Future oceans could see 30% loss of biodiversity

Dr. Hall-Spencer of the University of Plymouth has said that underwater volcanoes are the key to understanding how future changes in carbon dioxide content will affect the ocean’s biodiversity.

"I am investigating underwater volcanoes where carbon dioxide bubbles up like a Jacuzzi, acidifying large areas of the seabed, and we can see at these vents which types of organisms are able to thrive and which ones are most vulnerable,” Hall-Spencer said at a meeting of the American Association for the Advancement of Science (AAAS)

As one moves toward a vent, the pH drops, and only certain organisms can survive. Using this gradual change in pH, the scientists can model what a future sea bed might look like under different pH’s. By his estimates this could mean a 30% loss in biodiversity over the next century.

Lower more acidic pH’s make calcification more difficult, a process essential to certain types of sea-dwelling organisms with hard shells; the research has also found however, that other soft bodied species will also be affected to some degree. The study looks at various vents all over the world, and all show a similar pattern of decline as one moves closer and consequently decreases pH of the water. The decreasing pH is not the only problem however, Dr. Hall-Spencer says the increase in temperatures will also cause organisms to die.

Currently with around a third of all carbon dioxide released going into the oceans, the pH has decreased by 0.1 units; by 2100 this could drop around 0.4 units on the pH scale. This is a huge change says Dr. Hall-Spencer, “Fifty-five million years ago when we had an event like this (and that took over 10,000 years to occur), it took the oceans over 125,000 years to recover, just to get the chemistry back to normal. It took two to 10 million years for the organisms to re-evolve, to get back into a normal situation. So what we do over the next 100 years or 200 years can have implications for ocean ecosystems from tens of thousands to millions of years. That's the implication of what we're doing to the oceans right now,” he told the BBC.