Climate change-induced increase of carbon dioxide, according to modelling approaches, is going to cause the acidification of the world’s oceans. By the year 2100 the current pH might drop by 0.5. Our research is focusing on the question ‘how do fish respond to such changes?’

At the department "Marine Animal Physiology" of the Alfred Wegener Institute, researchers developed a device that enables onboard measurements of the impact of decreased pH values on the gill functioning of freshly caught fish (see overview photograph). In order to simulate blood circulation, specially prepared gill tissue is constantly flushed with a saline solution. Special devices allow measurements to be taken of gill performance in plain and acidified seawater for more than 6 hours (see detailed photograph).

Under these controlled conditions we are measuring energy consumption of the gills. Chemical inhibitors are added, to allow the identification of the most important energy-consuming cellular processes and to determine their role in gill functioning. First results reveal that certain metabolic processes are almost doubling their rate under acidified conditions. In contrast, the total energy available to the gills is decreasing.

This could have serious ecological implications if the predictions hold true. If there is less energy available for processes sustaining populations, such as reproduction and growth, it would be to the detriment of the whole ecosystem.

Text: Christian Bock & Katrin Deigweiher
Photographs: Christian Bock & Zora Zittier