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 Rain is important for how carbon dioxide affects grasslands
06.03.2019 | University of Gothenburg

nachricht Northeast-Atlantic fish stocks: Recovery driven by improved management
04.02.2019 | Johann Heinrich von Thünen-Institut, Bundesforschungsinstitut für Ländliche Räume, Wald und Fischerei

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: Revealing the secret of the vacuum for the first time

New research group at the University of Jena combines theory and experiment to demonstrate for the first time certain physical processes in a quantum vacuum

For most people, a vacuum is an empty space. Quantum physics, on the other hand, assumes that even in this lowest-energy state, particles and antiparticles...

Im Focus: Sussex scientists one step closer to a clock that could replace GPS and Galileo

Physicists in the EPic Lab at University of Sussex make crucial development in global race to develop a portable atomic clock

Scientists in the Emergent Photonics Lab (EPic Lab) at the University of Sussex have made a breakthrough to a crucial element of an atomic clock - devices...

Im Focus: Sensing shakes

A new way to sense earthquakes could help improve early warning systems

Every year earthquakes worldwide claim hundreds or even thousands of lives. Forewarning allows people to head for safety and a matter of seconds could spell...

Im Focus: A thermo-sensor for magnetic bits

New concept for energy-efficient data processing technology

Scientists of the Department of Physics at the University of Hamburg, Germany, detected the magnetic states of atoms on a surface using only heat. The...

Im Focus: The moiré patterns of three layers change the electronic properties of graphene

Combining an atomically thin graphene and a boron nitride layer at a slightly rotated angle changes their electrical properties. Physicists at the University of Basel have now shown for the first time the combination with a third layer can result in new material properties also in a three-layer sandwich of carbon and boron nitride. This significantly increases the number of potential synthetic materials, report the researchers in the scientific journal Nano Letters.

Last year, researchers in the US caused a big stir when they showed that rotating two stacked graphene layers by a “magical” angle of 1.1 degrees turns...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

International Modelica Conference with 330 visitors from 21 countries at OTH Regensburg

11.03.2019 | Event News

Selection Completed: 580 Young Scientists from 88 Countries at the Lindau Nobel Laureate Meeting

01.03.2019 | Event News

LightMAT 2019 – 3rd International Conference on Light Materials – Science and Technology

28.02.2019 | Event News

 
Latest News

Researchers measure near-perfect performance in low-cost semiconductors

18.03.2019 | Power and Electrical Engineering

Nanocrystal 'factory' could revolutionize quantum dot manufacturing

18.03.2019 | Materials Sciences

Long-distance quantum information exchange -- success at the nanoscale

18.03.2019 | Physics and Astronomy

VideoLinks
Science & Research
Overview of more VideoLinks >>>