Week 5 - The impact of ocean acidification

Will marine organisms be able to adapt to ocean acidification given the time scale for the predicted changes?

Adaptation to changing conditions is by evolution where those most able to withstand the changes will tend to survive.  This takes many generations so organisms with short life cycles (bacteria and other micro organisms) can adapt faster than longer lived organisms such as fish and mammals.

The rapid pace of ocean acidification may mean that some organisms go extinct because they cannot adapt quickly enough.

Not all organisms are equally affected by ocean acidification.  Those without shells or similar structures requiring calcium may not be directly affected.  Others might even benefit from greater acidity or the lack of competition from those affected.

The changes may be felt throughout the food chain as changes in prey populations affect their predators.

The marine environment is already under threat from other man-made problems such as overfishing and pollution including plastics.  Ocean acidification is another driver towards mass extinctions.

I think it was a talk I attended by The Black Fish UK where the audience was asked about major marine predators.  Apparently, one of them is the domestic chicken as they are largely fed on fishmeal!

For more information on plastic pollution see Plastic Soup Foundation and Beat the Microbead.


Increased carbon dioxide in the atmosphere is likely to lead to sea level rise. Are rising sea levels more of a threat to humanity than ocean acidification?

Very difficult to decide.  Both will have negative effects but the sections of the humanity affected may be different.

Those in low lying developing countries such as the Pacific island nations, India, Pakistan, Bangladesh, Vietnam, Egypt and others will be the first to feel the effects of sea level rise.  Even in the developed countries most of the population lives within 100 km of the coast, many of them in cities.  Some of the wealthy cities (New York, London, Venice) may be able to build expensive flood prevention schemes but even these may only delay the inevitable flooding from major sea level rises.  Flooding, especially, salt water inundation, will be a threat to land grown food production.

We depend on the survival of some marine organisms which take in carbon dioxide and produce oxygen.  Anything that damages this process will have an effect on the atmosphere and may result in a further increase in greenhouse gases.  Many coastal communities depend on the sea for their food and changes in the marine environment may reduce that food supply.