Acidification of the sea hampers reproduction of marine species

Decreasing pH the biggest threat to marine animal life for thousands of years

By absorbing carbon dioxide from the atmosphere, and from the human use of fossil fuels, the world's seas function as a giant buffer for the Earth's life support system. The chemical balance of the sea has long been regarded as immovable. Today, researchers know that the pH of the sea's surface water has gone down by 0.1, or 25 percent, just since the beginning of industrialisation just over a century ago. Jon Havenhand and Michael Thorndyke, researchers at the University of Gothenburg, along with colleagues in Australia, have studied how this acidification process affects marine animal life.

As part of the study, which is one of the world's first on this subject, they have allowed sea urchins of the species Heliocidaris erythrogramma to fertilise themselves in water where the pH has been lowered from its normal 8.1 to a pH value of 7.7. This means an environment three times as acidic, and corresponds to the change expected by the year 2100. The results are alarming.