Comparative genomics of marine bacteroidetes: ecological insights

Programa de Doctorado en Oceanografía

Ecology of marine bacteroidetes: a genomics approach

Institut de Ciències del Mar (ICM-CSIC). Doctorado en oceanografía. Con mención de Calidad de la ANECA

Flujos meridionales en el Océano Índico Ecuatorial

[ES]Un modelo estacionario propuesto por Joyce (1988a) es evaluado en el Océano Índico ecuatorial, usando el estrés de vientos NCEP y temperaturas y salinidades de WOA05 y Argo. El transporte zonal integrado de los datos WOA05 se parece al de los datos Argo en el monzón de invierno (WM) y en los periodos de transición (TP), presentando valores mayores en el caso de datos Argo. En cambio, para el monzón de verano (SM) los transportes zonales integrados de los datos WOA05 y Argo tienen direcciones opuestas debido a que en los datos de WOA05 la Corriente de Somalia (SC) es débil y casi inexistente. Aunque los datos Argo tienen mayor cantidad de estructuras mesoscalares que los datos WOA05, los datos Argo obtienen una SC que se ajusta mejor a los estudios previos y, en consecuencia, los datos Argos son los únicos que serán utilizados para estimar transporte de volumen y calor. Los datos Argo muestran una SC que fluye hacia el sur durante el WM y hacia el norte durante el SM, y un flujo en el océano interior contrario a la corriente. Durante el WM, la SC es somera (~200dbar) y bajo ella fluye una contracorriente. El transporte de calor meridional estimado para datos Argo muestra una inversión estacional. El transporte de calor neto en cada estación tiene la misma dirección que el calor transportado por la SC.

Is there a seamount effect on microbial community structure and biomass?: the case study of Seine and Sedlo seamounts (Northeast Atlantic)

[EN] Seamounts are considered to be ??hotspots?? of marine life but, their role in oceans primary productivity is still under discussion. We have studied the microbial community structure and biomass of the epipelagic zone (0?150 m) at two northeast Atlantic seamounts (Seine and Sedlo) and compared those with the surrounding ocean. Results from two cruises to Sedlo and three to Seine are presented. Main results show large temporal and spatial microbial community variability on both seamounts. Both Seine and Sedlo heterotrophic community (abundance and biomass) dominate during winter and summer months, representing 75% (Sedlo, July) to 86% (Seine, November) of the total plankton biomass. In Seine, during springtime the contribution to total plankton biomass is similar (47% autotrophic and 53% heterotrophic). Both seamounts present an autotrophic community structure dominated by small cells (nano and picophytoplankton). It is also during spring that a relatively important contribution (26%) of large cells to total autotrophic biomass is found. In some cases, a ??seamount effect?? is observed on Seine and Sedlo microbial community structure and biomass. In Seine this is only observed during spring through enhancement of large autotrophic cells at the summit and seamount stations. In Sedlo, and despite the observed low biomasses, some clear peaks of picoplankton at the summit or at stations within the seamount area are also observed during summer. Our results suggest that the dominance of heterotrophs is presumably related to the trapping effect of organic matter by seamounts. Nevertheless, the complex circulation around both seamounts with the presence of different sources of mesoscale variability (e.g. presence of meddies, intrusion of African upwelling water) may have contributed to the different patterns of distribution, abundances and also changes observed in the microbial community.

Zooplankton, micronekton and biological pump: Beyond the mesopelagic zone

[EN] Migrant biota transports carbon to the mesopelagic zone due to their feeding at the shallower layers and their defecation, respiration, excretion and mortality at depth. The so-called active flux has been considered a small number compared to gravitational sinking. Recent assessments in subtropical waters show an important effect due to predation by interzonal diel vertical migrants (DVMs). The consumption and subsequent transport of epipelagic zooplankton by DVMs (mainly micronekton) to the mesopelagic zone seemed similar to the mean gravitational export. However, the consequences of this active transport to the bathypelagic zone are almost unknown. Here, we show the effect of the Atlantic and Pacific equatorial upwelling systems on the vertical distribution of acoustic backscatter from the surface to bathypelagic depths. The enhancement of the acoustic signal below the upwelling zone was observed to reach 4000 m depth, coinciding with high abundances and activity of bacteria at those depths. The results suggest an active carbon transport from the epipelagic driven by zooplankton and micronekton, enhancing the efficiency of the biological pump and giving an insight about the fate of an increased productivity at the shallower layers of the ocean

