Description: In order to gain knowledge about the potential effects of acidification in aquatic ecosystems, global change research based on microalgae as sentinel species has been often developed. However, these studies are limited to single species tests and there is still a research gap about the behaviour of microalgal communities under this environmental stressor. Thus, the aim of this study was to assess the negative effects of CO2 under an ecologically realistic scenario. To achieve this objective, two types of toxicity tests were developed; i) single toxicity tests and ii) multispecies toxicity tests, in order to evaluate the effects on each species as well as the interspecific competition. For this purpose, three microalgae species (Tetraselmis chuii, Phaeodactylum tricornutum and Nannochloropsis gaditana) were exposed to two selected pH levels (7.4, 6.0) and a control (pH 8.0). The pH values were choosen for testing different scenarios of CO2 enrichment including the exchange atmosphere-ocean (pH 7.4) and natural or anthropogenic sources of CO2 (pH 6.0). The effects on growth, cell viability, oxidative stress, plus inherent cell properties (size, complexity and autofluorescence) were studied using flow cytometry (FCM). Results showed that T. chuii was the most resistant species to CO2 enrichment with less abrupt changes in terms of cell density, inherent cell properties, oxidative stress and cell viability. Although P. tricornutum was the dominant species in both single and multispecies tests, this species showed the highest decrease in cell density under pH 6.0. Effects of competence were recorded in the multispecies control (pH 8) but this competence was eclipsed by the effects of low pH. The knowledge of biological interactions made by different microalgae species is a useful tool to extrapolate research data from laboratory to the field.

Description: The Arctic Ocean is characterized by being covered by sea ice with a large degree of seasonal variability between summer and winter. Along the whole life cycle of sea ice, diverse physical and chemical processes determine the concentration of the sea-ice sediments (SIS) and the chemical species entrapped in it and their final fate. Initially, sea ice incorporates particles (SIS) and associated chemical species (metals, nutrients, contaminants, etc.) during its formation mainly in the continental shelves, while dissolved solutes are excluded. As sea ice drifts offshore to the central Arctic Basin, it intercepts chemical species from the atmosphere and, the sediments in the ice may also incorporate some chemical solute compounds from the surface waters by scavenging (although this is likely small). Eventually, transported components, chemical species and SIS, are released to the underlying water column during melting. Thus, sea ice becomes an important transpo rt and distribution agent. However, the efficiency of interception of atmospheric fluxes by sea ice, the origin of the entrapped SIS and transit times of sea ice in the Arctic, as well as the importance of the transport of chemical species and particulate matter (SIS) and its release in the ablation area are all poorly understood. In an attempt to address these questions, a suite of natural (7Be and 210Po-210Pb) and artificial (137Cs, 239,240Pu) radionuclides were analysed in samples from precipitation, sea ice, surface water, water beneath ice and sea-ice sediments collected during the ARK XXII/2 expedition in 2007. The distributions of 7Be and 210Pb showed enrichment in sea ice (129 ± 90 and 5.1 ± 2.9 Bq·m-3, respectively) with respect to surface water (7.1 ± 1.3 and 1.1 ± 0.36 Bq·m-3, respectively). Given that only 4% of the total amount of 210Pb in sea ice comes from seawater and that any 7Be (T1/2 = 53 days) trapped in sea ice during its formation has decayed during drift, the direct atmospheric flux appears as the most important source of both radionuclides in sea ice. From mass balance calculations we estimate that sea ice intercepts about 30% of the 7Be atmospheric flux. This figure may be extrapolated to other chemical species with atmospheric sources, such as metals, nutrients, and contaminants. Given that 7Be and 210Pb are intercepted and accumulated during sea ice transit and also scavenged by SIS, we can use both radionuclides to assess sea ice transit time. Using the 210Pb inventory in ice floes respect to the 210Pb atmospheric flux intercepted by sea ice and the 7Be/210Pbex activity ratio in SIS, we estimated transit times from less than 0.5 to 3 years along the Eurasian Basin. Results are consistent with information reported by satellite maps and back-trajectories analysis of the sampled sea ice floes. Indeed, the SIS presence indicates that the ice floes come from continental shelves, and their origin can be constrained using artificial radionuclides (137Cs and the 239,240Pu) in SIS. Data shows that most of the SIS in the Eurasian Basin originated from the Siberian shelves, in agreement with back-trajectory analyses and main drift patterns. The relevance of sea ice as a significant transport and source of radionuclides in melting areas, such as the Fram Strait, is reflected in the annual fluxes of dissolved 7Be and 210Pb carried by sea ice (67 ± 55 and 13 ± 7 Bq·m-2·y-1, respectively), which are comparable to atmospheric inputs in this region (113-131 and 10-18.3 Bq·m-2·y-1, for 7Be and 210Pb). In addition, the annual mass flux of SIS to the Fram Strait, assessed using a 7Be mass balance and the mean annual ice area efflux through the Fram Strait, is on average 240 (4.5 - 1700) ·106 tons. As a reference, the discharge of sediment load from Arctic rivers is of about 115·106 tons per year.

Description: La papilomatosis es una entidad tumoral generalmente benigna que ataca la piel y mucosas de diferentes zonas del cuerpo. Esta enfermedad puede limitar la reproducción en los cetáceos y una de sus causas puede ser la infección por papilomavirus. La observación de pequeñas verrugas en la piel o mucosas de estos animales hace inferir la presencia de lesiones papilomatosas.

Description: Published

Description: delfines, mamíferos marinos, virus, papilomavirus

Description: Entre las enfermedades virales de más reciente diagnóstico que afectan los delfines nariz de botella (Tursiops truncatus) se describe la papilomatosis, una entidad tumoral generalmente benigna que afecta piel y mucosas de diferentes zonas del cuerpo, tanto de animales acuáticos como terrestres incluido el hombre. Con el objetivo describir el cuadro anatomopatológico de lesiones papilomatosas en genitales externos de delfines nariz de botella (Tursiops truncatus) se realizaron biopsias de lesiones genitales de 17 delfines entre los años 2005 – 2010, previa anestesia del área con lidocaína al 2 %, mediante un ponche de 5mm realizado sobre la lesión tumoral. Se realizó la descripción clínica, histopatológica y ultramicroscopica de las lesiones. La descripción anatomopatológica permitió definir las lesiones orogenitales como típicas de una papilomatosis, lo que se corroboró con la observación de partículas virales por microscopia electrónica de transmisión. Se describe por primera vez la parafimosis producto de lesiones papilomatosas en las poblaciones de delfines Tursiops truncatus.

Description: Papillomatosis are among the viral illnesses of more recent diagnosis that may affect the bottlenose dolphins Tursiops truncatus. The illness is described like a benign tumour, affecting skin and mucous, of aquatic and terrestrial animals included man. The goal of this paper is to describe the anatomopathologic symptoms of papilloma lesions in external side of genitals of bottlenose dolphins. There were carried out 17 biopsies of genitals lesions using 5mm punch, between 2005 and 2010, previous blockade of the area with lidocaína 2%. Clinical, histopathology and ultramicroscopic features of the lesions were described. The anatomopathologic description allowed defining the orogenitals lesions like typical of a papillomatosis, it was corroborated with the observation of the viral particles by electronic transmission microscopy. It was described for the first time the parafimosis caused by papilloma in bottlenose dolphins.

Description: Published

Description: papilomatosis, Tursiops truncatus, verruga orogenitales, warts orogenitals