Acidophilic phytoplankton in Argentina: the case study of Lake Caviahue (Patagonia)

This article presents a review of the studies carried out over a 10-year period in Lake Caviahue, a natural acidic lake located in Patagonia. The main patterns of the phytoplankton populations are described. Five extremophiles phytoplanktonic species were studied in relation to the zooplankton and nutrients bioavailability under the environmental conditions registered in Lake Caviahue: very low pH (~3), high concentrations of iron (18.4 mg L-1) and sulphur (130 mg L-1). During the 10-years studies, the biomass (0.2 and 1.4 mg fw L-1) and the biodiversity were very low being Keratococcus rhaphidioides the dominant species (60 to 100% of the total biomass). Philodina sp. (Bdelloidea) was the only zooplankter responsible of the zooplankton biomass. From the lack of relationship between phytozooplankton biomass, as well as from the results obtained in the feeding experiments, we conclude that no control of algal abundance by the zooplankton occurs. The microalgae were nitrogen limited in the lake and according to the results from experiments with nutrient addition, the phytoplankton showed nitrogen limitation on growth rate and yield. The species have also the capacity to use mixotrophically alternative sources of organic and inorganic carbon and organic nitrogen. The importance of the uptake and the expression of CO2 concentrating mechanisms (CCMs) were demonstrated in Euglena and in the ellipsoidal form of Watanabea but not in the spherical form of Watanabea and in Palmellopsis. The two forms of Watanabea differed in their possession of a CCM.Fil: Diaz, Monica Mabel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Patagonia Norte. Instituto de Investigación en Biodiversidad y Medioambiente; ArgentinaFil: Beamud, Sara Guadalupe. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Patagonia Norte. Instituto de Investigación en Biodiversidad y Medioambiente; Argentin

Primera detección del alga invasiva Didymosphenia geminata en el lago Nahuel Huapi: Argentina, Patagonia

The benthic diatom Didymosphenia geminata (L yngbye) M. Schmidt is a ver y aggressive invasive species found in riversand streams in different parts of the world. It has become a major concern for its tendency to form conspicuous blooms in oligotrophic aquatic systems with potential for detrimental impacts on recreational fi shing. Given its explosive development and the notable appearance in Lake Nahuel Huapi during the austral summer of 2013, our aim was to document the fi rst record for a large (557 km 2 ) lentic waterbody in the Andean Patagonia region.Fil: Beamud, Sara Guadalupe. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Patagonia Norte. Instituto de Investigación en Biodiversidad y Medioambiente; ArgentinaFil: Baffico, Gustavo Daniel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Patagonia Norte. Instituto de Investigación en Biodiversidad y Medioambiente; ArgentinaFil: Pedrozo, Fernando Luis. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Patagonia Norte. Instituto de Investigación en Biodiversidad y Medioambiente; ArgentinaFil: Diaz, Monica Mabel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Patagonia Norte. Instituto de Investigación en Biodiversidad y Medioambiente; Argentin

Limnology of an acidic system : Agrio River-Caviahue Lake, Province of Neuquén, Argentina

Durante un período de 10 años se estudió el sistema Río Agrio-Lago Caviahue, que constituye un caso único en Sudamérica por sus aguas de extrema acidez (pH<4). La acidez se origina en las efusiones magmáticas del volcán Copahue que alimentan al Río Agrio Superior. El sistema hídrico se neutraliza luego de recorrer una extensión de 50 km (Río Agrio Inferior). Esta situación define un gradiente natural de acidez, concentración y transporte de nutrientes y metales, el cual se expresa en una baja diversidad, tanto del plancton lacustre como del epiliton lótico. El pH bajo permite que se mantengan en disolución la mayoría de los elementos presentes, condicionando ambientes con alto contenido de metales y de fósforo en su tramo superior. A diferencia de otros lagos andinos de la Patagonia, el Lago Caviahue experimenta variaciones de pH y conductividad por cortos períodos, situación que es controlada por la actividad magmática. El sedimento lacustre es rico en materia orgánica la cual controla la disponibilidad del fósforo. Las condiciones extremas del lago, la disponibilidad de amonio y de carbono inorgánico y orgánico disueltos sostienen una alta densidad planctónica, representada en particular por Keratococcus raphidioides. El reemplazo de especies algales (sucesión estacional) no ocurre en el lago y los pequeños cambios observados están relacionados con la geoquímica de la cuenca. La biomasa epilítica exhibe una fuerte zonación vinculada al cambio de pH. El desarrollo algal conspicuo está compuesto en su mayoría por algas verdes filamentosas. (e.g., Ulothrix spp.).The Río Agrio-Lago Caviahue system which constitutes a unique case in South America of waters of extreme acidity (pH<4), has been studied during the last 10 years. The high acidity is originated by the magmatic effusions of the Volcano Copahue which feeds the sources of the Río Agrio. The water system neutralizes after crossing an extension of 50 km. This situation defines a natural gradient of acidity, concentration and transport of nutrients and metals. The system shows low species diversity in the lacustrine plankton as well as in the stream epilithon. The low pH allows the dissolution of the majority of the present elements, determining environments rich in metals and phosphorus. Unlike other Andean lakes of the Patagonia, the Lake Caviahue experiments short periods of variations in pH and conductivity, situation that is controlled by the volcanic activity. The sediments of the lake are rich in organic matter (OM) being the OM who controls the phosphorus availability.The extreme conditions of the lake, the ammonium and dissolved inorganic and organic carbon concentrations maintain a high planktonic density, mainly represented by Keratococcus raphidioides. The replacement of algal species (seasonal succession) not occurs in this lake and the small changes observed are related to the geochemistry of the basin. The epilithic biomass along the Río Agrio Inferior exhibits a strong distribution linked to the changes in pH. The conspicuous algae developments are mainly composed by filamentous green algae (e.g., Ulothrix spp.)

