The German research network BIOACID examines the effects of acidification on the life and biogeochemical cycles in the ocean – and on all those who depend on it. In this series of short videos, BIOACID members report about their research. The BIOACID science portraits complement a photo exhibition on ocean acidification that is funded by the German Federal Ministry of Education and Research (BMBF) as part of the Science Year 2016*17 – Seas and Oceans.

Prof. Ulf Riebesell, marine biologist at GEOMAR Helmholtz Centre for Ocean Research Kiel and coordinator of the German research network on ocean acidification BIOACID, has been among the first scientists who investigated the effects of carbon dioxide on marine organisms. In this BIOACID Science Portrait, Ulf Riebesell tells how the KOSMOS mesocosms, “giant test tubes”, help researchers to find out more about the reactions of plankton communities to ocean acidification – and what these field experiments mean to him.

Janina Büscher, marine biologist at GEOMAR Helmholtz Centre for Ocean Research Kiel, focuses on a beauty from the cold and dark depths of the ocean: The cold-water coral Lophelia pertusa. This species can be found all over the globe – and it seems to be less susceptible to ocean acidification than scientists had expected.

Silke Lischka, marine biologist at GEOMAR Helmholtz Centre for Ocean Research Kiel is a pteropod expert. These planktonic snails are also called sea butterflies, because they flutter through the ocean with their foot that has developed into two small wings. The organisms are food for fish, sea birds and whales – and they also control part of the food web because they also eat a lot themselves. Ocean acidification affects their delicate calcium carbonate shells.

How does climate change alter the ocean? How can the ocean provide food for our planet’s growing population? Dr. Catriona Clemmesen-Bockelmann, fisheries biologist at GEOMAR and her colleagues investigate, how ocean acidification and warming affect economically important fish species.

Dr. Lennart Bach, marine biologist at GEOMAR Kiel investigates a tiny organism that can hardly be seen with the naked eye – and is still visible from space. The single-celled calcifying alga that his research focuses on is called Emiliania huxleyi. It is a true multi-talent: Its calcium carbonate platelets carry organic material from the surface to the deep ocean, which regulates carbon dioxide concentrations in the atmosphere. A gas that it releases – and that we perceive as the typical sea smell – is thought to serve as cooling agent in the climate system.

Dr. Nicola Wannicke, marine biologist at Leibniz Institute for Baltic Sea Research in Warnemünde (IOW) investigates winners of ocean acidification: Cyanobacteria benefit from eutrophication as well as rises in temperature and carbon dioxide concentrations. When the Baltic Sea warms in Summer and much carbon dioxide dissolves in the sea water, the algae thrive especially well. Since they release toxins that are dangerous for humans and animals, beaches need to be closed off from time to time.

María Algueró-Muñiz, marine biologist at Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research (AWI), works at the North Sea Island Helgoland. In summer, she goes out by boat to collect moon jellyfish for her experiments on the impact of ocean acidification, warming and deoxygenation. She concentrates on the „ephyrae“ state of jellyfish. The more she knows about this early and critical life stage, the better she can assess how the complete population will develop in the future.

Christiane Hassenrück, marine biologist at Max Planck Institute for Marine Microbiology (MPI Bremen) went to Papua New Guinea to dive into the future ocean: Volcanic carbon dioxide (CO₂) bubbling up from the seafloor turns the water at coral reefs more acidic. At the laboratory and at the office – where she spends most of her working time – Christiane Hassenrück studies the genetic material of microorganisms from different reef locations.

Felix Mark, marine ecophysiologist at Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research (AWI), investigates the effects of climate change on two closely-related fish species in the Arctic. Due to rising water temperatures, the Atlantic cod is moving northwards and might take over the habitat of the native polar cod.

Bladderwrack, Fucus vesiculosus, provides a perfect basis for ecosystems in the Baltic Sea. Many other organisms thrive in the Fucus forests. Also fish lay their eggs there. "This is why we have to investigate the influence of climate change on this species of alga," says Angelika Graiff, marine biologist at the University of Rostock.

Maria Moreno de Castro, modeler at Helmholtz-Zentrum Geesthacht (HZG), became a scientist because she likes to solve mysteries. Just like a detective, she tries to track uncertainties in scientific findings. “Our daily life is full of uncertainties. In science it's the same: There are many outcomes, any solutions, many responses that we are not certain and we don't know. We have to deal with this uncertainty, we have to understand it and know the origins.”

More BIOACID Science Portraits on the website about the photo exhibition "Ocean Acidification: The Other Carbon Dioxide Problem".