title: Trade-off between taxon diversity and functional diversity in European lake ecosystems.
abstract: Inferring ecosystem functioning and ecosystem services through inspections of the species inventory is a major aspect of ecological field studies. Ecosystem functions are often stable despite considerable species turnover. Using metatranscriptome analyses, we analyse a thus-far unparalleled freshwater data set which comprises 21 mainland European freshwater lakes from the Sierra Nevada (Spain) to the Carpathian Mountains (Romania) and from northern Germany to the Apennines (Italy) and covers an altitudinal range from 38 m above sea level (a.s.l) to 3110 m a.s.l. The dominant taxa were Chlorophyta and streptophytic algae, Ciliophora, Bacillariophyta and Chrysophyta. Metatranscriptomics provided insights into differences in community composition and into functional diversity via the relative share of taxa to the overall read abundance of distinct functional genes on the ecosystem level. The dominant metabolic pathways in terms of the fraction of expressed sequences in the cDNA libraries were affiliated with primary metabolism, specifically oxidative phosphorylation, photosynthesis and the TCA cycle. Our analyses indicate that community composition is a good first proxy for the analysis of ecosystem functions. However, differential gene regulation modifies the relative importance of taxa in distinct pathways. Whereas taxon composition varies considerably between lakes, the relative importance of distinct metabolic pathways is much more stable, indicating that ecosystem functioning is buffered against shifts in community composition through a functional redundancy of taxa.
authors.affiliation: Biodiversity Department and Centre for Water and Environmental Research, University of Duisburg-Essen, 45141, Essen, Germany.
authors.forename: Lars
authors.initials: L
authors.lastname: Grossmann
authors.affiliation: Biodiversity Department and Centre for Water and Environmental Research, University of Duisburg-Essen, 45141, Essen, Germany.|Genome Informatics, Institute of Human Genetics, University of Duisburg-Essen, University Hospital Essen, 45122, Essen, Germany.
authors.forename: Daniela
authors.initials: D
authors.lastname: Beisser
authors.affiliation: Biodiversity Department and Centre for Water and Environmental Research, University of Duisburg-Essen, 45141, Essen, Germany.
authors.forename: Christina
authors.initials: C
authors.lastname: Bock
authors.affiliation: Department of Environmental Microbiology, Helmholtz Centre for Environmental Research - UFZ, Permoserstr. 15, 04318, Leipzig, Germany.|German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, Deutscher Platz 5e, 04103, Leipzig, Germany.
authors.forename: Antonis
authors.initials: A
authors.lastname: Chatzinotas
authors.affiliation: Biodiversity Department and Centre for Water and Environmental Research, University of Duisburg-Essen, 45141, Essen, Germany.
authors.forename: Manfred
authors.initials: M
authors.lastname: Jensen
authors.affiliation: Department of Zoology and Didactics of Biology, Bergische Universität Wuppertal, 42119, Wuppertal, Germany.
authors.forename: Angelika
authors.initials: A
authors.lastname: Preisfeld
authors.affiliation: Institute of Ecology, University of Innsbruck, Technikerstrasse 25, A-6020, Innsbruck, Austria.
authors.forename: Roland
authors.initials: R
authors.lastname: Psenner
authors.affiliation: Genome Informatics, Institute of Human Genetics, University of Duisburg-Essen, University Hospital Essen, 45122, Essen, Germany.
authors.forename: Sven
authors.initials: S
authors.lastname: Rahmann
authors.affiliation: Biodiversity Department and Centre for Water and Environmental Research, University of Duisburg-Essen, 45141, Essen, Germany.
authors.forename: Sabina
authors.initials: S
authors.lastname: Wodniok
authors.affiliation: Biodiversity Department and Centre for Water and Environmental Research, University of Duisburg-Essen, 45141, Essen, Germany.
authors.forename: Jens
authors.initials: J
authors.lastname: Boenigk
mesh_terms: D044822:Biodiversity; D000460:Chlorophyta / Q000145:classification; D016798:Ciliophora / Q000145:classification; D017377:Diatoms / Q000145:classification; D017753:Ecosystem; D005858:Germany; D007558:Italy; D060106:Lakes; D012383:Romania; D013030:Spain; D059467:Transcriptome
keywords: community composition; functional diversity; lake ecosystems; microbial ecology; protists; taxon diversity