Climate Change - Ocean acidification - what does it mean?

The phrase 'ocean acidification' means that the pH of seawater is falling.

The pH scale is used by scientists to describe strength of acids and alkalis. 

Sea water normally had a pH around 8.2 

It has now reduced to 8.1, and will continue to reduce, as more CO2 is added to the air by human activities.



Some of the extra CO2 in the air dissolves in the sea, and this affects sealife.

Here is what one expert scientist has said about this -
"A drop of 0.1-unit pH is equivalent to about a 26% increase in the ocean hydrogen ion concentration.
"pH is likely to drop by 0.3-0.4 units by the end of the 21st century.

"This will increase ocean hydrogen ion concentration (or acidity) by 100-150% above what it was in preindustrial times."



Humanity's greenhouse gas emissions may be acidifying the oceans at a faster rate than at any time in the last 300 million years. 

With ocean acidification, corals cannot absorb the calcium carbonate they need to maintain their skeletons.

The stony skeletons that support corals and reefs will dissolve.


Picture A shows healthy coral.     Picture B shows dead and dying coral.
A healthy coral reef with living Acropora palmata and good water quality and a degraded coral reef with dead A. palmata and poor water quality.  

The U.S. Geological Survey (USGS) is conducting research on ocean acidification in the Arctic, Gulf of Mexico and Florida estuaries, and the Caribbean and Pacific.

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