Phytoplankton taxonomic and functional diversity in two shallow alluvial lakes with contrasting river connectivity

The mechanisms behind phytoplankton diversity patterns in natural ecosystems still remain elusive. In two shallow lakes with contrasting river connectivity, we first explored how diversity within each sampling (alfa diversity, α), among samplings (beta diversity, β1), and among hydrological seasons (β2) contributed to the diversity registered throughout the whole year (gamma diversity, γ). Then we estimated the importance of several environmental and temporal factors as structuring factors of these diversity patterns. To do this, we sampled the two lakes—one laterally isolated and other laterally connected lake with the Paraná River System—during a complete hydrological year. For the analyses, we considered both the species and the functional group level. At the species level, temporal variation (β1 + β2) made the main contribution for gamma diversity at the connected lake, possibly related to the constant species input from the river system. For the isolated lake, however, α was the main contributor. Regarding functional groups, α was the most important for both lakes, although no element of gamma diversity was different from the null model. Environmental factors like conductivity, turbidity, nutrient availability, and flood phases appeared as more relevant for the connected lake. Temporal processes (e.g., succession, ecological drift) were critical for the observed diversity patterns in both lakes. These results were consistent particularly considering the taxonomical approach. Our main findings are that the environment influences phytoplankton diversity patterns; however, other dynamics occurring on temporal scales may be more relevant for the phytoplankton community.Fil: Frau, Diego. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto Nacional de Limnología. Universidad Nacional del Litoral. Instituto Nacional de Limnología; ArgentinaFil: Pineda, Alfonso. UNIVERSIDADE ESTADUAL DE MARINGÁ (UEM);Fil: Mayora, Gisela Paola. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto Nacional de Limnología. Universidad Nacional del Litoral. Instituto Nacional de Limnología; ArgentinaFil: Devercelli, Melina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto Nacional de Limnología. Universidad Nacional del Litoral. Instituto Nacional de Limnología; Argentin

Nutrient Dynamics in Wetlands of the Middle Paraná River Subjected to Rotational Cattle Management

The progressive degradation of wetlands has stressed the need of developing sustainable management strategies for maintaining their ecological character within the context of sustainable development. Rotational cattle grazing is a common grazing strategy in aquatic systems but its effect on nutrient dynamics in lakes is scarcely known. The objectives of this study were to evaluate if cattle produces a significant increase of TN and TP in wetlands, and if the value of these nutrients decrease after cattle are removed. Samples of water, sediment and macrophytes were collected for nutrient, organic matter and other chemical analyses. Results showed a significant increase in water nutrients during the presence of cattle, decreasing during their absence. These changes occurred surprisingly rapid, suggesting a high resilience of these systems to this impact. The presence of submerged vegetation in lakes ameliorated the effect of cattle on water nutrients, suggesting an important role of these plants in ecosystem management. Rotational management would minimize the increase of nutrients in water, maintaining the ecological integrity of wetlands.Fil: Mesa, Leticia Mariana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto Nacional de Limnología. Universidad Nacional del Litoral. Instituto Nacional de Limnología; ArgentinaFil: Mayora, Gisela Paola. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto Nacional de Limnología. Universidad Nacional del Litoral. Instituto Nacional de Limnología; ArgentinaFil: Saigo, Miguel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto Nacional de Limnología. Universidad Nacional del Litoral. Instituto Nacional de Limnología; ArgentinaFil: Giri, Federico. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto Nacional de Limnología. Universidad Nacional del Litoral. Instituto Nacional de Limnología; Argentina. Universidad Nacional del Litoral. Facultad de Humanidades y Ciencias; Argentin

Interactive effects of fish predation and sublethal insecticide concentrations on freshwater zooplankton communities

