Acidifying oceans could affect sea life, visiting researcher warns

Rising carbon emissions causing acidifying oceans will affect humans, a visiting researcher warns.

Doctoral candidate and former Craighead Diocesan School student Allanah Paul spoke at Aoraki Polytechnic in Timaru on Monday about the effects of Earth’s oceans absorbing carbon dioxide.

Paul, who has been studying for a PhD at the GEOMAR Helmholtz Centre for Ocean Research in the northern German city of Kiel since 2011, said the oceans had absorbed about a third of human-emitted carbon dioxide and there was “unequivocal evidence” their pH was decreasing. A solution’s pH is a measure of how acidic or basic it is.

Paul said sea water’s pH usually measured about 8.1, but some projections suggested that figure could fall to 7.7 by the end of the century if carbon emissions continued to increase. That represented an increasing concentration of positive hydrogen ions. “There has been a 30 per cent increase in sea water acidity since the beginning of the Industrial Revolution.”

Such a reduction in sea water’s pH would likely affect biological processes in plankton, fish and other sea organisms.

Paul, whose research involves the effects of acidification in specific Baltic Sea environments, said others’ research indicated decreasing pH in sea water could cause the shells which shellfish such as oysters and mussels make from calcium carbonate to become brittle.

Acidifying oceans could affect different species and different parts of the food web in different ways.

Research she had participated in simulated future acidification and measured its effects on zooplankton, phytoplankton, the availability of food and its quality at the bottom of the food web.

“Climate change will have measurable impacts. There will be winners and losers.”

Paul said acidifying oceans would also likely have economic effects, including on people who depended on the sea for their food or income.

“The shellfish industry is a big industry in New Zealand.”

Paul’s Baltic Sea research was being reviewed. She was preparing further work on ocean acidification under preparation.

Paul hesitated to suggest what could be done to prevent such an increasing concentration, stating she was working to “provide the baseline information” for decision-makers.

Jack Montgomerie, The Timaru Herald, 20 April 2015. Article.

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