Food web ecology
Biodiversity in freshwater ecosystems is threatened by human activities due to the combined effects of multiple stressors such as eutrophication, hydromorphological degradation, and non-native species. These activities may also impair ecosystem functioning and hence the provision of goods and services that humans rely on. However, to which extent altered biodiversity is the cause of altered ecosystem functioning or a concomitant phenomenon remains unclear.
We study the functional role of micro-and macroorganisms and the consequences of the human-induced loss of multi-group biodiversity for ecosystem functioning. Our work involves a significant field component, including large-scale studies and mesocosm experiments in the MOBICOS facilities. We use a range of techniques but primarily combine natural abundance and enriched stable isotopes with estimates of ecosystem productivity and respiration to quantify food web topology and consumer-resource interactions. Building on that, we are working on indicators to assess the functional status of freshwater ecosystems and inform catchment management on how to mitigate human impacts on ecosystem material cycling.
Head of the research group: PD Dr. Mario Brauns
Long-term monitoring of biodiversity and ecosystem functioning
We are equipped with a THERMO Flash 2000 elemental analyser interfaced to a THERMO Delta Advantage isotope ratio mass spectrometer and analyse 13C and 15N isotopes and CN elemental concentrations of organic matter samples. During analysis, samples are interspersed with several replicates of four different laboratory reference materials. These reference materials have been previously calibrated against the international reference materials IAEA-CH-3, IAEA-CH-6, IAEA-CH-7, IAEA-N-1 and IAEA-N-2. Moreover, we calibrated our IRMS to measure enriched CN stable isotopes up to 4 atom percent for 13C and 6.5 atom percent for 15N. Please contact Mario Brauns for more information.