Nov 13 – 15, 2024
Leipziger KUBUS Helmholtz-Zentrum für Umweltforschung – UFZ
Europe/Berlin timezone
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Integrating High Throughput Molecular and Optical Methods to Study Protistan Abundances in Groundwater Ecosystems

Nov 14, 2024, 12:21 PM
1m
Leipziger KUBUS/1-A - Hall 1 A (Leipziger KUBUS)

Leipziger KUBUS/1-A - Hall 1 A

Leipziger KUBUS

150
Poster Flexpool Poster Flash Talks

Speaker

Nadine Möbius (FSU Jena, Institute of Biodiversity, German Center for Integrative Biodiversity Research (iDiv) Halle Jena Leipzig)

Description

Heterotrophic protists occupy key nodes in terrestrial food webs due to their high abundance, fast turnover and functional importance as microbial grazers. However, their impact on groundwater bacterial communities and organic carbon transfer to higher trophic levels remains largely unknown. Assessing their role in trophic interactions using molecular techniques has been limited by the variability in 18S rRNA gene copy numbers, complicating the quantification of protists.
The key objective of our novel approach is the establishment of protist enumeration by Imaging Flow Cytometry (IFC), combined with qPCR assays and 18S rRNA gene targeted amplicon sequencing, to derive taxon-specific correction factors, facilitating precise estimation of key taxa abundances from molecular data and provide biomass estimates from IFC. In addition, we aim to compare protistan communities between carbonate-rock (Hainich Critical Zone Exploratory) and sandstone aquifers (Saale-Elster-Sandstone Observatory) located in Thuringia, using molecular and cultivation-dependent approaches as well as metatranscriptomics.
Protistan monocultures were used to successfully generate initial reference image datasets using IFC, covering sizes from 3 to 50 µm and various morphotypes. Convolutional neural network (CNN) training achieved 85% precision in predicting protistan taxa based on morphological features.
Enrichments of groundwater protistan communities initially exhibited predominance of nanoflagellates (3-15 µm) and flagellates (15-20 µm), followed by successional changes in favor of ciliates and amoebae (Acanthamoeba, Hartmannella, Vahlkampfia) within 1-2 weeks where differences between the geological settings were observed. By 4-6 weeks, occasionally heliozoans and Aspidisca sp. (Ciliates) emerged. Amplicon sequencing confirmed high abundances of previously identified groundwater taxa such as Cercomonas spp., Thaumatomonas sp., Neocercomonas sp. (Cercomonadida), Sandona sp., Allantion sp. (Glissomonadida), Spumella sp., Paraphysomonas sp. (Chrysomonada), Rhogostoma sp. and Glaucoma sp.
Our results show that IFC enables high-throughput automated quantification. Innovative abundance estimation and community assessment will enhance our understanding of food web structures in aquifers with different geological settings.

Status Group Postdoctoral Researcher

Primary author

Nadine Möbius (FSU Jena, Institute of Biodiversity, German Center for Integrative Biodiversity Research (iDiv) Halle Jena Leipzig)

Co-authors

Dr Anna Maria Fiore-Donno (University of Cologne, Institute of Zoology) Prof. Antonis Chatzinotas (German Center for Integrative Biodiversity Research (iDiv) Halle Jena Leipzig, Helmholtz Centre for Environmental Research-UFZ, Department of Environmental Microbiology; University of Leipzig) Prof. Martin Schlegel (German Center for Integrative Biodiversity Research (iDiv) Halle Jena Leipzig, University of Leipzig, Institute of Biology, Biodiversity and Evolution) Dr Martina Herrmann (FSU Jena, Institute of Biodiversity, German Center for Integrative Biodiversity Research (iDiv) Halle Jena Leipzig) Ms Susanne Dunker (German Center for Integrative Biodiversity Research (iDiv) Halle Jena Leipzig, Helmholtz Centre for Environmental Research-UFZ, Department for Physiological Diversity)

Presentation materials