Somogyi, B., Felföldi, T., V.-Balogh, K., Boros, E., Pálffy, K., Vörös, L. 2016. The role and composition of winter picoeukaryotic assemblages in shallow Central European great lakes. Journal of Great Lakes Research, 42, 1420-1431.
Studies on autotrophic picoplankton (APP; <3 μm) in shallowlakes aremainly confined to the spring through fall seasons, when sampling efforts are not complicated by adverse and unsafe conditions that occur during winter. The aimof the presentworkwas to study the role and diversity ofwinter APP communities in temperate shallow lakes by means of analysis of measures of size-fractionated photosynthesis and culture-based molecular taxonomic identification. Our results show that APP comprised a substantial part of planktonic primary production in shallow Central European great lakes (13–46% in Lake Balaton and 11–42% in Lake Fertő). Better acclimation of APP than that of the larger phytoplankton (>3 μm) to low-temperature and low-light winter environment was confirmed by their highermaximum photosynthetic rate and light utilization parameter. Maximum photosynthetic rate and light saturation parameter increased significantly with both temperature and available light, butwith different impact on the two size groups. Twenty-two picoeukaryotic strainswere isolated and identified based on 18S rRNA gene sequence analysis. Taxonomic composition of the picoeukaryotic community in the studied shallowlakeswas similar to other freshwater lakes in the temperate zone: members of genera Choricystis and Mychonastes were dominant, however, in Lake Balaton, common freshwater taxa such as Stichococcus
and Nannochloris bacillaris were also found.
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