Bacterioplankton seasonality in deep high-mountain lakes

• Published in: Frontiers in microbiology Vol. 13
• Main Authors: Zufiaurre, Aitziber, Felip, Marisol, Camarero, Lluís, Sala-Faig, Marc, Juhanson, Jaanis, Bonilla-Rosso, German, Hallin, Sara, Catalan, Jordi
• Format: Journal Article
• Language: English
• Published: Frontiers Media S.A 14-09-2022
• Subjects: Actinobacteria hgcl_clade; bacteria coexistence; core community; Fysisk geografi; microbial ecology; Microbiology; Mikrobiologi; Physical Geography; under-ice ecology; Verrucomicrobia
• ISSN: 1664-302X; 1664-302X
• DOI: 10.3389/fmicb.2022.935378

Due to global warming, shorter ice cover duration might drastically affect the ecology of lakes currently undergoing seasonal surface freezing. High-mountain lakes show snow-rich ice covers that determine contrasting conditions between ice-off and ice-on periods. We characterized the bacterioplankton seasonality in a deep high-mountain lake ice-covered for half a year. The lake shows a rich core bacterioplankton community consisting of three components: (i) an assemblage stable throughout the year, dominated by Actinobacteria, resistant to all environmental conditions; (ii) an ice-on-resilient assemblage dominating during the ice-covered period, which is more diverse than the other components and includes a high abundance of Verrucomicrobia; the deep hypolimnion constitutes a refuge for many of the typical under-ice taxa, many of which recover quickly during autumn mixing; and (iii) an ice-off-resilient assemblage, which members peak in summer in epilimnetic waters when the rest decline, characterized by a dominance of
Flavobacterium
, and
Limnohabitans
. The rich core community and low random elements compared to other relatively small cold lakes can be attributed to its simple hydrological network in a poorly-vegetated catchment, the long water-residence time (
ca.
4 years), and the long ice-cover duration; features common to many headwater deep high-mountain lakes.