Stresses imposed by insecticides and predators are possibly the most rigorous filters to which aquatic organisms are exposed in rivers and lakes associated with agricultural lands. However, their interactive effects on zooplankton communities are still unclear. This study elucidated the zooplankton community response to fish predation, the insecticide chlorpyrifos (CLP), and a combination of both factors, using a 30-day mesocosm experiment. The zooplankton assemblage was influenced by fish presence prior to CLP toxicity. Fish predation reduced microcrustacean density leading to a community dominated by microzooplankton (i.e.: rotifers and copepod nauplii). CLP decreased the species richness in treatments with and without fish, yielding an increase in the abundance of bdelloid rotifers, in the genera Lepadella and Trichocerca. The zooplankton:phytoplankton (<20 μm) ratio decreased substantially when the two stressors, fish predation and insecticide toxicity, were combined. Although CLP dissipated relatively rapidly in the aqueous phase and accumulated in sediment and fish tissue, zooplankton richness was unable to recover. A possible explanation for this could be the inhibitory effect of CLP on resting stage hatchings in the sediment. Therefore, the combined effects of fish predation and CLP might influence zooplankton richness, leading to an assemblage dominated by rotifers that appeared to be resistant to both factors, with a limited capability to control phytoplankton growth. Thus, the effects of natural and anthropogenic stressors should be considered together when assessing community dynamics in aquatic ecosystems.Fil: Gutierrez, Marìa Florencia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto Nacional de Limnología. Universidad Nacional del Litoral. Instituto Nacional de Limnología; ArgentinaFil: Rojas Molina, Florencia Mercedes. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto Nacional de Limnología. Universidad Nacional del Litoral. Instituto Nacional de Limnología; ArgentinaFil: Frau, Diego. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto Nacional de Limnología. Universidad Nacional del Litoral. Instituto Nacional de Limnología; ArgentinaFil: Mayora, Gisela Paola. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto Nacional de Limnología. Universidad Nacional del Litoral. Instituto Nacional de Limnología; ArgentinaFil: Battauz, Yamila Soledad. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto Nacional de Limnología. Universidad Nacional del Litoral. Instituto Nacional de Limnología; Argentina. Universidad Autónoma de Entre Ríos; Argentin

Multiscale environmental heterogeneity in a large river-floodplain system

River-floodplain systems host very high biodiversity and provide a great variety of ecosystem services due largely to their high environmental heterogeneity, which is strongly dependent on spatial and temporal scales of observation. We aimed to describe the main patterns of environmental variation of the subtropical system of the Middle Paraná River at different scales of analysis using univariate and multivariate statistics. Physical, chemical and biological variables were analyzed during different hydro-sedimentological phases along four consecutive years in 31 aquatic environments. We considered four aquatic habitat types with different degrees of hydrological connectivity and water flow characteristics (major rivers, secondary channels, floodplain lakes permanently connected to the major rivers, and floodplain lakes temporarily connected to the major rivers) from two geomorphologic units with different drainage patterns: anastomosing and meandering. The environmental heterogeneity was mainly associated with the habitat types and relative contributions of lateral tributaries with different water qualities to each unit, in combination with the influence of the hydro-sedimentological regime. The heterogeneity of the system was significantly higher during low water than during high water phases. However, although the extreme flood reduced dissimilarities between habitat types within each geomorphologic unit, it increased differences between major rivers and between units. In conclusion, at different spatial scales, floods may simultaneously have a homogenization effect due to increased hydrological connectivity and a differentiation effect due to enhanced inputs of water from regions with variable geological characteristics and land uses. Finally, geomorphologic units can play a key role in maintaining the environmental heterogeneity during floods of high magnitude, even when land barriers among aquatic environments disappear.Fil: Mayora, Gisela Paola. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto Nacional de Limnología. Universidad Nacional del Litoral. Instituto Nacional de Limnología; ArgentinaFil: Scarabotti, Pablo Augusto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto Nacional de Limnología. Universidad Nacional del Litoral. Instituto Nacional de Limnología; ArgentinaFil: Schneider, Berenice. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto Nacional de Limnología. Universidad Nacional del Litoral. Instituto Nacional de Limnología; ArgentinaFil: Alvarenga Mariani, Patricio Francisco. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto Nacional de Limnología. Universidad Nacional del Litoral. Instituto Nacional de Limnología; ArgentinaFil: Marchese Garello, Mercedes Rosa. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto Nacional de Limnología. Universidad Nacional del Litoral. Instituto Nacional de Limnología; Argentin

Can top-down and bottom-up forces explain phytoplankton structure in a subtropical and shallow groundwater-connected lake?