Consideraciones sobre la extracción del petróleo en aguas de Canarias: mesa redonda celebrada el jueves 27 de septiembre de 2012 en la sede de la Real Sociedad Económica de Amigos del País de Gran Canaria

[ES] Se plantea la cuestión de las prospecciones petrolíferas en aguas de Canarias desde el punto de vista de la geología del petróleo como recurso mineral, como fuente de energía y energías alternativas y el impacto que para la vida marina tendría la posible explotación del petróleo en aguas de Canarias

Descripción temporal de la estructura de mesoescala alrededor de las islas Shetland del Sur (Antártica)

[ES]El objetivo del presente trabajo es analizar la variabilidad espacial de la temperatura superficial del mar (SST) para el área comprendida entre el Paso Drake y el Estrecho de Bransfield (Antártica). Se realizaron distribuciones de SST en toda la región y en diferentes escalas temporales, conservándose importantes variaciones espaciales de la distribución de SST, demostrando que existe una importante variabilidad de la SST entre verano e invierno, alcanzando diferencias superiores a 3ºC, donde las estructuras de mesoescala superficialmente sólo se registran entre los meses de diciembre y abril, periodo correspondiente al verano Austral.

Effect of temperature and food concentration on the relationship between growth

[EN] The in situ activity of the enzymes aminoacyl-tRNA synthetases (AARS) and the growth rates of naupliar stages of the planktonic marine copepod Paracartia grani were measured in the laboratory under different temperature and food concentrations. We assessed the effect of these parameters on growth and protein synthesis rates of P. grani nauplii. Growth and protein synthesis rates of P. grani nauplii depended on temperature and food concentration. AARS activity is valid as an index of somatic growth for P. grani nauplii when growth is not limited by food availability. However, the relationship between protein-specific AARS activity and nauplii growth varied according to food availability levels. The degradation of proteins during starvation and/or the ß-oxidation of fatty acids affected the relationship between specific AARS activity and growth rates. The results presented here add to previous studies showing that the AARS activity is a useful tool for estimating somatic growth of this and other key copepod species. Nevertheless, further research is required to elucidate the validity of AARS activity as a universal proxy for growth.

The General Curvilinear Environmental Model (GCEM)

[EN] The General Curvilinear Environmental Model is a high-resolution system composed of the General Curvilinear Coastal Ocean Model (GCCOM) and the General Curvilinear Atmospheric Model (GCAM). Both modules are capable of reading a general curvilinear grid, orthogonal as well as non-orthogonal in all three directions. These two modules are weakly coupled using the distributed coupling toolkit (DCT). The model can also be nested within larger models and users are able to interact with the model and run it using a web based computational environment.

El C02 y su efecto en los océanos

[ES] El CO2 es uno de los principales gases efecto invernadero que es liberado a la atmosfera debido a la actividad humana, siendo una parte importante transferida a los oceanos.El aumento de las emisiones de carbono ha supuesto un incremento en el contenido de CO2 en la atmosfera. Del total de emisiones de CO2 debidas a la actividad antropogenica y a la deforestacion, un 47% permanece en la atmosfera, un 27% es absorbido por las plantas y un 26% es captado por los oceanos. Como consecuencia de la acumulacion en la atmosfera de CO2 y otros gases efecto invernadero como oxidos de nitrogeno y metano se esta viendo alterado el efecto invernadero natural terrestre, produciendose un aumento en la temperatura tanto en la superficie terrestre como en el oceano. Al igual que en la atmosfera, el contenido de CO2 en los oceanos esta aumentando. Los estudios del grupo QUIMA-ULPGC en la estacion ESTOC (1995-2010) han sido considerados como un importante aporte a la comunidad internacional y han sido incluidos los datos de pCO2 y pH en el Cuarto informe del IPCC (Interguvernamental Panel of Climate Change, 2007) sobre cambios climaticos oceánicos y del nivel del mar.

