Diurnal variation in the convection-driven vertical distribution of phytoplankton under ice and after ice-off in large Lake Onego (Russia)

Article Article scientifique Article Diurnal variation in the convection-driven vertical distribution of phytoplankton under ice and after ice-off in large Lake Onego (Russia) eng 2019 author Suarez Bolanos Ena 776371 author Tiffay Marie-Caroline 632028 author Kalinkina Nataliia author Tchekryzheva Tatjana author Sharov Andrey author Tekanova Elena author Syarki Maria author Zdorovennov Roman E. author Makarova Elena 774277 author Mantzouki Evanthia 821094 author Venail Patrick 805736 author Ibelings Bastiaan Willem 781963 193-204 10.1080/20442041.2018.1559582 2044-2041 https://www.tandfonline.com/doi/full/10.1080/20442041.2018.1559582 When sunlight penetrates the ice layer covering lakes in winter, it warms the top water layer and sets up convection, with several potentially contrasting effects on phytoplankton. While convective mixing keeps cells in suspension and prevents sedimentation losses, it may also transport phytoplankton well below the euphotic zone. We investigated diurnal variations in the vertical distribution of phytoplankton under ice and just after ice-off in Lake Onego (Russia), a lake with moderate to high colored dissolved organic carbon (CDOM) levels. We showed that diurnal variation in convection under ice restricts phytoplankton access to light in the morning hours to a narrow euphotic zone, whereas cells are mixed through a deep aphotic layer in the afternoon. After ice-off, low chlorophyll a was found on the open-water side of the thermal bar as convection distributed cells throughout the water column. By contrast, the inshore side had significantly higher concentrations of chlorophyll a (p < 0.001) because the mixing depth brought about by diurnal microstratification was reduced, resulting in greater access to light in the afternoon. Overnight, convective cooling broke down microstratification, which redeveloped the next day. Our work highlights the importance of studying diurnal variation in light availability for photoautotrophic growth, both under ice and after ice-off in lakes characterized by high CDOM. Convection Dissolved organic carbon Life under ice Light Phytoplankton Thermal bar Dewey 550 Autre Life under Ice 41 Département F.-A. Forel des sciences de l'environnement et de l'eau 153 false 757 Microbial Ecology Inland Waters 9 2 bb896bdc-3a72-41c9-a43d-86985f402d35 Article (Published version) Public esuarezetal2019.pdf 2158771 application/pdf CC BY-NC-ND openAccess Faculté des sciences / Section des sciences de la Terre et de l'Environnement / Département F.-A. Forel des sciences de l'environnement et de l'eau

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Diurnal variation in the convection-driven vertical distribution of phytoplankton under ice and after ice-off in large Lake Onego (Russia)	Inland Waters			2019	470	450

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Makarova, Elena