Friday April 8, 2022, 2 pm GMT+2
Juliana CHACÓN1*, Uwe JOHN2, Juliane KRETSCHMANN1, Stefan NEUHAUS2, Herwig STIBOR3, Anže ŽERDONER ČALASAN1, Marc GOTTSCHLING1
Dinophyte diversity in Bavarian lakes and algal species successions at Munich Botanical Gardens (Germany): Using phylogenetic placement of environmental sequences and reliable taxonomic databases to study algal biodiversity
1 Systematics, Biodiversity and Evolution of Plants, Ludwig-Maximilians-University Munich (LMU), Munich, Germany
2 Alfred-Wegener-Institut Helmholtz-Zentrum für Polar- und Meeresforschung, AWI, Bremerhaven, Germany
3 Aquatic Ecology, Biology II, LEMAR, Ludwig-Maximilians University Munich (LMU), Munich, Germany
*Juliana.chacon@bio.lmu.de
Reliable determination of organisms is the necessary prerequisite to explore their spatial and temporal distribution and to study their evolution, ecology and dispersal. The Bavarian state in Germany provides a great study system for research on the origin and diversification of freshwater organisms including dinophytes, due to the presence of extensive lake districts and ice age river valleys, which are ecologically very diverse. In this study, we obtained amplicon sequence data (SSU-rRNA) from environmental samples collected in Upper Bavaria. Using bioinformatic pipelines, we found 186 dinophycean operational taxonomic units (OTUs) that were further classified by means of a phylogenetic placement approach. The Maximum likelihood tree as inferred from a well-curated reference alignment comprised a systematically representative set of 241 dinophytes, covering the known molecular diversity and considering type material. Environmental OTUs were scattered over the reference tree, but accumulated mostly in freshwater lineages, especially taxa that are frequently encountered in Bavaria (i.e., Apocalathium, Ceratium or Peridinium). Particularly within Peridiniaceae, intraspecific sequence variation was suitable to determine species of Peridinium. Twenty-one OTUs showed identical sequences to known and vouchered sequences, of which two have been gained from type material, namely Palatinus apiculatus and Theleodinium calcisporum. Our approach indicates that high-throughput sequencing of environmental samples is effective for reliable determination of freshwater dinophytes and highlights the importance of well-curated reference data bases. We are now using this methodology within a biomonitoring project, which is being conducted at the ponds of the Munich Botanical Gardens. Our metabarcoding approach aims to examine the algal diversity in terms of seasonality and annual species successions. The goal is to develop awareness of the importance of the microalgal biodiversity in this microbial domain and their impact in the context of the current climate change.