News

The quality of lake ice is of paramount importance for ice safety and lake ecology under ice, but its temporal and spatial variability is largely unknown. An international research team with IGB researcher Hans-Peter Grossart conducted a coordinated sampling campaign of lake ice quality throughout the Northern Hemisphere. The team, led by Sweden's Uppsala University, was able to show that lake ice during this period generally consisted of unstable white ice, which at times accounted for up to 100 percent of the total ice thickness.

A Chinese team, in collaboration with IGB researcher Sabine Hilt, has shown in a large mesocosm experiment how heat waves, nutrients and pesticides promote algae growth and cause aquatic plants to dwindle. This shift in plant types may increase the total amount of greenhouse gas emissions from shallow lakes, as Sabine Hilt and Dutch colleagues demonstrated in another mesocosm experiment.

Researchers from IGB have investigated which factors promote the formation of vivianite and thus increase the amount of recoverable phosphorus.

Dörthe Tetzlaff's team combined a mathematical model with field data to analyse the pathways of nitrate in the Demnitzer Mühlenfließ - a typical catchment in the north-eastern German lowlands with mixed landscape use.

Ulrike Berninger, Professor of Ecology at the University of Salzburg in Austria, has long been interested in mixotrophic plankton. This refers to the small organisms floating in water that combine the properties of both zooplankton and phytoplankton. Depending on the environmental situation or individual requirements, these unicellular organisms can either take up food particles via phagocytosis or carry out photosynthesis using sunlight.

Fish are an important element in the food web of lakes. This also applies to the experimental enclosures of the LakeLab. However, in this case, the number of fish must be controlled so that the results from the individual cylinders can be compared with each other. Because fish from the lake repeatedly jump into the enclosures, all fish must first be removed with nets from the cylinders before starting a new experiment. Today, 5 small perch were released into each enclosure for this year's LakeLab experiment.

As energy supplier and stimulus of the internal clock, light is of fundamental importance to plants and animals. This also applies to fish and microscopic organisms in lakes. Like other species, they have adapted to the day-night rhythm during evolution. But what happens if a lake is illuminated by artificial lighting at night, or if not enough light penetrates into the water during the day? These questions are examined during this year's summer experiment at the Lake Lab.