Bottom-up and top-down control of phytoplankton is one of the most important hypothesis that explains and predicts the structure of aquatic community. Our aim was to elucidate whether predation and resource limitation can control phytoplankton composition and abundance in a subtropical shallow lake with groundwater connection to the river system. During 12 months, the lake was sampled at three points. Physico-chemical parameters, phytoplankton and zooplankton were sampled fortnightly, whereas fish were sampled every 3 months. The results showed that Euglenophyta dominated the total biovolume, followed by Dinophyta and Cryptophyta. As for the species composition, Chlorophyta was the dominant group (80 species recorded), followed by phylum Cyanobacteria (26 species recorded). Redundancy analysis (RDA) indicated that temperature and nitrate + nitrite concentration mainly explained biovolume changes, with zooplankton predation not having any measurable effect on phytoplankton during the high-water (HW) period. During low-water (LW) period top-down by fish was more important. At higher taxonomic resolution (species biovolume), phosphorus was another controlling factor. We concluded that phytoplankton in this lake is mainly regulated by hydrological changes as a macrofactor that affects nutrient availability and other environmental conditions. Even though bottom-up top-down forces do not have a central effect, we found evidence of positive nutrient influences at the HW period and fish effect at the LW period.Fil: Frau, Diego. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto Nacional de Limnología. Universidad Nacional del Litoral. Instituto Nacional de Limnología; ArgentinaFil: Devercelli, Melina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto Nacional de Limnología. Universidad Nacional del Litoral. Instituto Nacional de Limnología; ArgentinaFil: José De Paggi, Susana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto Nacional de Limnología. Universidad Nacional del Litoral. Instituto Nacional de Limnología; Argentina. Universidad Nacional del Litoral. Facultad de Bioquímica y Ciencias Biológicas; ArgentinaFil: Scarabotti, Pablo Augusto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto Nacional de Limnología. Universidad Nacional del Litoral. Instituto Nacional de Limnología; Argentina. Universidad Nacional del Litoral. Facultad de Humanidades y Ciencias; ArgentinaFil: Mayora, Gisela Paola. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto Nacional de Limnología. Universidad Nacional del Litoral. Instituto Nacional de Limnología; ArgentinaFil: Battauz, Yamila Soledad. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto Nacional de Limnología. Universidad Nacional del Litoral. Instituto Nacional de Limnología; ArgentinaFil: Senn, Mariana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto Nacional de Limnología. Universidad Nacional del Litoral. Instituto Nacional de Limnología; Argentin

Hydroclimatological patterns and limnological characteristics of unique wetland systems on the argentine high andean plateau

High-elevation wetlands in South America are not well described despite their high sensitivity to human impact and unique biodiversity. We describe the hydroclimatological and limnological characteristics of 21 wetlands on the High Andean Plateau of Argentina, synthesizing information gathered over ten years (2010?2020). We collected physical-chemical, phytoplankton, and zooplankton data and counted flamingos in each wetland. We also conducted an extensive analysis of climatic patterns and hydrological responses since 1985. These wetlands are shallow, with a wide range of salinity (from fresh to brine), mostly alkaline, and are dominated by carbonate and gypsum deposits and sodium-chloride waters. They tend to have high nutrient concentrations. Plankton shows a low species richness and moderate to high dominance of taxa. Flamingos are highly dependent on the presence of Bacillariophyta, which appears to be positively linked to silica and soluble reactive phosphorus availability. Climatic conditions show a strong region-wide increase in average air temperature since the mid-1980s and a decrease in precipitation between 1985?1999 and 2000?2020. These high-elevation wetlands are fundamentally sensitive systems; therefore, having baseline information becomes imperative to understanding the impact of climatic changes and other human perturbations. This work attempts to advance the body of scientific knowledge of these unique wetland systems.Fil: Frau, Diego. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto Nacional de Limnología. Universidad Nacional del Litoral. Instituto Nacional de Limnología; ArgentinaFil: Moran, Brendan J.. University of Massachusetts-Amherst; Estados UnidosFil: Arengo, Felicity. American Museum of Natural History; Estados UnidosFil: Marconi, Patricia. Fundación Yuchan; ArgentinaFil: Battauz, Yamila Soledad. Universidad Autonoma de Entre Rios; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto Nacional de Limnología. Universidad Nacional del Litoral. Instituto Nacional de Limnología; ArgentinaFil: Mora, Maria Celeste. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto Nacional de Limnología. Universidad Nacional del Litoral. Instituto Nacional de Limnología; ArgentinaFil: Manzo, Ramiro Andrés. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto Nacional de Limnología. Universidad Nacional del Litoral. Instituto Nacional de Limnología; ArgentinaFil: Mayora, Gisela Paola. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto Nacional de Limnología. Universidad Nacional del Litoral. Instituto Nacional de Limnología; ArgentinaFil: Boutt, David F.. University of Massachusetts-Amherst; Estados Unido

Dynamic of chemical species with ecological importance in the system of the Middle Paraná river: influence of hidrological phases and relations with phytoplankton

