A new study from the University of Miami’s Rosenstiel School of Marine and Atmospheric Science (RSMAS) concluded that ocean acidification and increasing ocean temperatures will likely decrease diversity and resilience of coral reef ecosystems within the century.
The study was completed by RSMAS 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.
The research team studied three natural volcanic CO2 seeps in Papua New Guinea to determine how ocean acidification will impact coral reef ecosystem diversity. They explain the effects of long-term exposure to high levels of CO2 and low pH on Indo-Pacific coral reefs. This is a condition that is expected to occur by the end of this century, along with the increase in anthropogenic CO2 emissions. These man-made CO2 emissions will change the current pH level of seawater and eventually cause acidification of the oceans.
Chris Langdon, RSMAS professor and co-principal investigator of the study explains, “These ‘champagne reefs’ are natural analogs of how coral reefs may look in 100 years if ocean acidification conditions continue to get worse.”
Their research shows shifts in the composition of coral species and reductions in both biodiversity and recruitment on the reef as pH declined from 8.1 to 7.8. The team also reported that reef development would stop at a pH below 7.7. According to the IPCC’s 4th Assessment Report, ocean pH will decline from 8.1 to 7.8 by the end of the century, due to the rising concentration of atmospheric CO2.
“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 in this study are replenished by larvae from healthy reefs nearby. According to Langdon, if the pH was low throughout the whole region, these healthy reefs would not be there to reseed the damaged ones. Unfortunately, this is the scenario predicted for the year 2100.
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Copyright © 2011 by Marine Science Today, a publication of OceanLines LLC