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 A new indicator for marine ecosystem changes: the diatom/dinoflagellate index
21.08.2017 | Leibniz-Institut für Ostseeforschung Warnemünde

nachricht Value from wastewater
16.08.2017 | Hochschule Landshut

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: Fizzy soda water could be key to clean manufacture of flat wonder material: Graphene

Whether you call it effervescent, fizzy, or sparkling, carbonated water is making a comeback as a beverage. Aside from quenching thirst, researchers at the University of Illinois at Urbana-Champaign have discovered a new use for these "bubbly" concoctions that will have major impact on the manufacturer of the world's thinnest, flattest, and one most useful materials -- graphene.

As graphene's popularity grows as an advanced "wonder" material, the speed and quality at which it can be manufactured will be paramount. With that in mind,...

Im Focus: Exotic quantum states made from light: Physicists create optical “wells” for a super-photon

Physicists at the University of Bonn have managed to create optical hollows and more complex patterns into which the light of a Bose-Einstein condensate flows. The creation of such highly low-loss structures for light is a prerequisite for complex light circuits, such as for quantum information processing for a new generation of computers. The researchers are now presenting their results in the journal Nature Photonics.

Light particles (photons) occur as tiny, indivisible portions. Many thousands of these light portions can be merged to form a single super-photon if they are...

Im Focus: Circular RNA linked to brain function

For the first time, scientists have shown that circular RNA is linked to brain function. When a RNA molecule called Cdr1as was deleted from the genome of mice, the animals had problems filtering out unnecessary information – like patients suffering from neuropsychiatric disorders.

While hundreds of circular RNAs (circRNAs) are abundant in mammalian brains, one big question has remained unanswered: What are they actually good for? In the...

Im Focus: RAVAN CubeSat measures Earth's outgoing energy

An experimental small satellite has successfully collected and delivered data on a key measurement for predicting changes in Earth's climate.

The Radiometer Assessment using Vertically Aligned Nanotubes (RAVAN) CubeSat was launched into low-Earth orbit on Nov. 11, 2016, in order to test new...

Im Focus: Scientists shine new light on the “other high temperature superconductor”

A study led by scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg presents evidence of the coexistence of superconductivity and “charge-density-waves” in compounds of the poorly-studied family of bismuthates. This observation opens up new perspectives for a deeper understanding of the phenomenon of high-temperature superconductivity, a topic which is at the core of condensed matter research since more than 30 years. The paper by Nicoletti et al has been published in the PNAS.

Since the beginning of the 20th century, superconductivity had been observed in some metals at temperatures only a few degrees above the absolute zero (minus...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Call for Papers – ICNFT 2018, 5th International Conference on New Forming Technology

16.08.2017 | Event News

Sustainability is the business model of tomorrow

04.08.2017 | Event News

Clash of Realities 2017: Registration now open. International Conference at TH Köln

26.07.2017 | Event News

 
Latest News

Cholesterol-lowering drugs may fight infectious disease

22.08.2017 | Health and Medicine

Meter-sized single-crystal graphene growth becomes possible

22.08.2017 | Materials Sciences

Repairing damaged hearts with self-healing heart cells

22.08.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>