Fil: Mayora, Gisela Paola. Universidad Nacional del Litoral. Facultad de Bioquímica y Ciencias Biológicas; Argentina.Se evaluó la dinámica de nutrientes y materia orgánica disuelta cromofórica (MODC) en el sistema del río Paraná Medio, considerando las fluctuaciones hidrosedimentológicas y las relaciones con el fitoplancton. Desde el río hacia su llanura, disminuyó el sílice disuelto y nitrógeno inorgánico disuelto; y aumentó la clorofila-a y componentes orgánicos. El pico sedimentológico aportó sales, amonio, fósforo reactivo soluble y nutrientes particulados; pero removió otros componentes disueltos y clorofila-a. Durante la inundación aumentó el ingreso de sílice desde el Paraná Superior, y la llanura actuó como fuente de fósforo reactivo soluble, MODC, carbono y nitrógeno orgánicos disueltos. La inundación homogenizó las variables limnológicas (excepto nitrato). El pico sedimentológico aumentó la homogeneidad de la conductividad y alcalinidad, y la heterogeneidad del clima lumínico y biomasa fitoplanctónica. En las lagunas aisladas, la biomasa del fitoplancton se asoció negativamente al peso molecular de la MODC; mientras la feofitina-a/clorofila-a (indicador del estado fisiológico algal) se asoció positivamente al peso molecular de la MODC y disminuyó durante la inundación. La fosfatasa alcalina algal mineralizó fósforo principalmente en los ambientes más aislados, donde la MODC limitaría su biodisponibilidad. Los fitoflagelados mixotróficos habrían sido favorecidos por la MODC más aromática, y ciertas especies silíceas disminuirían la concentración de sílice en las lagunas aisladas. Puede concluirse que el pico sedimentológico y la planicie aluvial intensifican las transformaciones químicas, probablemente al aumentar las superficies donde éstas ocurren y el tiempo de residencia del agua. La MODC debería considerarse para evaluar el desarrollo del fitoplancton debido a sus múltiples relaciones.Nutrients and chromophoric dissolved organic matter (CDOM) were analyzed in the Middle Paraná River system, considering their relations with hydrosedimentological fluctuations and phytoplankton. From the main channel to the floodplain, dissolved silica and inorganic nitrogen decreased; whereas CDOM, chlorophyll-a, and dissolved organic nutrients and carbon increased. In the main channel, materials inputs and removals changed temporally. Sediment peak supplied salts, ammonium, soluble reactive phosphorus, and particulate nutrients; but incremented other dissolved nitrogen forms and dissolved organic carbon removals. During inundation, floodplain constituted a source of soluble reactive phosphorus, dissolved organic carbon, CDOM, and dissolved organic nitrogen; whereas the Upper Paraná increased silica supply. Inundation and sediment peak decreased phytoplanktonic biomass. Flooding homogenized limnological variables (except nitrate). Sediment peak increased conductivity and alkalinity homogeneity, and light environment and chlorophyll-a heterogeneity. In isolated lakes, algal biomass was negatively associated to CDOM molecular weight; whereas pheophytin-a/chlorophyll-a ratio (algal physiology indicator) was positively associated to CDOM molecular weight and decreased during inundation. Algal alkaline phosphatase mineralized organic phosphorus mainly in most isolated environments, where CDOM would limit phosphate bioavailability for phytoplankton. As regards phytoplankton composition, mixotrophic phytoflagellates were related to high-molecular-weight CDOM, and siliceous phytoplankton were inversely related to silica. It can be concluded that floodplain and sediment peak intensify chemical transformations, probably due to increments in water residence time and surfaces where reactions occur. The hydrosedimentological pulse affects quantity and quality of exported materials, and CDOM appear as an important factor that should be taken into account for evaluating phytoplankton development.Secretaría de Ciencia y Técnica de Santa FeAgencia Nacional de Promoción Científica y Tecnológic

Phenolic exudates from Ludwigia peploides and Azolla sp. enhance germination of Polygonum ferrugineum seeds

