Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

UGA ecologists provide close-up of coral bleaching event

04.06.2014

Study documents corals before, during and after October 2009 episode

New research by University of Georgia ecologists sheds light on exactly what happens to coral during periods of excessively high water temperatures. Their study, published in the journal Limnology and Oceanography, documents a coral bleaching event in the Caribbean in minute detail and sheds light on how it changed a coral's community of algae—a change that could have long-term consequences for coral health, as bleaching is predicted to occur more frequently in the future.


An Orbicella faveolata coral in the Caribbean shows bleached areas adjacent to areas that retain their color. Bleaching occurs when heat-sensitive symbiotic algae that inhabit corals are expelled during episodes of excessively high water temperatures. (Credit: Dustin Kemp/UGA)

Millions of people around the world depend on coral reefs and the services they provide. While coral reefs make up less than 0.1 percent of the sea floor, they serve as habitats for about 25 percent to 35 percent of all the oceans' fishes, roughly 500 million people worldwide rely on them as a source of protein and for coastal protection, and they are responsible for billions of dollars in tourism and fisheries revenue.

Corals, in turn, depend upon single-celled algae that inhabit them, providing most of their food and giving them their color. But many species of these algae are highly sensitive to temperature, and are unable to survive as ocean waters warm. The coral can expel these algae when the water temperature grows too high, a phenomenon known as coral bleaching.

Lead author Dustin Kemp, a postdoctoral associate in the UGA Odum School of Ecology, had the opportunity to study a bleaching event while conducting research at a reef off Puerto Morelos, Mexico. He and his colleagues had been working there since 2007, taking samples seasonally from six colonies of Orbicella faveolata, also known as mountainous star coral, and their associated symbiotic algae.

Orbicella is the major reef-building coral in most of the Caribbean, but although common, it has an unusual trait. While most species of coral associate with just one dominant type of symbiotic algae, O. faveolata is able to associate with up to four co-dominant types at once—some of which are heat-tolerant and some of which are not—making it a particularly interesting coral to study.

In October 2009, the researchers' sampling trip coincided with a period of unusually high temperatures, allowing them the rare opportunity to collect samples while a bleaching event was taking place.

"We were able to follow this coral at a very high precision and document how diverse assemblages of symbiotic algae are differently affected by the bleaching phenomenon," Kemp said. "This was probably the first study ever to look at it under natural conditions this closely."

Kemp took hundreds of samples approximately every 12 inches along established transects—a narrow section where measurements are taken—across all six coral colonies. He made sure to include samples from areas that appeared bleached as well as from those that still retained color. Because they had been collecting at the site for two years, and continued collecting after this event, the researchers were able to compare the communities of symbiotic algae before, during and after bleaching.

They observed that before the bleaching event, these particular corals contained three different types of algae, two of which were somewhat tolerant of the warm-water bleaching perturbation.

During the bleaching event, heat-sensitive algae were found to be much less prevalent while the heat-tolerant algae remained. Two months later, heat-tolerant algae had taken over the parts of the coral formerly occupied by the heat-sensitive algae.

"The corals didn't die after this bleaching event, they recovered—and that's good, that's important—but there could be potential tradeoffs associated with the shift to heat-tolerant algae," said Kemp, adding that, for example, some heat-tolerant algae may provide less food than those they might replace. "That question of tradeoffs is what we're working on now."

Kemp is currently conducting research at reefs in the Caribbean and Pacific, looking at how heat-tolerant algae affect corals in areas where corals have been documented to have stable, long-term associations with heat-tolerant algae.

"In the Caribbean, we've lost 80 percent of the corals just in my lifetime," Kemp said. "We know that increased ocean temperatures are one of the major threats to coral reefs worldwide. So understanding coral-algae dynamics, and how different algae can handle increased temperature, is important to see how the whole ecosystem will be affected by this environmental perturbation."

The study's coauthors are Xavier Hernandez-Pech and Roberto Iglesias-Prieto of the Universidad Nacional Autónoma de México, William K. Fitt of the UGA Odum School of Ecology and Gregory W. Schmidt of the UGA department of plant biology. The research was supported by the National Science Foundation and the World Bank. The paper is available online at http://aslo.org/lo/pdf/vol_59/issue_3/0788.pdf.

For more information about the Odum School of Ecology, see www.ecology.uga.edu.

Dustin Kemp | Eurek Alert!
Further information:
http://news.uga.edu/releases/article/ecologists-close-up-coral-bleaching-event-0614/

Further reports about: Ecology October UGA corals ecologists heat-sensitive perturbation phenomenon species symbiotic temperature temperature

More articles from Ecology, The Environment and Conservation:

nachricht Value from wastewater
16.08.2017 | Hochschule Landshut

nachricht Species Richness – a false friend? Scientists want to improve biodiversity assessments
01.08.2017 | Carl von Ossietzky-Universität Oldenburg

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

Gold shines through properties of nano biosensors

17.08.2017 | Physics and Astronomy

Greenland ice flow likely to speed up: New data assert glaciers move over sediment, which gets more slippery as it gets wetter

17.08.2017 | Earth Sciences

Mars 2020 mission to use smart methods to seek signs of past life

17.08.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>