Limnological Institute
Welcome to the Group of Chemical Ecology & Ecophysiology
Welcome to the Group of Chemical Ecology & Ecophysiology at the Limnological Institute, University of Konstanz.
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Freshwater model organisms in ecophysiological research:
host-parasite interactions
Daphnia magna is the largest representative of the genus Daphnia. These small freshwater crustaceans are also known as water fleas and are among the oldest model systems in biological research. Like any other organism, Daphnia are constantly challenged by microorganisms trying to invade their body. One of these villains is Pasteuria ramosa, a bacterial parasite castrating its host after successful establishment. The comparison of a healthy (left) and a heavily infected (right) female under a stereomicroscope reveals the consequences of parasite invasion: while the uninfected animal holds developing neonates in its brood chamber, this chamber is empty in the infected animal.
image© Nina Schlotz
Freshwater model organisms in ecophysiological research:
nutritional ecology of essential lipids
The dietary availability of essential lipids like sterols and PUFAs (PolyUnsaturatedFattyAcids) can crucially affect the fitness of Daphnia. Algae and cyanobacteria might not provide sufficient amounts of these essential nutrients. When experimentally provided along with a deficient diet, essential lipids can increase growth and reproduction in male and female D. magna (left: animals raised on the green alga Scenedesmus obliquus; right: animals raised on the PUFA-enriched diet).
image©Tamara Massier/Dominik Martin-Creuzburg
Cross-ecosystem fluxes:
Export of essential lipids from aquatic to terrestrial ecosystems
Cross-ecosystem fluxes can crucially influence the productivity of adjacent habitats. Emerging aquatic insects represent one important pathway through which freshwater-derived organic matter can enter terrestrial food webs and may be of superior food quality for terrestrial consumers, because they contain high concentrations of essential polyunsaturated fatty acids (PUFA). Emergence traps were installed above different water depths, insects collected, and fatty acids analysed. Here, Chironomidae contributed most to insect biomass and total PUFA export, Chaoborus flavicans contributed most to the export of EPA, ARA, and especially DHA. Insect-mediated PUFA fluxes are strongly affected by lake morphometry.
image© Nina Schlotz/Dominik Martin-Creuzburg