SINGAPORE – Acidifying oceans caused by rising carbon dioxide levels are cutting the shell weights of tiny marine animals in a process that could accelerate global warming, a scientist believes.
William Howard, of the University of Tasmania in Australia, described the findings as an early-warning signal, adding the research was the first direct field evidence of marine life being affected by rising acidity of the oceans.
Oceans absorb large amounts of CO2 emitted by mankind through burning of fossil fuels.
The Southern Ocean between Australia and Antarctica is the largest of the ocean carbon sinks.
But scientists say the world’s oceans are becoming more acidic as they absorb more planet-warming CO2, disrupting the process of calcification used by sea creatures to build shells as well as coral reefs.
Laboratory experiments had earlier predicted these impacts.
Howard and co-author Andrew Moy, also of the University of Tasmania, studied the shells of tiny amoeba-like animals called foraminifera in the Southern Ocean and compared the shell weights to data from sediment core records dating back 50,000 years. Their findings, in the latest issue of Nature Geoscience, show shell weights of modern-day foraminifera falling 30-35 per cent.
“The big challenge will be how do we scale up this kind of change to understand what it means for the ecosystem. And to be honest, we don’t know yet,” he said. – (Reuters)