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Brazilian flathead Percophis brasiliensis is a commercially important perciform fish caught as bycatch by trawlers throughout its latitudinal distribution range (from 23° S in Brazil to 47° S in Argentina). It is associated with the catches of Argentine hake Merluccius hubbsi and Patagonian red shrimp Pleocticus muelleri in San Matías Gulf (SMG). The main objective of this study was to describe the first data on the growth of this species in SMG and to compare the results with available information for other areas of the Argentine Continental Shelf (ACS). The study was carried out using 294 specimens (196 females, 97 males and one of indeterminate sex) collected over four non-consecutive years from commercial/recreational fishing and during research cruises. The age of individuals was determined by reading and counting opaque-hyaline rings on the sagittae otoliths. The maximum ages observed were 14 years for females and 12 years for males. Growth parameters were estimated using the von Bertalanffy mode. Significant differences in L∞ parameter between sexes were found (L∞ males = 54.58 cm; L∞ females = 78.31 cm, p < 0.05). Growth parameters were different from those determined in previous studies for the ACS. Fil: López, María Eugenia. Universidad Nacional de la Patagonia "San Juan Bosco"; Argentina. Universidad Nacional de la Patagonia Austral. Centro de Investigaciones y Transferencia Golfo San Jorge. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro de Investigaciones y Transferencia Golfo San Jorge. Universidad Nacional de la Patagonia "San Juan Bosco". Centro de Investigaciones y Transferencia Golfo San Jorge; Argentina Fil: Ocampo Reinaldo, Matías. Universidad Nacional del Comahue. Centro de Investigación Aplicada y Transferencia Tecnológica en Recursos Marinos "Almirante Storni". - Provincia de Río Negro. Ministerio de Agricultura, Ganadería y Pesca. Centro de Investigación Aplicada y Transferencia Tecnológica en Recursos Marinos "Almirante Storni". Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet Centro Nacional Patagónico. Centro de Investigación Aplicada y Transferencia Tecnológica en Recursos Marinos "Almirante Storni"; Argentina. Universidad Nacional del Comahue; Argentina Fil: Rodrigues, Karina Andrea. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Instituto Nacional de Investigaciones y Desarrollo Pesquero; Argentina Fil: Rico, Maria Rita. Instituto Nacional de Investigaciones y Desarrollo Pesquero; Argentina Fil: Sáez, Margarita. Instituto Nacional de Investigaciones y Desarrollo Pesquero; Argentina Fil: González, Raul Alberto Candido. Universidad Nacional del Comahue; Argentina. Universidad Nacional del Comahue. Centro de Investigación Aplicada y Transferencia Tecnológica en Recursos Marinos "Almirante Storni". - Provincia de Río Negro. Ministerio de Agricultura, Ganadería y Pesca. Centro de Investigación Aplicada y Transferencia Tecnológica en Recursos Marinos "Almirante Storni". Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet Centro Nacional Patagónico. Centro de Investigación Aplicada y Transferencia Tecnológica en Recursos Marinos "Almirante Storni"; Argentina

Primary production hotspots in the marine environment occur where the combination of light, turbulence, temperature and nutrients makes the proliferation of phytoplankton possible. Satellite-derived surface chlorophyll-a distributions indicate that these conditions are frequently associated with sharp water mass transitions named “marine fronts”. Given the link between primary production, consumers and ecosystem functions, marine fronts could play a key role in the production of ecosystem services (ES). Using the shelf break front in the Argentine Sea as a study case, we show that the high primary production found in the front is the main ecological feature that supports the production of tangible (fisheries) and intangible (recreation, regulation of atmospheric gases) marine ES and the reason why the provision of ES in the Argentine Sea concentrates there. This information provides support to satellite chlorophyll as a good indicator of multiple marine ES. We suggest that marine fronts could be considered as marine ES hot spots. Fil: Martinetto, Paulina Maria del Rosario. Universidad Nacional de Mar del Plata; Argentina Fil: Alemany, Daniela. Universidad Nacional de Mar del Plata; Argentina Fil: Botto, Florencia. Universidad Nacional de Mar del Plata; Argentina Fil: Mastrángelo, Matías. Universidad Nacional de Mar del Plata; Argentina Fil: Falabella, Valeria. Wildlife Conservation Society; Argentina Fil: Acha, Eduardo Marcelo. Universidad Nacional de Mar del Plata; Argentina Fil: Antón, Gustavo. Instituto Nacional de Investigaciones y Desarrollo Pesquero; Argentina Fil: Bianchi, Alejandro. Universidad de Buenos Aires; Argentina Fil: Campagna, Claudio. Servicio Hidrografía Naval; Argentina Fil: Cañete, Guillermo. Wcs Argentina; Argentina Fil: Filippo, Pablo. Fundación Vida Silvestre Argentina; Argentina Fil: Iribarne, Oscar Osvaldo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentina Fil: Laterra, Pedro. Universidad Nacional de Mar del Plata; Argentina Fil: Martínez, Patricia. Fundación Bariloche; Argentina Fil: Negri, Rubén. Instituto Nacional de Investigaciones y Desarrollo Pesquero; Argentina Fil: Piola, Alberto Ricardo. Instituto Nacional de Investigaciones y Desarrollo Pesquero; Argentina Fil: Romero, Silvia Inés. Ministerio de Defensa. Armada Argentina. Servicio de Hidrografía Naval; Argentina Fil: Santos, David. Ministerio de Defensa. Armada Argentina. Servicio de Hidrografía Naval; Argentina Fil: Saraceno, Martín. Universidad Nacional de la Patagonia "San Juan Bosco"; Argentina

Estuarine abiotic characteristics vary with tidal variations and fresh water input, both driven by climatic conditions and often cyclical climatic events. Estuaries are very productive and bivalves often represent a substantial proportion of the biomass with important ecological role. Salinity fluctuation is often a key environmental factor affecting bivalves shell growth and individual condition index (CI), parameters that in turn can be used to show the quality of the environment for one population. The stout razor clam Tagelus plebeius is an euryhaline filter-feeder species that inhabits sandy-silt tidal flats within a wide salinity range. The objective of this study was to evaluate, by survey sampling and in situ transplant experiments among sites with different salinity, whether shell growth and CI of T. plebeius vary with the salinity regime. We hypothesized a higher growth and CI related to the intermediate salinity. Clams and abiotic parameters were sampled in three estuaries of the northern Argentinian coast with different salinity regimes (Bahía Samborombón (36°19′S), Mar Chiquita coastal lagoon (37°32′S) and Bahía Blanca (38° 47′S)) and in three sites along the salinity gradient of the Mar Chiquita coastal lagoon where the manipulative experiments were also conducted. Shells were more elongated in sites with lower salinity; but the growth rate (k) and the CI were higher in sites with intermediate salinity. Furthermore, clams transplanted from intermediate salinity sites to those with higher or lower salinity showed a disadvantage in shell growth. Considering the scenario of climatic-driven salinity changes in these estuaries and given that T. plebeius is the only native bivalve species in those intertidal zones, having a relevant ecological role and conspicuous fossil presence in Holocene outcrops, our results highlight the relevance of this clam as a valuable target for future studies on conservation biology and paleobiology. Fil: Addino, Mariana del Sol. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentina Fil: Alvarez, Maria Fernanda. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Limnología "Dr. Raúl A. Ringuelet". Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Instituto de Limnología; Argentina Fil: Brey, Thomas. Geomar-Helmholtz Centre for Ocean Research Kiel; Alemania Fil: Iribarne, Oscar Osvaldo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentina Fil: Lomovasky, Betina Judith. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentina

El glifosato es el herbicida más utilizado a nivel mundial. Puede llegar a los cuerpos de agua y afectar a las comunidades microbianas. Comparamos los efectos del glifosato grado técnico y dos formulados comerciales sobre una comunidad periférica de agua dulce. Se llevó a cabo un experimento de laboratorio con cuatro tratamientos: glifosato ácido grado técnico, Glifosato II Atanor, Roundup Max, a una concentración de 3 mg de ingrediente activo/L, y un Control. A los 2, 5 y 9 días posteriores a la aplicación de los herbicidas se determinaron la concentración de pigmentos, peso seco, peso seco libre de cenizas y densidad algal del perifiton. Se registró un incremento de la abundancia de Cyanobacteria y una disminución de Chlorophyta y Bacillariophyta en todos los tratamientos con herbicida. Este efecto fue mayor con la adición de Roundup Max y Glifosato II Atanor, y fue menor con glifosato grado técnico, sugiriendo que los aditivos en los formulados comerciales pueden intensificar los efectos del glifosato Glyphosate is the most widely used herbicide worldwide. It may reach water bodies and affect microbial communities. We compared the effects of two commercial formulations and technical-grade glyphosate on a freshwater periphytic community. A laboratory bioassay was carried out with four treatments: technical-grade glyphosate acid, Glifosato II Atanor, Roundup Max, at a concentration of 3 mg active ingredient/L, and Control. At 2, 5 and 9 days after herbicide application, pigments concentration, dry weight, ash-free dry weight, and periphytic algal density were determined. An increase of Cyanobacteria and a decrease of Chlorophyta and Bacillariophyta abundances were registered in all treatments with the herbicide. This effect was greater when Roundup Max and Glifosato II Atanor® were added, and was lower with technical-grade glyphosate, suggesting that additives in the commercial formulations may enhance glyphosate effects. Fil: Gonzalez, Daniela. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Ecología, Genética y Evolución; Argentina Fil: Juarez, Angela Beatriz. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Biodiversidad y Biología Experimental; Argentina Fil: Krug, Cecilia Pamela. Universidad Nacional de San Martín. Instituto de Investigación en Ingeniería Ambiental; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Santos, Marina. Instituto Nacional de Tecnología Industrial; Argentina Fil: Vera, Maria Solange. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Ecología, Genética y Evolución de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Ecología, Genética y Evolución de Buenos Aires; Argentina

Sphagnum-dominated ecosystem plays major roles as carbon sinks at the global level. Associated microbial communities, in particular, eukaryotes, play significant roles in nutrient fixation and turnover. In order to understand better the ecological processes driven by these organisms, the first step is to characterise these associated organisms. We characterised the taxonomic diversity, and from this, inferred the functional diversity of microeukaryotes in Sphagnum mosses in tropical, subtropical and temperate climatic zones through an environmental DNA diversity metabarcoding survey of the V9 region of the gene coding for the RNA of the small subunit of the ribosomes (SSU rRNA). As microbial processes are strongly driven by temperatures, we hypothesised that saprotrophy would be highest in warm regions, whereas mixotrophy, an optimal strategy in oligotrophic environments, would peak under colder climates. Phylotype richness was higher in tropical and subtropical climatic zones than in the temperate region, mostly due to a higher diversity of animal parasites (i.e. Apicomplexa). Decomposers, and especially opportunistic yeasts and moulds, were more abundant under warmer climates, while mixotrophic organisms were more abundant under temperate climates. The dominance of decomposers, suggesting a higher heterotrophic activity under warmer climates, is coherent with the generally observed faster nutrient cycling at lower latitudes; this phenomenon is likely enhanced by higher inputs of nutrients most probably brought in the system by Metazoa, such as arthropods. Fil: Singer, David. Universidade de Sao Paulo; Brasil. Universite de Neuchatel; Suiza Fil: Metz, Sebastián Darío. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Biotecnológicas. Instituto de Investigaciones Biotecnológicas "Dr. Raúl Alfonsín" (sede Chascomús). Universidad Nacional de San Martín. Instituto de Investigaciones Biotecnológicas. Instituto de Investigaciones Biotecnológicas "Dr. Raúl Alfonsín" (sede Chascomús); Argentina Fil: Unrein, Fernando. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Biotecnológicas. Instituto de Investigaciones Biotecnológicas "Dr. Raúl Alfonsín" (sede Chascomús). Universidad Nacional de San Martín. Instituto de Investigaciones Biotecnológicas. Instituto de Investigaciones Biotecnológicas "Dr. Raúl Alfonsín" (sede Chascomús); Argentina Fil: Shimano, Satoshi. Hosei University; Japón Fil: Mazei, Yuri. Universidad Estatal de Moscú ; Rusia Fil: Mitchell, Edward A. D.. Jardin Botanique de Neuchâtel; Suiza Fil: Lara Pandis, Enrique Miguel. Consejo Superior de Investigaciones Científicas. Real Jardín Botánico; España

