gradually more acidic

Ocean acidification is caused when the CO2 emitted by human activity, mainly burning fossil fuels, dissolves into the oceans.

It is happening independently of, but in combination with, global warming.

These changes are taking place at rates as much as 100 times faster than the last tens of millions of years. Ocean acidification could represent an equal – or perhaps even greater threat – to the biology of our planet than global warming… “We are seeing signs of its impact even in the deep oceans”, said Dr Eva Calvo, Marine Science Institute.