Even bacteria in reservoirs have four seasons
Planktonic microbial communities have critical impacts on the pelagic food web and water quality status in freshwater ecosystems, yet no general model of bacterial community assembly linked to higher trophic levels and hydrodynamics has been assessed. In the recent study, published in Microbiome, hydrobiologists from the Institute of Hydrobiology, Biology Centre CAS, utilized a two-year survey of planktonic communities from bacteria to zooplankton on three freshwater reservoirs to investigate their spatiotemporal dynamics.
Image: Aquatic bacteria in the Římov reservoir in four seasons. Under the microscope, there is not much difference, genetically it is much more interesting. Cells taken with an Olympus BX50 fluorescence microscope at 100x magnification, scale bar indicates 10 micrometers. Photo: Radka Malá, Michaela Štojdlová
We observed the site-specific presence and microdiversification of bacteria in lacustrine and riverine environments, as well as in deep hypolimnia. Moreover, we determined recurrent bacterial seasonal patterns driven by both biotic and abiotic conditions, which could be integrated into the well-known Plankton Ecology Group (PEG) model describing primarily the seasonalities of larger plankton groups. Importantly, bacteria with different ecological potentials showed finely coordinated successions affiliated with four seasonal phases, including the spring bloom dominated by fast-growing opportunists, the clear-water phase associated with oligotrophic ultramicrobacteria, the summer phase characterized by phytoplankton bloom-associated bacteria, and the fall/winter phase driven by decay-specialists.
Our findings elucidate the principles driving the spatiotemporal microbial community distribution in freshwater ecosystems. We suggest an extension to the original PEG model by integrating recurrent bacterial seasonal trends.
Publication
Park, H., Shabarova, T., Salcher, M.M. et al. In the right place, at the right time: the integration of bacteria into the Plankton Ecology Group model. Microbiome 11, 112 (2023). https://doi.org/10.1186/s40168-023-01522-0
