Microbiota and Microsatellite genotypes of Pacific oysters stemming from three oyster bed in the Northern Wadden Sea

Background: Studies of oyster microbiomes have revealed that a limited number of microbes, including pathogens, can dominate microbial communities in host tissues such as gills and gut. Much of the bacterial diversity however remains underexplored and unexplained, although environmental conditions and host genetics have been implicated. We used 454 next generation 16S rRNA amplicon sequencing of individually tagged PCR reactions to explore the diversity of bacterial communities in gill tissue of the invasive Pacific oyster Crassostrea gigas stemming from genetically differentiated beds under ambient outdoor conditions and after a multifaceted disturbance treatment imposing stress on the host. Results: While the gill associated microbial communities in oysters were dominated by few abundant taxa (i.e. Sphingomonas, Mycoplasma) the distribution of rare bacterial groups correlated to relatedness between the hosts under ambient conditions. Exposing the host to disturbance broke apart this relationship by removing rare phylotypes thereby reducing overall microbial diversity. Shifts in the microbiome composition in response to stress did not result in a net increase in genera known to contain potentially pathogenic strains. Conclusion: The decrease in microbial diversity and the disassociation between population genetic structure of the hosts and their associated microbiome suggest that disturbance (i.e. stress) may play a significant role for the assembly of the natural microbiome. Such community shifts may in turn also feed back on the course of disease and the occurrence of mass mortality events in oyster populations.

Horizontal profiles of longwave and shortwave radiation components over sea ice near Barrow, Alaska during the 2011 melt

An integrated instrument package for measuring and understanding the surface radiation budget of sea ice is presented, along with results from its first deployment. The setup simultaneously measures broadband fluxes of upwelling and downwelling terrestrial and solar radiation (four components separately), spectral fluxes of incident and reflected solar radiation, and supporting data such as air temperature and humidity, surface temperature, and location (GPS), in addition to photographing the sky and observed surface during each measurement. The instruments are mounted on a small sled, allowing measurements of the radiation budget to be made at many locations in the study area to see the effect of small-scale surface processes on the large-scale radiation budget. Such observations have many applications, from calibration and validation of remote sensing products to improving our understanding of surface processes that affect atmosphere-snow-ice interactions and drive feedbacks, ultimately leading to the potential to improve climate modelling of ice-covered regions of the ocean. The photographs, spectral data, and other observations allow for improved analysis of the broadband data. An example of this is shown by using the observations made during a partly cloudy day, which show erratic variations due to passing clouds, and creating a careful estimate of what the radiation budget along the observed line would have been under uniform sky conditions, clear or overcast. Other data from the setup's first deployment, in June 2011 on fast ice near Point Barrow, Alaska, are also shown; these illustrate the rapid changes of the radiation budget during a cold period that led to refreezing and new snow well into the melt season.

Bibliotecas Populares en Mendoza : Acciones de gobierno desde 1983 hasta el 2010

Las Bibliotecas Populares surgieron por una iniciativa gubernamental que, más allá de los muchos altibajos que debieron afrontar, se mantienen hasta el presente gracias al esfuerzo de grupos de personas de la sociedad civil que reciben eventualmente apoyo del Estado. Es por esto, que se considera importante describir y analizar críticamente las acciones de Gobierno referidas a Bibliotecas Populares, focalizando la atención en Mendoza en el período comprendido entre 1983 y 2010. El trabajo de investigación del que da cuentas esta ponencia buscó interpretar, desde la narrativa de los actores sociales involucrados, el grado de complementariedad, armonía o conflicto, entre el rol que se les otorga por Ley a las Bibliotecas Populares y el que actúan en la práctica y conocer en qué medida han sido apoyadas desde el ámbito de Gobierno, con políticas que les permitieran profundizar su esencia de asociaciones autónomas de la sociedad civil. El desarrollo de este estudio exploratorio, realizado desde el punto de vista metodológico cualitativo, recurre al análisis de documentos y a entrevistas en profundidad. Para la exposición de los resultados se divide el espacio temporal y, valiéndose de un relato cronológico, en las etapas que se reconocen se profundiza el estudio de cuatro categorías de análisis: participación, legislación, recursos y acciones de Gobierno. Entre las conclusiones se aprecian los avances en cuanto a la contención legal y asignaciones presupuestarias, pero se observa la ausencia de una política pública creativa de fomento y estímulo que garantice un mejor futuro para las Bibliotecas Populares en Mendoza.