The release of allelochemicals by aquatic macrophytes can inhibit or benefit other plants. Here we studied allelopathic interactions between syntopic species native to the Neotropical region. First, we quantified the phenolic exudation in monospecies cultures of Ludwigia peploides (L) and Azolla sp. (A) and in co-cultures of both species growing together (A+L) compared to control water. Then, we studied the germination of Polygonum ferrugineum seeds exposed to the exudates and control water. Incubation water from L had a significant lower pH than the other treatments, and a lower conductivity than the control. L alone or in co-culture with A reduced the dissolved oxygen content of the incubation water. Phenolic compounds were undetectable in control water (C) and the A treatment. In water of L and A+L treatments, phenolic concentration increased during the 5-day bioassay, with significant differences from day 3 on compared to treatments C and A. On day 5, more phenolic exudates were found in the A+L than in the L treatment. The germination rate but not germination speed was significantly higher in P. ferrugineum seeds treated with A+L exudates, and correlated positively with the phenolic concentration. Our results suggest that the allelopathic potential of aquatic macrophytes such as L. peploides can be higher in multispecies patches than in monospecies ones. Furthermore, phenolic exudates of macrophytes might stimulate the germination of plants native to the same region, which may have implications in the formation of vegetation patterns in aquatic ecosystems.Fil: Schneider, Berenice. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto Nacional de Limnología. Universidad Nacional del Litoral. Instituto Nacional de Limnología; ArgentinaFil: Mayora, Gisela Paola. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto Nacional de Limnología. Universidad Nacional del Litoral. Instituto Nacional de Limnología; Argentin

Influence of macrophyte integrity on zooplankton habitat preference, emphasizing the released phenolic compounds and chromophoric dissolved organic matter

Macrophyte health status can influence the composition of their exudates causing different effects on zooplankton behavior and distribution in nature. We hypothesize that: (1) the release of phenolic compounds and chromophoric dissolved organic matter (CDOM) depends on macrophyte species and its health status (broken macrophytes: BM, or healthy macrophytes: HM); (2) the repellency effect depends on zooplankton species, macrophyte species and its health status; and (3) higher concentrations of phenolic compounds and CDOM produce a stronger repellency effect. Phenolic compounds and CDOM were analyzed in exudates of BM and HM of Salvinia sp., Eichhornia crassipes, Pistia stratiotes, Azolla sp. and Ludwigia peploides. Through a flow-through experiment, the repellency produced by these exudates was assessed in two copepods (Notodiaptomus conifer and Argyrodiaptomus falcifer) and one cladoceran (Ceriodaphnia dubia). Our hypotheses were partially validated. The quantity of exudated phenolic compounds and CDOM depended on macrophyte species and, to a lesser extent, on the plant health status. The repellency effect was affected by macrophyte and zooplankton species but not by the health status of plants. Only C. dubia and A. falcifer increased their evasion behavior when phenolic compound and CDOM concentrations increased. In brief, the structuring effect of repellent substances depends on different factors. Under a certain threshold concentration, zooplankton behavior might depend on the information associated with the plant odor (e.g., predation risk, structural complexity) more than on the quantity of the released chemical compounds. Above this threshold, evasion would be the only possible option to avoid damaging effects.Fil: Gutierrez, Marìa Florencia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto Nacional de Limnología. Universidad Nacional del Litoral. Instituto Nacional de Limnología; ArgentinaFil: Mayora, Gisela Paola. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto Nacional de Limnología. Universidad Nacional del Litoral. Instituto Nacional de Limnología; Argentin

Phytoplankton-based water quality metrics: Feasibility of their use in a Neotropical shallow lake

Urban lakes constitute important recreational areas, but often they are eutrophicated. In this study we discuss the utility of 12 ecological quality metrics to test whether they: (1) can be applied to Neotropical lakes; (2) are sensitive to environmental variations throughout the year; and (3) are affected by heterogeneous spatial distribution of phytoplankton. Phytoplankton and environmental variables (including nutrients) were sampled monthly in an urban lake (four littoral and one limnetic station) throughout 1 year (n = 60 samples). Twelve ecological quality metrics were tested using total phosphorus as a proxy of eutrophication through general lineal models. The best adjusted metrics were then transformed to an ecological quality ratio (EQR) to allow comparisons. The Phytoplankton Assemblage Index (Q-index) and the Cyanobacteria Bloom Index (CBI) were the most accurate. Differences in water quality estimation occurred across the year, with an overestimation of water quality in the absence of cyanobacteria blooms. There were no differences due to effects of the spatial distribution of phytoplankton. The Q-index was related to temperature and soluble reactive phosphorus, whereas the CBI was related to conductivity. We conclude that the Q-index is the most accurate metric for monitoring purposes, responding well to variations in phosphorus.Fil: Frau, Diego. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto Nacional de Limnología. Universidad Nacional del Litoral. Instituto Nacional de Limnología; ArgentinaFil: Mayora, Gisela Paola. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto Nacional de Limnología. Universidad Nacional del Litoral. Instituto Nacional de Limnología; ArgentinaFil: Devercelli, Melina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto Nacional de Limnología. Universidad Nacional del Litoral. Instituto Nacional de Limnología; Argentin