Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Marine biodiversity essential to preserving species

22.08.2002


A new study of marine ecosystems suggests that the preservation of biodiversity is more than just a lofty goal - it’s an absolute necessity to keep the system healthy and prevent both local or regional extinction of multiple species.



The population balance between various fish species, their competitors and their predators are all essential to the proper functioning of the ecosystem, the study showed, and overfishing of any one species can have ripple effects that destabilize the whole fishery.

The study was conducted by marine zoologists at Oregon State University and published this week in a professional journal, the Proceedings of the National Academy of Sciences. It was done on coral reefs in the Bahamas, which allowed the type of experimental manipulations that are usually impossible to do in a marine ecosystem.


"The research showed that all fish species within a food web are connected with one another, and the removal of any one species can cause whole populations to break down," said Mark Hixon, an OSU professor of zoology. "This is especially true when you take away the predatory species, which are a key to the natural balance and health of marine ecosystems." The study is particularly relevant to the global problems now being experienced in many commercial fisheries, Hixon said, because many of the fish species most commonly targeted by fisheries are marine predators.

In particular, this study confirmed the operation in a marine ecosystem of a concept that has long been recognized with animals in terrestrial ecosystems – that of "density dependent mortality." Basically, when a species population size is low, the mortality rate will also be low – predators tend to target species that are more abundant. And when a species population is high, the mortality rate will increase, as predators take advantage of the easy availability of food.

Other than the interaction between prey and predator, Hixon said, there is also an important role for competitors – two or more species that fight for the same resources. The competing species have negative effects on each other’s population, and distracted competitors can be more vulnerable to predation.

"This interaction has been known for some time in land ecosystems," Hixon said. "But it’s been much more difficult to demonstrate in the open ocean."

With experimental manipulations on coral reefs in the clear waters of the Bahamas, OSU scientists were able to isolate some reefs from others and selectively remove certain fish, their competitors or predators to observe the effect.

"We found that the removal of any one species can have ramifications for the whole ecosystem," Hixon said. "Without predation, a fish species can increase its population to an unsupportable size. Lacking food, fish become vulnerable to disease, changes in water conditions and ultimate collapse of that species or the whole fishery. Everything is connected to everything else."

In the Pacific Northwest, some of the key predatory species are lingcod, some larger rockfish and other groundfish.

The findings may help explain why some fish populations undergo such dramatic changes either naturally or when pressured by external forces such as fishing, Hixon said. It’s not unusual for fish populations within a certain species and location to vary by as much as 10 to 100 times.

However, when there’s a proper and natural balance between a species, its competitors and its predators, Hixon said, there is much less risk of population collapse or regional extinction.

The study was funded by a 4-year, $400,000 grant from the National Science Foundation, and also the National Undersea Research Program of the U.S. National Oceanic and Atmospheric Administration.

In continuing research, OSU scientists hope to study these processes within the context of marine reserves, and see if the maintenance of balanced and healthy fish populations in such reserves can have a positive influence on the availability of species elsewhere, including those sought in commercial or recreational fisheries outside the reserves.


By David Stauth, 541-737-0787
SOURCE: Mark Hixon, 541-737-5364


Mark Hixon | EurekAlert!

More articles from Ecology, The Environment and Conservation:

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

nachricht Removing fossil fuel subsidies will not reduce CO2 emissions as much as hoped
08.02.2018 | International Institute for Applied Systems Analysis (IIASA)

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: Writing and deleting magnets with lasers

Study published in the journal ACS Applied Materials & Interfaces is the outcome of an international effort that included teams from Dresden and Berlin in Germany, and the US.

Scientists at the Helmholtz-Zentrum Dresden-Rossendorf (HZDR) together with colleagues from the Helmholtz-Zentrum Berlin (HZB) and the University of Virginia...

Im Focus: Gamma-ray flashes from plasma filaments

Novel highly efficient and brilliant gamma-ray source: Based on model calculations, physicists of the Max PIanck Institute for Nuclear Physics in Heidelberg propose a novel method for an efficient high-brilliance gamma-ray source. A giant collimated gamma-ray pulse is generated from the interaction of a dense ultra-relativistic electron beam with a thin solid conductor. Energetic gamma-rays are copiously produced as the electron beam splits into filaments while propagating across the conductor. The resulting gamma-ray energy and flux enable novel experiments in nuclear and fundamental physics.

The typical wavelength of light interacting with an object of the microcosm scales with the size of this object. For atoms, this ranges from visible light to...

Im Focus: Basel researchers succeed in cultivating cartilage from stem cells

Stable joint cartilage can be produced from adult stem cells originating from bone marrow. This is made possible by inducing specific molecular processes occurring during embryonic cartilage formation, as researchers from the University and University Hospital of Basel report in the scientific journal PNAS.

Certain mesenchymal stem/stromal cells from the bone marrow of adults are considered extremely promising for skeletal tissue regeneration. These adult stem...

Im Focus: Like a wedge in a hinge

Researchers lay groundwork to tailor drugs for new targets in cancer therapy

In the fight against cancer, scientists are developing new drugs to hit tumor cells at so far unused weak points. Such a “sore spot” is the protein complex...

Im Focus: The Future of Ultrafast Solid-State Physics

In an article that appears in the journal “Review of Modern Physics”, researchers at the Laboratory for Attosecond Physics (LAP) assess the current state of the field of ultrafast physics and consider its implications for future technologies.

Physicists can now control light in both time and space with hitherto unimagined precision. This is particularly true for the ability to generate ultrashort...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

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

13.04.2018 | Event News

Unique scope of UV LED technologies and applications presented in Berlin: ICULTA-2018

12.04.2018 | Event News

IWOLIA: A conference bringing together German Industrie 4.0 and French Industrie du Futur

09.04.2018 | Event News

 
Latest News

Diamond-like carbon is formed differently to what was believed -- machine learning enables development of new model

19.04.2018 | Materials Sciences

Electromagnetic wizardry: Wireless power transfer enhanced by backward signal

19.04.2018 | Physics and Astronomy

Ultrafast electron oscillation and dephasing monitored by attosecond light source

19.04.2018 | Physics and Astronomy

VideoLinks
Science & Research
Overview of more VideoLinks >>>