Light as a Controlling Factor of Winter Phytoplankton in a Monomictic Reservoir

0559100 - ÚI 2023 RIV DE eng J - Journal Article
Fott, J. - Nedbalová, L. - Brabec, Marek - Kozáková, Radka - Řeháková, Klára - Hejzlar, Josef - Šorf, M. - Vrba, Jaroslav
Light as a Controlling Factor of Winter Phytoplankton in a Monomictic Reservoir.
Limnologica. Roč. 95, July 2022 (2022), č. článku 125995. ISSN 0075-9511. E-ISSN 1873-5851
R&D Projects: GA ČR(CZ) GA15-04034S; GA ČR GA206/03/1491; GA MŠMT(CZ) EF16_025/0007417
Institutional support: RVO:67985807 ; RVO:67985912 ; RVO:60077344
Keywords : Chlorophyll a * CE-QUAL model * PEG model * Ice cover * Climate change * Daphnia
OECD category: Statistics and probability; Ecology (ARU-G); Marine biology, freshwater biology, limnology (BC-A)
Impact factor: 1.7, year: 2022
Method of publishing: Limited access
https://dx.doi.org/10.1016/j.limno.2022.125995

Factors affecting the seasonal succession of plankton communities in freshwater temperate lakes have been thoroughly studied for decades. However, there are still relatively few data describing the winter season patterns in detail, as the focus has been mostly on spring to autumn conditions. Ice cover is often the crucial factor limiting light availability for winter phytoplankton, but in warm monomictic lakes is usually lacking and the gradually increasing solar radiation should, theoretically, drive phytoplankton growth. In this study conducted in 2002–2010, we documented regular sharp increases in phytoplankton chlorophyll a, starting just after the winter solstice and lasting throughout the total circulation and/or unstable inverse stratification period in the monomictic Slapy reservoir (Czechia). Chlorophyll a concentrations analysed in one-week intervals reached their yearly minimum of 0.2–0.8 µg L−1 in the solstice period, and the spring peak occurred before the onset of stable thermal stratification. The regular pattern was slightly disrupted in some years, associated with short periods of ice cover. Winter phytoplankton were species poor and dominated by diatoms, cryptophytes, green algae, and cyanobacteria. Using semiparametric regression approach, we aimed to test if selected environmental parameters had a significant effect on the observed winter trend. The resulting model revealed that solar radiation and water temperature positively influenced log chlorophyll a concentrations, whereas water age had a significant negative effect. On the other hand, zooplankton density and ice cover effects were not significant. The shapes of the marginal effects of water temperature and solar radiation were nonlinear, and the interaction of these two major factors was significant. The model-based estimated chlorophyll a concentrations showed a shift from radiation dominance to temperature-positive effects along the temperature gradient. This might represent as yet neglected pattern of phytoplankton seasonal development in warm monomictic lakes worldwide.
Permanent Link: https://hdl.handle.net/11104/0332519