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.


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


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. 




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

A strong case for limiting climate change

Ocean Acidification

A strong case for limiting climate change

In November 2017, the German research network on ocean acidification BIOACID (Biological Impacts of Ocean Acidification) reaches its conclusion after eight years of extensive interdisciplinary scientific activity.

Tropical coral reefs lose two thirds of their zooplankton through ocean acidification

Climate change

Tropical coral reefs lose two thirds of their zooplankton through ocean acidification

Tropical coral reefs lose up to two thirds of their zooplankton through ocean acidification. This is the conclusion reached by a German-Australian research team that examined two reefs with so-called carbon dioxide seeps off the coast of Papua New Guinea. At these locations volcanic carbon dioxide escapes from the seabed, lowering the water's acidity to a level, which scientists predict for the future of the oceans. The researchers believe that the decline in zooplankton is due to the loss of suitable hiding places. It results from the changes in the coral reef community due to increasing acidification. Instead of densely branched