Science Portrait: Felix Mark

Felix Mark is a marine ecophysiologist at Alfred Wegener Institute. He 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.

Videos

Three perspectives on ocean acidification

Learn from Hans-Otto Pörtner, coordinating lead author of the fifth IPCC report, how the ocean really fares. Follow Felix Mark to the Arctic, as he sets out to investigate how fish react to their changing environment. And join Jelle Bijma on a journey into the past, as he tries to unveil the archive of the history of Earth.

    •    The ocean - A changing ecosystem
    •    Atlantic and Polar Cod under stress
    •    Traces of the past

Gallery

A dive into the reef

Few sea inhabitants are affected so strongly by the rising temperatures and the drop in the pH value of the oceans than the stony coral. Ocean acidification means that the corals run out of energy to form their lime skeleton. In addition, the rise in water temperature prevents the symbiosis between the corals and unicellular algae, the so-called zooxanthellae. These zooxanthellae live in the coral, supply it with energy and nutrients and also give it its colour. Temperature stress leads corals to reject their zooxanthellae. This causes the corals to pale and frequently to die due to the lack of energy supply. Scientists from the Alfred Wegener Institute currently wish to find out how quickly the coral reefs are changing and whether the animals are able to adapt to the environmental changes. 

 

 

News

Ocean sink for man-made CO2 measured

New Study

Ocean sink for man-made CO2 measured

Not all of the CO2 generated during the combustion of fossil fuels remains in the atmosphere. The ocean take up considerable quantities of these man-made CO₂ emissions from the atmosphere. Without this sink, the concentration of CO2 in our atmosphere.

Ocean acidification stimulates mass development of toxic algae

New Study

Ocean acidification stimulates mass development of toxic algae

If carbon dioxide concentrations in the atmosphere and thereby in the ocean continue to rise, this could favour the mass development of toxic algae, with far-reaching consequences for the pelagic food web. This was discovered during a long-term experiment off the Canary Islands conducted by an international group of scientists with the participation of the Alfred Wegener Institute.

Arctic Survivalists

New Study

Arctic Survivalists

They form the basis of the Arctic food web – and are extremely tough: even when the water becomes more acidic and the available light or temperatures change, various phytoplankton assemblages in the Arctic demonstrate undiminished productivity and biodiversity. This was the main finding presented in a study by researchers at the Alfred Wegener Institute, which they jointly release with their Canadian colleagues advanced online in the journal Nature Climate Change. Yet the question of whether this source of food for seals, whales and commercially harvested fish species in the Arctic can ultimately cope with global climate