Spring phytoplankton of Rı́o de la Plata: a temperate estuary of South America

Environmental modulation of the plankton community composition and size-structure along the eutrophic intertidal coast of the Río de la Plata estuary, Argentina

“…twofold higher at the most polluted area of the estuary. Nonetheless, our estimations are lower than those reported for the freshwater tidal zone (56x10 3 pg C mL -1 ) as well as the mixohaline zone (231x10 3 pg C mL -1 ) of the Río de la Plata estuary (Gómez et al, 2004). The nanophytoplankton biomass, mostly comprised of small diatoms and cyanobacteria, represented a large proportion (84%) of the total phytoplankton biomass.…”

“…We also observed that phytoplankton density was higher at the most polluted area. Nevertheless, our estimation was twentyfold higher than the highest density observed by Gómez et al (2004), three-times higher than that estimated by Gómez and Bauer (1998), and about thirtyfold higher than the average value estimated for the other eleven sites in this study. In contrast, the density was lower in the outer portion of the estuary mouth, where the salinity level was higher.…”

“…1,100 cell mL -1 ) along the intertidal coast of the Río de la Plata estuary was ten-times higher than the density observed along the fluvial-mixohaline axis (Gómez et al, 2004) and four-times higher than along the coastal fringe (Gómez and Bauer, 1998) in the same system. In these studies, however, the authors observed that density significantly increase in environmentally eutrophic sites located in the upper zone of the Río de la Plata.…”

“…Because of the extensive human population along the Río de la Plata's shores, the estuary is subjected to sewage input from large and small coastal cities, industrial waste discharges, spills of oil and other materials associated with maritime transport, and changes in the topography of the river bottom through the dredging of access channels (Framiñán and Brown, 1996). Different studies on the Río de la Plata estuary have analyzed the diversity and structure of the phytoplankton in the coastal fringe and the fluvial-mixohaline axis (Roggiero, 1988;Gómez and Bauer, 1998;Gómez et al, 2002Gómez et al, , 2004Kogan, 2005). Moreover, environmental modulation of phytoplankton biomass and production has been extensively evaluated along a large-scale gradient between the Río de la Plata estuary and the shelf-brake off Uruguay (Calliari et al, 2005(Calliari et al, , 2009.…”

Morphology-based classification of functional groups for potamoplankton

“…Both studies emphasized the large proportion and long survival of diatoms in rivers compared with lakes. Moreover, other algae such as flagellates (Cloern et al, 1983;De Oliveira and Calheiros, 2000;Gómez et al, 2004), filamentous cyanobacteria (Köhler and Hoeg, 2000), non-diatoms that indicate altered conditions (Mihaljević et al, 2013), are also important. The composition and persistence of potamoplankton assemblages in riverine ecosystems mainly depend on physical (light, water temperature, and turbidity) and hydrological factors (discharge, flow velocity, water level, suspended sediment concentration and water residence time) (Köhler, 1993;Gosselain et al, 1994;Kirk, 1994;Reynolds et al, 1994;Reynolds and Descy, 1996;Train and Rodrigues, 1997;Centis et al, 2010;Salmaso and Zignin, 2010), and resolved silicate concentration (Dortch and Whitledge, 1992;Tavernini et al, 2011).…”