Flow cytometry patterns of autotrophic picoplankton from eutrophic shallow lakes

HUBER P.; QUIROGA M. V.; KRANEWITTER V.; TORREMORELL A.; LAGOMARSINO L.; LLAMES M. E.; UNREIN F.

Granada

Congreso; ASLO 2015 Aquatic Sciences Meeting, Aquatic sciences: Global and Regional Perspectives - North meets South; 2015

Association for the Sciences of Limnology & Oceanography

Abstract ID: 27004. Presentation Choice: Poster. Confirmation #: 27004. Picophytoplankton from eutrophic shallow lakes are generally underrepresented in global models. Here we used flow cytometry to map phytoplankton in six eutrophic Pampean shallow lakes at different spatiotemporal scales. Besides cell number we analysed cytometric diversity, light scatter and fluorescence. High-frequency sampling in the turbid lake Chascomús revealed that relative side-scatter (SSC) of picocyanobacteria (Pcy) and picoeukaryotic algae (Peuk) was synchronized with the daily light cycle, and that red chlorophyll fluorescence (FL3) was negatively correlated with turbidity, suggesting a rapid acclimatization to changes in underwater light climate. Long-term study in the same lake showed that picophytoplankton was permanently dominated by Pcy (ca. 90%), with a clear seasonality. Contrarily to other temperate lakes, maximum values were observed in winter-spring and minimum during summer. At a regional scale, Pcy dominated picophytoplankton in all lakes, excepting some turbid lakes dominated by large filamentous cyanobacteria where Pcy were almost absent. Marked changes in cytometric diversity (sensu Li 1997) were observed between vegetated and phytoplankton-turbid shallow lakes.