Phytoplankton community composition and size-abundance spectra in areas of the Alborán sea with different hydrological characteristics

[EN] Size-abundance spectra (SAS) were analyzed in different phytoplankton assemblages of the Alborán Sea collected in areas with contrasting hydrological features (upwelling areas and anticyclonic gyre). Abundance of micro-plankton cells decreased following the hydrological gradient from the most productive stations towards offshore stations. This size-fraction of phytoplankton was dominated by diatoms. Pico-plankton followed an opposite gradient. Concordantly, the slope of the SAS trended to decrease from coastal areas (upwelling) towards the anticyclonic gyre. However, phytoplankton assemblages featuring similar SAS values presented a quite different taxonomical composition of their diatom communities. According to the previous available information about the taxonomical composition of the phytoplankton communities in the Alborán Sea, these differences in diatom composition are indicative of differences in productivity of the phytoplankton. Consequently, the utility of phytoplankton SAS as an indicator of changes in the phytoplankton communities of the Alborán Sea is discussed.

Potential Respiration in Oxyrrhis marina and Rhodomonas salina

Máster en Oceanografía

Inter-decadal changes of thermodynamic stability variables in a transatlantic section along 7.5º N

Máster en Oceanografía

Meridional changes in water mass distributions off NW Africa during November 2007/2008

[EN] An optimum multiparameter analysis was applied to a data set for the eastern boundary of the North Atlantic subtropical gyre, gathered during November of two consecutive years and spanning from 16 to 36º N. This data set covers over 20º of latitude with good meridional and zonal resolution over the whole coastal transition zone. The contribution from six water types in the depth range between 100 and 2000 m is solved. In the 100 to 700 m depth range the central waters of southern and northern origin meet abruptly at the Cape Verde Frontal Zone. This front traditionally has been reported to stretch from Cape Blanc, at about 21.5º N, to the Cape Verde Islands, but in our case it penetrates as far as 24º N over the continental slope. South of 21º N latitude we actually find a less saline and more oxygenated variety of South Atlantic Central Water, which we ascribe to less diluted equatorial waters. In the 700 to 1500 m depth range the dominant water type is a diluted form of Antarctic Intermediate Water (AAIW), whose influence smoothly disappears north of the Canary Islands as it is replaced by Mediterranean Water (MW); at latitudes where both water masses coexist, we observe MW offshore while AAIW is found near-shore. North Atlantic Deep Water is the dominating water type below about 1300/1700 m depth south/north of the Canary Islands; this abrupt change in depth suggests the existence of different paths for the deep waters reaching both sides of the archipelago.

Meridional and zonal changes in water properties along the continental slope off central and northern Chile

[EN] The Humboldt-09 cruise covered a narrow meridional band along the Chilean continental slope (44?23º S). Here we use physical and biochemical data from a long meridional section (4000 km) and three short zonal sections (100 km) to describe the distribution of the different water masses found in this region. Six water masses were identified: Subantarctic Water (SAAW), Summer Subantarctic Water (SSAW), Subtropical Water (STW), Equatorial Subsurface Water (ESSW), Antarctic Intermediate Water (AAIW), and Pacific Deep Water (PDW). For the first time, a novel set of source water mass properties (or water types) is introduced for SSAW, and nutrient and dissolved oxygen water types are proposed for all the water masses. Optimum multiparameter (OMP) analysis was used through an iterative process to obtain a sound definition of the water types that minimizes the residuals of the method. Both the classic OMP and the quasi-extended OMP models reproduced the data rather well. Finally, the spatial distribution of the different water masses was calculated with the quasi-extended OMP, which is not influenced by the respiration of organic matter. The distribution of the different water masses is presented over the meridional and zonal transects and in property-property diagrams. A smooth meridional transition from subantarctic to tropical and equatorial water masses is observed in this area. This transition takes place in surface, central, and intermediate waters over distances of the order of 1000 km. The meridional transition contrasts with the abrupt zonal changes found in the cross-slope direction, which are of comparable magnitude but over distances of the order of 100 km. Both AAIW and SAAW (fresh and well oxygenated) partially mix with the hypoxic ESSW and, therefore, play an important role in the ventilation of the southern part of the oxygen minimum zone.