Ocean acidification will likely reduce diversity, resiliency in coral reef ecosystems

ScienceDaily (2011-05-29) -- Ocean acidification, along with increased ocean temperatures, will likely severely reduce the diversity and resilience of coral reef ecosystems within this century, new research suggests.
http://www.sciencedaily.com/releases/2011/05/110529184043.htm

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.

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 human-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.

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 human-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.

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).

Significant role played by oceans in ancient global cooling

During their lifetime, foraminifera incorporate certain elements and elemental isotopes depending on environmental conditions. By analyzing the ratios of different isotopes and elements, the researchers are able to reconstruct the past environmental conditions that surrounded the foraminifera during their life. (Credit: Image courtesy of Rensselaer Polytechnic Institute)

ScienceDaily (2011-05-28) -- Thirty-eight million years ago, tropical jungles thrived in what are now the cornfields of the American Midwest and furry marsupials wandered temperate forests in what is now the frozen Antarctic. A debate has long been raging in the scientific community on what changes in our global climate system led to such a major shift from the more tropical, greenhouse climate of the Eocene to the modern and much cooler climates of today. Researchers have now found some of the strongest evidence to date that the Antarctic Circumpolar Current (ACC) played a key role in the major shift in the global climate that began approximately 38 million years ago.

http://www.sciencedaily.com/releases/2011/05/110526141406.htm