Biogeography of Protists

Protists (eukaryotic microbes) fulfill critical ecological functions as they are the dominant primary producers in aquatic environments and, at the same time, are the major consumers of bacteria and thus at the basis of food webs. Further, protist diversity is tremendous but their distribution pattern are not well understood. Doubts about the generalizability of biogeographic patterns as known for animals and plants to other organisms are highly appropriate! To that end, the post-glacial biogeography of Europe is an ideal test case for further testing the generalizability of biogeographic patterns in protists. I this project, we aim to investigate protist distribution pattern in European freshwaters in light of the post-glacial distribution patterns of macro-organisms. We will address variation in protist diversity pattern in natural aquatic ecosystems and relate these changes to environmental factors based on plankton samples from 250 European lakes including lakes from Spain, France, Italy, Switzerland, Austria, Romania, Hungary, the Czech Republic, Slovakia, Poland, Sweden, Norway, Greece, Croatia and Bulgaria. The project will analyze biogeography, phylogeopgraphy and diversity of protist molecular diversity in European freshwater lakes at the community based on massive parallel sequencing data. Taken together the project will test the validity of general biological theories for microbial eukaryotes

Funding: FWF P19706 & P21151 TWF P0404/690 ÖAW Climate change program


Environmental-change induced community shifts occur specifically in sensitive alpine lake ecosystems. We directly address (i) the already ongoing changes in the natural world (aquatic ecosystems) and their relation to global change phenomena, (ii) relevant indicator organisms (phytoplankton) by analysing time series of sample material, and (iii) the differential impacts of land use change and climate change. Here we build on a robust dataset on the microbial community analysis of an alpine lake gradient to analyse short-term environmental change induced ecosystem responses to climate change.

Funding: Several national individual research grants to members of the network


This research project focusses on the comparative analysis of diversity pattern of plants, animals, protists, bacteria and archaea. By means of cultivation independent high throughput sequencing techniques we analyse diversity pattern in freshwater, soil, and marine environments. This project brings together descriptive diversity analyses with experimental approaches in order to understand the ecological and evolutionary basis of the observed diversity pattern. Further, the comparative approach shall illuminate some fundamental conflicts in the ‘everything is everywhere’ debate. Specifically for protist taxa this approach shall clarify whether their distribution pattern correspond to that of multicellular eukaryotes (plants and animals) or to that of bacteria.

DFG Priority Programme (Schwerpunktprogramm 1704)

Flexible until it snaps: Dynamics of genes & traits, densities & diversity in communities challenged by environmental change

One of the main and crucial questions to be addressed within this subproject of the SPP DynaTrait is whether diversity allows feedbacks within ecological communities, through trait dynamics, that in turn promotes the maintenance of diversity - specifically in response to environmental change. Changes in environmental conditions, such as pollutant exposure and water temperature increases interact with unknown additive, synergistic or antagonistic effects on biota. Community feedbacks spanning the dynamics of genes and traits, densities and diversity are presumably of key importance for buffering the community response to, for instance, environmental changes. Here we focus on model communities consisting of protist species that differ in major functional traits that are relevant at the ecosystem level (being autotrophs, mixotrophs or heterotrophs). The focus of the project lies on the dynamic responses to environmental stressors, specifically to ionic silver, and on the effect of such stressors to constrain the communities ability to dynamically respond to additional stressors such as heat waves. Shifts in selected morphological and physiological traits may not or may only indirectly be linked to the environmental cues under view. Past approaches relying mainly on morphological and physiological data alone may therefore miss some key aspects in the organisms and ecosystems response. A much broader approach considering many different potential reactions and feedbacks at a given time would be desireable or even essential to comprehensively address this issue. We consequently combine classical morphological and ecophysiological analyses with (meta-)transcriptome analyses based on high throughput sequencing technologies.


Resource-efficient treatment of wastewaters in NRW

Using Tetrahymena to eliminate bacteria in wastewater treatment plant effluent

Effluent discharge from sewage treatment plants is the most important source of entry for pathogenic and antibiotic-resistant microorganisms in surface waters. Studies show that treatment plant wastewaters carry a large number of antibiotic-resistant bacteria – including those exhibiting multi-drug resistance. In this joint research project between the University of Wuppertal and the University of Duisburg-Essen, we explore how the ciliate Tetrahymena pyriformis can be used as a "biological filter" to remove pathogenic and antibiotic-resistant bacteria from treated wastewater. The project, which is carried out in cooperation with LANUV NRW, will serve as a pilot study, ultimately aiming to reduce the bacterial load of treated water as it is returned to the environment.

The impact of flooding on biodiversity at the soil-water boundary

Flooding has a dramatic effect on local biodiversity, not least by flushing soil organisms out of their natural habitat and into the water column, and vice versa. Such temporary changes, as when soil fungi and yeasts enter aquatic habitats, alter the structure and function of the receiving ecosystem by altering metabolic pathways, thus potentially changing species distribution patterns in the long term. In this project, we focus on potentially key organisms – including fungi (decomposers), heterotrophic nanoflagellates (bacterivores), algae (primary producers), and bacteria - to explore the effect of flooding on the functional dynamics of microbial diversity at the interface of terrestrial and aquatic environments.