D - F
ERDPHPC
Ecologic Role and Distribution Patterns of the Heterotrophic Planktonic Community from the Rio de la Plata Estuary, Southwestern Atlantic and Antarctic During the years 2002 to 2004,we plan to study the ecological role of nano- and microplanktonic heterotrophic protists (flagellates, ciliates, dinoflagellates, radiolarians and foraminifers) in association with picoplanktonic components in the Southwestern Atlantic (including the Atlantic Sector of the Antarctic Ocean, the Argentine Sea, and the Rio de la Plata estuary), analyzing the main specific associations, their distribution patterns and their relationships with biotic and abiotic environmental parameters. Materials for this survey, largely available already, are collected from the icebreaker "Almirante Irizar" (Direccion Nacional del Antartico; Argentine Sea and Antarctic Ocean), and the BIP "Capitan Canepa" (Instituto Nacional de Investigacion y Desarrollo Pesquero; Rio de la Plata estuary) by means of continuous pump and discrete bottle samplings during the summers of 1999 through 2003. At oceanographic stations, located at 30ft. intervals, but with a lower spacing in areas of steep environmental gradients (as indicated by variables measured continuously or semi-continuously, mainly temperature and fluorometry), two series of samples will be collected: one aimed at measurementes of temperature, salinity, nutrients, pico- and nanoplankton, and the second for studies of the microzooplankton. Preservation of these materials will follow different protocols, according to the purpose of the sample (taxonomic identifications, cell counts, etc.). Through epifluorescence techniques we will emphasize the analysis of the specific composition and the numerical abundance of one of the least known size fractions in this area: the nanozooplankton, including its trophic affinities and factors that favor mixotrophy. Microzooplankton will be examined and counted under the inverted microscope using the Utherm?l method. Situ-derived information, complemented with laboratory grazing experments, will furnish an integrated picture of the structure and dynamics of the microheterotrophic plankton that contributes to the "biological pump" in the area. Espanol: Nombre del Proyecto: Rol ecologico y patrones distributivos de la comunidad heterotrofica microbiana planctonica del estuario del Rio de la Plata, Atlantico Sudoccidental y Antartico. (Proyecto en colaboracion con Universidad de Buenos Aires) Director: Dra. Viviana Andrea Alder Co-Director: Dr. Demetrio Boltovskoy E-mails: viviana@bg.fcen.uba.ar / demetrio@bg.fcen.uba.ar Resumen del Proyecto: Se estudiara el rol ecologico de los protozoos heterotroficos nano y microplanctonicos en relacion con los componentes picoplanctonicos del Atlantico Sudoccidental y Antartico, analizando sus asociaciones especificas, sus patrones distributivos y sus dependencias de los parametros bioticos y abioticos. El material, en gran parte ya disponible, es colectado por los buques "Almirante Irizar" (DNA; Mar Argentino y Oceano Antartico) y BIP "Capitan Canepa" (INIDEP; estuario del Rio de la Plata) mediante muestreos continuos con bomba de succion y con botellas oceanograficas, durante los veranos 1999 a 2003. En cada estacion oceanografica se colectaran dos series de muestras, que seran preservadas segun diferentes protocolos: la primera destinada para las determinaciones de salinidad, nutrientes, pico y nanoplancton, y la segunda para el estudio de la fraccion microzooplanctonica. Mediante la aplicacion de t?cnicas de epifluorescencia se realizara la evaluacion numerica del nanozooplancton, incluyendo el estudio de sus afinidades troficas y de los factores que favorecen la mixotrofia. El microzooplancton sera cuantificado bajo microscopio invertido (tecnica de Uthermol). La informacion obtenida in situ, sera complementada con experimentos de pastoreo en laboratorio, aportando una vision integral de la estructura y dinamica de los componentes microheterotroficos planctonicos que contribuyen a la "bomba biologica" en el area. Duracion: 2002 - 2004