The Trophic state of Patagonian Argentinean lakes and its relationship with depth distribution in sediment Phosphorus

The parameters used to determine the trophic state of a water body are: total phosphorus (TP), transparency (Secchi disk depth) and chlorophyll a. However, these parameters show strong seasonal fluctuations which may hinder the estimation of trophic state. Some authors have proposed that sediments be used as an additional tool to evaluate the trophic state of a water body. The aim of this study was to determine the depth distribution of sediment TP in relation with the lake trophic state. Nine sediment corers from water bodies located in Patagonian Region (Argentina) were studied. The nutrient concentrations in pore water and in sediments were analyzed. The results obtained showed that there is a relationship between the depth distribution of sediment TP and the trophic state for all studied environments. Two exceptions were noted to this general pattern (Lakes Caviahue and Lácar). Our findings indicate that both pore water and sediments could be considered as the best parameters to estimate the tropic state of a water body compared to the water column.Fil: Temporetti, Pedro Felix. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Patagonia Norte. Instituto de Investigación en Biodiversidad y Medioambiente; Argentina. Universidad Nacional del Comahue; ArgentinaFil: Beamud, Sara Guadalupe. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Patagonia Norte. Instituto de Investigación en Biodiversidad y Medioambiente; Argentina. Universidad Nacional del Comahue; ArgentinaFil: Pedrozo, Fernando Luis. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Patagonia Norte. Instituto de Investigación en Biodiversidad y Medioambiente; Argentina. Universidad Nacional del Comahue; Argentin

Alga Didymo: Una pequeña gran invasora

La Patagonia ha sido y es hogar de un gran número de especies exóticas. Hace poco tiempo arribó a algunos cuerpos de agua dulce (ríos y lagos) un alga nativa del Hemisferio Norte que ha sido identificada como una gran invasora. Se trata de una diatomea microscópica conocida vulgarmente como “Didymo” o “moco de roca”. Presenta la capacidad de desarrollar grandes biomasas en condiciones de baja cantidad de nutrientes, que la hacen apreciable a simple vista. Además, puede ser dispersada a lo largo de extensas distancias, colonizando nuevos ambientes. Si bien no existe en la actualidad la posibilidad de erradicarla, es posible aplicar metodologías de prevención y control de su dispersión.Fil: Betancurt Ruggirello, Romina Florencia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigaciones en Biodiversidad y Medioambiente. Universidad Nacional del Comahue. Centro Regional Universidad Bariloche. Instituto de Investigaciones en Biodiversidad y Medioambiente; ArgentinaFil: Baffico, Gustavo Daniel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigaciones en Biodiversidad y Medioambiente. Universidad Nacional del Comahue. Centro Regional Universidad Bariloche. Instituto de Investigaciones en Biodiversidad y Medioambiente; ArgentinaFil: Beamud, Sara Guadalupe. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigaciones en Biodiversidad y Medioambiente. Universidad Nacional del Comahue. Centro Regional Universidad Bariloche. Instituto de Investigaciones en Biodiversidad y Medioambiente; Argentin

Utilisation of organic compounds by osmotrophic algae in an acidic lake of Patagonia (Argentina)

