Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Gulf of Maine marine ecosystem may have entered new phase

04.08.2004


For most of the past 4,500 years, cod was king in the Gulf of Maine’s coastal waters. Today, cod have given way to the Jonah crab with potential long-term consequences for coastal fisheries, according to a University of Maine research report published in the journal Ecosystems.



With crabs and lobsters at the top of the proverbial heap, the Gulf may have entered a new stable phase marked by the presence of expansive kelp beds and the near absence of sea urchins. These findings could signal the likelihood of significant biological changes in other heavily fished parts of the world’s oceans as well.

The authors of the report are Robert S. Steneck, professor of marine sciences at UMaine’s Darling Marine Center, and former UMaine graduate students John Vavrinec and Amanda Leland. They received support for their research from the Pew Foundation for Marine Conservation, Maine Sea Grant, the Maine Department of Marine Resources and the National Undersea Research Program.


The researchers analyzed fishing records and previous studies to gather evidence for the changes brought on by fishing pressure in marine ecosystems. Ancient coastal middens, for example, have revealed evidence suggesting that Native American fishing activities were beginning to affect near shore ecosystems several thousand years ago. Analysis of colonial and modern fish landing records shows that such changes accelerated with the adoption of new fishing technologies.

It is a revolution of sorts, an overturning of the established order brought on by fishing pressure, that leads to major changes in the coastal marine ecosystem, according to the article, "Accelerating Trophic-level Dysfunction in Kelp Forest Ecosystems of the Western North Atlantic." In the Gulf of Maine, the revolution was brought on by the drastic reduction in the number of cod and other top predators over the past century.

"To understand how these changes are accelerating, we looked at archaeological data for coastal Maine over the past 4,500 years. The long dominance of predators has given way to many species playing ’king of the hill,’" says Steneck.

"While there is no fear of these species going extinct," he adds, "entire sections of the food web have become so rare that they no longer perform critical ecological functions in the marine community. This is called food web (or trophic level) dysfunction."

When such species as cod were no longer able to perform their function of keeping their prey species in check, the ecosystem entered a new phase marked by abundant sea urchins and a lack of kelp beds. Urchins ate so much kelp that they created areas known as "urchin barrens" where only low growing algae could survive.

In turn, the harvesting of urchins during the 1990s has led to the re-emergence of kelp beds and the dominance of crabs and lobsters. The report cites an experiment in which adult urchins were stocked in an area to see if they would survive and reproduce. Crabs ate most of the urchins.

"The problem is, this ’trophic level dysfunction’ is accelerating. Ecosystem changes persist for shorter and shorter periods of time because the ’driver’ species increasingly fall below functional population densities," Steneck explains.

"When a threshold is reached, the system changes fundamentally. Everything that came before it is thrown out the window. What this does in the long run is make the system unpredictable."

For the first time, adds Steneck, the low diversity of marine organisms, including Maine’s fabled groundfish, have left the system too reliant on a single species (lobster) and too vulnerable to continued and unpredictable large-scale fluctuations.

Robert Steneck | EurekAlert!
Further information:
http://www.maine.edu

More articles from Ecology, The Environment and Conservation:

nachricht Joint research project on wastewater for reuse examines pond system in Namibia
19.12.2016 | Technische Universität Darmstadt

nachricht Scientists produce a new roadmap for guiding development & conservation in the Amazon
09.12.2016 | Wildlife Conservation Society

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: Interfacial Superconductivity: Magnetic and superconducting order revealed simultaneously

Researchers from the University of Hamburg in Germany, in collaboration with colleagues from the University of Aarhus in Denmark, have synthesized a new superconducting material by growing a few layers of an antiferromagnetic transition-metal chalcogenide on a bismuth-based topological insulator, both being non-superconducting materials.

While superconductivity and magnetism are generally believed to be mutually exclusive, surprisingly, in this new material, superconducting correlations...

Im Focus: Studying fundamental particles in materials

Laser-driving of semimetals allows creating novel quasiparticle states within condensed matter systems and switching between different states on ultrafast time scales

Studying properties of fundamental particles in condensed matter systems is a promising approach to quantum field theory. Quasiparticles offer the opportunity...

Im Focus: Designing Architecture with Solar Building Envelopes

Among the general public, solar thermal energy is currently associated with dark blue, rectangular collectors on building roofs. Technologies are needed for aesthetically high quality architecture which offer the architect more room for manoeuvre when it comes to low- and plus-energy buildings. With the “ArKol” project, researchers at Fraunhofer ISE together with partners are currently developing two façade collectors for solar thermal energy generation, which permit a high degree of design flexibility: a strip collector for opaque façade sections and a solar thermal blind for transparent sections. The current state of the two developments will be presented at the BAU 2017 trade fair.

As part of the “ArKol – development of architecturally highly integrated façade collectors with heat pipes” project, Fraunhofer ISE together with its partners...

Im Focus: How to inflate a hardened concrete shell with a weight of 80 t

At TU Wien, an alternative for resource intensive formwork for the construction of concrete domes was developed. It is now used in a test dome for the Austrian Federal Railways Infrastructure (ÖBB Infrastruktur).

Concrete shells are efficient structures, but not very resource efficient. The formwork for the construction of concrete domes alone requires a high amount of...

Im Focus: Bacterial Pac Man molecule snaps at sugar

Many pathogens use certain sugar compounds from their host to help conceal themselves against the immune system. Scientists at the University of Bonn have now, in cooperation with researchers at the University of York in the United Kingdom, analyzed the dynamics of a bacterial molecule that is involved in this process. They demonstrate that the protein grabs onto the sugar molecule with a Pac Man-like chewing motion and holds it until it can be used. Their results could help design therapeutics that could make the protein poorer at grabbing and holding and hence compromise the pathogen in the host. The study has now been published in “Biophysical Journal”.

The cells of the mouth, nose and intestinal mucosa produce large quantities of a chemical called sialic acid. Many bacteria possess a special transport system...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

12V, 48V, high-voltage – trends in E/E automotive architecture

10.01.2017 | Event News

2nd Conference on Non-Textual Information on 10 and 11 May 2017 in Hannover

09.01.2017 | Event News

Nothing will happen without batteries making it happen!

05.01.2017 | Event News

 
Latest News

Water - as the underlying driver of the Earth’s carbon cycle

17.01.2017 | Earth Sciences

Interfacial Superconductivity: Magnetic and superconducting order revealed simultaneously

17.01.2017 | Materials Sciences

Smart homes will “LISTEN” to your voice

17.01.2017 | Architecture and Construction

VideoLinks
B2B-VideoLinks
More VideoLinks >>>