Scientists have carried out the first-ever ecosystem-scale experiment of the effect of increasing carbon dioxide (CO2) emissions on the world’s oceans.
What the impact of higher CO2 levels as a result of climate change will be is a concern as oceans are the principal ‘sink’ for CO2.
But awareness of the impact is limited as previous studies have been short-term and undertaken in laboratories.
For the latest research an international team of scientists studied areas of the sea off Italy where volcanic CO2 vents increase levels of acid in the water, a process known as acidification.
They say their findings, published in the journal Nature, provide the first in situ insights into how shallow water marine communities might change when susceptible organisms are removed as a result of ocean acidification.
Rocky shore areas where water was more acidic had almost a third (30 per cent) less species numbers compared with water at normal levels.
Evidence of coral reef dissolution was also uncovered and the number of sea urchins was significantly reduced when water became more acidic.
The scientists also found that corallinaceae, which help to protect against coral reef erosion in the tropics, was significantly reduced the more acidic the water became.
Dr Jason Hall-Spencer at the University of Plymouth said the research provides vital information on what major oceanic changes should be expected to occur over the coming decades.
“Our field studies provide a window on the future of the oceans in a high CO2 world,” he said.
“We show the dramatic ecological consequences of ocean acidification including the removal of corals, snails and sea urchins and the proliferation of invasive alien algae.
“Our observations verify concerns, based on laboratory experiments and model predictions, that marine food webs will be severely disrupted and major ecological tipping points are likely if human CO2 emissions continue unabated.”
inthenews.com, 9 June 2008. Article.
