Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Research: Coral reefs’ decline actually began centuries ago

15.08.2003


Global warming and pollution are among the modern-day threats commonly blamed for decline of coral reefs, but new research shows the downfall of those resplendent and diverse signatures of tropical oceans actually may have begun centuries ago.


According to a paper set to appear Friday (8/15) in the journal Science, the downward spiral started when people first began killing off reef-frequenting large fish, turtles, seals and other top predators or herbivores – a process that started thousands of years ago in some parts of the world and just a century or so ago in others.

"What really struck us was the universality of the decline trajectories," said Karen Bjorndal, one of 12 authors on the paper and zoology professor and director of the Archie Carr Center for Sea Turtle Research at the University of Florida. "It didn’t matter if we were looking at the Red Sea, Australia or the Caribbean. As soon as human exploitation began, whether in the 1600s in Bermuda or tens of thousands of years ago in the Red Sea, the same scenarios were put into play."

The project is an outgrowth of research published in 2001 that tied overfishing to worldwide declines of coastal ecosystems. That paper argued that overfishing disturbs the ecological balance of marine environments, with the killing of green sea turtles, for example, ultimately contributing to the die-off of sea grasses. The authors of the current paper, who were among the scientists involved in that research, zeroed in on coral reefs, long seen as seriously threatened by modern pollution, global warming and diseases that cause the coral organism to die and "bleach," its mosaic of colors turning a uniform skeletal white. The goal: reconstruct the ecological history of the reefs from before the first people appeared to fish them some 40,000 years ago to the present era.



The scientists pored over historical and archaeological records surrounding major reef systems in 14 regions in the Atlantic and Pacific oceans and the Red Sea, including the reefs of the Caribbean and the Great Barrier Reef. Each scientist handled a different region, with Bjorndal tackling the Bahamas and the Cayman Islands. She said her research led her to more than 400 references for the Bahamas alone, including papers on archaeological findings and colonial fishing-catch records. Among her sources: research by UF anthropologists showing that indigenous Bahamians hunted green turtles to such an extent they seriously depleted the herbivore long before the first colonists arrived.

"I used to think that green turtles were basically in pristine shape when Columbus arrived, and I don’t think that anymore," she said.

The researchers discovered that all the reefs experienced declines as a result of human activity, although the declines occurred over different periods of time and were more advanced in some places than others. Regardless of geography, the researchers learned, the declines follow the same pattern. First, people deplete large predators such as sharks and large herbivores, which tend to be both easy to kill or capture and slow to rebuild their populations. Next to go are smaller animals, such as small fishes, followed last by sea grasses, corals and other so-called "architectural" parts of the coral reefs.

By 1900 -- decades before the first scuba divers experienced the splendor of coral reefs -- this slow death had already started in more than 80 percent of the reefs worldwide, the scientists found. Today, in the regions where the process is most advanced, such as Jamaica, the corals are either dead or dying, the fish are tiny, few other organisms such as shellfish exist, and the formerly vibrant reef structure is dull and coated with algae. The Great Barrier Reef sometimes is said to be largely pristine, but it’s actually as much as a third of the way toward ecological extinction, Bjorndal said.

For the first time, Bjorndal said, the research will give managers of the world’s coral reefs – and the countries that have jurisdiction over these resources -- a yardstick they can use to determine how far their particular reef system has progressed along the ecological "extinction continuum." She and the other scientists hope the result will help spur strengthened conservation efforts. She noted that, with the exception of the extinct Caribbean monk seal and a handful of other top predators, most reef organisms have been depleted but are not yet extinct – offering at least some hope for the future.

"If we could step back in with strong management decisions we could restore the ecosystem, but that’s a matter of political will and funding and a lot of other influences that are difficult to predict," she said.



Writer: Aaron Hoover, 352-392-0186, ahoover@ufl.edu
Source: Karen Bjorndal, 352-392-5194, kab@zoo.ufl.edu

Aaron Hoover | EurekAlert!
Further information:
http://www.ufl.edu/

More articles from Ecology, The Environment and Conservation:

nachricht International network connects experimental research in European waters
21.03.2017 | Leibniz-Institut für Gewässerökologie und Binnenfischerei (IGB)

nachricht World Water Day 2017: It doesn’t Always Have to Be Drinking Water – Using Wastewater as a Resource
17.03.2017 | ISOE - Institut für sozial-ökologische Forschung

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: Giant Magnetic Fields in the Universe

Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.

The results will be published on March 22 in the journal „Astronomy & Astrophysics“.

Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...

Im Focus: Tracing down linear ubiquitination

Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.

Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...

Im Focus: Perovskite edges can be tuned for optoelectronic performance

Layered 2D material improves efficiency for solar cells and LEDs

In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...

Im Focus: Polymer-coated silicon nanosheets as alternative to graphene: A perfect team for nanoelectronics

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...

Im Focus: Researchers Imitate Molecular Crowding in Cells

Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to simulate these confined natural conditions in artificial vesicles for the first time. As reported in the academic journal Small, the results are offering better insight into the development of nanoreactors and artificial organelles.

Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

International Land Use Symposium ILUS 2017: Call for Abstracts and Registration open

20.03.2017 | Event News

CONNECT 2017: International congress on connective tissue

14.03.2017 | Event News

ICTM Conference: Turbine Construction between Big Data and Additive Manufacturing

07.03.2017 | Event News

 
Latest News

Argon is not the 'dope' for metallic hydrogen

24.03.2017 | Materials Sciences

Astronomers find unexpected, dust-obscured star formation in distant galaxy

24.03.2017 | Physics and Astronomy

Gravitational wave kicks monster black hole out of galactic core

24.03.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>