Département Ecologie aquatique

Département Ecologie aquatique

Le département Écologie aquatique de l'Eawag se compose de huit groupes de recherche et englobe un grand nombre de disciplines diverses de l'écologie et de la biologie de l'évolution, couvrant ainsi l'éventail complet depuis le niveau individuel jusqu'aux écosystèmes en passant par les associations. En savoir plus

News

Les insectes aquatiques sont moins envahissants

Le moustique tigre d'Asie (_Aedes albopictus_) est l'une des rares espèces d'insectes aquatiques à avoir été introduite sur plusieurs continents et à y être envahissante. Photo: James Gathany, CDC
23 septembre 2022 –

Chez les insectes qui passent tout ou partie de leur vie en eau douce, la proportion d'espèces envahissantes est nettement plus faible que chez les insectes terrestres. C'est ce que montre une étude de l'Institut fédéral de...

Chez les insectes qui passent tout ou partie de leur vie en eau douce, la proportion d'espèces envahissantes est nettement plus faible que chez les insectes terrestres. C'est ce que montre une étude de l'Institut fédéral de recherches sur la forêt, la neige et le paysage WSL en collaboration avec l'Institut fédéral suisse des sciences et technologies de l’eau Eawag et une équipe internationale de chercheurs.
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Project Aquascope

Imagerie sous-marine en temps réel pour la surveillance du phytoplancton des lacs et du zooplancton (en Anglais)

Publications

Packman, A. I., Robinson, C. T., & Lamouroux, N. (2021). Hydraulic drivers of populations, communities and ecosystem processes. Journal of Ecohydraulics, 6(2), 91-94. doi:10.1080/24705357.2021.1951506, Institutional Repository
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.

SNSF Fellowships Ambizione / Eccellenza / Prima

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Projet de recherche

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
We test how natural selection acts on quantitative immune defence traits and how ecological factors create variation in the form and strength of selection.

Natural selection on immune function
Assess the distribution and genetic structure of all amphipod species in Switzerland.

Amphipod.CH

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