We investigated whether algal osmotrophy in naturally acidic Lake Caviahue is an important process for acquisition of organic carbon and organic nitrogen. To accomplish this, we quantified algal assimilation of organic compounds, measured the specific growth rate and biomass yield, and documented incorporation of organic compounds by phytoplankton in situ using microautoradiography. Substrate uptake quantification and microautoradiographic investigations were performed using 3 H-leucine, 3 H-glucose, 3 H-thymidine, 14C-aspartic acid, 14C-acetic acid and 14C-bicarbonates. The results showed that the most important species of the phytoplankton community, Keratococcus rhaphidioides and Watanabea sp., took up various sources of organic carbon and nitrogen under both light and dark conditions. They were also able to assimilate leucine, thymidine, aspartic acid and acetate under high levels of inorganic nitrogen and phosphorus, while they could use leucine, arginine, glutamine and glucose under low levels of nitrogen and phosphorus. The assimilation rates were higher in light than in darkness, and the algal specific growth rates increased when organic sources were added. We proposed that osmotrophy complements the main photosynthetic process of the phytoplankton in Lake Caviahue, which helps to overcome the scarcity of light and inorganic nitrogen and carbon in the water column.Fil: Beamud, Sara Guadalupe. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Patagonia Norte. Instituto de Investigación en Biodiversidad y Medioambiente; Argentina. Universidad Nacional del Comahue; ArgentinaFil: Karrasch, B.. Helmholtz Centre For Environmental Research; AlemaniaFil: Pedrozo, Fernando Luis. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Patagonia Norte. Instituto de Investigación en Biodiversidad y Medioambiente; Argentina. Universidad Nacional del Comahue; ArgentinaFil: Diaz, Monica Mabel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Patagonia Norte. Instituto de Investigación en Biodiversidad y Medioambiente; Argentina. Universidad Nacional del Comahue; Argentin

The use of an algal bioindicator in the assessment of different chemical remediation strategies for PAH-contaminated soils and sediments

Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous petroleum-derived pollutants that tend to accumulate in soils and sediments. Among the in situ chemical oxidation technologies applied at PAH-contaminated sites are Fenton reagent (FN), persulfate ion (PS) and permanganate ion (PM). The natural phytoplankton of an aquatic environment is useful as a biological indicator of the treatment efficacy of pollutant degradation. The objective of this work was to assess the use of an algal species, native from Los Barreales Reservoir (Argentina), as an efficacy indicator of the chemical remediation of PAH-contaminated soils and sediments. Oxidations with FN, PS or PM were carried out on soils and sediments previously contaminated with two types of PAHs (phenanthrene (Ph) or Benzo(a)anthracene (Ba)), analysing pH, residual oxidant, PAH degradation and heterotrophic bacteria abundance in soils or sediments after 7 days. Then, a bioassay was carried out by incubating the obtained soils or sediments, and the native alga Scenedesmus quadricauda (Turpin, Brébisson), analysing its abundance after 7 days. S. quadricauda abundance was related to PAH degradation efficacy, residual oxidants and changes in system pH. In this sense, the application of PS produced the lowest growth of the indicator in assays both with soils and sediments. Fenton reaction results varied depending on the contaminating PAH, with the best percentages of PAH degradation and growth of S. quadricauda for Ba. PM oxidation resulted in the best development of the indicator. This study constitutes a first approach to the use of S. quadricauda as an efficiency indicator of soil/sediment chemical remediation.Fil: Rotondo, Leandro Nahuel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigaciones en Biodiversidad y Medioambiente. Universidad Nacional del Comahue. Centro Regional Universidad Bariloche. Instituto de Investigaciones en Biodiversidad y Medioambiente; ArgentinaFil: Mora, Veronica Cecilia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigación y Desarrollo en Fermentaciones Industriales. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Centro de Investigación y Desarrollo en Fermentaciones Industriales; ArgentinaFil: Temporetti, Pedro Felix. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigaciones en Biodiversidad y Medioambiente. Universidad Nacional del Comahue. Centro Regional Universidad Bariloche. Instituto de Investigaciones en Biodiversidad y Medioambiente; ArgentinaFil: Beamud, Sara Guadalupe. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigaciones en Biodiversidad y Medioambiente. Universidad Nacional del Comahue. Centro Regional Universidad Bariloche. Instituto de Investigaciones en Biodiversidad y Medioambiente; ArgentinaFil: Pedrozo, Fernando Luis. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigaciones en Biodiversidad y Medioambiente. Universidad Nacional del Comahue. Centro Regional Universidad Bariloche. Instituto de Investigaciones en Biodiversidad y Medioambiente; Argentin

Using trait-based approaches to study phytoplankton seasonal succession in a subtropical reservoir in arid central western Argentina

