Acidification on the rise in Arctic Ocean

Acidification on the rise in Arctic Ocean

May 12th, 2013

As per a new scientific report, the concentration of carbon dioxide in the Arctic Ocean is rapidly escalating which is making its water more acidic.
It was assessed by the Arctic Monitoring and Assessment Programme (AMAP) that the ocean chemistry of the region is undergoing widespread changes.
Key findings of the report:

• The rising acidification may bring major changes in the marine ecosystem, but say there is huge uncertainty over what those changes will be.
• Even if CO2 emissions stopped now, it would take tens of thousands of years for Arctic Ocean chemistry to revert to pre-industrial levels.
• Acidification is specifically rapid in Arctic as its water is cold which aids fast absorption of atmospheric CO2 and the recent decreases in summer sea ice have exposed more sea surface to atmospheric CO2.
• The susceptibility of Arctic region is aggravated by increasing flows of freshwater from rivers and melting land ice, as freshwater is less effective at chemically neutralizing the acidifying effects of CO2.
• Acidification is fast in surface waters and more slowly in deep waters.
• Slow mixing of river water with the seawater forms a sort of freshwater lens on the top of the sea in some places, and freshwater lowers the concentration of ions that buffers pH change. The loss of ice also is allowing fast uptake of CO2.
• The pH of seawater has decreased about 0.02 per decade since the late 1960s in the Iceland and Barents seas.
• Average acidity of surface ocean waters worldwide is now about 30% higher than before the Industrial Revolution.
• The possible major changes to the makeup of Arctic marine ecosystem may prove harmful to key prey species like sea butterflies. Other species may thrive. It may also harm the development of fish eggs.

What is Ocean Acidification?
Ocean acidification is the name given to the ongoing decrease in the pH of the Earth’s oceans, caused by the uptake of anthropogenic carbon dioxide (CO₂) from the atmosphere. About 30–40% of the carbon dioxide released by humans into the atmosphere dissolves into the oceans, rivers and lakes. To maintain chemical equilibrium, some of it reacts with the water to form carbonic acid. Some of these extra carbonic acid molecules react with a water molecule to give a bicarbonate ion and a hydronium ion, thus increasing the ocean’s “acidity” (H⁺ ion concentration). Absorbed CO2 in seawater (H2O) forms carbonic acid (H2CO3), lowering the water’s pH level and making it more acidic

• This increases the hydrogen ion concentration in the water, and limits organisms’ access to carbonate ions, which are needed to form hard parts like those found in calcifying organisms which include organisms such as coccolithophores, corals, foraminifera, echinoderms,crustaceans and molluscs.