Aquatic Biology

Aquatic Biology

About 71 percent of the Earth's surface is covered by water. Aquatic ecosystems are therefore of great importance as a habitat for a wide variety of organisms. At the Section for Aquatic Biology, we research and teach in processes, structures and pathways in all aquatic environments - lakes, meadows, streams, inlets, sea ice and oceans. Geographically, our research covers aquatic ecosystems in temperate, tropical and arctic regions, and we work with both basic and applied science, e.g. environmental science issues.

Freshwater Areas

Our research in freshwater areas is all about the life found in fresh water. We work with both physical and chemical structures, plants, wildlife and microbial populations as well as interactions among these components. Freshwater biological research projects include conservation and management of freshwater resources as well as structures and functions of freshwater ecosystems. In particular, we focus on invasive plants and their effects on biodiversity, such as reeds in the USA, submerged plants in New Zealand, as well as nutrient absorption and removal in wetlands and streams.


Estuaries are the transition between freshwater and seawater. A good example is the Danish stream Gudenåen where freshwater flows through Randers Fjord and the Kattegat. Only relatively few plants and animals have adapted to life in an estuary. In turn, the number of individuals is high in estuaries because freshwater adds large quantities of nutrients resulting in a higher primary production. In the Vadehavet, where the tide dominates, invasive species such as Pacific oysters and American razor shells are spreading. We examine how the species affect the ecosystem, and we work with parasites in marine organisms and the effects of these at individual and population level.

The Ocean

We also work at larger water depths in the oceans. What are the pathways and volumes of material flowing into and out of an ocean? How large quantities of CO2 can the oceans, for example, absorb from the atmosphere and which mechanisms in the ocean are controlling this? How large quantities of carbon (primary production) can the oceans produce for the benefit of the next step in the food chain such as zooplankton, fish and larger animals? What are the physical and optical conditions in the oceans of this production, and how does it distribute itself in space and time? We also zoom in on the ecology of marine organisms and work on e.g. isotope and growth analysis of fish otoliths and the relationships between environmental forcing and ocean productivity. The Section has especially focused this research in Greenland, the North Atlantic, the Arctic Ocean and the Antarctic.

Section Head

Tenna Riis

Associate professor
H bldg. 1135, 217
P +4587156578
P +4560202641

Contact Information:

Aqatic Biology
Aarhus Universitet
Department of Bioscience
Ole Worms Allé 1
8000 Aarhus C

Telephone:+45 8715 4348
Fax: +45 8715 4302