Biogeochemical Processes in Sediments and Lake Management

A new IGB Dossier shows options for action for policy-makers and authorities at the nutrient-polluted Lake Arendsee.

Even deep clear water lakes, which are considered particularly valuable ecosystems, can show signs of eutrophication and algae growth - often for no apparent reason. A new study by four researchers from the Leibniz-Institute of Freshwater Ecology and Inland Fisheries (IGB) now shows that the causes are not always to be found in increasing nutrient inputs from the catchment area or in re-dissolution processes in the deep areas of a lake, but also in the shallower areas up to a water depth of around 20 metres.

Using long-term monitoring data from 46 German lakes, researchers from IGB have shown that surface temperatures of lakes have risen faster than air temperatures over the last 30 years. Ooxygen concentrations in the deep water have decreased. Modelling suggests that this trend will continue. The good news is that the lack of oxygen in the hypolimnion would be alleviated if the nutrient loads from urban and agricultural discharges could be reduced.

IGB researcher Prof Michael Hupfer has been elected as a new member of the Leibniz-Sozietät der Wissenschaften zu Berlin e.V. The learned society is thus honouring his achievements in the field of aquatic ecology and his commitment to water protection. 

Oxygen is essential for most aquatic organisms. Chemical and biological processes, such as the ability to self-purify, are also dependent on oxygen. However, environmental changes and rising water temperatures are altering the oxygen content of lakes, ponds and pools. Oxygen concentrations in the deep layers of lakes are decreasing worldwide. In addition, oxygen depletion can lead to an increased release of greenhouse gases. IGB researchers are investigating the extent and consequences of this. In the process, they are also questioning some theories about the laws of lake ecology.

At around 380 kilometres, the Spree is not one of Germany’s longest rivers, but it is one of its most famous. As the capital’s river, it is representative of water bodies in Germany and around the world that are under increasing pressure. While private and commercial interests in its water resources continue to grow, it is also clear that there will be significantly less water available in the future. What needs to be done to counteract this is the subject of controversial debate.

For many years, IGB research group leader Michael Hupfer has been investigating the impact of opencast lignite mining and post-mining landscapes on the region's water bodies, in particular the River Spree. Now, he has been appointed to the Scientific and Technical Advisory Board “Water Management Measures” of the Lausitzer und Mitteldeutsche Bergbau-Verwaltungsgesellschaft mbH (LMBV).