Department Aquatic Ecology

Aquatic Ecology

Eawag’s Department of Aquatic Ecology is currently home for eight research groups that cover the broad disciplines of ecology and evolution from the individual to the community and ecosystem level, utilizing a wide range of tools and techniques from microscopes to molecular genetics. Read more

News

Urine treatment: from trial and error to exciting innovation

Energy-efficient evaporation of excess water in a test at the SAC's Legler Hut at 2280 m a.s.l. (Michel Riechmann, Eawag)
May 4, 2022 –

What has been a purification process in wastewater treatment plants for decades can also be used decentrally or semi-centrally as a recycling process for nutrients. Early separation of "solid and liquid" plays a key role here. It...

What has been a purification process in wastewater treatment plants for decades can also be used decentrally or semi-centrally as a recycling process for nutrients. Early separation of "solid and liquid" plays a key role here. It allows for flexible solutions in terms of process technology, especially in the treatment of urine. New studies also show that the processes can be used not only for human urine, but also for that of cows or pigs.
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Aquascope

Real-time underwater imaging for lake phytoplankton and zooplankton monitoring

Publications

Nickel, J., Schell, T., Holtzem, T., Thielsch, A., Dennis, S. R., Schlick-Steiner, B. C., … Cordellier, M. (2021). Hybridization dynamics and extensive introgression in the Daphnia longispina species complex: new insights from a high-quality Daphnia galeata reference genome. Genome Biology and Evolution, 13(12), evab267 (23 pp.). doi:10.1093/gbe/evab267, Institutional Repository

Hybridization and introgression are recognized as an important source of variation that influence adaptive processes; both phenomena are frequent in the genus Daphnia, a keystone zooplankton taxon in freshwater ecosystems that comprises several species complexes. To investigate genome-wide consequences of introgression between species, we provide here the first high-quality genome assembly for a member of the Daphnia longispina species complex, Daphnia galeata. We further resequenced 49 whole genomes of three species of the complex and their interspecific hybrids both from genotypes sampled in the water column and from single resting eggs extracted from sediment cores. Populations from habitats with diverse ecological conditions offered an opportunity to study the dynamics of hybridization linked to ecological changes and revealed a high prevalence of hybrids. Using phylogenetic and population genomic approaches, we provide first insights into the intra- and interspecific genome-wide variability in this species complex and identify regions of high divergence. Finally, we assess the length of ancestry tracts in hybrids to characterize introgression patterns across the genome. Our analyses uncover a complex history of hybridization and introgression reflecting multiple generations of hybridization and backcrossing in the Daphnia longispina species complex. Overall, this study and the new resources presented here pave the way for a better understanding of ancient and contemporary gene flow in the species complex and facilitate future studies on resting egg banks accumulating in lake sediment.
Briscoe, A. G., Nichols, S., Hartikainen, H., Knipe, H., Foster, R., Green, A. J., … Bass, D. (2021). High-throughput sequencing of faeces provides evidence for dispersal of parasites and pathogens by migratory waterbirds. Molecular Ecology Resources, 22(4), 1303-1318. doi:10.1111/1755-0998.13548, Institutional Repository

Examination of faecal material has demonstrated how a broad range of organisms are distributed by bird movements. Such research has largely focused on dispersal of plant seeds by frugivores and of freshwater organisms by waterbirds. However, with few exceptions (e.g. avian influenza, Ebola virus), there is a dearth of evidence for transport of parasites and pathogens. High-throughput sequencing methods now provide a powerful means of addressing this knowledge gap by elucidating faecal contents in unprecedented detail. We collected faeces excreted by a range of migratory waterbirds in south-west Spain and pooled faecal DNA to create libraries reflective of feeding behavior. We created sets of libraries using high-throughput metagenomic and amplicon sequencing. For the latter we employed two sets of primers to broadly target the V4 region of the 18S rRNA gene (one set amplifying the region across all eukaryotes, the other excluding amplification of metazoans). Libraries revealed a wide diversity of eukaryotes, including parasites of the faecal producers themselves, parasites of food items, or those incidentally ingested. We also detected novel microbial eukaryotic taxa and found that parasite assemblage profiles were relatively distinct. Comparing the performance of the methods used supports their joint use for future studies of diversity and abundance. Because viable stages of many parasites are likely to be present in faeces, our results suggest significant levels of bird-mediated dispersal of parasites (both from avian and other hosts). Our methods revealed much hidden biodiversity, and allowed identification of the individuals who produced the faecal samples to species level, facilitating the study of interaction networks.
Li, F., Zhang, Y., Altermatt, F., & Zhang, X. (2021). Consideration of multitrophic biodiversity and ecosystem functions improves indices on river ecological status. Environmental Science and Technology, 55(24), 16434 (11 pp.)-16444. doi:10.1021/acs.est.1c05899, Institutional Repository

Biological quality elements have been developed worldwide to assess whether a water body is in a good status or not. However, current studies mainly focus on a single taxonomic group or a small set of species, often limited by methods of morphological identification, and lack further aspects of biodiversity (e.g., across taxa and multiple attributes) and ecosystem functions. Here, we advance a framework for assessing the river's ecological status based on complete biodiversity data measured by environmental DNA (eDNA) metabarcoding and measurements of ecosystem functions in addition to physicochemical elements across a large riverine system in China. We identified 40 indicators of biodiversity and ecosystem functions, covering five taxonomic groups from bacteria to invertebrates, and associated with multiple attributes of biodiversity and ecosystem functions. Our data show that human impact on ecosystems could be accurately predicted by these eDNA-based indicators and ecosystem functions, using cross-validation with a known stressor gradient. Moreover, indices based on these indicators of biodiversity and ecosystem functions not only distinguish the physicochemical characteristics of the sites but also improve the assessment accuracy of 20–30% for the river’s ecological status. Overall, by incorporating eDNA-based biodiversity with physicochemical and ecosystem functional elements, the multidimensional perspectives of ecosystem states provide additional information to protect and maintain a good ecological status of rivers.

SNSF Fellowships Ambizione / Eccellenza / Prima

Information for potential candidates

Eco Seminars

15.09.​2022,
9.00 am
Swiss Tech Convention Center Lausanne
Eawag Info Day 2022 - Dynamics of water: new tools, new opportunities

Eawag Info Day 2022

Research Projects

Using freshwater isopods to understand how gut microbiome mediates host function in the face of environmental stress

The Asellus triangle: the host, the microbiome, and global change
Functional characterization of isopod-microbe symbiosis

Defensive Actinobacteria in freshwater- and terrestrial Isopods
The architecture of community structure, functional traits and trophic networks across blue-green ecosystems

Architecture of blue-green communities
New tools to monitor changes in ecosystem conditions and to quantify genetic changes of populations in (semi-)natural environments to predict how human mediated environmental change will influence stability and resilience of ecosystems.

Stability and the eco-evolutionary dynamics of ecosystems

More current Research Projects