Plankton: The foundation of life in the sea

Biologist Prof. Dr Helmut Hillebrand, Professor at the University of Oldenburg and Director at HIFMB Oldenburg.



Ecological stability

Ecosystem Functioning

Earth’s rainforests are often described as the planet’s ‘green lungs’ because they produce tremendous amounts of oxygen. However, an even greater volume of the oxygen we breathe originates in the ocean. The algal communities living there produce at least half of the gas that is vital for breathing and as such essential for human life. But climate change is altering the algal world in our seas: as a result of increasing water temperatures, cold-loving species are migrating towards the Poles, to the extent still possible. In their old habitats, the species communities are reorganising themselves. As a rule, the less specialised organisms remain behind; the species diversity as a whole is decreasing – with far-reaching impacts for the ocean’s food webs. As primary producers, algae form the basis of these webs.

But which climatic influences lead to which reactions in the ecosystem? To address this, here at the HIFMB, a cooperation between the University of Oldenburg and the Alfred Wegener Institute, we use ‘planktotrons’: large water tanks that allow us to investigate the changes in the algal community, or phytoplankton, and its first predatory fauna, the zooplankton. Using the tanks, we can alter parameters like light, temperature and nutrients – all of which are affected by anthropogenic climate change in the real world – in a controlled way, which allows us to investigate their impact on species diversity.

The goal of our research is to integrate our findings in general ecological concepts. By doing so, we will hopefully be able to make predictions concerning the complex interactions in plankton communities and to learn more about the fate of these algal communities that are vital for our survival.