Sunday, May 29, 2011

Tiny Bubbles Signal Severe Impacts To Coral Reefs Worldwide

New research shows ocean acidification will likely reduce diversity, resiliency in coral reef ecosystems.

A new study from University of Miami (UM) Rosenstiel School of Marine & Atmospheric Science scientists Chris Langdon, Remy Okazaki and Nancy Muehllehner and colleagues from the Australian Institute of Marine Science and the Max-Planck Institute for Marine Microbiology in Germany concludes that ocean acidification, along with increased ocean temperatures, will likely severely reduce the diversity and resilience of coral reef ecosystems within this century.

This is a video of Dr. Chris Langdon, speaking on Champagne reefs
Credit: University of Miami Rosenstiel School of Marine & Atmospheric Science
The research team studied three natural volcanic CO2 seeps in Papua New Guinea to better understand how ocean acidification will impact coral reefs ecosystem diversity. The study details the effects of long-term exposure to high levels of carbon dioxide and low pH on Indo-Pacific coral reefs, a condition that is projected to occur by the end of the century as increased man-made CO2 emissions alter the current pH level of seawater, turning the oceans acidic.

"These 'champagne reefs' are natural analogs of how coral reefs may look in 100 years if ocean acidification conditions continue to get worse," said Langdon, UM Rosenstiel School professor and co-principal investigator of the study.

A new study of Papua New Guinea's "champagne reefs" in Nature Climate Change by the University of Miami, the Australian Institute of Marine Science and the Max-Planck Institute for Marine Microbiology in Germany concludes that ocean acidification, along with increased ocean temperatures, will likely severely reduce the diversity and resilience of coral reef ecosystems within this century. These reefs provide sobering illustrations of how coral reefs may look in 100 years if ocean acidification conditions continue to worsen.
Credit: Katharina Fabricius/Australian Institute of Marine Science

The study shows shifts in the composition of coral species and reductions in biodiversity and recruitment on the reef as pH declined from 8.1 to 7.8. The team also reports that reef development would cease at a pH below 7.7. The IPCC 4th Assessment Report estimates that by the end of the century, ocean pH will decline from the current level of 8.1 to 7.8, due to rising atmospheric CO2 concentrations.

"The seeps are probably the closest we can come to simulating the effect of man-made CO2 emissions on a coral reef," said Langdon. "They allow us to see the end result of the complex interactions between species under acidic ocean conditions."

The reefs detailed in this study have healthy reefs nearby to supply larvae to replenish the reefs. If pH was low throughout the region -- as projected for year 2100 -- then there would not be any healthy reefs to reseed damaged ones, according to Langdon.

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The study titled "Losers and winners in coral reefs acclimatized to elevated carbon dioxide concentrations," was published in the June issue of the journal Nature Climate Change. The paper's co-authors include Katharina Fabricius Sven Uthicke, Craig Humphrey, Sam Noonan, Glenn De'ath and Janice Lough from the Australian Institute of Marine Science and Martin Glas from Max-Planck Institute for Marine Microbiology. The research was funded by the Australian Institute of Marine Science, the University of Miami, and the Max-Planck Institute of Marine Microbiology through the Bioacid Project (03F0608C).

Contacts and sources:
Barbra Gonzalez
University of Miami Rosenstiel School of Marine & Atmospheric Science 

The University of Miami's mission is to educate and nurture students, to create knowledge, and to provide service to our community and beyond. Committed to excellence and proud of the diversity of our University family, we strive to develop future leaders of our nation and the world. Founded in the 1940's, the Rosenstiel School of Marine & Atmospheric Science has grown into one of the world's premier marine and atmospheric research institutions. Offering dynamic interdisciplinary academics, the Rosenstiel School is dedicated to helping communities to better understand the planet, participating in the establishment of environmental policies, and aiding in the improvement of society and quality of life. For more information, please visit www.rsmas.miami.edu.





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