Functional diversity is the component of diversity that influences ecosystem dynamics, stability, productivity, nutrient balance, and other aspects of ecosystem functioning. We evaluate the spatio-temporal variability of the functional traits (biological traits analysis), functional diversity indices (functional richness, functional evenness, functional divergence and functional dispersion) and AZTI marine biotic index in response to the distinct levels of sewage contamination at different sites on intertidal abrasion platforms. Variations in macrobenthic functional structure between reference and impacted sites were evident in the study area. The functional richness showed a pattern with higher values in the reference sites; Functional evenness showed a similar pattern, but only during spring. Functional divergence presented lower values in the impacted sites during autumn and spring. The functional diversity indices (functional richness and functional evenness) and the AZTI marine biotic index presented a negative relationship, indicating that functional diversity is related to benthic environmental health. Thus, biological traits analysis and functional diversity indices, especially FRic that reveals differences in macrobenthic functional structure between impacted and reference sites during all seasons, represent an informative and useful tool to describe the different aspects of sewage impacts in benthic assemblages on rocky shores. These analyses have a high potential for future monitoring programmes. Fil: Garaffo, Griselda Valeria. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentina Fil: Jaubet, Maria Lourdes. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentina Fil: Llanos, Elizabeth Noemi. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentina Fil: Saracho Bottero, Maria Andrea. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentina Fil: Elias, Rodolfo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentina

Neohelice granulata provides an interesting animal model for studying behavioural process because it is widely distributed, ensuring variability related to different environmental conditions. The aim of this study was to analyse variation in site fidelity with relation to landscape heterogeneity. Field observations were carried out in three geographically distant marshes in Argentina (Mar Chiquita, San Antonio Oeste, and Riacho San José), which differ in their environmental characteristics and where crabs display different reproductive strategies. We analysed potential variation in burrow fidelity with relation to body size, sex and presence of vegetation (mudflat and saltmarsh) at all study sites. In addition, we analysed the influence of tidal flooding on fidelity in the Mar Chiquita saltmarsh. To achieve these goals, we used a mark-recapture method in which we tagged approximately 100 crabs during mid-summer for each zone at each site (a total of 668 crabs) for geographical comparison and approximately 370 crabs to evaluate the influence of tidal flooding. We found more faithful individuals in Mar Chiquita than in San Antonio Oeste and Riacho San José. For the San Antonio Oeste and Riacho San José populations and for Mar Chiquita previous to flooding samples we also found differences in site fidelity related to crab body size. At San Antonio Oeste and Riacho San José the relationship between size and proportion of faithful crabs was negative (smaller crabs were more faithful than larger crabs). In Mar Chiquita, a higher proportion of fidelity previous to flooding and a size-dependent response to flooding were detected, suggesting that fidelity may be modulated by tides having different effects on crabs with different body sizes. Equal proportions of males and females displaying site fidelity were observed at all study zones and sites. Our study suggests that N. granulata burrow fidelity behaviour changes with latitude and landscape (mudflat or saltmarsh) and can be sensitive to variables such as body size and frequency of flooding. Fil: Nuñez, Jesus Dario. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentina Fil: Ribeiro, Pablo Damián. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentina Fil: Ocampo, Emiliano Hernan. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentina Fil: Luppi, Tomas Atilio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentina

Effects of contamination on aquatic organisms have been investigated and employed as biomarkers in environmental quality assessment for years. A commonly referenced aquatic organism, mollusks represent a group of major interest in toxicological studies. Both gastropods and bivalves have external mineral shells that protects their soft tissue from predation and desiccation. These structures are composed of an organic matrix and an inorganic matrix, both of which are affected by environmental changes, including exposure to hazardous chemicals. This literature review evaluates studies that propose mollusk shell alterations as biomarkers of aquatic system quality. The studies included herein show that changes to natural variables such as salinity, temperature, food availability, hydrodynamics, desiccation, predatory pressure, and substrate type may influence the form, structure, and composition of mollusk shells. However, in the spatial and temporal studies performed in coastal waters around the world, shells of organisms sampled from multi-impacted areas were found to differ in the form and composition of both organic and inorganic matrices relative to shells from less contaminated areas. Though these findings are useful, the toxicological studies were often performed in the field and were not able to attribute shell alterations to a specific molecule. It is known that the organic matrix of shells regulates the biomineralization process; proteomic analyses of shells may therefore elucidate how different contaminants affect shell biomineralization. Further research using approaches that allow a clearer distinction between shell alterations caused by natural variations and those caused by anthropogenic influence, as well as studies to identify which molecule is responsible for such alterations or to determine the ecological implications of shell alterations, are needed before any responses can be applied universally. Fil: Yokota Harayashiki, Cyntia Ayumi. Universidade Federal de Sao Paulo.; Brasil Fil: Marquez, Federico. Universidad Nacional de la Patagonia "San Juan Bosco"; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Instituto de Biología de Organismos Marinos; Argentina Fil: Cariou, Elsa. Universite de Nantes; Francia Fil: Castro, Ítalo Braga. Universidade Federal de Sao Paulo.; Brasil

Land-sea interface is an ecotone where the intersection of marine and terrestrial ecosystems create unique ecological conditions for terrestrial mobile species and freshwater-adapted organisms to exploit marine-derived food resources. Mammalian carnivores play an important role in almost any ecosystem where they live due to theirtop-down (or trophic cascade) effects on prey species and primary producers, thus structuring ecosystems along varied food-web pathways. We use camera trapping tostudy the patterns of coexistence, habitat use and activity pattern of carnivores speciesin a coastal area in southern Buenos Aires province, Argentina. We were able to detectfive of the seven species of Mammalian carnivores being the Pampas fox Lycalopexgymnocercus and Geoffroy´s cat Leopardus geoffroyi the two most common.Geoffroy´s cat seems to use more intensively those areas close to the shoreline, whilewe found little support of it for Pampas fox; which seems to use more inland areas.Congruently, we found evidence of a lack of spatial and, to a lower extent, temporalavoidance between the two most common carnivore species of our study area. Ourfindings support those previous studies indicating that the coastal dunes have animportant role in the conservation of the biodiversity of Buenos Aires province. Wildlifeconservation is compatible with carefully-designed ecotourism and limitedinfrastructure development and this may be a unique chance for the areas of BuenosAires coast that have not been affected yet by poorly planned, conservation-unfriendlyurbanization. Fil: Caruso, Nicolás. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Ciencias Biológicas y Biomédicas del Sur. Universidad Nacional del Sur. Departamento de Biología, Bioquímica y Farmacia. Instituto de Ciencias Biológicas y Biomédicas del Sur; Argentina. Universidad Nacional del Sur. Departamento de Biología, Bioquímica y Farmacia. Cátedra de Fisiología Animal; Argentina Fil: Luengos Vidal, Estela Maris. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Ciencias Biológicas y Biomédicas del Sur. Universidad Nacional del Sur. Departamento de Biología, Bioquímica y Farmacia. Instituto de Ciencias Biológicas y Biomédicas del Sur; Argentina. Universidad Nacional del Sur. Departamento de Biología, Bioquímica y Farmacia. Cátedra de Fisiología Animal; Argentina Fil: Manfredi, Matilde Claudia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Ciencias Biológicas y Biomédicas del Sur. Universidad Nacional del Sur. Departamento de Biología, Bioquímica y Farmacia. Instituto de Ciencias Biológicas y Biomédicas del Sur; Argentina Fil: Araujo, Maria Soledad. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Ciencias Biológicas y Biomédicas del Sur. Universidad Nacional del Sur. Departamento de Biología, Bioquímica y Farmacia. Instituto de Ciencias Biológicas y Biomédicas del Sur; Argentina Fil: Lucherini, Mauro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Ciencias Biológicas y Biomédicas del Sur. Universidad Nacional del Sur. Departamento de Biología, Bioquímica y Farmacia. Instituto de Ciencias Biológicas y Biomédicas del Sur; Argentina. Universidad Nacional del Sur. Departamento de Biología, Bioquímica y Farmacia. Cátedra de Fisiología Animal; Argentina Fil: Casanave, Emma Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Ciencias Biológicas y Biomédicas del Sur. Universidad Nacional del Sur. Departamento de Biología, Bioquímica y Farmacia. Instituto de Ciencias Biológicas y Biomédicas del Sur; Argentina. Universidad Nacional del Sur. Departamento de Biología, Bioquímica y Farmacia. Cátedra de Fisiología Animal; Argentina

Understanding processes driving patterns of species distribution anddiversity is one of the main objectives of community ecology. The aim of our study was to evaluate the spatial variation in assemblage compositionof stream-dwelling macroinvertebrates and identify which factors (e.g. water quality,land cover) are the most important drivers. We applied the elements of the metacommunity structure approach on a dataset of 38 communities from the Futaleufú basin in northwestern Patagonia. To better understandassemblage variation, we deconstructed our macroinvertebrate dataset into differenttaxonomic and trait groups. We then identified the most influential factors drivingcommunity composition using random forests. We found that half of our datasets (i.e. macroinvertebrate groups) exhibited a nestedstructure with clumped species loss, while the other half showed a quasi-nested patternwith either clumped or stochastic species loss. Overall, water quality was the most important driver of community variation,although climate, geography, and land cover were more or less relevant in particularcases. We found differences in the relative importance of the selected explanatoryvariables among datasets. This would suggest that different components of the macroinvertebratecommunity respond differently to environmental factors. Our findings could be of value for conservation planning, as they suggestthat preserving the most species-rich streams would, to some extent, guarantee theconservation of the entire species pool. Fil: Williams Subiza, Emilio Adolfo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Centro de Investigación Esquel de Montaña y Estepa Patagóica. Universidad Nacional de la Patagonia "San Juan Bosco". Facultad de Ciencias Naturales - Sede Esquel. Centro de Investigación Esquel de Montaña y Estepa Patagónica; Argentina Fil: Brand, Cecilia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Centro de Investigación Esquel de Montaña y Estepa Patagóica. Universidad Nacional de la Patagonia "San Juan Bosco". Facultad de Ciencias Naturales - Sede Esquel. Centro de Investigación Esquel de Montaña y Estepa Patagónica; Argentina Fil: Miserendino, Maria Laura. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Centro de Investigación Esquel de Montaña y Estepa Patagóica. Universidad Nacional de la Patagonia "San Juan Bosco". Facultad de Ciencias Naturales - Sede Esquel. Centro de Investigación Esquel de Montaña y Estepa Patagónica; Argentina

Small water bodies are critical for maintaining freshwater biodiversity, but are among the least investigated of aquatic environments. We examined physical and chemical variables at two reaches in Arroyo Tambillos, a small, high-elevation Andean stream, across four seasons to examine how local factors and seasonality affected the structure of the macroinvertebrate community. The Arroyo Tambillos community was numerically dominated by ephemeropterans (mainly Massartellopsis irrazavali) while the dipteran Chironomidae were the most species rich. Total macroinvertebrate abundance washighest in summer, driven mainly by taxa that were secondary in dominance (Austrelmis sp. and Andesiops peruvianus), while richness did not differ between seasons. However, benthic composition was different in Fall 2013 (March) compared to other seasons, largely because of the increased abundance of Chironomidae. Canonical correspondence analysis discriminated Chironomidae species distributions in Fall 2013 by substrate type (i.e., big and small boulder substrate). By contrast, discharge, velocity, and depth were the variables which most affected the macroinvertebrate abundance and distributions. Contrary to our expectations, most community changes observed occurred in fall instead in summer. Nivo-kryal stream communities like the one described here have become increasingly important for conserving mountain stream biodiversity as anthropogentic impacts and climate change increasingly impact lower stream reaches. Therefore, monitoring high-altitude streams like the Arroyo Tambillos may be critical for preventing the future loss of unique and sensitive stream biota. Fil: Scheibler, Erica Elizabeth. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto Argentino de Investigaciones de las Zonas Áridas. Provincia de Mendoza. Instituto Argentino de Investigaciones de las Zonas Áridas. Universidad Nacional de Cuyo. Instituto Argentino de Investigaciones de las Zonas Áridas; Argentina Fil: Fernández Campón, María Florencia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto Argentino de Investigaciones de las Zonas Áridas. Provincia de Mendoza. Instituto Argentino de Investigaciones de las Zonas Áridas. Universidad Nacional de Cuyo. Instituto Argentino de Investigaciones de las Zonas Áridas; Argentina. Universidad Nacional de Cuyo; Argentina Fil: Lagos Silnik, Susana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto Argentino de Investigaciones de las Zonas Áridas. Provincia de Mendoza. Instituto Argentino de Investigaciones de las Zonas Áridas. Universidad Nacional de Cuyo. Instituto Argentino de Investigaciones de las Zonas Áridas; Argentina Fil: Wellnitz, Todd. University of Wisconsin; Estados Unidos

