Shallow lakes are highly sensitive ecosystems that are susceptible to changes in their physical, chemical, and biological properties. In this study, we investigated the changes in the phytoplankton and bacterioplankton communities from January to early April in lake Balaton, the largest shallow lake of Central Europe using a multi-approach investigation. Samples were taken weekly from the lake’s three distinct sites. The composition and quantity of phytoplankton were identified by light microscopy. 16S and 18S eDNA amplicon sequencing were used to identify planktonic bacteria, archaea, and eukaryotic phytoplankton. Co-occurrence network analysis was applied to assess time-shifted interactions. Our results showed that the phytoplankton and bacterioplankton communities in the lake achieved significant changes over the study period. Specifically, the change of relative abundance of characteristic freshwater bacteria (e.g., acI-A, acI-B, LD12) indicated a temporal shift in the composition of the communities. Shifts in the phytoplankton community structure were coupled with the abundance changes of the members of bacterioplankton. Overall, our study demonstrated the potential of a multi-approach method, combining high-throughput sequencing, microscopy, and network analysis, to better understand the dynamics of phytoplankton and bacterioplankton communities in shallow lakes.

Primary Presenter: Andras Hidas, Centre for Ecological Research (hidasandris@gmail.com)

Authors:

András Hidas, Institute of Aquatic Ecology, Centre for Ecological Research, Budapest, Hungary; Eötvös Loránd University, Doctoral School of Environmental Sciences, Budapest, Hungary  (hidas.andras@ecolres.hu)

Boglárka Somogyi, Balaton Limnological Research Institute, Tihany, Hungary  ()

Attila Szabó, Institute of Aquatic Ecology, Centre for Ecological Research, Budapest, Hungary; Department of Aquatic Sciences and Assessment, Swedish University of Agricultural Sciences, Uppsala, Sweden  ()

Dóra Fehér, Institute of Aquatic Ecology, Centre for Ecological Research, Budapest, Hungary; National Multidisciplinary Laboratory for Climate Change, Centre for Ecological Research, Budapest, Hungary  ()

Lajos Vörös, Balaton Limnological Research Institute, Tihany, Hungary  ()

Tamás Felföldi, Institute of Aquatic Ecology, Centre for Ecological Research, Budapest, Hungary; National Multidisciplinary Laboratory for Climate Change, Centre for Ecological Research, Budapest, Hungary  ()