Study: Marine life at risk in CO2 rise

PLYMOUTH, England, Sept. 12 (UPI) -- A "natural laboratory" in the Mediterranean revealing effects of carbon dioxide levels in oceans paints a bleak picture for future marine life, researchers say.

Scientists from the University of Plymouth in England, along with Brazilian researchers, studying single celled organisms called Foraminifera around natural volcanic carbon dioxide vents off of Naples, Italy, found that increasing levels of the gas caused diversity of the creatures to fall from 24 species to 4, ScienceDaily.com reported Tuesday.

"Previous studies have shown a reduction in diversity of 30 percent, but this is even bigger for forams (Foraminifera)," Jason Hall-Spencer, one of the study's co-authors, said. "A tipping point occurs at mean pH 7.8. This is the pH level predicted for the end of this century."

Increasing carbon dioxide levels acidify the ocean, lowering pH, which has a devastating effect on organisms that have calcium carbonate shells like Foraminifera, he said.

"At a mean pH level of 7.8, calcified organisms begin to disappear, and non-calcifying ones take over," Hall-Spencer said. "We are headed towards that being the case in this century.

"The big concern for me is that unless we curb carbon emissions we risk mass extinctions, degrading coastal waters and encouraging outbreaks of toxic jellyfish and algae," he said.

"Our natural laboratory provides a glimpse into the future of our oceans," he said.

"These are the first CO2 vents to be used to study ocean acidification. They allow us to observe how ecosystems react to changes in ocean acidity. We can see for our own eyes what increasing CO2 levels do to marine communities," Hall-Spencer said.