The magazine of the european research area European Commission Copenhagen, a missed chance?

11

SPECIAL REPORT

 

CLIM

A

T

E

OCEANS

One certainty, thousands of unknowns

In addition to calcareous organisms, other 

marine species could suffer directly from ocean 

acidification, but research in this field is only 

in its infancy. The fall in pH reduces the ocean’s 

capacity to absorb sounds and this could affect 

the ability of marine mammals to know where 

they are and locate their prey. Similarly, few 

studies have looked at the impact of acidifi-

cation on fish. “US research managed to high-

light a link between acidification and the 

growth of otoliths. These bones of the inner 

ear play a major role in the balance of fish but 

it is not known to what extent an abnormal 

development could have negative effects,” 

explains Jean-Pierre Gattuso.

To study the effects of acidification, the 

EPOCA researchers are looking at marine eco-

systems with a naturally high CO

2

 concentra-

tion, such as off the island of Ischia in southern 

Italy. But the majority of the research is con-

centrated on Polar Regions that capture more 

CO

2

 as the gas dissolves better in cold waters. 

“Acidification is more rapid at the poles. Its 

impact on ecosystems is therefore more easily 

detectable,” says Jean-Pierre Gattuso.  

An understanding of the effects of this phe-

nomenon on the marine biotope is a fundamen-

tal prerequisite for determining the acidity level 

that must not be exceeded if the present oce-

anic balance is to be maintained. “No maximum 

tolerance threshold has yet been set. The time 

frame is not long enough. The first studies on 

ocean acidification were carried out just 15 years 

ago at the most,” explains Jean-Pierre Gattuso.