Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Coral Reef Resilience: Better Feeders Survive Bleaching

28.04.2006


Eating as the key to health
Coral bleaching has severely damaged or killed 30 percent of the world’s coral reefs, turning brightly colored coral a ghostly white. Research shows that some “super-feeding” corals can survive. Photo: Jon Witman/Brown University


Global warming and other threats are killing coral reefs through a phenomenon known as bleaching. But why do some corals survive? A new study, published in Nature, is the first to document a trait that helps some coral species live through, and recover from, bleaching. The survivors’ secret: Ramped up feeding rates.

In an experiment with three species of Hawaiian corals researchers found that, when bleached, the branching coral Montipora capitata sharply increased its intake of tiny plankton, making it much more likely to bounce back. The findings suggest that any coral, regardless of shape or location, may recover from bleaching if it can ramp up feeding.

James Palardy, a Brown University graduate student and co-author of the Nature paper, said the results indicate that these corals may become the dominant species in reefs and could play a role in protecting these critical marine ecosystems.



“These ‘super-feeders’ have an ecological advantage, one that may protect reefs from extinction,” Palardy said. “If our results hold up with other species, we may well see that these resilient corals are the future for our reefs.”

Coral reefs reduce beach erosion, support tourism and serve as breeding grounds and habitat for fish. A 2006 report by the United Nations Environment Programme put the value of coral reefs at $100,000 to $600,000 per square kilometer per year.

But the UNEP report states that 30 percent of the world’s coral reefs are severely damaged or dead and that 60 percent of remaining reefs will vanish by 2030. Several factors are to blame, from pollution to overfishing. Scientists say the biggest new threat is global warming. Because corals are highly sensitive to temperature, even small amounts of warming can trigger bleaching.

When water temperatures rise, coral expel single-celled algae called zooxanthellae, which live inside coral tissue and give corals their color and, more importantly, supply the bulk of their food energy. If bleaching persists, corals die, leaving behind ghostly limestone skeletons.

Some corals can survive bleaching. The reasons for this, however, aren’t well understood. Palardy and his colleagues had a hunch: In the absence of algae-derived nutrition, corals may tap energy reserves or increase feeding, a process where corals use their tiny tentacles to “grab” passing plankton and stuff them into their stomachs.

To study the role metabolism and feeding might play in coral resiliency, Palardy, a Brown Ph.D. student in the Department of Ecology and Evolutionary Biology, collaborated with Andréa Grottoli, an assistant professor of geological sciences at Ohio State University, and Lisa Rodrigues, a post-doctoral research fellow in biology at Villanova University.

The team took chunks of three types of healthy Hawaiian corals – M. capitata, another branching coral called Porites compressa and the mounding coral Porites lobata – from colonies off the coast of Oahu and put them in eight outdoor tanks. Water in four of the tanks was kept at 27° C, the typical reef water temperature. In the other four, water temperature was elevated to 30° C, warm enough to trigger bleaching. After 30 days in the tanks, the team measured chlorophyll concentrations, photosynthetic rates, and lipid levels in some corals. The remaining corals were returned to the reef to recover.

After two weeks on the reef, researchers covered some of the healthy and bleached corals with fine mesh boxes, which kept plankton out of reach. The boxes went over the corals eight hours a day, then removed for an hour each night for five days. The goal: Empty their stomachs, so that the plankton the corals consumed could be accurately measured. Researchers dissected the corals and painstakingly counted plankton in their stomachs. Researchers also created a system of measurements that gauged the corals’ energy input from feeding.

Four weeks later, the scientists weighed the remaining corals and again measured chlorophyll concentrations, photosynthetic rates and lipid levels.

The results: P. compressa and P. lobata depleted their energy reserves during bleaching. And when these bleached and unbleached corals were compared, feeding didn’t increase. In contrast, the feeding rates of bleached M. capitata increased five-fold, allowing them to replenish their energy reserves – making it more likely that they’ll survive and spawn after a bleaching event.

“The results were a surprise,” Palardy said. “Previous studies showed that thick tissue layers or mounded shapes made corals resilient. But we found a new resiliency factor – feeding. In evolutionary terms, corals that eat more may win.”

The National Science Foundation, the Mellon Foundation, and a William Penn Fellowship funded the work.

Wendy Lawton | EurekAlert!
Further information:
http://www.brown.edu

More articles from Ecology, The Environment and Conservation:

nachricht Litter is present throughout the world’s oceans: 1,220 species affected
27.03.2017 | Alfred-Wegener-Institut, Helmholtz-Zentrum für Polar- und Meeresforschung

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

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: A Challenging European Research Project to Develop New Tiny Microscopes

The Institute of Semiconductor Technology and the Institute of Physical and Theoretical Chemistry, both members of the Laboratory for Emerging Nanometrology (LENA), at Technische Universität Braunschweig are partners in a new European research project entitled ChipScope, which aims to develop a completely new and extremely small optical microscope capable of observing the interior of living cells in real time. A consortium of 7 partners from 5 countries will tackle this issue with very ambitious objectives during a four-year research program.

To demonstrate the usefulness of this new scientific tool, at the end of the project the developed chip-sized microscope will be used to observe in real-time...

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...

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

Researchers shoot for success with simulations of laser pulse-material interactions

29.03.2017 | Materials Sciences

Igniting a solar flare in the corona with lower-atmosphere kindling

29.03.2017 | Physics and Astronomy

As sea level rises, much of Honolulu and Waikiki vulnerable to groundwater inundation

29.03.2017 | Earth Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>