engleski

The spatial-seasonal differences of microbial communities in the freshwater network ecosystem

World-famous Plitvice Lakes represent a rare surface freshwater ecosystem composed of a network of streams and cascading lakes connected by the interlake streams. The tributaries, water supplying streams of the catchment area, are heavily influenced by surrounding terrestrial systems and characterized by the water flow change downstream. To determine microbial communities' diversity and spatial-seasonal changes within the freshwater network system, we conducted a study for two years at 26 locations. Water samples were collected from the surface of all main streams. Environmental parameters were measured in situ and from filtered samples. The hypervariable V4 region of the prokaryotic 16S rDNA and the ITS2 of the fungal rDNA were sequenced. Tributaries generally had richer microbial communities than interlake streams and the Korana River. Bacterial communities of Interlake streams and Korana River showed more similarity than with tributaries. Bacteroidota and Proteobacteria dominated the bacterial community of the tributaries. At the same time, within interlake streams, Actinobacteria appeared with a higher abundance. Bdellovibrionota and Patescibacteria in tributaries and Armatimonadota in interlake streams were observed. Interlake streams were more influenced by seasonality, where higher oscillations of environmental parameters were observed. Ascomycota, Basidiomycota, and Chytridiomycota dominated fungal communities with a higher abundance of Chytridiomycota in winter and Basidiomycota in spring. Appearances of the Mortierellomycota and Olpidiomycota were observed in tributaries, while in interlake streams and Korana River, Rozellomycota were more abundant. This study explains the categorically dependent microbial changes in the freshwater network ecosystem.

freshwater network ecosystem, microbial communities, spatial-seasonal

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