Photosynthetic picoplankton in Argentina lakes

IZAGUIRRE, IRINA; UNREIN, F; MODENUTTI, B; ALENDE LUZ

Freshwater Phytoplankton from Argentina

Schweizerbart Science Publishers

Año: 2014;

This chapter provides an overview of the studies on photosynthetic picoplankton (PPP) carriedout in water bodies from different latitudes of Argentina, including Patagonian lakes and shallow lakesfrom the Chaco-Pampean Plain Region. The PPP of the different aquatic systems: shallow and deep lakes,turbid and transparent water bodies, and lakes with contrasting trophic state are characterized. We focusour attention on light intensity as the major axes of niche differentiation in Pcy. We present examplesregarding the distribution of distinct Pcy ecotypes adapted to high- and low-light intensities at differentdepths in the water column of deep and shallow transparent lakes. In ultraoligotrophic Patagonian lakesphycoerythrin (PE)-rich picocyanobacteria (Pcy) are dominant, whereas eutrophic and hypertrophicshallow lakes from the Pampa Plain present a wide range of PPP abundances dominated by phycocyanin(PC)-rich Pcy. The relevance of the depth of the euphotic layer and nutrient concentration as the mainabiotic features explaining the variability encountered are discussed. The PPP from eutrophic shallowlakes and relict oxbow lakes from wetlands from the Lower Paraná Basin are mainly represented by PCrichPcy, and Peuk in a lesser extent. Changes in the free-fl oating plants coverage were found to play acrucial role in structuring the PPP, and on the other hand, there is evidence of a negative relation betweenthe PPP abundance and the hydrometric level. For different aquatic systems the PPP populations arecompared by means of the patterns resulting from the fl ow cytometry analyses.