ALKOR AL397

During its 397th cruise, the German research vessel ALKOR transports nine mesocosms employed in the field experiment of the SOPRAN project (Surface Ocean Processes in the Anthropocene) from southern Finland back to Kiel.

Ocean acidification, a chemical process triggered by the uptake of carbon dioxide from the atmosphere, is a threat to many calcifying organisms. In the more acidic water, they have difficulties to build their shells and skeletons. But there seem to be creatures, too, that benefit from the change in ocean chemistry: Cyanobacteria. Some of those organisms are also known as “blue-green algae” are toxic to humans and animals – a reason why beaches have to be closed off during cyanobacteria blooms every summer.

Laboratory experiments show that a higher amount of carbon dioxide in sea water stimulates the bacteria’s growth. Scientists from SOPRAN (Surface Ocean Processes in the Anthropocene) investigate if this also is true for the Baltic Sea. For their field experiment, the German research vessel ALKOR brought nine mesocosms to Tvärminne Zoological Station at Finland’s southernmost tip. The mesocosms were anchored close to the coast. The water in their 25 metres long plastic tubes was enriched with carbon dioxide. For eight weeks, the scientists analyse the development inside the mesocosms and collect samples for further measurements.