Carbon dioxide poses risk to marine life survival

Aug 06, 2008
Heliocidaris erythogramma.

(PhysOrg.com) -- Climate change and the subsequent acidification of the world's oceans will significantly reduce the successful fertilisation of certain marine species by the year 2100, an international team of biological scientists has found.

A team from Macquarie University's marine ecology group, led by Dr Jane Williamson, joined forces with the University of Gothenburg in Sweden to study the effects of seawater acidification on sea urchin fertility for the first time, finding a link between decreased pH (increased acid) levels and a reduction in sperm swimming speed and motility.

Williamson said sea urchin gametes and larvae used in the research were exposed to the same acid levels that are predicted to be present in the world's oceans by the year 2100.

The surface of the ocean absorbs up to 30 per cent of the yearly emissions of carbon dioxide. This absorbed carbon dioxide dissolves in the water and forms a weak acid that is gradually increasing the acidity of the oceans.

"It is widely believed that seawater is chemically well-buffered, but these results show that the acidification process already well underway may threaten the viability of many marine species," Williamson said.

"Our results show that carbon dioxide-induced acidification of seawater, at levels predicted for the year 2100, reduced fertilisation success of an ecologically dominant marine species by 25 per cent."

The Macquarie University research is especially significant, as equivalent results have only previously been found at far more extreme levels of acidification.

"What we have now is evidence that the world's marine life is far more sensitive to ocean acidification than first suspected, and that means our oceans may be very different places in the not too distant future," Williamson said.

Researchers measured sperm swimming speed, sperm motility, fertilisation success and larval developmental success in individual male x female crosses in the Heliocidaris erythrogramma species using control (pH 8.1) and acidified (pH 7.7) seawater.

The Heliocidaris erythrogramma species is found commonly in inshore waters around south-eastern Australia.

The findings of the Macquarie University study will be published in the August 5 issue of science journal, Current Biology (www.current-biology.com).

Provided by Macquarie University

Explore further: Warning coloration paved the way for louder, more complex calls in certain species of poisonous frogs

add to favorites email to friend print save as pdf

Related Stories

Scientists sound alarm over ocean acidification

Oct 08, 2014

Ocean acidification has risen by a quarter since pre-industrial times as a result of rising carbon emissions, casting a shadow over the seas as a future source of food, scientists warned on Wednesday.

Sensitive youngsters

Sep 26, 2014

Young individuals of a species are often more sensitive towards environmental stress than their adult counterparts. Scientists from GEOMAR Helmholtz Centre for Ocean Research Kiel now observed this effect in the sea star ...

Recommended for you

Cat dentals fill you with dread?

Oct 24, 2014

A survey published this year found that over 50% of final year veterinary students in the UK do not feel confident either in discussing orodental problems with clients or in performing a detailed examination of the oral cavity ...

User comments : 0