February - ocean acidification

As ocean acidification continues it will reduce the ability of sea water to take up carbon dioxide from the atmosphere, thus accelerating the build-up of greenhouse gases in the atmosphere and increasing the rate of climate change.

Nearly half of all the carbon dioxide produced by burning fossil fuel over the last 250 years has been absorbed by the surface waters of our seas and oceans. Whilst this has made a vital contribution to reducing carbon dioxide levels in the atmosphere and as such the degree of climate change and temperature rise already experienced, it has not been without cost. The carbon dioxide absorbed by the sea water reacts with it to form carbonic acid - the seas are becoming more acidic, ie their pH is decreasing.

The impact of both the rate and the level of change of pH on marine organisms and ecosystems is of concern, as pH has been relatively stable for at least the last 400,000 years and probably for as long as the last 20 million years. Increased acidification will affect the viability of a wide range of organisms including microscopic plants (phytoplankton) and animals (zooplankton) at the very bottom of the marine food chain. For other animals such as corals, shellfish and sea urchins increased acidity will reduce their ability to produce their calcareous shells. These effects could lead to disruption of the major marine ecosystems of the world.

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