Ballast water has been identified as a leading vector for introduction of non-indigenous species. Recently, the International Maritime Organization implemented management standards—D-2—where all large, commercial ships trading internationally are required to adopt an approved treatment system using technologies such as ultraviolet radiation or chlorination. However, current management regulations are based only on the total abundance of viable taxa transported (i.e. total propagule pressure), largely ignoring species richness (i.e. colonization pressure). To determine the efficacy of chlorine treatment in reducing invasion risks and changes in transported biological communities inside ballast tanks, we used DNA metabarcoding-based approaches to estimate colonization pressure (here, the number of species/operational taxonomic units [OTUs] introduced) and relative propagule pressure (relative abundance of each species/OTU) of zooplankton communities in control and chlorine treated tanks during four transatlantic voyages. Our study demonstrated that transport itself did not significantly reduce colonization pressure of zooplankton species, nor did chlorine treatment. Chlorine treatment altered community structure by reducing relative propagule pressure of some taxa such as Mollusca and Rotifera, while increasing relative propagule pressure of some Oligohymenophorea and Copepoda species. Synthesis and applications. Chlorine treatment may not reduce invasion risks as much as previously thought. Reduction in total propagule pressure does not mean reduction in abundance of all species equally. While some taxa might experience drastically reduced abundance, others might not change at all or increase due to hatching from dormant stages initiated by chlorine exposure. Therefore, management strategies should consider changes in total propagule pressure and colonization pressure when forecasting risk of new invasions. We therefore recommend adopting new approaches, such as DNA metabarcoding-based methods, to assess the whole biodiversity discharged from ballast water. As species responses to chlorine treatment are variable and affected by concentration, we also recommend a combination of different technologies to reduce introduction risks of aquatic organisms. Fil: Lin, Yaping. Geomar-Helmholtz Centre for Ocean Research Kiel; Alemania Fil: Zhan, Aibin. Chinese Academy of Sciences; República de China Fil: Hernández, Marco R.. University of Windsor. Great Lakes Institute for Enviromental Research; Canadá Fil: Paolucci, Esteban Marcelo. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; Argentina Fil: MacIsaac, Hugh J.. University of Windsor. Great Lakes Institute for Enviromental Research; Canadá Fil: Briski, Elizabeta. Geomar-Helmholtz Centre for Ocean Research Kiel; Alemania

Global-change stressors act under different timing, implying complexity and uncertainty in the study of interactive effects of multiple factors on planktonic communities. We manipulated three types of stressors acting in different time frames in an in situ experiment: ultraviolet radiation (UVR); phosphorus (P) concentration; temperature (T) in an oligotrophic Mediterranean high-mountain lake. The aim was to examine how the sensitivity of phytoplankton and bacterioplankton to UVR and their trophic relationship change under nutrient acclimation and abrupt temperature shifts. Phytoplankton and bacteria showed a common pattern of metabolic response to UVR × P addition interaction, with an increase in their production rates, although evidencing an inhibitory UVR effect on primary production (PP) but stimulatory on bacterial production (HBP). An abrupt T shift in plankton acclimated to UVR and P addition decreased the values of PP, evidencing an inhibitory UVR effect, whereas warming increased HBP and eliminated the UVR effect. The weakening of commensalistic and predatory relationship between phyto- and bacterioplankton under all experimental conditions denotes the negative effects of present and future global-change conditions on planktonic food webs towards impairing C flux within the microbial loop. Fil: Durán Romero, Cristina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Instituto Patagónico para el Estudio de los Ecosistemas Continentales; Argentina. Universidad de Granada; España Fil: Medina Sánchez, Juan Manuel. Universidad de Granada; España Fil: Carrillo, Presentación. Universidad de Granada; España

The present study reported the effect of natural and anthropic environmental variables on the fish assemblages in the pampean streams, in the coastal strip along the Río de la Plata, Buenos Aires province, Argentina. Five streams were sampled at 12 sites surrounded by land devoted to different uses. A correspondence analysis sorted the streams into two groups: a less impacted group formed by sites surrounded by livestock- raising pastures and a more impacted one passing through urban sites and including a stream adjacent to a modest rural urbanization with a dairy in the stream’s basin. The nutrient concentrations were significantly higher in the more impacted group; with species richness, diversity, abundance, and biomass being significantly lower. A canonical-correspondence analysis linked the more impacted sites to high concentrations of soluble reactive phosphorus and impoverished fish assemblages, composed of species tolerant to environmental pollution. On the other hand, sites with higher oxygen concentrations and pH were related to richer assemblages pointing to good environmental conditions at the sites surrounded by livestock-raising pastures. The downstream sites on the less impacted streams contained fish assemblages in which the juvenile stages of species corresponding to the Río de la Plata were dominant., Instituto de Limnología "Dr. Raúl A. Ringuelet"

In South America, the order Atheriniformes includes the monophyletic genus Odontesthes with 20 species that inhabit freshwater, estuarine and coastal environments. Pejerrey Odontesthes argentinensis is widely distributed in coastal and estuarine areas of the Atlantic Ocean and is known to foray into estuaries of river systems, particularly in conditions of elevated salinity. However, to our knowledge, a landlocked self‐sustaining population has never been recorded. In this study, we examined the pejerrey population of Salada de Pedro Luro Lake (south‐east of Buenos Aires Province, Argentina) to clarify its taxonomic identity. An integrative taxonomic analysis based on traditional meristic, landmark‐based morphometrics and genetic techniques suggests that the Salada de Pedro Luro pejerrey population represents a novel case of physiological and morphological adaptation of a marine pejerrey species to a landlocked environment and emphasises the environmental plasticity of this group of fishes Fil: Colautti, Dario César. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Limnología "Dr. Raúl A. Ringuelet". Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Instituto de Limnología; Argentina Fil: Miranda, Leandro Andres. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Biotecnológicas. Instituto de Investigaciones Biotecnológicas "Dr. Raúl Alfonsín" (sede Chascomús). Universidad Nacional de San Martín. Instituto de Investigaciones Biotecnológicas. Instituto de Investigaciones Biotecnológicas "Dr. Raúl Alfonsín" (sede Chascomús); Argentina Fil: González Castro, M.. Universidad Nacional de Mar del Plata; Argentina Fil: Villanova, Vanina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Strüssmann, Carlos A.. Tokyo University Of Marine Science And Technology; Japón Fil: Mancini, Miguel Alberto. Universidad Nacional de Río Cuarto; Argentina Fil: Maiztegui, Tomás. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Limnología "Dr. Raúl A. Ringuelet". Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Instituto de Limnología; Argentina Fil: Berasain, Gustavo. Provincia de Buenos Aires. Ministerio de Asuntos Agrarios; Argentina Fil: Hattori, Ricardo Shohei. Tokyo University of Marine Science and Technology; Japón Fil: Grosman, Manuel Fabián. Universidad Nacional del Centro de la Provincia de Buenos Aires; Argentina Fil: Sanzano, Pablo Miguel. Universidad Nacional del Centro de la Provincia de Buenos Aires; Argentina Fil: Lozano, I.. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Llamazares Vegh, Sabina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Salinas, V.. Universidad Nacional de Río Cuarto; Argentina Fil: Del Ponti, O.. Universidad Nacional de La Pampa; Argentina Fil: Fresno, P.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Biotecnológicas. Instituto de Investigaciones Biotecnológicas "Dr. Raúl Alfonsín" (sede Chascomús). Universidad Nacional de San Martín. Instituto de Investigaciones Biotecnológicas. Instituto de Investigaciones Biotecnológicas "Dr. Raúl Alfonsín" (sede Chascomús); Argentina Fil: Minotti, Priscilla Gail. Universidad Nacional de San Martín; Argentina Fil: Yamamoto, Y.. Tokyo University Of Marine Science And Technology; Japón Fil: Baigún, C.. Universidad Nacional de San Martín; Argentina

The sea anemone Calliactis tricolor (Le Sueur, 1817) is an ecologically important member of the benthic community in coastal and coral reefs of the tropical Atlantic, particularly by their propensity to establish mutualistic symbiotic relationships with hermit crabs. This species is presumably distributed throughout the Gulf of Mexico; however, it had never been registered in the southwestern part of the Gulf. Here we document the first record of C. tricolor in two coral reef localities of the Veracruz Reef System, Mexico, and update the number of species of sea anemones known for the region. Fil: Tello Musi, José Luis. Universidad Nacional Autonoma de Mexico. Facultad de Estudios Superiores de Iztacala; México Fil: González Muñoz, Ricardo Enrique. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentina Fil: Acuña, Fabian Horacio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentina Fil: Simoes, Nuno. Universidad Nacional Autonoma de Mexico. Facultad de Ciencias; México

Water quality was monitored along an Andean river of global importance using the freshwater bivalve Diplodon chilensis as sentinel species. Bivalves were placed in cages at three sites (S1-3) in the Chimehuin river in order to evaluate the long-term effects of a trout hatchery (S2), and the open dump and sewage treatment plant of a nearby city (S3). Water samples and bivalves were collected at 0 (September 2011), 3 (December 2011), 6 (March 2012), 9 (July 2012), and 12 (September 2012) months, from S3, S2 and from a reference site upstream (S1), and physicochemical parameters and the biological response of the caged bivalves were studied. ROS production, antioxidant response, oxidative damage, energy status and morphometric ratios were included as response biomarkers. Most of biomarkers showed site-and time dependence including bivalves transplanted at S1, revealing natural variability. Both anthropogenic perturbed sites (S2 and S3) showed differences in the exposed-bivalves with respect to the reference site (S1) in their biomarker responses after 9 and 12 months of exposure (July and September, respectively). Multivariate analysis showed alterations in hemocytes (ROS, TOSC and NRRT50), energy balance in digestive gland (energy and DGF), and in the detoxification response (GST) and GSH values in gill when bivalves were exposed to hatchery waste; whereas metal and bacterial pollution (S3 in July) caused GSH increase and a reduction of lysosomal damage in hemocytes. Results show that changes in the water quality of Chimehuin river due to the anthropogenic impact can be detected using the biomarkers analyzed on D. chilensis, being a useful tool for studies of long-term monitories. Fil: Yusseppone, Maria Soledad. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentina Fil: Bianchi, Virginia Angélica. 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; Argentina Fil: Castro, Juan Manuel. 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; Argentina Fil: Luquet, Carlos Marcelo. 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; Argentina Fil: Sabatini, Sebastian Eduardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales; Argentina Fil: Rios, Maria del Carmen. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales; Argentina Fil: Rocchetta, Iara. 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; Argentina

