The Water's Edge
|Maike Nicolai||November 17th 2013|
Helmholtz-Zentrum Ozeanforschung Kiel
Exposed to simulated ocean acidification, the larvae work hard to maintain the high stomach pH values. “The energetic demands to maintain the stomach pH increase’, says Dr. Marian Hu, co-first author of the study. Using antibody staining techniques, Hu discovered a high concentration of pH regulatory cells that cover the inner surface of the stomach. Such cells typically consume a lot of energy. Culturing experiments and feeding trials revealed that in order to compensate for the decreased efficiency of digestion, the larvae feed more.
“While earlier studies mainly focused on understanding calcification under acidified conditions, other vital processes, such as digestion and gastric pH regulation, were neglected”, says Meike Stumpp. “We can now demonstrate that they deserve much more attention.” “All living processes are run or controlled by enzymes. They are the key in understanding the functions and reactions of organisms, and finally ecosystems, in a changing world”, AWI-scientist Dr. Reinhard Saborowski adds.
“If the organisms are unable to compensate for extra costs caused by ocean acidification, by eating more, they suffer negative consequences in the form of reduced growth and fertility and in extreme cases death”, Dr. Sam Dupont points out. The researcher from the University of Gothenburg is senior author of the study.
The researchers in Germany and Sweden have spent several years developing their techniques. “Studying digestion in larvae is not easy since they are only about a fifth of a millimeter in length”, Dupont admits. „But now we are able to analyze this important process and get an impression of how sea urchin larvae might react to future living conditions.“