Database of diazotrophs in global ocean: abundances, biomass and nitrogen fixation rates

[EN] Marine N2 fixing microorganisms, termed diazotrophs, are a key functional group in marine pelagic ecosystems. The biological fixation of dinitrogen (N2) to bioavailable nitrogen provides an important new source of nitrogen for pelagic marine ecosystems 5 and influences primary productivity and organic matter export to the deep ocean. As one of a series of efforts to collect biomass and rates specific to different phytoplankton functional groups, we have constructed a database on diazotrophic organisms in the global pelagic upper ocean by compiling about 12 000 direct field measurements of cyanobacterial diazotroph abundances (based on microscopic cell counts or qPCR 10 assays targeting the nifH genes) and N2 fixation rates. Biomass conversion factors are estimated based on cell sizes to convert  abundance data to diazotrophic biomass. The database is limited spatially, lacking large regions of the ocean especially in the Indian Ocean. The data are approximately log-normal distributed, and large variances exist in most sub-databases with non-zero values differing 5 to 8 orders of magnitude. 15 Lower mean N2 fixation rate was found in the North Atlantic Ocean than the Pacific Ocean. Reporting the geometric mean and the range of one geometric standard error below and above the geometric mean, the pelagic N2 fixation rate in the global ocean is estimated to be 62 (53–73) TgNyr−1 and the pelagic diazotrophic biomass in the global ocean is estimated to be 4.7 (2.3–9.6) TgC from cell counts and to 89 (40–20 200) TgC from nifH-based abundances. Uncertainties related to biomass conversion factors can change the estimate of geometric mean pelagic diazotrophic biomass in the global ocean by about ±70 %. This evolving database can be used to study spatial and temporal distributions and variations of marine N2 fixation, to validate geochemical estimates and to parameterize and validate biogeochemical models. The database is 25 stored in PANGAEA (http://doi.pangaea.de/10.1594/PANGAEA.774851).

Adaptación de la Directiva Europea de Gestión de la Calidad de Aguas de Baño a las playas de Canarias

[ES] Hemos realizado una serie de consideraciones con respecto a la Directiva 2006/7/CE para lograr su correcta aplicación en las playas de baño de Canarias. En nuestras aguas se producen algunos fenómenos que no se producen en el resto de la Unión Europea. Por esta razón hemos establecido una serie de conceptos que no están previstos de forma explicita en los artículos de la Directiva y que, con algunas matizaciones, podremos adaptarlos a la generalidad de la Directiva, o ?sensu contrario?, adecuar la Directiva a nuestra realidad ambiental. En este sentido, hemos adaptado conceptos como ?contaminación de corta duración?, ?tendencia a la proliferación de macroalgas?, ?tendencia a la proliferación de fitoplancton marino?, ?proliferación de cianobacterias? y otros a las especificidades que se producen en nuestras costas y que podrían alterar la calidad de las aguas de baño