To make robust projectios of the impacts of climate change, it is critical to understand how abiotic factors may interact to constrain the distribution and productivity of marine flora and fauna. We evaluated the effects of projected end of the century ocean acidification (OA) and warming (OW) on the thermal tolerance of an important living marine resource, the sea urchin Loxechinus albus, a benthic shallow water coastal herbivore inhabiting part of the Pacific coast of South America. After exposing young juveniles for a 1-month period to contrasting pCO2 (~500 and 1400 μatm) and temperature (~15 °C and 20 °C) levels, critical thermal maximum (CTmax) and minimum (CTmin) as well as thermal tolerance polygons were assessed based on self-righting success as an end point. Transcription of heat shock protein 70 (HSP70), a chaperone protecting cellular proteins from environmental stress, was also measured. Exposure to elevated pCO2 significantly reduced thermal tolerance by increasing CTmin at both experimental temperatures and decreasing CTmax at 20 °C. There was also a strong synergistic effect of OA × OW on HSP70 transcription levels which were 75 times higher than in control conditions. If this species is unable to adapt to elevated pCO2 in the future, the reduction in thermal tolerance and HSP response suggests that near-future warming and OA will disrupt their performance and reduce their distribution with ecological and economic consequences. Given the wider latitudinal range (6 to 56°S) and environmental tolerance of L. albus compared to other members of this region's benthic invertebrate community, OW and OA may cause substantial changes to the coastal fauna along this geographical range. Fil: Manriquez Carrillo, Patricio Hector Rafael. Centro de Estudios Avanzados En Zonas Áridas; Chile. Laboratorio de Ecología y Conducta de la Ontogenia Tem; Chile Fil: González, Claudio P.. Centro de Estudios Avanzados En Zonas Áridas; Chile. Laboratorio de Ecología y Conducta de la Ontogenia Tem; Chile Fil: Brokordt, Katherina. Universidad Catolica del Norte; Chile Fil: Pereira, Luis. Universidad Católica del Norte; Chile Fil: Torres, Rodrigo. Centro de Investigacion En Ecosistemas de la Patagonia; Chile Fil: Lattuca, María Eugenia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; Argentina Fil: Fernandez, Daniel Alfredo. Universidad Nacional de Tierra del Fuego. Instituto de Ciencias Polares, Recursos Naturales y Ambiente; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; Argentina Fil: Alter, Katharina. Universitat Hamburg; Alemania Fil: Peck, Myron. Universitat Hamburg; Alemania Fil: Cucco, Andrea. Universitat Hamburg; Alemania Fil: Antognarelli, Fabio. Universitat Hamburg; Alemania Fil: Marras, Stefano. Universitat Hamburg; Alemania Fil: Domenici, Paolo. Universitat Hamburg; Alemania

Physical, chemical and biological processes facilitate cross-habitat connections in lakes, prompting food webs to be supported by different subsidies. We tested the hypothesis that the pelagic food web is subsidized by littoral resources and fish foraging behaviour plays a major role in carbon flux and on food web structure in shallow hypereutrophic lakes. We performed a fish diet and carbon and nitrogen isotope analyses to predict the linkage between littoral and pelagic habitats in three shallow hypereutrophic lakes. Lakes differed in morphology, fetch, macrophyte composition and width of the littoral zone. δ13C signals of seston differed among lakes, but were similar to other producers. Macroinvertebrates and fish carbon signatures were more enriched in the lake co-dominated by emergent and submerged vegetation. Fish foraging behaviour indicates that more than the 80% of the carbon that sustain adult fish was channelled from the littoral. In conclusion, littoral carbon were relevant and sustain, in part, food web in these shallow lakes. Factors like the extension of the littoral zone, lake morphometry, and the dominance of multi-chain omnivorous fish facilitate the connection among lake compartments and the transference of littoral carbon to lake food web. Fil: Gonzalez Sagrario, Maria de Los Angeles. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentina Fil: Rodríguez Golpe, Daniela Carmen. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentina Fil: La Sala, L.. Universidad Nacional de Mar del Plata; Argentina Fil: Sanchez Vuichard, Guillermina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentina Fil: Minotti, Priscilla Gail. Universidad Nacional de San Martín. Instituto de Investigación e Ingeniería Ambiental. Laboratorio de Ecología, Teledetección y Ecoinformática; Argentina Fil: Panarello, Hector Osvaldo. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Geocronología y Geología Isotópica. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Geocronología y Geología Isotópica; Argentina

Bivalves are among the main groups of invasive freshwater species, with the Asian clam genus Corbicula in particular being widely distributed. While global studies have focused on Corbicula fluminea (Müller, 1774), the invasive potential of Corbicula largillierti (Philippi, 1844) and Corbicula fluminalis (Müller, 1774) is still unknown. The spread of invasive species may be intensified by climate change. We estimated and compared environmentally suitable areas for these species under hypothetical climate scenarios, generating global maps of invasion risk. We found large climatically suitable areas for C. largillierti and C. fluminalis (under species distribution models) and that their invasive potential is currently underestimated. The analysis revealed many areas in which changing climate may favour the invasion of Corbicula spp. Fil: Reyna, Paola. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Diversidad y Ecología Animal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto de Diversidad y Ecología Animal; Argentina Fil: Nori, Javier. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Diversidad y Ecología Animal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto de Diversidad y Ecología Animal; Argentina Fil: Ballesteros, Maria Laura. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Diversidad y Ecología Animal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto de Diversidad y Ecología Animal; Argentina Fil: Hued, Andrea Cecilia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Diversidad y Ecología Animal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto de Diversidad y Ecología Animal; Argentina Fil: Tatian, Marcos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Diversidad y Ecología Animal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto de Diversidad y Ecología Animal; Argentina

Due to strong seasonality and spatial variation in ecosystem productivity, fish can show ontogenetic and/or seasonal changes in habitat use and move between different habitats to exploit the richest food resources. Here, we evaluate the spatial patterns of the size distribution of Patagonian hoki Macruronus magellanicus in relation to the highly productive frontal systems of the southern Patagonian shelf. Additionally, we assessed diet composition in relation to size. Fish data came from 10 scientific cruises that were carried out between April 1978 and March 1979 during cold and warm seasons of the year. Samples were collected using demersal hauls that for the purposes of this study were ascribed to frontal or non-frontal zones. Based on the analysis of the total length of 3660 Patagonian hoki individuals, a generalized linear model was constructed to evaluate the association between fish size and fronts. Moreover, prey items consumed by fish grouped into 4 size classes were evaluated by analysing the contents of 1067 stomachs. Our results showed that smaller fish (juveniles) were more frequently located along frontal areas and preyed upon zooplankton. In contrast, larger fish (adults) preyed on larger items and showed no spatial relationship with fronts. The positive relationship observed between small-sized fish and fronts may be related to the low trophic level of these fish and the abundance of small-sized prey in frontal zones. Fil: Alemany, Daniela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentina Fil: Iribarne, Oscar Osvaldo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentina Fil: Acha, Eduardo Marcelo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentina. Instituto Nacional de Investigaciones y Desarrollo Pesquero; Argentina

The shallow sandy marine subtidal ecosystem off Mar del Plata, Argentina, is the scene of multiple fisheries activities, in particular the prawn-shrimp Artemesia longinaris and Pleoticus muelleri grounds. We examined the δ 13 C vs δ 15 N isotope signatures of 22 species commonly found in the area in order to understand how this ecosystem supports the fishery, with special emphasis on imposex-Affected gastropod populations. Our results indicate that the main food source for Olivancillaria urceus and Buccinanops monilifer were bivalves and crustaceans. Buccinanops duartei and Olivancillaria carcellesi feed on bivalves and also on macroalgae. These findings indicate, for the first time, a slight selectivity of some of the gastropods studied for local drifted algal sources and how gastropods may scavenge available food from by-catch returned to the sea. The fishes Urophysis brasiliensis and Callorhynchus callorhynchus appeared to be the top predators of this area with B. duartei and O. carcellesi constituting important components of their diet. Fil: Arrighetti, Florencia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales “Bernardino Rivadavia”; Argentina Fil: Teso, Silvia Valeria. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales “Bernardino Rivadavia”; Argentina Fil: Brey, T.. Alfred Wegener Institute for Polar and Marine Research; Alemania Fil: Penchaszadeh, Pablo Enrique. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales “Bernardino Rivadavia”; Argentina

Scorched mussels (Bivalvia: Mytilidae) are an important component of rocky shore assemblages around the world. The mussel beds of the mid-intertidal coasts of the south-western Atlantic are composed of two species of scorched mussels, which dominate the physiognomy and structure of the rocky shore communities. The present study investigates the variation in the shell-shape allometric trajectories of both species of mussels throughout their distributional range in the southwestern Atlantic coast, from latitude 34°S to 53°S. Shells of Brachidontes rodriguezii were collected at two Uruguayan localities and four Argentinean localities, while shells of Perumytilus purpuratus were collected at six Argentinean localities. Shell shapes of the specimens were studied by geometric morphometrics using landmark and semi-landmark methods. Different evolutionary histories and thermal regimes characterize these two species. Brachidontes rodriguezii seems to have a long history in the region and is present in a restricted area, the warm temperate region of the south-western Atlantic, while P. purpuratus seems to have a recent history and is present in a wide thermal range, involving the cold-temperate regions of the south-western Atlantic and south-eastern Pacific and the warm-temperate region of the south-eastern Pacific. Based on these considerations, we prompt the hypothesis that allometric trajectories of P. purpuratus shell shape is more variable and adapted to a specific habitat than B. rodriguezii. The impact of allometry was larger in P. purpuratus than in B. rodriguezii. Graphical evidence was gathered, showing that these two species differ in allometric growth forms and that the allometric shell morphology changes reflect environmental constraints and adaptation. While the intertidal mussel beds of the South American coasts are ecologically similar in appearance, we found that the allometric variation of the scorched mussels occurs in response to diverging evolutionary processes such as phenotypic plasticity in P. purpuratus and canalization in B. rodriguezii. Fil: Marquez, Federico. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Instituto de Biología de Organismos Marinos; Argentina Fil: Adami, Mariana Laura. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; Argentina Fil: Trovant, Berenice. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Instituto de Diversidad y Evolución Austral; Argentina Fil: Nieto Vilela, Rocío Aimé. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Instituto de Biología de Organismos Marinos; Argentina Fil: González José, Rolando. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Instituto Patagónico de Ciencias Sociales y Humanas; Argentina

The stress gradient hypothesis states that positive interactions become more important as physical stress increases. Organisms living in Patagonian intertidal ecosystems are subjected to high desiccation stress due to elevated temperatures and strong winds. In coastal environments, sponges and macroalgae are common benthic organisms, and they occur from the subtidal to intertidal zones. As human pressure has increased in these systems, both sponges and macroalgae have become more abundant, which has led to more frequent interactions between them. To evaluate the interaction between Hymeniacidon perlevis and Ulva lactuca in 2 contrasting environments, we sampled their abundance and conducted field factorial experiments consisting of sponge transplants and manipulation of algal presence. Our results show that in harsher environments, U. lactuca facilitates H. perlevis likely through the reduction of direct solar radiation or high substrate temperature beneath its canopy, whereas in milder environments, U. lactuca negatively affects H. perlevis throughout other physical or chemical mechanisms (e.g. abrasion, feeding interference through changing current dynamics, depletion of oxygen, allelochemical compound production). Fil: Gastaldi, Marianela. Universidad Nacional del Comahue. Centro Regional Universitario Bariloche; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Firstater, Fausto Nahuel. Universidad Nacional del Comahue. Centro Regional Universitario Bariloche; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Narvarte, Maite Andrea. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional del Comahue. Centro Regional Universitario Bariloche; Argentina Fil: Daleo, Pedro. Universidad Nacional de Mar del Plata; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentina

In this stu, dy of northern Patagonia in Argentina, we examined the annual cycle of the epiphyte composition and abundance on Ulva sp. with respect to intertidal elevation, season and position on host. We found spatial segregation in most environmental gradients. Local environmental conditions, intertidal levels, seasons and portion of host thalli had specific patterns of algal epiphytic community. The host population exhibited seasonality and differential morphological attributes according to the intertidal elevation. Thalli of Ulva sp. had the highest maximum diameters and were heavier in spring and summer at the upper elevation. Epiphytes were more abundant growing on host thalli at middle elevations. Epiphytic Dinophyceae, Chlorophyceae and Cyanophyceae presented clear seasonality. Epiphyte abundances were related to periods with high seawater temperature, long days and high radiation. Lyngbya sp., Cocconeis sp., Navicula spp., Rhabdonema arcuatum, Stylonema alsidii and Myrionema strangulans had the highest frequency. The highest epiphyte abundance was observed in holdfasts, with M. strangulans having the highest frequency and cover. These results are relevant to commercial aquaculture ventures for food and feed sources and application in bioremediation. Fil: Gauna, Maria Cecilia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto Argentino de Oceanografía. Universidad Nacional del Sur. Instituto Argentino de Oceanografía; Argentina Fil: Escobar, Juan Francisco. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico; Argentina Fil: Odorisio, Mariangeles. Universidad Nacional del Sur. Departamento de Biología, Bioquímica y Farmacia; Argentina Fil: Caceres, Eduardo Jorge. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas; Argentina Fil: Parodi, Elisa Rosalia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto Argentino de Oceanografía. Universidad Nacional del Sur. Instituto Argentino de Oceanografía; Argentina

The influence of nutrient availability and light conditions on phytoplankton size-structure, nutritional strategy and production was studied in a phosphorus-poor estuary in the northern Baltic Sea receiving humic-rich river water. The relative biomass of mixotrophic nanophytoplankton peaked in spring when heterotrophic bacterial production was high, while autotrophic microphytoplankton had their maximum in summer when primary production displayed highest values. Limiting substance (phosphorus) only showed small temporal variations, and the day light was at saturating levels all through the study period. We also investigated if the phytoplankton taxonomic richness influences the production. Structural equation modelling indicated that an increase of the taxonomic richness during the warm summer combined with slightly higher phosphorus concentration lead to increased resource use efficiency, which in turn caused higher phytoplankton biomass and primary production. Our results suggest that climate warming would lead to higher primary production in northerly shallow coastal areas, which are influenced by humic-rich river run-off from un-disturbed terrestrial systems. Fil: Paczkowska, Joanna Marianna. Universidad de Umea; Suecia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Centro para el Estudio de Sistemas Marinos; Argentina. Umeå Marine Sciences Centre; Suecia Fil: Rowe, Owen F.. Universidad de Umea; Suecia. Umeå Marine Sciences Centre; Suecia. University of Helsinki; Finlandia. Helsinki Commission; Finlandia Fil: Figueroa, Daniela. Umeå Marine Sciences Centre; Suecia. Universidad de Umea; Suecia. Swedish Meteorological and Hydrological Institute; Suecia Fil: Andersson, Agneta. Umeå Marine Sciences Centre; Suecia. Universidad de Umea; Suecia

Here, we review the rocky intertidal zone and shallowsubtidal of the Argentinian coast. We start by describing patterns ofdistribution of biodiversity before considering interactions among species thatshape these patterns. Nonnative and invasive species are then discussed and putinto the context of global change and other local impacts. We conclude byconsidering the special features of Argentinean rocky shores which are shapedby their environmental setting and phylogeographic history leading to low diversity,missing functional groups for some taxa and a gradient of increasing diversitytowards higher latitudes in the south. Fil: Palomo, Maria Gabriela. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; Argentina Fil: Bagur Creta, Maria. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; Argentina Fil: Callá, Sofía Luz. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; Argentina Fil: Dalton, María Cecilia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; Argentina Fil: Soria, Sabrina Andrea. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; Argentina

Common carp (Cyprinus carpio) is a global invader that exhibits a wide distribution in Argentina, particularly in shallow lakes and wetlands of the Pampean region. The hydrological conditions of these environments are driven by variations in annual precipitation that determine inter annual changes in water levels leading to flood-drought cycles. The present study focused on understanding the C. carpio population responses to annual rainfall regime and long-term flood and drought events in the Ajó wetlands located in the east of the Pampean region. The results of a two-year biological sampling program showed that C. carpio feeding rate, reproduction, condition, and recruitment were associated with the hydrological cycle. Otolith derived age structure of the population and back-calculated recruitment strength revealed that extraordinary flooding events generated strong cohorts while dry years resulted in low recruitment. Its long-life span (maximum 14 years in Ajó) coupled with a high fecundity, and broad diet allows C. carpio to persist in refugia during dry years and capitalize on wet years when inundation of the floodplain enhances recruitment and facilitates spread. Management and control strategies for this invader should therefore incorporate hydrological variability by promoting intensive removal campaigns during dry years when populations are dominated by large fish confined in remnant water-bodies and, during wet years, carp harvest fisheries should be promoted to reduce population density when increased connectivity is likely to facilitate spread., Facultad de Ciencias Naturales y Museo, Instituto de Limnología "Dr. Raúl A. Ringuelet"

Among those factors that determine the success of a fish cohort, trophic interactions play a key role, especially during the larval and juvenile stages. The Argentine hake Merluccius hubbsi is the most abundant demersal fish in the southwestern Atlantic and also one of the main commercial resources for Argentina. By employing C and N stable isotope analysis, we evaluated M. hubbsi changes in trophic niche and trophic position throughout their early life from early larvae to juveniles 2+ (8−330 mm total length, TL) during their drift from the spawning to the nursery ground. We analyzed 121 individuals and 7 possible resources in different sectors as fish move from the spawning to the nursery ground in the coastal region of northern Argentine Patagonia. Our results show that Argentine hakes occupy different trophic niches during their ontogenetic development. While larval stages (8−34 mm TL) feed almost exclusively on copepods, larger juveniles showed shrimps as their main prey. Individuals between 35 and 89 mm TL showed the most generalist diet, with a mix of both pelagic and epibenthic prey. Therefore, our results indicate that the change from a planktonic to a demersal habitat (settlement), which is of paramount importance in the early life history of hakes, is a gradual process. Fil: Botto, Florencia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentina Fil: Gaitán, Esteban Nicolás. Instituto Nacional de Investigaciones y Desarrollo Pesquero; Argentina Fil: Iribarne, Oscar Osvaldo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentina Fil: Acha, Eduardo Marcelo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentina

This work demonstrated a 10-day batch culture experiment to test the physiology and toxicity of harmful dinoflagellate Karenia mikimotoi in response to ocean acidification (OA) under two different phosphate concentrations. Cells were previously acclimated in OA (pH = 7.8 and CO2 = 1100 μatm) condition for about three months before testing the responses of K. mikimotoi cells to a two-factorial combinations experimentation. This work measured the variation in physiological parameters (growth, rETR) and toxicity (hemolytic activity and its toxicity to zebrafish embryos) in four treatments, representing two factorial combinations of CO2 (450 and 1100 μatm) and phosphate concentration (37.75 and 4.67 umol l−1). Results: OA stimulated the faster growth, and the highest rETRmax in high phosphate (HP) treatment, low phosphate (LP) and a combination of high CO2 and low phosphate (HC*LP) inhibited the growth and Ek in comparison to low CO2*high phosphate (LCHP) treatment. The embryotoxicity of K. mikimotoi cells enhanced in all high CO2 (HC) conditions irrespective of phosphate concentration, but the EC50 of hemolytic activity increased in all high CO2 (HC) and low phosphate (LP) treatments in comparison of LCHP. Ocean acidification (high CO2 and lower pH) was probably the main factor that affected the rETRmax, hemolytic activity and embryotoxicity, but low phosphate was the main factor that affected the growth, α, and Ek. There were significant interactive effects of OA and low phosphate (LP) on growth, rETRmax, and hemolytic activity, but there were no significant effects on α, Ek, and embryotoxicity. If these results are extrapolated to the aquatic environment, it can be hypothesized that the K. mikimotoi cells were impacted significantly by future changing ocean (e.g., ocean acidification and nutrient stoichiometry). Fil: Wang, Hong. Wenzhou Medical University; China. Xinyang Vocational And Technical College; China Fil: Niu, Xiaoqin. Wenzhou Medical University; China Fil: Feng, Xinqian. Wenzhou Medical University; China Fil: Gonçalves, Rodrigo Javier. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Centro para el Estudio de Sistemas Marinos; Argentina Fil: Guan, Wanchun. Wenzhou Medical University; China

Knowledge on the trophic ecology of elasmobranch species in all their size classes is important to determine complex trophic roles and relationships between members of the community, which ultimately promotes the development of more effective conservation measures. This study investigates the diet of young‐of‐the‐year from two shark and one skate species that are common within the Southwest Atlantic Ocean. Identification and analysis of stomach contents indicated that the broadnose sevengill shark Notorynchus cepedianus fed mostly on fishes (96.08%IRI), whereas the angular angel shark Squatina guggenheim, and the smallnose fanskate Sympterygia bonapartii preyed mainly on crustaceans (68.73–99.96%IRI). In particular, Artemesia longinaris, a widely distributed small shrimp, was an important prey item for the two crustacean feeders. The high proportion of stomachs with food and the trophic levels suggest that the three species are active predators at a very young age. A high frequency of neonates was also observed for all species, suggesting that parturition events are probably occurring nearby. Overall, this study suggest that the nearshore waters of northern Argentina are functioning as an important feeding ground for co‐occurring elasmobranch species within an important estuarine habitat. Fil: Milessi, Andres. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas; Argentina. Instituto Nacional de Investigaciones y Desarrollo Pesquero; Argentina Fil: de Wysiecki, Agustín María. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Jaureguizar, Andrés Javier. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Provincial del Sudoeste. Instituto Argentino de Oceanografía; Argentina. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas; Argentina

Una solución adecuada al problema que deben resolver muchos países con respecto al tratamiento y el vertido de aguas cloacales, y su potencial impacto sobre el ambiente, podría ser verterlas por medio de emisarios submarinos. Hasta diciembre de 2014, los residuos cloacales de Mar del Plata se vertían de forma directa a la zona intermareal, sin tratamiento previo. En el año 2009 se comenzó a construir el emisario submarino (ES); la obra se inició con la incorporación de dos escolleras de abrigo y un frente de atraque. El ES, inaugurado en diciembre del 2014, descarga las aguas residuales sobre el submareal (4 km mar adentro). El objetivo de este trabajo fue evaluar los cambios en la estructura de la comunidad bentónica intermareal durante las distintas fases del proceso de construcción del ES (Antes, Durante y Después). Se consideraron tres sitios de muestreo localizados a diferentes distancias del efluente cloacal. Los resultados mostraron cambios en la comunidad bentónica intermareal como respuesta a la puesta en funcionamiento del ES. La abundancia de las especies sensibles a la contaminación aumentó en la etapa posterior a la puesta en funcionamiento del ES. Si bien la riqueza de especies alcanzó su pico máximo durante la fase de construcción del ES, la equitatividad y la diversidad aumentaron en la etapa posterior. Se observaron agrupamientos según la similitud en la composición específica según el factor etapa (Antes). Sin embargo, no se observaron agrupamientos con respecto a los sitios. En conclusión, los resultados obtenidos mostraron los cambios ocurridos en la estructura comunitaria intermareal asociados al nuevo vertido de aguas residuales generado por el emisario submarino construido en la ciudad. An adequate solution to the problem many countries must solve with respect to the treatment and discharge of sewage water, and its potential impacts on the environment, could be discharging them by means of submarine outfalls. Until December 2014, wastewater from Mar del Plata city was discharged untreated directly to the intertidal zone. In 2009, the construction of the submarine outfall (SO) began; two breakwaters and a docking front were built. The SO was inaugurated in December 2014 and the wastewater discharges directly over the subtidal (4 km offshore). The aim of this study was to evaluate the changes in the structure of the intertidal benthic community during the different phases of the SO construction [Before (A), During (Du) and After (De)]. Three sampling sites were located at different distances from the sewage effluent. The results showed changes in the intertidal benthic community in response to the functioning of the SO. The abundance of species sensitive to pollution increased in the posterior phase of the SO construction. Although the species richness peaked during the construction phase of the ES, evenness and diversity index increased in the subsequent phase (After). Groupings were observed according to the similarity in the specific composition according to the phase factor (Before, During and After). However, grouping of species according to the sites were not observed. In conclusion, the results obtained showed the changes occurred in the intertidal community structure associated with the new wastewater discharge generated by the submarine outfall built in the city.

An understanding of the mechanisms that shape animal-population dynamics is a fundamental consideration in conservation biology and ecology. Populations of the species of South-American sea lions (SASLs) Otaria flavescens reveal different growth rates, which variations could be linked to changes in the accessibility of nutritional resources in any given location. The available information on differences in the SASL diet on a local scale, however, is relatively scarce. We therefore searched for evidence of geographical variations in the diet of the SASLs in Northern Patagonia—namely, in the Golfo San Matías (GSM) and the Golfo Nuevo (GN), both of which bays are quite different regarding their physiography, oceanography, and anthropic pressures. From 2005–2013, stomach samples ( nGSM = 39; nGN = 31) were collected from animals found dead on the coast or accidentally caught in fishing nets. The dietary composition differed between the two gulfs with respect to the most common species, the zoological groups, and the sizes of the primary prey. In the GSM, the SASLs fed on demersal–pelagic fish, while in the GN the diet exhibited a high contribution of benthic species. Differences in the items and sizes of prey consumed at each area are discussed in terms of differential prey availability along with the opportunistic feeding behavior of this predator. These differences, in addition to the species’s main prey as targets for major fisheries, must be taken into account in order to understand the different population dynamics of this apex predator and thus ensure its conservation. Fil: Jarma, Dayana Ayelen. Universidad Nacional del Comahue. Centro de Investigación Aplicada y Transferencia Tecnológica en Recursos Marinos "Almirante Storni". - Provincia de Río Negro. Ministerio de Agricultura, Ganadería y Pesca. Centro de Investigación Aplicada y Transferencia Tecnológica en Recursos Marinos "Almirante Storni". Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet Centro Nacional Patagónico. Centro de Investigación Aplicada y Transferencia Tecnológica en Recursos Marinos "Almirante Storni"; Argentina Fil: Romero, Maria Alejandra. Universidad Nacional del Comahue; Argentina. Universidad Nacional del Comahue. Centro de Investigación Aplicada y Transferencia Tecnológica en Recursos Marinos "Almirante Storni". - Provincia de Río Negro. Ministerio de Agricultura, Ganadería y Pesca. Centro de Investigación Aplicada y Transferencia Tecnológica en Recursos Marinos "Almirante Storni". Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet Centro Nacional Patagónico. Centro de Investigación Aplicada y Transferencia Tecnológica en Recursos Marinos "Almirante Storni"; Argentina Fil: García, Néstor A.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Centro para el Estudio de Sistemas Marinos; Argentina Fil: Svendsen, Guillermo. Universidad Nacional del Comahue; Argentina. Universidad Nacional del Comahue. Centro de Investigación Aplicada y Transferencia Tecnológica en Recursos Marinos "Almirante Storni". - Provincia de Río Negro. Ministerio de Agricultura, Ganadería y Pesca. Centro de Investigación Aplicada y Transferencia Tecnológica en Recursos Marinos "Almirante Storni". Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet Centro Nacional Patagónico. Centro de Investigación Aplicada y Transferencia Tecnológica en Recursos Marinos "Almirante Storni"; Argentina Fil: González, Raul Alberto Candido. Universidad Nacional del Comahue; Argentina. Universidad Nacional del Comahue. Centro de Investigación Aplicada y Transferencia Tecnológica en Recursos Marinos "Almirante Storni". - Provincia de Río Negro. Ministerio de Agricultura, Ganadería y Pesca. Centro de Investigación Aplicada y Transferencia Tecnológica en Recursos Marinos "Almirante Storni". Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet Centro Nacional Patagónico. Centro de Investigación Aplicada y Transferencia Tecnológica en Recursos Marinos "Almirante Storni"; Argentina Fil: Dans, Silvana Laura. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Centro para el Estudio de Sistemas Marinos; Argentina. Universidad Nacional de la Patagonia "San Juan Bosco"; Argentina Fil: Crespo, Enrique Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Centro para el Estudio de Sistemas Marinos; Argentina. Universidad Nacional de la Patagonia "San Juan Bosco"; Argentina

The global expansion of aquaculture is a constant propagule pressure that enables the establishment of exotic species in freshwater and marine environments. Here, we provide the first report on the presence of exotic coho salmon (Oncorhynchus kisutch) at the extreme south of Patagonia, in the island of Tierra del Fuego (TDF). During the last 6 years, 43 juvenile coho salmon were captured along the Beagle Channel, while one adult was captured in fresh water. Scale analysis showed that migration from fresh water as smolt would occur during their first winter of life. Mitochondrial DNA analyses revealed two haplotypes previously reported in North America and a new haplotype not reported before. We developed an environmental DNA assay for detecting coho salmon DNA from fresh water, obtaining positive results in three rivers. Additionally, one of these rivers was monitored monthly for a year, and we detected coho salmon DNA over 7 months, revealing the probable occurrence of coho salmon juveniles in fresh water. These results suggest the potential establishment of self-sustaining populations of coho salmon in TDF. Fil: Chalde, Tomás. Universidad Nacional de Tierra del Fuego; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; Argentina Fil: Nardi, Cristina Fernanda. Universidad Nacional de Tierra del Fuego, Antártida e Islas del Atlántico Sur. Instituto de Ciencias Polares, Ambientales y Recursos Naturales; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Fernandez, Daniel Alfredo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; Argentina. Universidad Nacional de Tierra del Fuego, Antártida e Islas del Atlántico Sur. Instituto de Ciencias Polares, Ambientales y Recursos Naturales; Argentina

Productivity and trophic structure of aquatic ecosystems result from a complex interplay of19 bottom-up and top-down forces that operate across benthic and pelagic food web compartments.20 Projected global changes urge the question how this interplay will be affected by browning21 (increasing input of terrestrial dissolved organic matter), nutrient enrichment and warming. We22 explored this with a process-based model of a shallow lake food web consisting of benthic and23 pelagic components (abiotic resources, primary producers, grazers, carnivores), and compared24 model expectations with the results of a browning and warming experiment in nutrient-poor25 ponds harboring a boreal lake community. Under low nutrient conditions, the model makes three26 major predictions. (1) Browning reduces light and increases nutrient supply; this decreases27 benthic and increases pelagic production, gradually shifting productivity from the benthic to the28 pelagic habitat. (2) Because of active habitat choice, fish exert top-down control on grazers and29 benefit primary producers primarily in the more productive of the two habitats. (3) Warming30 relaxes top-down control of grazers by fish and decreases primary producer biomass, but effects31 of warming are generally small compared to effects of browning and nutrient supply.32 Experimental results were consistent with most model predictions for browning: light penetration,33 benthic algal production, and zoobenthos biomass decreased, and pelagic nutrients and pelagic34 algal production increased with browning. Also consistent with expectations, warming had35 negative effects on benthic and pelagic algal biomass and weak effects on algal production and36 zoobenthos and zooplankton biomass. Inconsistent with expectations, browning had no effect on37 zooplankton and warming effects on fish depended on browning. The model is applicable also to38 nutrient-rich systems, and we propose that it is a useful tool for the exploration of the39 consequences of different climate change scenarios for productivity and food web dynamics in40 shallow lakes, the worldwide most common lake type. Fil: Rivera Vasconcelos, Francisco. Umea University. Department of Ecology and Environmental Science; Suecia Fil: Diehl, Sebastian. Umea University. Department of Ecology and Environmental Science; Suecia Fil: Rodriguez, Patricia Laura. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; Argentina Fil: Hedström, Per. Umea University. Department of Ecology and Environmental Science; Suecia Fil: Karlsson, Jan. Umea University. Department of Ecology and Environmental Science; Suecia Fil: Byström, Pär. Umea University. Department of Ecology and Environmental Science; Suecia

Changes in the abundance of some species in the San Matías Gulf (north Patagonia, Argentina) have been observed in recent years; in particular increases in crustaceans populations that could be influencing the trophic relationships and food web structure. The Argentine hake Merluccius hubbsi has been the main demersal resource that supports a fishery since 1971. Given that M. hubbsi is a generalist and opportunistic predator, its diet from the perspective of specific composition and feeding strategy was evaluated. Fourteen species were identified belonging to four zoological groups (3 fishes, 4 molluscs, 6 crustaceans and 1 bryozoan). The most commonly consumed prey was the lobster krill Munida gregaria (index of relative importance -%IRI- 72.19%) followed by the white shrimp Peisos petrunkevitchi (%IRI 19.04%) and M. hubbsi (%IRI 7.95%). Most prey were infrequently consumed and at low abundances, which it is common for a generalist-opportunistic predator. Substantial changes in the diet composition were detected when compared to a previous study, showing a large increase in crustacean occurrence in concordance with the abundance changes observed in the environment. The results from this study highlighted the importance to consider information about population trends and trophic relationships to better understand the dynamics of marine communities under exploitation. Fil: Alonso, Rosana B.. Universidad Nacional del Comahue. Escuela de Ciencias Marinas; Argentina Fil: Romero, Maria Alejandra. Universidad Nacional del Comahue. Escuela de Ciencias Marinas; Argentina. Universidad Nacional del Comahue. Centro de Investigación Aplicada y Transferencia Tecnológica en Recursos Marinos "Almirante Storni". - Provincia de Río Negro. Ministerio de Agricultura, Ganadería y Pesca. Centro de Investigación Aplicada y Transferencia Tecnológica en Recursos Marinos "Almirante Storni". Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet Centro Nacional Patagónico. Centro de Investigación Aplicada y Transferencia Tecnológica en Recursos Marinos "Almirante Storni"; Argentina Fil: Ocampo Reinaldo, Matías. Universidad Nacional del Comahue. Escuela de Ciencias Marinas; Argentina. Universidad Nacional del Comahue. Centro de Investigación Aplicada y Transferencia Tecnológica en Recursos Marinos "Almirante Storni". - Provincia de Río Negro. Ministerio de Agricultura, Ganadería y Pesca. Centro de Investigación Aplicada y Transferencia Tecnológica en Recursos Marinos "Almirante Storni". Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet Centro Nacional Patagónico. Centro de Investigación Aplicada y Transferencia Tecnológica en Recursos Marinos "Almirante Storni"; Argentina Fil: Bustelo, Pablo E.. Universidad Nacional del Comahue. Escuela de Ciencias Marinas; Argentina Fil: Medina, Alonso I.. Universidad Nacional del Comahue. Escuela de Ciencias Marinas; Argentina Fil: Gonzalez, Raúl. Universidad Nacional del Comahue. Escuela de Ciencias Marinas; Argentina. Universidad Nacional del Comahue. Centro de Investigación Aplicada y Transferencia Tecnológica en Recursos Marinos "Almirante Storni". - Provincia de Río Negro. Ministerio de Agricultura, Ganadería y Pesca. Centro de Investigación Aplicada y Transferencia Tecnológica en Recursos Marinos "Almirante Storni". Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet Centro Nacional Patagónico. Centro de Investigación Aplicada y Transferencia Tecnológica en Recursos Marinos "Almirante Storni"; Argentina

Euphausiid larvae were collected in the Weddell Scotia Confluence region in summer 2011, in the West Antarctic Peninsula and Scotia Sea in 2012, and in the South Orkneys Shelf in 2014. From 2011 to 2014 the larval stages geographic distribution and the distribution of water masses were consistent with published information. The densities observed were compared between the cruises and with the 1981 and 1995 values by means of a kernel estimate of absolute and relative densities at a fixed grid of points. The values of Thysanoessa macrura were higher in 2011 and 2012 and those of Euphausia superba were lower than those observed in 1981 and 1995. Euphausia frigida did not show significant variations in absolute density but their relative values were higher than those of E. superba. No significant variations were observed in absolute values between 1981 and 1995. The opposite pattern was found in 2014, with significantly higher densities of E. superba than those of T. macrura. No single factor could be identified to explain these variations in density, suggesting the existence of complex mechanisms coupling the reproductive biology with oceanographic phenomena. Their description will require ample spatial and temporal monitoring rather than locally detailed observations. Fil: Rombola, Emilce Florencia. Ministerio de Relaciones Exteriores, Comercio Interno y Culto. Dirección Nacional del Antártico. Instituto Antártico Argentino; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Franzosi, Claudio Atilio. Ministerio de Relaciones Exteriores, Comercio Interno y Culto. Dirección Nacional del Antártico. Instituto Antártico Argentino; Argentina Fil: Tosonotto, Gabriela Viviana. Ministerio de Relaciones Exteriores, Comercio Interno y Culto. Dirección Nacional del Antártico. Instituto Antártico Argentino; Argentina Fil: Alder, Viviana Andrea. Ministerio de Relaciones Exteriores, Comercio Interno y Culto. Dirección Nacional del Antártico. Instituto Antártico Argentino; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Ecología, Genética y Evolución de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Ecología, Genética y Evolución de Buenos Aires; Argentina Fil: Marschoff, Enrique Ricardo. Ministerio de Relaciones Exteriores, Comercio Interno y Culto. Dirección Nacional del Antártico. Instituto Antártico Argentino; Argentina

The solubility equilibrium of calcite is influenced by physicochemical, climatic and biological factors. Annual cycles of exceptionally prolonged drought, in conjunction with naturally occurring diffuse organic pollution, generate the unique conditions for the precipitation of lithified carbonate structures (microbialites). The aim of this article is to analyze the possible implications of calcite precipitation produced in mats of Cladophora sp. in an Andean subtropical basin, considering it is the first time this phenomenon is described for the region. We collected samples from selected sites at the Lules River Basin, in four sampling dates between the years 2003 and 2004, within a monitoring work of 15 years. Samples were analyzed using an electron microscope and X-ray diffraction analysis. We found that Gomphonema sp. attached to Cladophora sp. contributes to precipitation of calcite and formation of microbialite like structures, in the studied area. This work presents an initial discussion of the discovery of microbialites-like structures attached to Cladophora sp. mats in a subtropical Andean stream and the environmental conditions that lead to their production, as well as the possible ecological implications of these microbialites. Resumen La fase sólida de las sales de los cuerpos de agua juega un papel importante en la concentración de los elementos mayoritarios. El equilibrio de solubilidad de la calcita está influenciado por factores fisicoquímicos, climáticos y biológicos. Los ciclos anuales de sequía excepcionalmente prolongada, junto con la contaminación orgánica difusa de origen natural, generan condiciones únicas para la precipitación de estructuras de carbonato litificado (microbialitos). El objetivo de este artículo es analizar las posibles implicaciones de la precipitación de calcita producida en Cladophora sp. en una cuenca subtropical andina, considerando que es la primera vez que se describe este fenómeno para la región. Recolectamos muestras en sitios seleccionados en la Cuenca del Río Lules, en cuatro fechas de muestreo entre 2003 y 2004, en el marco de un trabajo de monitoreo de quince años. Usamos red Surber para realizar los muestreos. Las muestras de algas, una vez libres de macroinvertebrados, se secaron y pesaron. Analizamos utilizando microscopía electrónica y difracción de rayos X. Encontramos que Gomphonema sp. unido a Cladophora contribuye a la precipitación de calcita y la formación de estructuras similares a microbialitos, en el área estudiada. Este trabajo presenta una discusión inicial sobre el descubrimiento de estructuras similares a microbialitos unidas a filamentos de Cladophora sp. en una cuenca andina subtropical y las condiciones ambientales que conducen a su producción, así como las posibles implicaciones ecológicas de lo mencionado anteriormente.

Mixotrophy by planktonic algae can dominate picoplankton predation in oligotrophic environments. We compared the grazing activity and prey preference of different mixotrophic taxa from natural communities of two oligotrophic shallow lakes (Escondido and Morenito) by performing eight laboratory grazing experiments using three different fluorescent prey (bacteria, picocyanobacteria, and picoeukaryotic algae). Eight taxa of mixotrophic flagellates (MF) corresponding to five different Classes, and two size categories of heterotrophic flagellates were distinguished. Chesson index showed that the ten identified protists preferred picocyanobacteria than bacteria, while picoeukaryotic algae were not ingested by any flagellate. In both lakes, MFs were responsible for ca. 80% of the picoplankton ingestion due to flagellates, and more than 50% of the total grazing impact when considering all flagellates, ciliates, and rotifers. Pseudopedinella spp. (Dictyochophyceae), Chrysochromulina parva (Haptophyceae), and Dinobryon divergens (Chrysophyceae) were the most important predators, while Plagioselmis lacustris (Cryptophyceae) and Chrysophyceae > 5 µm showed the lowest grazing rates. Overall, our findings support the idea of MF being the main picoplankton predators in oligotrophic systems. Besides, we also conclude that herbivory represents a key process in the mixotrophic carbon cycling in oligotrophic environments. Fil: Gerea, Marina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. 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; Argentina Fil: Queimaliños, Claudia Patricia. 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; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Unrein, Fernando. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Biotecnológicas. Universidad Nacional de San Martín. Instituto de Investigaciones Biotecnológicas; Argentina

This study aimed to describe the composition of mollusk assemblages in subtropical Brazilian mangroves with different levels of urbanization in their watersheds. Mangroves are important ecosystems, which are vanishing worldwide due to human impacts. The knowledge about the consequences of human pressure on the fauna of these ecosystems is still incipient. In addition, although Brazil is the country with the second largest mangrove area, there is a lack of studies on the mangrove fauna in this country. Mollusks are the second most abundant group of mangrove invertebrates and can be useful indicators of mangrove health. For this reason, mollusk species were assessed in two mangroves surrounded by a dense human population and in two mangroves away from urban centers. A total of 3820 individuals, representing 15 species, were sampled. The results revealed that the mollusk abundance, diversity estimators, and sediment organic matter content were not good indicators of the effects of urbanization on the mangroves studied. However, the species composition of mollusk assemblages differed according to the urbanization level. This survey of the mangrove malacofauna represents another step toward the effort to investigate and conserve the fauna of these important estuarine environments., Instituto de Limnología "Dr. Raúl A. Ringuelet"

Few studies have intensively assessed the dynamic of all planktonic components and their microbial communities in hypertrophic shallow lakes. The aim of this work was to study the potential drivers shaping the microbial food-web components (heterotrophic bacteria and strictly phototrophic microplankton). Thus, we studied the monthly abundances and functional groups of the different planktonic food-web components (heterotrophic bacteria, picocyanobacteria, picoeukariotes, heterotrophic flagellates, ciliates, phytoplankton, zooplankton) in two interconnected and hypertrophic Pampean shallow lakes (Gómez and Carpincho) during dry-wet periods (27-month study). We hypothesized that temporal (intra and inter-annual) factors exert a major role in shaping the microbial food-web components in both lakes. Both shallow lakes showed similar dynamic in the environmental variables, that followed inter-annual and seasonal variations. In Gómez, the variation of microbial components was mainly explained by a combination of environmental, predation and temporal factors (38.2%), whereas in Carpincho by pure temporal drivers (31.8%). Microbial and predator components were significantly different between dry-wet periods. The connection and closeness between both lakes seem not to play a major role in the factors driving the microbial component abundances. These lakes are strongly influenced by temporal factors, which regulate not only the microbial components, but also the physical, chemical and biological variables. Fil: Schiaffino, María Romina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro de Investigaciones y Transferencia del Noroeste de la Provincia de Buenos Aires. Universidad Nacional del Noroeste de la Provincia de Buenos Aires. Centro de Investigaciones y Transferencia del Noroeste de la Provincia de Buenos Aires; Argentina Fil: Diovisalvi, Nadia Rosalia. Universidad Nacional de San Martin. Instituto Tecnologico de Chascomus. - Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Conicet - la Plata. Instituto Tecnologico de Chascomus.; Argentina Fil: Marfetán Molina, Diego. Universidad Nacional de Rosario; Argentina Fil: Fermani, Paulina. Universidad Nacional de San Martin. Instituto Tecnologico de Chascomus. - Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Conicet - la Plata. Instituto Tecnologico de Chascomus.; Argentina Fil: Li Puma, C.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro de Investigaciones y Transferencia del Noroeste de la Provincia de Buenos Aires. Universidad Nacional del Noroeste de la Provincia de Buenos Aires. Centro de Investigaciones y Transferencia del Noroeste de la Provincia de Buenos Aires; Argentina Fil: Lagomarsino, Leonardo. Universidad Nacional de San Martin. Instituto Tecnologico de Chascomus. - Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Conicet - la Plata. Instituto Tecnologico de Chascomus.; Argentina Fil: Quiroga, María Victoria. Universidad Nacional de San Martin. Instituto Tecnologico de Chascomus. - Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Conicet - la Plata. Instituto Tecnologico de Chascomus.; Argentina Fil: Pérez, G.L.. 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; Argentina

Glaciers along the western Antarctic Peninsula are retreating at unprecedented rates, opening up sublittoral rocky substrate for colonization by marine organisms such as macroalgae. When macroalgae are physically detached due to storms or erosion, their fragments can accumulate in seabed hollows, where they can be grazed upon by herbivores or be degraded microbially or be sequestered. To understand the fate of the increasing amount of macroalgal detritus in Antarctic shallow subtidal sediments, amesocosm experiment was conducted to track 13C- and 15N-labeledmacroalgal detritus into the benthic bacterial, meiofaunal, and macrofaunal biomass and respiration of sediments from Potter Cove (King George Island).We compared the degradation pathways of two macroalgae species: one considered palatable for herbivores (the red algae Palmaria decipiens) and other considered nonpalatable for herbivores (the brown algae Desmarestia anceps). The carbon from Palmaria was recycled at a higher rate than that of Desmarestia, with herbivores such as amphipods playing a stronger role in the early degradation process of the Palmaria fragments and the microbial community taking over at a later stage. In contrast, Desmarestia was more buried in the subsurface sediments, stimulating subsurface bacterial degradation. Macrofauna probably relied indirectly on Desmarestia carbon, recycledby bacteria and microphytobenthos. The efficient cycling of the nutrients and carbon from the macroalgae supports a positive feedback loop among bacteria, microphytobenthos, and meiofaunal and macrofaunal grazers, resulting in longer term retention ofmacroalgal nutrients in the sediment, hence creating a food bank for the benthos. Fil: Braeckman, U.. University of Ghent; Bélgica Fil: Pasotti, F.. University of Ghent; Bélgica Fil: Vázquez, Susana Claudia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Nanobiotecnología. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Instituto de Nanobiotecnología; Argentina Fil: Zacher, K.. Alfred Wegener Institute; Alemania Fil: Hoffmann, R.. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Nanobiotecnología. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Instituto de Nanobiotecnología; Argentina Fil: Elvert, M.. Alfred Wegener Institute; Alemania Fil: Marchant, H.. Max Planck Institute for Marine Microbiology; Alemania Fil: Buckner, C.. Max Planck Institute for Marine Microbiology; Alemania Fil: Quartino, M. L.. Ministerio de Relaciones Exteriores, Comercio Interno y Culto. Dirección Nacional del Antártico. Instituto Antártico Argentino; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; Argentina Fil: Mac Cormack, Walter Patricio. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Nanobiotecnología. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Instituto de Nanobiotecnología; Argentina Fil: Soetaert, K.. Ministerio de Relaciones Exteriores, Comercio Interno y Culto. Dirección Nacional del Antártico. Instituto Antártico Argentino; Argentina Fil: Wenzhöfer, F.. Utrecht University; Países Bajos Fil: Vanreusel, A.. University of Ghent; Bélgica

17 pages, 5 figures, 3 tables, supplemental material https://doi.org/10.1128/AEM.02659-18.-- Data availability.All sequences generated in this study can be accessed through European Nucleotide Archive (ENA) under the study accession number PRJEB27291 and accession numbers ERR2639355 to ERR2639364, High-throughput sequencing (HTS) of the 16S rRNA gene has been used successfully to describe the structure and dynamics of microbial communities. Picocyanobacteria are important members of bacterioplankton communities, and, so far, they have predominantly been targeted using universal bacterial primers, providing a limited resolution of the picocyanobacterial community structure and dynamics. To increase such resolution, the study of a particular target group is best approached with the use of specific primers. Here, we aimed to design and evaluate specific primers for aquatic picocyanobacterial genera to be used with high-throughput sequencing. Since the various regions of the 16S rRNA gene have different degrees of conservation in different bacterial groups, we therefore first determined which hypervariable region of the 16S rRNA gene provides the highest taxonomic and phylogenetic resolution for the genera Synechococcus, Prochlorococcus, and Cyanobium. An in silico analysis showed that the V5, V6, and V7 hypervariable regions appear to be the most informative for this group. We then designed primers flanking these hypervariable regions and tested them in natural marine and freshwater communities. We successfully detected that most (97%) of the obtained reads could be assigned to picocyanobacterial genera. We defined operational taxonomic units as exact sequence variants (zero-radius operational taxonomic units [zOTUs]), which allowed us to detect higher genetic diversity and infer ecologically relevant information about picocyanobacterial community composition and dynamics in different aquatic systems. Our results open the door to future studies investigating picocyanobacterial diversity in aquatic systems, This study was supported by the Argentinean Network for the Assessment and Monitoring of Pampean Shallow Lakes (PAMPA2–CONICET), the ANPCyT (PICT-2014-1290 and PICT-2016-1079), and by MAGGY (grant CTM2017-87736-R) to S. G. Acinas and REMEI (grant CTM2015-70340-R) to J. M. Gasol from the Spanish Ministry of Economy and Competitiveness (MINECO)

The diversity of ascidians from the Southwestern Atlantic between 30°S and 40°S (southern Brazil, Uruguay and northern Argentina) remains as one of the poorest known of the West Atlantic. The objective of this work is to compile, analyze and discuss all published records of ascidians from Uruguay. They show the historical relevance of the studies performed by Herdman, Monniot F. and Monniot C. on ascidians collected at deep-sea stations by the HMS Challenger and the RV Atlantis II in the Argentine Basin. Total literature records include 38 ascidian species which are enumerated here for the first time. On the basis of the current knowledge, the ascidian fauna of Uruguayan waters encompasses: a) shallow-water species with temperate distribution (3 spp.); b) shelf and deep-sea species with Antarctic and Sub-Antarctic distribution (13 spp.); c) deep-sea species until now only collected off Río de La Plata (11 spp.); d) deep-sea species displaying a wide distribution (11 spp.). Only nine species have been recorded for the continental shelf; the remaining species were collected either from the slope (21) or the abyssal plain (5) or both deep-sea zones (3). Future research should be directed to record coastline and shelf species, assess the presence of exotic elements, and re-describe enigmatic species first described by Herdman (1882, 1886). Fil: Fabrizio Scarabino. Centro Universitario Regional del Este - CURE, Universidad de la República y Museo Nacional de Historia Natural, Montevideo, ; Uruguay Fil: Maggioni, Tamara. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Diversidad y Ecología Animal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto de Diversidad y Ecología Animal; Argentina Fil: Taverna, Anabela Jesús. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Diversidad y Ecología Animal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto de Diversidad y Ecología Animal; Argentina Fil: Lagger, Cristian Fabian. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Instituto de Diversidad y Evolución Austral; Argentina Fil: Schwindt, Evangelina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Instituto de Biología de Organismos Marinos; Argentina Fil: Guzmán López. Dirección Nacional de Recursos Acuáticos, Montevideo; Uruguay Fil: Leonardo Ortega. Dirección Nacional de Recursos Acuáticos, Montevideo; Uruguay Fil: Felipe García-Rodríguez. Centro Universitario Regional del Este -CURE, Universidad de la República, Montevideo ; Uruguay Fil: Tatian, Marcos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Diversidad y Ecología Animal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto de Diversidad y Ecología Animal; Argentina

As bryozoans have a rich fossil record, the analysis of their bathymetric ranges and the occurrence of different colonial growth-forms in living assemblages may be valuable for palaeoecological interpretation. The bryozoan fauna from 58 benthic stations (18–92 m) collected on the Atlantic continental shelf off Tierra del Fuego (Southwest Atlantic) was analyzed to assess its biodiversity and the relationship of species richness and colonial growth-forms with depth. In the 58 stations analyzed here, which covered an area of ∼5600 km2, 90 species were found. Of these, 43 species were already known for this area, whereas the remaining 47 are new records. Therefore, the present study increases by 87% the known biodiversity for the study area, which now reaches 101 species. There is a clear increase in bryozoan species richness with depth, but the ratio of erect-rigid/encrusting species remained unchanged, as all the growth-forms increased with depth. Stations were classified by cluster analysis in three groups differing mainly in species richness. Taxonomic turnover (beta diversity) increased with increasing differences in depth between stations. This was due to the presence of a new set of deeper species, but not to the demise of the shallower fauna in the deeper stations. Twenty-two potentially habitat-forming species were found along the bathymetric range surveyed in this study. They were absent at the shallowest station, its number was relatively low at intermediate depths (31–64 m) and then experienced a sharp increase at 70 m. Palaeoecological interpretations should take into account that fragile, calcareous growth-forms could be expected to occur at shallower depths in more protected areas. Fil: Liuzzi, Maria Gabriela. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales “Bernardino Rivadavia”; Argentina Fil: López Gappa, Juan José. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales “Bernardino Rivadavia”; Argentina Fil: Salgado, Lucía. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales “Bernardino Rivadavia”; Argentina

Although the perils of plastics to living organisms including humans have been neglected for decades, they have recently been recognized as a major environmental problem worldwide. Little progress has been made on understanding the factors that drive species´ and populations´ susceptibilities to the ingestion of plastic. Here, we propose using nutritional ecology as a multidisciplinary framework for bridging the gaps that link nutrition, behavior, plastics, physiology and ecology. We show that nutritional niches are tightly linked to plastic ingestion, illustrating the application of our framework in the context of nutritional niche theory, habitat-specific foraging from species to populations, and transfer patterns in food webs. Fil: Machovsky-capuska, Gabriel. University of Sydney; Australia Fil: Amiot, Christophe. Université d’Angers; Francia Fil: Denuncio, Pablo Ezequiel. Universidad Nacional de Mar del Plata; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentina Fil: Grainger, Richard. University of Sydney; Australia Fil: Raubenheimer, David. University of Sydney; Australia

Salinity is one of the most important structuring factors in the distribution and bioenergetics of estuarine fishes. The aims of this work were to study the distribution of the sub-Antarctic, eurythermic, euryhaline and coastal notothenioid Eleginops maclovinus in Lapataia estuary (Tierra del Fuego National Park), in relation to salinity conditions, and the effect of salinity on the oxygen con- sumption of this species. The spread of the mixing zone of Lapataia was studied and physicochemical properties (conductivity, pH, temperature and salinity) were mea- sured. Distribution of E. maclovinus juveniles was inves- tigated principally by electrofishing in the field. Oxygen consumption of absorptive and post-absorptive young-of- the-year individuals (8?10 cm total length) was analyzed by stop-flow respirometry measurements, performed at three salinities (1, 12 and 30 psu). The intermediate mixing zone is relatively small in this system, showing an exten- sion of *1.5 km upstream from Lapataia Bay. It was found that there was a strong relationship between the mixing zone and the distribution of juveniles of E. maclovinus. No differences were found in the metabolic baseline at different salinities. A punctual feeding provoked a typical SDA response, with a significant higher ingested food and metabolic scope at intermediate salinity (12 psu). An increased scope was reached by increasing the energy intake and not through a decrease in the standard metabolic rate. Under an available food condition, this capacity could result in an increased growth rate at inter- mediate salinity. Fil: Vanella, Fabián Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; Argentina Fil: Duarte, Claudia Alejandra. Universidad Nacional de Tierra del Fuego. Instituto de Ciencias Polares, Recursos Naturales y Ambiente; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Lattuca, María Eugenia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; Argentina Fil: Fernandez, Daniel Alfredo. Universidad Nacional de Tierra del Fuego. Instituto de Ciencias Polares, Recursos Naturales y Ambiente; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; Argentina Fil: Boy, Claudia Clementina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; Argentina

Losses of king crabs (deaths) in massive rearing conditions are frequently attributed to cannibalism. As several factors could influence cannibalism intensity during culture, the aim of the present study was to determine the effect of molt condition, stage and density on cannibalism among Lithodes santolla juveniles. Comparisons between intermolt and molt conditions and between C1 and C2 stages during intermolt were performed at three densities (6, 12 and 18 individuals per flask; that is equivalent to 236, 472 and 708 individuals m−2). After 16 days of juvenile coexistence, cannibalism (injured + dead) was higher during molting (33.9 ± 4.5 %) than intermolt (21.7 ± 3.9 %), even though only 36 % of crabs had molted. Although cannibalism was similar in C1 and C2 stages, the proportion of dead animals was higher by a factor of three in C1 stage, probably due to the fact that animals reach the first juvenile stage with low energetic reserves, after the lecithotrophic larval development. Density was the main factor influencing cannibalism in our experiments. Higher densities promoted higher deaths, while agonistic interactions evidenced by injured crabs remained constant. Walking appendages were lost more often than chelipeds during first agonistic encounters. We recommend the use of intermediate densities (450 crabs m−2 at most), the early detection of exuviae and the sorting of crabs after molting, for L. santolla rearing. Fil: Sotelano, María Paula. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; Argentina Fil: Lovrich, Gustavo Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; Argentina Fil: Tapella, Federico. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; Argentina

Volcanic eruptions discharge massive amounts of ash and pumice that decrease light penetration in lakes and lead to concomitant increases in phosphorus (P) concentrations and shifts in soluble C/P ratios. The consequences of these sudden changes for bacteria community composition, metabolism, and enzymatic activity remain unclear, especially for the dynamic period immediately after pumice deposition. Thus, the main aim of our study was to determine how ambient bacterial communities respond to pumice inputs in lakes that differ in dissolved organic carbon (DOC) and P concentrations and to what extent these responses are moderated by substrate C/P stoichiometry. We performed an outdoor experiment with natural lake water from two lakes that differed in dissolved organic carbon (DOC) concentration. We measured nutrient concentrations, alkaline phosphatase activity (APA), and DOC consumption rates and assessed different components of bacterial community structure using next-generation sequencing of the 16S rRNA gene. Pumice inputs caused a decrease in the C/P ratio of dissolved resources, a decrease in APA, and an increase in DOC consumption, indicating reduced P limitation. These changes in bacteria metabolism were coupled with modifications in the assemblage composition and an increase in diversity, with increases in bacterial taxa associated with biofilm and sediments, in predatory bacteria, and in bacteria with gliding motility. Our results confirm that volcanic eruptions have the potential to alter nutrient partitioning and light penetration in receiving waterways which can have dramatic impacts on microbial community dynamics. Fil: Modenutti, Beatriz Estela. Universidad Nacional del Comahue. Centro Regional Universitario Bariloche. Laboratorio de Limnologia; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Patagonia Norte. Instituto de Investigación en Biodiversidad y Medioambiente; Argentina Fil: Balseiro, Esteban Gabriel. Universidad Nacional del Comahue. Centro Regional Universitario Bariloche. Laboratorio de Limnologia; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Patagonia Norte. Instituto de Investigación en Biodiversidad y Medioambiente; Argentina Fil: Bastidas Navarro, Marcela Alejandra. Universidad Nacional del Comahue. Centro Regional Universitario Bariloche. Laboratorio de Limnologia; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Patagonia Norte. Instituto de Investigación en Biodiversidad y Medioambiente; Argentina Fil: Lee, Z. M.. Arizona State University; Estados Unidos Fil: Souza, María Sol. Universidad Nacional del Comahue. Centro Regional Universitario Bariloche. Laboratorio de Limnologia; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Patagonia Norte. Instituto de Investigación en Biodiversidad y Medioambiente; Argentina Fil: Corman, J. R.. Arizona State University; Estados Unidos Fil: Elser, J. J.. Arizona State University; Estados Unidos. University Of Wisconsin; Estados Unidos

Mollusk shells can provide important information regarding environmental parameters. It is known that shell morphology is affected by both natural and anthropogenic factors. However, few studies have investigated alterations in shell morphology over a historical perspective and considering chemical contamination and climate changes. The present study assessed shell form (shape and size) variations of limpet (Lottia subrugosa) shells sampled from 1950 to 1981 (past) in comparison with organisms obtained in 2018 (present). Differences between shells from the past and present (2018) were detected, being shell weight and height the two most important affected parameters. The differences observed were attributed to the possible increase in contamination over the years due to human population growth and to climate change. Additionally, when shells from the past were evaluated according to the decade they were sampled, results indicate that it was necessary an interval of 40 years to shell form be altered within populations. Fil: Harayashiki, Cyntia Ayumi Yokota. Universidade Federal de São Paulo; Brasil Fil: Martins, Camila Pratalli. Universidade Federal de São Paulo; Brasil Fil: Márquez, Federico. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Instituto de Biología de Organismos Marinos; Argentina. Universidad Nacional de la Patagonia "San Juan Bosco"; Argentina Fil: Bigatti, Gregorio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Instituto de Biología de Organismos Marinos; Argentina. Universidad Espíritu Santo; Ecuador Fil: Castro, Ítalo Braga. Universidade Federal de São Paulo; Brasil