<abstract xmlns="http://www.w3.org/1999/xhtml">

<p> The research was carried out in mesotrophic Lake Krasne during winter with thick ice/snow cover. Water samples for biological and physicochemical analyses were collected vertically from the water column. Several phytoplankton groups were identified during the study, however, only two main groups of motile phytoplankton, Cyanophyceae (the dominant species − Planktothrix rubescens) and Cryptophyceae (Cryptomonas spp. and Plagioselmis nannoplanctica), were analyzed in the gradient of nutrients, light and thermal conditions. In the studied water column, values of physicochemical parameters did not vary in a wide range. Nevertheless, high discrepancies were noted in the values of phytoplankton biomass and the concentration of chlorophyll-a which had shallower maxima and deeper minima. Statistically significant relationships were found between the biomass of two main phytoplankton groups, light conditions (PAR) and depth, however, no significant relationships were found between the biomass, biogenic compounds and water temperature. The studies showed that in the winter season with ice/snow cover, cryptomonads and Planktothrix rubescens occupied different ecological niches and the main factor determining their distribution were light conditions. The ice/snow cover probably plays an important role in protection of P. rubescens winter filaments against photoinhibition.</p>
</abstract>

The research was carried out in mesotrophic Lake Krasne during winter with thick ice/snow cover. Water samples for biological and physicochemical analyses were collected vertically from the water column. Several phytoplankton groups were identified during the study, however, only two main groups of motile phytoplankton, Cyanophyceae (the dominant species − Planktothrix rubescens) and Cryptophyceae (Cryptomonas spp. and Plagioselmis nannoplanctica), were analyzed in the gradient of nutrients, light and thermal conditions. In the studied water column, values of physicochemical parameters did not vary in a wide range. Nevertheless, high discrepancies were noted in the values of phytoplankton biomass and the concentration of chlorophyll-a which had shallower maxima and deeper minima. Statistically significant relationships were found between the biomass of two main phytoplankton groups, light conditions (PAR) and depth, however, no significant relationships were found between the biomass, biogenic compounds and water temperature. The studies showed that in the winter season with ice/snow cover, cryptomonads and Planktothrix rubescens occupied different ecological niches and the main factor determining their distribution were light conditions. The ice/snow cover probably plays an important role in protection of P. rubescens winter filaments against photoinhibition.

Winter bloom of some motile phytoplankton under ice cover in a mesotrophic lake: vertical distribution and environmental factors

Department of Botany and Hydrobiology, Institute of Environment Protection

The John Paul II Catholic University of Lublin

Oceanological and Hydrobiological Studies

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

The research was carried out in mesotrophic Lake Krasne during winter with thick ice/snow cover. Water samples for biological and physicochemical analyses were...

Winter bloom of some motile phytoplankton under ice cover in a mesotrophic lake: vertical distribution and environmental factors

Publié en ligne: 05 juin 2015

Pages: 164 - 171

Reçu: 28 nov. 2014

Accepté: 20 janv. 2015

DOI: https://doi.org/10.1515/ohs-2015-0016

© Faculty of Oceanography and Geography, University of Gdańsk, Poland

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.