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 Species may appear deceptively resilient to climate change
24.11.2017 | University of California - Davis

nachricht Scientists team up on study to save endangered African penguins
16.11.2017 | Florida Atlantic University

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: New proton record: Researchers measure magnetic moment with greatest possible precision

High-precision measurement of the g-factor eleven times more precise than before / Results indicate a strong similarity between protons and antiprotons

The magnetic moment of an individual proton is inconceivably small, but can still be quantified. The basis for undertaking this measurement was laid over ten...

Im Focus: Frictional Heat Powers Hydrothermal Activity on Enceladus

Computer simulation shows how the icy moon heats water in a porous rock core

Heat from the friction of rocks caused by tidal forces could be the “engine” for the hydrothermal activity on Saturn's moon Enceladus. This presupposes that...

Im Focus: Nanoparticles help with malaria diagnosis – new rapid test in development

The WHO reports an estimated 429,000 malaria deaths each year. The disease mostly affects tropical and subtropical regions and in particular the African continent. The Fraunhofer Institute for Silicate Research ISC teamed up with the Fraunhofer Institute for Molecular Biology and Applied Ecology IME and the Institute of Tropical Medicine at the University of Tübingen for a new test method to detect malaria parasites in blood. The idea of the research project “NanoFRET” is to develop a highly sensitive and reliable rapid diagnostic test so that patient treatment can begin as early as possible.

Malaria is caused by parasites transmitted by mosquito bite. The most dangerous form of malaria is malaria tropica. Left untreated, it is fatal in most cases....

Im Focus: A “cosmic snake” reveals the structure of remote galaxies

The formation of stars in distant galaxies is still largely unexplored. For the first time, astron-omers at the University of Geneva have now been able to closely observe a star system six billion light-years away. In doing so, they are confirming earlier simulations made by the University of Zurich. One special effect is made possible by the multiple reflections of images that run through the cosmos like a snake.

Today, astronomers have a pretty accurate idea of how stars were formed in the recent cosmic past. But do these laws also apply to older galaxies? For around a...

Im Focus: Visual intelligence is not the same as IQ

Just because someone is smart and well-motivated doesn't mean he or she can learn the visual skills needed to excel at tasks like matching fingerprints, interpreting medical X-rays, keeping track of aircraft on radar displays or forensic face matching.

That is the implication of a new study which shows for the first time that there is a broad range of differences in people's visual ability and that these...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Ecology Across Borders: International conference brings together 1,500 ecologists

15.11.2017 | Event News

Road into laboratory: Users discuss biaxial fatigue-testing for car and truck wheel

15.11.2017 | Event News

#Berlin5GWeek: The right network for Industry 4.0

30.10.2017 | Event News

 
Latest News

IceCube experiment finds Earth can block high-energy particles from nuclear reactions

24.11.2017 | Physics and Astronomy

A 'half-hearted' solution to one-sided heart failure

24.11.2017 | Health and Medicine

Heidelberg Researchers Study Unique Underwater Stalactites

24.11.2017 | Earth Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>