Education and Research. Infineon is leading the project.

Vehicles already offer diverse communication interfaces and more and more automated functions, such as distance and lane-keeping assist systems. At the same...

Im Focus: Molecular switch will facilitate the development of pioneering electro-optical devices

A research team led by physicists at the Technical University of Munich (TUM) has developed molecular nanoswitches that can be toggled between two structurally different states using an applied voltage. They can serve as the basis for a pioneering class of devices that could replace silicon-based components with organic molecules.

The development of new electronic technologies drives the incessant reduction of functional component sizes. In the context of an international collaborative...

Im Focus: LZH showcases laser material processing of tomorrow at the LASYS 2018

At the LASYS 2018, from June 5th to 7th, the Laser Zentrum Hannover e.V. (LZH) will be showcasing processes for the laser material processing of tomorrow in hall 4 at stand 4E75. With blown bomb shells the LZH will present first results of a research project on civil security.

At this year's LASYS, the LZH will exhibit light-based processes such as cutting, welding, ablation and structuring as well as additive manufacturing for...

Im Focus: Self-illuminating pixels for a new display generation

There are videos on the internet that can make one marvel at technology. For example, a smartphone is casually bent around the arm or a thin-film display is rolled in all directions and with almost every diameter. From the user's point of view, this looks fantastic. From a professional point of view, however, the question arises: Is that already possible?

At Display Week 2018, scientists from the Fraunhofer Institute for Applied Polymer Research IAP will be demonstrating today’s technological possibilities and...

Im Focus: Explanation for puzzling quantum oscillations has been found

So-called quantum many-body scars allow quantum systems to stay out of equilibrium much longer, explaining experiment | Study published in Nature Physics

Recently, researchers from Harvard and MIT succeeded in trapping a record 53 atoms and individually controlling their quantum state, realizing what is called a...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

In focus: Climate adapted plants

25.05.2018 | Event News

Save the date: Forum European Neuroscience – 07-11 July 2018 in Berlin, Germany

02.05.2018 | Event News

Invitation to the upcoming "Current Topics in Bioinformatics: Big Data in Genomics and Medicine"

13.04.2018 | Event News

 
Latest News

In focus: Climate adapted plants

25.05.2018 | Event News

Flow probes from the 3D printer

25.05.2018 | Machine Engineering

Less is more? Gene switch for healthy aging found

25.05.2018 | Life Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>