Limnological Methods in River Ecology
Water Quality vs. Stream Morphology
This course module focussed on limnological methods for small river morphology classification and water quality assessment. As a typical Middle European brook the catchment area of the Krebsbach lies within intensively cultivated pasture and forest land. Its small spring source remains predominantly anthropogenic unaffected within a beech forest.
We studied various abiotic stream patterns (cross sections & longitudinal profile of the river channel, bank morphology, discharge measurements, water chemistry) as well as biotic parameter (surber samples of aquatic organisms, waterside growth). A representive sample of the benthos species were taken to the lab. The students determined the organsisms to the lowest possible taxonomic level for calculating the saprobial status of this brook. Surprisingly, high marks in water quality due to high abundances of several indicator species such as Baetis alpinus/melanonyx, Rhitrogena spp., Amphinemura spp.) contradicted negative results in river morphology marks.
Lake Littoral Limnology
Species Colonization Dynamics in Dependence to Wave Exposure
We investigated species dynamics and colonization patterns of benthic organisms. We exposed artificial hard substrates in shallow water at three lake sites were we expected different wave regimes. Wave exposure was examined using the dissolution rate and mass loss of gypsum spheres.
Grazer - Periphyton - Interactions
Within this course, we conducted a field experiment on grazer influence on littoral periphyton and meiofauna communities. We have exposed pre-incubated artificial substrates in the littoral of Upper Lake Constance and manipulated grazer access with help of an enclosure/exclosure design. We took samples in a four-day interval and analysed Chlorophyll a, TOM and Meiofauna abundance. In addition, the students conducted a laboratory experiment to compare the influence of selected invertebrates on the periphyton community.
At the end of this course, the students presented their results in a judged poster session.