Long term patterns of picocyanobacteria from a hypertrophic shallow lake inferred through flow cytometry

QUIROGA V; HUBER, PAULA; OSPINA SERNA J; DIOVISALVI, NADIA; ODRIOZOLA, MARIANA; CUETO GR; LAGOMARSINO, L.; BUSTINGORRY, J.; ESCARAY, R.; ZAGARESE HORACIO; UNREIN, FERNANDO

Valparaiso

Congreso; 1ST ISME LATIN AMERICA CONGRESS; 2020

Ponticia Universidad Católica de Chile, Universidad de Antofagast

Picophytoplankton from eutrophic shallow lakes are generally underrepresented in global models.Here we analyzed picocyanobacteria (Pcy) dynamics along ten years (2007-2017) in the turbidhypertrophic shallow lake Chascomús (Pampa Plain, Argentina). We used ow cytometry to detectchanges in Pcy organism abundance (either single-cell or colonial), chlorophyll-a content (FL3),organism size/granularity (SSC) and cytometric diversity indexes (owDiv package for R) in relationto environmental conditions. Intra- and interannual changes (seasonality and trend) in the formerPcy features were evaluated through generalized additive models (GAM). A second GAM was testedfor each response variable with environmental factors as predictors. Contrarily to other freshwatersystems, Chascomús lake showed a Pcy seasonality with higher abundances during winter, whilethe interannual pattern resembled a dilution effect during wet periods. The winter Pcy communitywas less diverse and even, suggesting that this peak was due to the proliferation of few Pcy taxa.Pcy abundance, FL3, SSC, alpha cytometric diversity and evenness were partially explained by lake