INSTITUTO TECNOLOGICO DE CHASCOMUS
Unidad Ejecutora - UE
congresos y reuniones científicas
Long term patterns of picocyanobacteria from a hypertrophic shallow lake inferred through flow cytometry
HUBER M. P.; ODRIOZOLOA M.; BARLA M. J., ESCARAY, R. U., BUSTINGORRY J. F.; UNREIN F.; OSPINA SERNA, J. A,; CUETO, G.; ESCARAY R.; QUIROGA M. V:; DIOVISALVI N.; LAGOMARSINO L.; ZAGARESE H.
Congreso; ISME Latin America; 2019
Universidad Técnica Federico Santa María
Picophytoplankton from eutrophic shallow lakes are generally underrepresented in global models. Here we analyzedpicocyanobacteria (Pcy) dynamics along ten years (2007-2017) in the turbid hypertrophic shallow lake Chascomús(Pampa Plain, Argentina). We used flow cytometry to detect changes in Pcy organism abundance (either single-cellor colonial), chlorophyll-a content (FL3), organism size/granularity (SSC) and cytometric diversity indexes (flowDivpackage for R) in relation to environmental conditions. Intra- and interannual changes (seasonality and trend) in theformer Pcy features were evaluated through generalized additive models (GAM). A second GAM was tested for eachresponse variable with environmental factors as predictors. Contrarily to other freshwater systems, Chascomús lakeshowed a Pcy seasonality with higher abundances during winter, while the interannual pattern resembled a dilutioneffect during wet periods. The winter Pcy community was less diverse and even, suggesting that this peak was dueto the proliferation of few Pcy taxa. Pcy abundance, FL3, SSC, alpha cytometric diversity and evenness were partiallyexplained by lake depth, turbidity, expected incident radiation and the rate of change of irradiance, unrevealing theimportance of underwater light climate in this light limited turbid system. Cladocerans abundance was negativelyassociated with Pcy abundance and positively related with FL3 and SSC. The cladocerans effect was further assesthrough in vitro experiments. The cytometric fingerprint (beta diversity) detected differences in Pcy communitystructure strongly related with differences in cladoceran abundance among samples. These results suggest a possibleinduced shift from unicellular Pcy to microaggregates/colonial forms during periods of high cladoceran abundance.PICT 2016-1554, PICT-2016-1079