caa a22 4500 445894601 CHVBK 20180317145627.0 cr unu---uuuuu 170323e20110401xx s 000 0 eng 10.1007/s10750-010-0595-y doi (NATIONALLICENCE)springer-10.1007/s10750-010-0595-y Winter ecology of shallow lakes: strongest effect of fish on water clarity at high nutrient levels [Elektronische Daten] [Torben Sørensen, Gabi Mulderij, Martin Søndergaard, Torben Lauridsen, Lone Liboriussen, Sandra Brucet, Erik Jeppesen] While the structuring role of fish in lakes is well studied for the summer season in North temperate lakes, little is known about their role in winter when fish activity and light irradiance potentially are lower. This is unfortunate as the progressing climate change may have strong effects on lake winter temperature and possibly on trophic dynamics too. We conducted an enclosure experiment with and without the presence of fish throughout winter in two shallow lakes with contrasting phosphorus concentrations. In hypertrophic Lake Søbygård, absence of fish led to higher biomass of zooplankton, higher grazing potential (zooplankton:phytoplankton ratio) and, accordingly, lower biomass of phytoplankton and chlorophyll a (Chl a), while the concentrations of total nitrogen (TN), total phosphorus (TP), oxygen and pH decreased. The average size of egg-bearing Daphnia and Bosmina and the minimum size of egg-bearing specimens of the two genera rose. In the less eutrophic Lake Stigsholm, zooplankton and their grazing potential were also markedly affected by fish. However, the decrease in Chl a was slight, and phytoplankton biovolume, pH and the oxygen concentration were not affected. TN was higher when fish were absent. Our results indicate that: (i) there is a notable effect of fish on zooplankton community structure and size during winter in both eutrophic and hypertrophic North temperate lakes, (ii) Chl a can be high in winter in such lakes, despite low light irradiance, if fish are abundant, and (iii) the cascading effects on phytoplankton and nutrients in winter may be more pronounced in hypertrophic lakes. Climate warming supposedly leading to reduced winter mortality and dominance of small fish may enhance the risk of turbid state conditions in nutrient-enriched shallow lakes, not only during the summer season, but also during winter. Springer Science+Business Media B.V., 2011 Shallow nationallicence Eutrophic nationallicence Hypertrophic nationallicence Lakes nationallicence Phytoplankton nationallicence Zooplankton nationallicence Planktivorous fish nationallicence Nutrients nationallicence Sørensen Torben Department of Freshwater Ecology, National Environmental Research Institute, Aarhus University, Vejlsøvej 25, 8600, Silkeborg, Denmark aut Mulderij Gabi Department of Freshwater Ecology, National Environmental Research Institute, Aarhus University, Vejlsøvej 25, 8600, Silkeborg, Denmark aut Søndergaard Martin Department of Freshwater Ecology, National Environmental Research Institute, Aarhus University, Vejlsøvej 25, 8600, Silkeborg, Denmark aut Lauridsen Torben Department of Freshwater Ecology, National Environmental Research Institute, Aarhus University, Vejlsøvej 25, 8600, Silkeborg, Denmark aut Liboriussen Lone Department of Freshwater Ecology, National Environmental Research Institute, Aarhus University, Vejlsøvej 25, 8600, Silkeborg, Denmark aut Brucet Sandra Department of Freshwater Ecology, National Environmental Research Institute, Aarhus University, Vejlsøvej 25, 8600, Silkeborg, Denmark aut Jeppesen Erik Department of Freshwater Ecology, National Environmental Research Institute, Aarhus University, Vejlsøvej 25, 8600, Silkeborg, Denmark aut Hydrobiologia Springer Netherlands 664/1(2011-04-01), 147-162 0018-8158 664:1<147 2011 664 10750 https://doi.org/10.1007/s10750-010-0595-y text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s10750-010-0595-y text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Sørensen Torben Department of Freshwater Ecology, National Environmental Research Institute, Aarhus University, Vejlsøvej 25, 8600, Silkeborg, Denmark aut NATIONALLICENCE 700 1- Mulderij Gabi Department of Freshwater Ecology, National Environmental Research Institute, Aarhus University, Vejlsøvej 25, 8600, Silkeborg, Denmark aut NATIONALLICENCE 700 1- Søndergaard Martin Department of Freshwater Ecology, National Environmental Research Institute, Aarhus University, Vejlsøvej 25, 8600, Silkeborg, Denmark aut NATIONALLICENCE 700 1- Lauridsen Torben Department of Freshwater Ecology, National Environmental Research Institute, Aarhus University, Vejlsøvej 25, 8600, Silkeborg, Denmark aut NATIONALLICENCE 700 1- Liboriussen Lone Department of Freshwater Ecology, National Environmental Research Institute, Aarhus University, Vejlsøvej 25, 8600, Silkeborg, Denmark aut NATIONALLICENCE 700 1- Brucet Sandra Department of Freshwater Ecology, National Environmental Research Institute, Aarhus University, Vejlsøvej 25, 8600, Silkeborg, Denmark aut NATIONALLICENCE 700 1- Jeppesen Erik Department of Freshwater Ecology, National Environmental Research Institute, Aarhus University, Vejlsøvej 25, 8600, Silkeborg, Denmark aut NATIONALLICENCE 773 0- Hydrobiologia Springer Netherlands 664/1(2011-04-01), 147-162 0018-8158 664:1<147 2011 664 10750 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer