Field observations on rare or overlooked dinoflagellates from the Argentine Sea

Background and aims: Planktonic dinoflagellates have a great ecological significance in marine environments. While some dinoflagellate species commonly reach bloom concentrations and are thus conspicuous components of marine phytoplankton, others occur in very low abundances which make them difficult to detect in field studies. Here we analyzed dinoflagellate composition and abundance in five oceanographic expeditions carried out in continental shelf and slope waters of the Argentine Sea. M&M: Plankton abundance was estimated by the Utermöhl method, using inverted microscopy, whereas further optical and scanning electron microscopy was applied for the identification of dinoflagellate species. Results: We focused on the occurrence of seven dinoflagellates that have been previously poorly documented or overlooked in marine environments worldwide: Dinophysis microstrigiliformis; Gyrodinium sp.; Karlodinium elegans; Oxytoxum laticeps; Peridiniella danica; Peridiniella globosa and Prorocentrum nux. The latest and K. elegans are observed for the first time in field conditions after their original descriptions based on cell cultures. While most species were detected in low or moderate abundances, P. nux, which is the smallest Prorocentrum species, reached 82,000 cells L-1 in slope waters. Very small Gyrodinium cells (11.5 µm long; 8.7 µm wide) with a distribution restricted to slope waters during spring, were not possible to be accurately assigned to a species. Conclusions: This study contributes to the understanding of dinoflagellate diversity in the Argentine Sea and the worldwide distribution of little known species.Introducción y objetivos: Los dinoflagelados planctónicos son de gran relevancia en los ecosistemas marinos. Mientras que algunas especies suelen forman floraciones y ser componentes conspicuos del fitoplancton, otras se encuentran en abundancias muy bajas, lo cual hace difícil su detección. Aquí analizamos la composición y abundancia de dinoflagelados en cinco expediciones oceanográficas realizadas en aguas de la plataforma continental y del talud del Mar Argentino. M&M: La abundancia se estimó con microscopio invertido (método Utermöhl) y se utilizó microscopía óptica y electrónica de barrido para la identificación específica. Resultados: Nos enfocamos en la ocurrencia de siete dinoflagelados que previamente han sido poco documentados en ambientes marinos de todo el mundo: Dinophysis microstrigiliformis; Gyrodinium sp.; Karlodinium elegans; Oxytoxum laticeps; Peridiniella danica; Peridiniella globosa y Prorocentrum nux. Esta última especie y K. elegans se observan por primera vez en el campo desde su descripción basada en cultivos celulares. Si bien la mayoría de las especies se detectaron en abundancias bajas o moderadas, P. nux, el Prorocentrum más pequeño, alcanzó 82.000 células L-1 en aguas del talud. Células pequeñas de Gyrodinium sp. (11,5 µm de largo y 8,7 µm de ancho), con un una distribución restringida a las aguas del talud durante la primavera, no pudieron ser asignadas con precisión a nivel específico. Conclusiones: Este estudio contribuye al conocimiento de la diversidad de dinoflagelados en el Mar Argentino y la distribución mundial de especies poco conocidas.Fil: Fabro Cerreia Fus, Elena Ines. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. División Ficología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; ArgentinaFil: Almandoz, Gaston Osvaldo. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. División Ficología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; Argentin

Seasonal phytoplankton dynamics in extreme southern South America (Beagle Channel, Argentina)

The phytoplankton biomass and composition dynamics in relation with environmental factors were explored during an annual cycle (July 2006–2007) for the first time in the Beagle Channel. Samples were examined by light and scanning electron microscopy and carbon biomass was estimated using measured cell biovolumes. The annual cycle was characterized by a sharp contrast between low density and biomass during the autumn–winter period and a significant increase during spring and summer. The maximum biomass peak was observed during early spring (141 μg C l− 1 and 8.7 μg Chl a l− 1) and was associated with a bloom of the diatom genus Chaetoceros. In spite of a strong nutrient depletion that lead to the subsequent bloom decline, a second peak of biomass was observed after 2 weeks, mainly represented by the diatoms T. mendiolana and T. anguste-lineata. Towards the end of spring and during summer diatom density decreased and assemblages were enriched by unidentified tiny phytoflagellates and dinoflagellates. A total of 138 taxa were identified during the study period. From these, 10 are known as potentially toxic species: Alexandrium catenella, A. ostenfeldii, A. tamarense, Dinophysis acuminata, D. rotundata, Prorocentrum cordatum, Pseudo-nitzschia australis, P. calliantha, P. fraudulenta and P. cf. seriata. Their presence is noteworthy since the area sustains a growing aquiculture production.Fil: Almandoz, Gaston Osvaldo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. División Ficología; ArgentinaFil: Hernando, Marcelo Pablo. Universidad de Morón; ArgentinaFil: Ferreyra, Gustavo Adolfo. Université du Québec a Montreal; CanadáFil: Schloss, Irene Ruth. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Ministerio de Relaciones Exteriores, Comercio Interno y Culto. Dirección Nacional del Antártico. Instituto Antártico Argentino; ArgentinaFil: Ferrario, Martha Elba. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. División Ficología; Argentin

Dinoflagellates producers of yessotoxins in the Argentine Sea

Las yessotoxinas (YTXs) son un grupo de ficotoxinas descrito recientemente, asociado a toxicidad en moluscos y a cardiotoxicidad en ratones de laboratorio. Hasta el momento se conocen tres especies de dinoflagelados productoras de YTXs a nivel mundial: Protoceratium reticulatum, Gonyaulax spinifera y Lingulodinium polyedra. En este estudio se analizó la presencia de YTXs y de sus potenciales productores en cuatro campañas oceanográficas realizadas en diferentes estaciones del año entre los 38 y 55ºS. La detección de toxinas se realizó mediante cromatografía líquida de alta eficiencia acoplada con espectrometría de masas en tándem. Los análisis morfológicos incluyeron observaciones mediante microscopía óptica y electrónica de barrido. Se encontraron dos potenciales productores de YTXs, Protoceratium reticulatum y Gonyaulax spinifera, presentando densidades máximas de 660 y 140 cél. L-1 respectivamente durante las campañas de otoño y primavera, en las cuales se detectó YTX en muestras del Golfo San Jorge y del talud. Los datos obtenidos sugieren que la especie P. reticulatum es la principal productora de YTXs en el Mar Argentino presentando cuotas celulares entre 2,2 y 12,5 pg YTX cél.-1, mientras que G. spinifera representa un productor potencial en la región que no ha mostrado una asociación clara con la detección de YTX.Dinoflagellates producers of yessotoxins in the Argentine Sea. Yessotoxins (YTXs) consist of a recently described group of phycotoxins associated with shellfish toxicity and with cardiotoxicity in laboratory rodents. Until now there are only three dinoflagellate species considered as YTXs producers: Protoceratium reticulatum, Gonyaulax spinifera and Lingulodinium polyedra. In this study the presence of YTX and its potential producers in the Argentine Sea was analyzed by four oceanographic expeditions carried out between 38 and 55ºS and during different seasons. Toxin detection was performed by application of liquid chromatography coupled to tandem mass spectrometry. Morphological analysis included optical and scanning electron microscopy. Two YTXs potential producers were found: Protoceratium reticulatum and Gonyaulax spinifera, showing highest concentrations of 660 and 140 cell L-1 respectively, during autumn and spring. YTX were also detected during autumn and spring in samples from San Jorge Gulf and slope waters and were associated with the presence of P. reticulatum, showing toxin cell quotas of 2.2 and 12.5 pg YTX cell-1. The data obtained suggest that P. reticulatum is the main YTXs producer in the Argentine Sea, while G. spinifera represents a potential producer in the region which did not show a clear association with YTX detection.Fil: Fabro Cerreia Fus, Elena Ines. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. División Ficología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; ArgentinaFil: Krock, Bernd. Alfred-Wegener-Institut. Helmholtz-Zentrum für Polar und Meeresforschung; AlemaniaFil: Almandoz, Gaston Osvaldo. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. División Ficología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; Argentin

Spatiotemporal distribution of paralytic shellfish poisoning (PSP) toxins in shellfish from Argentine Patagonian coast

Harmful algal blooms (HABs) have been recorded in the Chubut Province, Argentina, since 1980, mainly associated with the occurrence of paralytic shellfish poisoning (PSP) toxins produced by dinoflagellates of the genus Alexandrium. PSP events in this area impact on fisheries management and are also responsible for severe human intoxications by contaminated shellfish. Within the framework of a HAB monitoring program carried out at several coastal sites along the Chubut Province, we analyzed spatiotemporal patterns of PSP toxicity in shellfish during 2000–2011. The highest frequency of mouse bioassays exceeding the regulatory limit for human consumption was detected in spring and summer, with average values of up to ≈70% and 50%, respectively. By contrast, a lower percentage of positive bioassays (2–8%) or no toxicity at all was usually detected during autumn and winter. The most intense PSP events were usually observed between November and January, with values of up to 4,000 μg STX eq 100 g−1, and showed a marked interannual variability both in their magnitude and location. In addition, a severe PSP outbreak was recorded during autumn, 2009, at Camarones Bay, with toxicity values of up to 14,000 μg STX eq 100 g−1. The scallop Aequipecten tehuelchus showed significantly higher toxicity values compared to other shellfish species in SJG and SMG, suggesting a lower detoxification capacity. Our results contribute to the understanding of HABs dynamics on the Argentine Patagonian coast.Fil: Gracia Villalobos, Leilen Luciana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Centro para el Estudio de Sistemas Marinos; ArgentinaFil: Santinelli, Norma Herminia. Universidad Nacional de la Patagonia "San Juan Bosco". Facultad de Ciencias Naturales - Sede Trelew. Departamento de Biología. Laboratorio de Hidrobiología; ArgentinaFil: Sastre, Alicia Viviana. Universidad Nacional de la Patagonia "San Juan Bosco". Facultad de Ciencias Naturales - Sede Trelew. Departamento de Biología. Laboratorio de Hidrobiología; ArgentinaFil: Marino, Raúl Germán. Ministerio de Salud de la Provincia del Chubut; ArgentinaFil: Almandoz, Gaston Osvaldo. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. División Ficología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; Argentin

Phytoplankton ecology during a spring-neap tidal cycle in the southern tidal front of san jorge gulf, patagonia

Tidal fronts are interfaces that separate stratified from mixed waters. The stratified surface zone of a front has lower inorganic nutrient concentrations than the mixed side, and thus, phytoplankton assemblages are expected to differ from one side of the front to the other. Here, we characterize the physics, nutrient dynamics, and biology of the southern front in San Jorge Gulf (SJG), Argentina, during a spring-neap tidal cycle. Baroclinic instabilities influence the shape and position of the front and presumably play an important role in the horizontal transport across the front. The highest phytoplankton biomass concentrations were found in the waters of the stratified side of the front during neap tide, with picophytoplankton, cyanobacteria, and nanophyto-plankton being the main contributors to the total autotrophic biomass. Bacteria contribute the most to heterotrophic biomass. In contrast, during spring tide, the carbon contribution of microphytoplankton was higher than during neap tide. In the mixed side, cells photoacclimate to optimum light conditions, suggesting that cells near the surface, which are probably photoinhibited, and cells below the euphotic zone, which are light-limited, are quickly advected by turbulent vertical motions to depths with optimal irradiance conditions.Fil: Flores Melo, Elizabeth Ximena. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Institut des Sciences de la Mer de Rimouski; CanadáFil: Schloss, Irene Ruth. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; Argentina. Universidad Nacional de Tierra del Fuego; Argentina. Institut des Sciences de la Mer de Rimouski; CanadáFil: Chavanne, Cédric. Institut des Sciences de la Mer de Rimouski; CanadáFil: Almandoz, Gaston Osvaldo. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Facultad de Ciencias Naturales y Museo, Universidad Nacional de la Plata; ArgentinaFil: Latorre, Maite Pilmayquen. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Centro para el Estudio de Sistemas Marinos; ArgentinaFil: Ferreyra, Gustavo Adolfo. Institut des Sciences de la Mer de Rimouski; Canadá. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; Argentin

Effects of salinity changes on coastal Antarctic phytoplankton physiology and assemblage composition

A natural marine phytoplankton assemblage from a coastal environment of Antarctica was experimentally exposed to low salinity sea water (30 vs 34 in the control) during 8. days in order to study their physiological and community responses to hypoosmotic stress conditions. Hypoosmotic conditions favour water influx into the cells, which results in increased turgor pressure and increased oxidative stress. This stress is linked to a number of other cellular toxic processes, including damages to proteins, enzyme inactivation and DNA breakage. Inhibition of the instantaneous growth rate started after 48. h exposure to low salinity, but at the end of experiment, growth was significantly higher in the low than in the normal (control) salinity treatment. Hypoosmotic conditions prevented phytoplankton biomass accumulation, as evidenced by reduced Chlorophyll-a concentrations as compared to the control treatment. However, in terms of cell numbers and species composition, we observed a gradual replacement of big centric by small pennate diatoms, which became dominant by the end of the experiment. In addition, the content of reactive oxygen species (ROS) and 2-thiobarbituric acid-reactive substances (TBARS), which are indicative of oxidative stress, were studied. In the low salinity treatments, ROS concentrations were significantly higher than control values on days 4 and 6, decreasing thereafter to nearly initial values. TBARS content increased during the first 48. h and then decreased until around day 0 values. This coincided with significant increased values of the antioxidants α-tocopherol and β-carotene in low salinity treatments over the control. These results suggest the existence of protection mechanisms against lipid peroxidation, and lead to the conclusion that the response to stress is species-specific, so that at the community level a change in the relative abundance of phytoplankton taxa appears as a response to hypoosmotic conditions. This could have important consequences for the trophic food web dynamics in areas influenced by high fresh water inputs.Fil: Hernando, Marcelo Pablo. Comisión Nacional de Energía Atómica; ArgentinaFil: Schloss, Irene Ruth. Ministerio de Relaciones Exteriores, Comercio Interno y Culto. Dirección Nacional del Antártico. Instituto Antártico Argentino; Argentina. Institut Des Sciences de la Mer de Rimouski; Canadá. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Malanga, Gabriela Fabiana. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Bioquímica y Medicina Molecular. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Instituto de Bioquímica y Medicina Molecular; ArgentinaFil: Almandoz, Gaston Osvaldo. Universidad Nacional de la Plata. Facultad de Ciencias Naturales y Museo. Division Ficología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Ferreyra, Gustavo Adolfo. Institut Des Sciences de la Mer de Rimouski; Canadá. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Aguiar, María Belén. Comisión Nacional de Energía Atómica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Puntarulo, Susana Ángela. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Bioquímica y Medicina Molecular. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Instituto de Bioquímica y Medicina Molecular; Argentin

Glacial Discharge and its Impact on Phytoplankton Taxonomic Composition in an Antarctic Fjord

The influence of glacial discharge on phytoplankton community composition remains an open question. The Antarctic Peninsula fjords offer an ideal system to understand the effect of ice-ocean forcing on phytoplankton community, providing an extreme in the spatial gradient from the glacio-marine boundary to the Western Antarctic Peninsula (WAP) continental shelf. In Andvord Bay, we found that glacial meltwater input altered surface salinity and was enriched in dissolved iron and nitrate, supporting phytoplankton biomass. The three major groups of phytoplankton fueled by glacial input were: cryptophytes, diatoms, and a group of unidentified small flagellates. In December, cryptophytes dominated the phytoplankton community and were correlated with relatively warmer temperatures in the surface layer; in addition, contrary to our hypothesis, no diatom bloom was observed in the fjord in spite of dissolved iron concentration >1 nM. By April, after the growth season, the overall phytoplankton abundance had decreased by an order of magnitude. Phytoplankton, in particular diatoms, were then limited by daytime length despite abundant macro-nutrient and iron concentrations. Mixed flagellates emerged as the dominant group during April due to the decline of other major taxa. Deep-learning algorithms for predicting the abundance of each major phytoplankton group captured the effects of these environmental factors on the phytoplankton community. Our results show that the fjord, under the influence of glacial meltwater, has relatively high phytoplankton biomass combined with high macro- and trace nutrient concentrations when compared to other WAP regions influenced by sea ice melting. Based on this study, we confirm that flagellates can be the dominant taxon in Antarctic fjords and we propose that iron concentration alone is insufficient to predict diatom growth. Furthermore, buoyant meltwater plumes can enrich the fjord with nitrate even if the main circulation is not driven by glacier meltwater discharge. As glacial meltwater continues to alter the phytoplankton taxonomic composition, it will have an important implication for higher trophic levels and add significant uncertainties to the prediction of regional ecosystem dynamics and biogeochemistry.Fil: Jack Pan, B.. University of California at San Diego. Scripps Institution of Oceanography; Estados UnidosFil: Vernet, Maria. University of California at San Diego. Scripps Institution of Oceanography; Estados UnidosFil: Manck, Lauren. University of California at San Diego. Scripps Institution of Oceanography; Estados UnidosFil: Forsch, Kiefer. University of California at San Diego. Scripps Institution of Oceanography; Estados UnidosFil: Ekern, Lindsey. University of California at San Diego. Scripps Institution of Oceanography; Estados UnidosFil: Mascioni, Martina. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. División Ficología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; ArgentinaFil: Barbeau, Katherine. University of California at San Diego. Scripps Institution of Oceanography; Estados UnidosFil: Almandoz, Gaston Osvaldo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. División Ficología; ArgentinaFil: Orona, Alexander James. Ocean Motion Technologies; Estados UnidosOcean Sciences Meeting 2020Estados UnidosOcean Sciences Meetin

Mixing processes at the pycnocline and vertical nitrate supply: Consequences for the microbial food web in San Jorge Gulf, Argentina

Little is known about the base of the food web that could support the high productivity and marine biodiversity found in San Jorge Gulf, Patagonia, Argentina. Here we examine the key components of the microbial food web, including the standing stock and physiological state of the phytoplankton in the context of key oceanographic variables in the gulf. Water samples were collected at 16 stations for biological and chemical analyses, together with measurements of vertical structure and currents. The dynamics of the water column and its impact on nutrient availability for primary producers was evaluated. Our results show that, in spite of the observed low surface nutrient concentrations and low biomass, phytoplankton cells were in good physiological state. This is possible because nutrients are replenished at the pycnocline depth, as estimated by means of Richardson’s dynamic stability. Turbulence created by tides and the shear between overlapping water masses favors the disruption of the pycnocline. We suggest that, during summer, San Jorge Gulf maintains not only high primary productivity but also high phytoplankton biomass turnover rate, which is supported by a high C:N ratio, consistent with strong zooplankton grazing and export of organic carbon to deep waters.Fil: Latorre, Maite Pilmayquen. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico; ArgentinaFil: Schloss, Irene Ruth. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; ArgentinaFil: Almandoz, Gaston Osvaldo. Universidad Nacional de La Plata; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Lemarchand, Karine. Université du Québec à Rimouski; CanadáFil: Flores Melo, Elizabeth Ximena. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; ArgentinaFil: Massé Beaulne, Valérie. Maurice Lamontagne Institute; CanadáFil: Ferreyra, Gustavo Adolfo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; Argentina. Université du Québec à Rimouski; Canad

Toxigenic dinoflagellates and associated toxins in San Jorge Gulf, Argentina

The occurrence of harmful algal blooms (HABs) is a global problem, and particularly in San Jorge Gulf (SJG), Argentina, which supports important fisheries, HABs represent a risk to human health. We studied the diversity and distribution of toxigenic dinoflagellates in the SJG using toxin detection and quantification, and assessed the connections between cell densities, toxins, and oceanographic parameters. Phytoplankton net samples were taken for microscopic and liquid chromatography-tandem mass spectrometry (LC-MSMS) analyses during an expedition aboard R/V Coriolis II in February 2014. Solid phase adsorption toxin tracking (SPATT) devices were also deployed to determine the presence of dissolved lipophilic toxins in seawater. Toxigenic dinoflagellate species and associated toxins showed different distribution patterns in the north and the south SJG. Protoceratium reticulatum and Dinophysis acuminata, together with yessotoxin and pectenotoxins, were predominantly detected in the northern SJG, mainly associated with low-nutrient, warmer waters. By contrast, Alexandrium catenella and paralytic shellfish toxins showed the highest relative abundances in the southern SJG, associated with high-nutrient, low-temperature waters. Cellular toxin content was also differently affected by environmental parameters, highlighting the complexity of HABs in this area. Spirolides were detected by SPATT for the first time in the SJG, suggesting the occurrence of A. ostenfeldii.Fil: Fabro Cerreia Fus, Elena Ines. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. División Ficología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Krock, Bernd. Alfred Wegener Institute for Polar and Marine Research; AlemaniaFil: Torres, Américo Iadran. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Centro para el Estudio de Sistemas Marinos; ArgentinaFil: Paparazzo, Flavio Emiliano. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Centro para el Estudio de Sistemas Marinos; ArgentinaFil: Schloss, Irene Ruth. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; Argentina. Université du Québec à Rimouski; CanadáFil: Ferreyra, Gustavo Adolfo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; Argentina. Université du Québec à Rimouski; CanadáFil: Almandoz, Gaston Osvaldo. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. División Ficología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Detection of the phycotoxin pectenotoxin-2 in waters around King George Island, Antarctica

In order to set a base line for the observation of planktonic community changes due to global change, protistan plankton sampling in combination with phycotoxin measurements and solid phase adsorption toxin tracking (SPATT) was performed in two bays of King George Island (KGI) in January 2013 and 2014. In addition, SPATT sampling was performed in Potter Cove during a one-year period from January 2014 until January 2015. Known toxigenic taxa were not firmly identified in plankton samples but there was microscopical evidence for background level presence of Dinophysis spp. in the area. This was consistent with environmental conditions during the sampling periods, especially strong mixing of the water column and low water temperatures that do not favor dinoflagellate proliferations. Due to the lack of significant abundance of thecate toxigenic dinoflagellate species in microplankton samples, no phycotoxins were found in net tow samples. In contrast, SPATT sampling revealed the presence of dissolved pectenotoxin-2 (PTX-2) and its hydrolyzed form PTX-2 seco acid in both bays and during the entire one-year sampling period. The presence of dissolved PTX in coastal waters of KGI is strong new evidence for the presence of PTX-producing species, i.e., dinoflagellates of the genus Dinophysis in the area. The presence of phycotoxins and their respective producers, even at the low background concentrations found in this study, may be the seed of possible proliferations of these species under changing environmental conditions. Furthermore, phycotoxins can be used as chemotaxonomic markers for a very specific group of plankton thus allowing to track the presence of this group over time.Fil: Krock, Bernd. Alfred Wegener Institut-Helmholtz Zentrum für Polarund Meeresforschung; AlemaniaFil: Schloss, Irene Ruth. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; Argentina. Ministerio de Relaciones Exteriores, Comercio Interno y Culto. Dirección Nacional del Antártico. Instituto Antártico Argentino; Argentina. Universidad Nacional de Tierra del Fuego; ArgentinaFil: Trefault, Nicole. Universidad de Santiago de Chile; ChileFil: Tillmann, Urban. Alfred Wegener Institut-Helmholtz Zentrum für Polarund Meeresforschung; AlemaniaFil: Hernando, Marcelo Pablo. Comisión Nacional de Energía Atómica; ArgentinaFil: Deregibus, Dolores. Ministerio de Relaciones Exteriores, Comercio Interno y Culto. Dirección Nacional del Antártico. Instituto Antártico Argentino; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Antoni, Julieta Silvina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo; ArgentinaFil: Almandoz, Gaston Osvaldo. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo; ArgentinaFil: Hoppenrath, Mona. Alfred Wegener Institut-Helmholtz Zentrum für Polarund Meeresforschung; Alemani