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The main focus of our research is the diversity, function and ecology of microbial communities (eukaryotes and prokaryotes) in aquatic environments in the context of

       - climate change and ecosystem function(ing)

       - environmental monitoring and ecosystem services

       - extreme environments

       - industrial applications


Climate change and ecosystem function(ing)

Microbial plankton holds a key position for the function(ing) of oceanic and freshwater ecosystems: (i) autotrophic microbes belongs to major light harvesters driving open ocean primary productivity; (ii) bacteria and fungi are mostly responsible for biogeochemical cycles; (iii) through selective grazing phagotrophic eukaryotic microbes contribute to the control of prokaryote dynamics and indirectly influence global biogeochemical cycles (top-down control); and (iv) microbial plankton is of critical importance to support higher life in the oceans by transferring energy and carbon to higher trophic levels (bottom-up control). Therefore, a better understanding of the response of microbial plankton communities (structure and function) to a changing environment is mandatory to predict the effects of global change on ecosystem processes. In this context, we study the structures and functions of microbial plankton communities in oceanic systems (mainly Eastern North-Atlantic, but also the global ocean) and diverse freshwater bodies including (high-)mountain lakes.  Therefore, we use state-of-the-art molecular tools such as eDNA metabarcoding, biocomputational tools (high-performance computing), biostatistical approaches (modeling, networking), cultivation techniques and diverse experimental approaches to quantify the flux of organic matter as a marker for ecosystem function(ing).


Sampling water for plankton on R/V Meteor in an eastern boundary upwelling system (EBUS).
Lab work on R/V Meteor in the tropical East Atlantic.
Ecosystem research in the tropics.
Ecosystem research in high Northern latitudes.
Sampling the polar seas with R/V Polarstern.


Environmental monitoring and ecosystem services

Mankind benefits from a variety of ecosystem services. Especially coastal waters have an extraordinary high value when it comes to ecosystem services. Many different industrial, economic and recreational interests meet in coastal areas. For sustainable long-term ecosystem service, these different interests have to find the balance between ecosystem exploitation and ecosystem health. This requires a permanent environmental monitoring.

In the past 200 years, basic research has accumulated a significant knowledge in microbial ecology. Microbes have excellent indicator qualities because they react quickly to changing environmental conditions. These include for example organic pollution, acidification, anoxia, heavy metals, and hydrocarbon contaminations. This knowledge can be used to help monitoring our environment. In specific, we use this knowledge to monitor the environmental impact of aquaculture, a rapidly growing industry worldwide. We develop monitoring tools based on environmental DNA (eDNA) metabarcoding of microbial communities and use these tools for environmental impact assessments of predominantly salmon farming worldwide. A major goal is to develop this tool for implementation into routine monitoring programs and (inter)national water framework directives. Environmental agencies and managers, policy makers and aquafarming industry benefit alike from such a low-cost, fast reliable and efficient eDNA-based monitoring tool.


Salmon farm in Norway.
Benthic sampling for salmon farm monitoring.
Salmon cage.


Extreme environments

Extreme environments provide a window to past conditions on the early earth, to the origin and evolution of life on our planet and are important research sites for astrobiology as analogues to extra-terrestrial bodies. Such environments include for example geothermal fields with hot springs on Iceland, hypersaline water bodies, polar regions or diverse deep-sea habitats. We study the microbial organisms in such environments and their diverse adaptation strategies which enable them to thrive at the limits of life. Genomics, tanscriptomics and cultivation approaches are being used in this research, accompanied by a wealth of biocomputational tools.


Flying to the glacier.
Sampling glacier lakes.
Sampling plankton beneath the ice.
Solar saltern pond in France.
Salt lake in a tropical crater.
Sampling the deep-sea with ROV Jason (WHOI).
Hydrothermal field in Iceland.
Hydrothermal field in Iceland.
Hydrothermal field in Iceland.


Industrial applications

We use our expertise in microbial ecology and extremophile microbial communities to better monitor and improve industrial processes, which rely on microbial activities. Several industrial applications take advantage of natural microbial processes. These include for example the purification of wastewater and the production of alternative energy, such as biogas. We work together with different industrial partners to optimize such processes by manipulating microbial communities involved in these processes. We use a variety of experimental approaches and test the effects of our experimental manipulations using state-of-the-art molecular tools.


Experimental fermenters for biogas production from organic waste.
Biogas plant contributing to our research project (picture taken by Günter Doppelbauer, Yara GmbH & Co. KG).