Study: Changes to ocean expected to damage shellfish around world

Massive global greenhouse gas pollution is changing the chemistry of the world’s oceans so much that scientists now predict it could severely damage shellfish populations and the nations that depend on the harvests if significant action isn’t taken.

A new study from the Woods Hole Oceanographic Institution in Massachusetts shows that ocean acidification is becoming a very serious problem. The study was published in July online in the journal Fish and Fisheries.

“What the study found was that in the next 10 to 50 years many countries are going to see impacts, particularly countries that are heavily reliant on clams and oysters and mussels, and will not be able to adapt by shifting to other foods or aquaculture methods,” said Jackie Savitz, senior scientist and chief strategist for the international ocean conservation and advocacy organization Oceana.

The acid test

Oceans do a good job of removing CO₂ from the atmosphere but many marine organisms are paying the price. The International Panel on Climate Change has estimated that every day the oceans soak up over 25mt of CO₂ produced by burning fossil fuels. This is having an effect on ocean chemistry, making the waters more acidic and reducing the levels of calcium carbonate minerals needed by many marine organisms to build shells and skeletons. Using models and modern sea data, the average surface pH of seawater is estimated to have dropped from 8.2 by 0.1 units since the 1900s and is predicted to fall to about 7.8 by 2100. ‘For the next few decades, we have a pretty good idea of what is going to happen. As models go, the chemistry of the oceans can be predicted pretty well,’ says Scott Doney, from the Woods Hole Oceanographic Institution in Massachusetts, US.

The Climate Show #16: Keith Hunter on oceans, acids and the carbon cycle

(ocean acidification discussion starts at ~30 min)

We learned a lot this week, as Professor Keith Hunter of the University of Otago, one of the world’s leading ocean chemists, gave us a masterclass on ocean acidification and what it means for the future of the oceans. Plus we discuss Australia’s new carbon tax, green growth campaigns in New Zealand, why China’s aerosols may have been doing us a favour and why cleaning them up might unleash more warming, and climate models having trouble with rapid climate events. On the solutions front we look at a tiny electric aeroplane setting a new speed record and a solar initiative in NZ. No John Cook in this show, but he’ll be back soon.