The application of trait-based approaches has become a widely applied tool to analyse community assembly processes and dynamics in phytoplankton communities. Its advantages include summarizing information of many species without losing essentials of the main driving processes. Here, we used trait-based approaches to study phytoplankton temporal succession in a subtropical reservoir. We applied a combined approach including morphological traits (i.e. volume, surface) and functional clustering of species (morphology-based functional groups (MBFG) and Reynolds’ groups) and related the clustering of species with the environment. We found that this reservoir is characterized by a low richness and a bimodal distribution of phytoplankton biomass. Taxonomic and functional classifications were coincident, and the dominant species and groups biomasses were explained by the same group of variables. For instance, group X2, MBFG V and Carteria sp. biomasses were explained by: pH, Secchi disk depth, N-NH4; while group B, MBFG VI and Cyclotella ocellata biomasses were explained by stability of the water column, incident solar radiation, Secchi disk depth and N-NH4. From our results, we state that functional and taxonomic classifications are complementary rather than opposed approaches, and their specific uses depend exclusively on the aim of the study and the characteristics of the environment under evaluation. Our work is the first description of phytoplankton dynamics in a reservoir in the arid central western Argentina (Cuyo region).Fil: Beamud, Sara Guadalupe. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigaciones en Biodiversidad y Medioambiente. Universidad Nacional del Comahue. Centro Regional Universidad Bariloche. Instituto de Investigaciones en Biodiversidad y Medioambiente; ArgentinaFil: León, José Gabriel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Provincia de Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Universidad Nacional de Cuyo. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales; Argentina. Provincia de Mendoza. Departamento General de Irrigación; ArgentinaFil: Kruk, Betina Claudia. Universidad de la República. Facultad de Ciencias; UruguayFil: Pedrozo, Fernando Luis. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigaciones en Biodiversidad y Medioambiente. Universidad Nacional del Comahue. Centro Regional Universidad Bariloche. Instituto de Investigaciones en Biodiversidad y Medioambiente; ArgentinaFil: Diaz, Monica Mabel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigaciones en Biodiversidad y Medioambiente. Universidad Nacional del Comahue. Centro Regional Universidad Bariloche. Instituto de Investigaciones en Biodiversidad y Medioambiente; Argentin

The effect of pH on phosphorus sorbed from sediments in a river with a natural pH gradient

Phosphorus (P) is an essential nutrient for algal growth and its increase in water bodies produces eutrophication. On the other hand, sediments play an essential role in the processes of transformation and accumulation of P in aquatic systems. pH became a major factor to control the availability of P bound sediment not only for algal utilization and the consequent eutrophication of lakes but also for P precipitation to sediment. Most studies focused on the effect of pH on P release from sediments were performed in laboratories where the pH gradient was simulated by adding hydrochloric acid solutions or sodium hydroxide. The aim of this paper is to evaluate the effect of pH on sediment P dynamics (release/uptake) in a river (River Agrio, Argentina) with a natural pH gradient (1.5–6.7) both in water and in sediments. The results obtained showed that: all chemical species analyzed in water decreased according to pH-gradient increase; pH affects sediment P retention capacity, demonstrating that P retention capacity is lower at high pH; P retention capacity is different dependent on the time of year: in fall, the average retention coefficient (R) was 41; in winter, the average R was 38; and in summer, the average R was 46. It was found that sediment P, in all the pH gradient, was controlled, mainly, by the oxyhydroxides of Fe and Al and, to a lesser extent, by the Organic Matter and not by Ca as would be expected in higher pH sediments.Fil: Temporetti, Pedro Felix. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigaciones en Biodiversidad y Medioambiente. Universidad Nacional del Comahue. Centro Regional Universidad Bariloche. Instituto de Investigaciones en Biodiversidad y Medioambiente; ArgentinaFil: Beamud, Sara Guadalupe. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigaciones en Biodiversidad y Medioambiente. Universidad Nacional del Comahue. Centro Regional Universidad Bariloche. Instituto de Investigaciones en Biodiversidad y Medioambiente; ArgentinaFil: Nichela, Daniela Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigaciones en Biodiversidad y Medioambiente. Universidad Nacional del Comahue. Centro Regional Universidad Bariloche. Instituto de Investigaciones en Biodiversidad y Medioambiente; ArgentinaFil: Baffico, Gustavo Daniel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigaciones en Biodiversidad y Medioambiente. Universidad Nacional del Comahue. Centro Regional Universidad Bariloche. Instituto de Investigaciones en Biodiversidad y Medioambiente; ArgentinaFil: Pedrozo, Fernando Luis. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigaciones en Biodiversidad y Medioambiente. Universidad Nacional del Comahue. Centro Regional Universidad Bariloche. Instituto de Investigaciones en Biodiversidad y Medioambiente; Argentin