Relació entre la distribució de nutrients i oxigen dissolt i la composició elemental del fitoplàncton a la Mar Catalana (N - O Mar Mediterrània)

Memoria de tesis doctoral presentada por Mariona Segura i Noguera para obtener el título de Doctora en Ciencias del Mar por la Universitat Politècnica de Catalunya (UPC), realizada bajo la dirección de la Dra. Dolors Blasco Font de Rubinat del Institut de Ciències del Mar (ICM-CSIC).-- 287 pagesEl present treball es planteja l’estudi de les relacions que s’estableixen entre els elements químics essencials des d’un punt de vista biològic, tant a l’interior de les cèl·lules del fitoplàncton, com a l’exterior, és a dir a la mar. Els elements essencials són el carboni (C), l’hidrogen (H), el nitrogen (N), l’oxigen (O), el fòsfor (P) i el sofre (S) (Reynolds, 1997). L’interès en l’estudi d’aquests elements rau en que permeten moure’ns entre diferents nivells d’organització biològica, mitjançant l’estudi de les relacions entre els elements (estequiometria), i mitjançant l’estima de fluxos i balanços de massa entre i des d’una gran varietat d’entitats biològiques, des d’orgànuls i cèl·lules fins a conques senceres o fins tota la biosfera (Sterner i Elser, 2002). [...]Aquesta tesi ha estat realitzada gràcies al suport dels projectes : • CANYONS (Estudio multidisciplinar de la dinámica de un cañón submarino y su repercusión sobre la ecología del margen continental del Mediterráneo Noroccidental. 1999-2002, CYCIT, MAR99-1060-C03), • HABES (Harmful Algal Bloom Expert System, EU, EVK2-CT-2000-00092), • PUDEM (Morfodinámica de playas urbanizadas: integración de datos experimentales y modelos teóricos. 2003-2006, MEC, REN2003-06637-C02), i • CACO (Estudio del efecto del cambio global en comunidades marinas del Mediterráneo noroccidental, MEC, REN2002-01339/MAR) així com a la concessió d’una beca predoctoral I3P-Generales del CSIC, i una beca predoctoral del CSIC a càrreg del projecte CANESP (Population Dynamics and Toxicity of Harmful Microalgae in Coastal Embayments, MEC / National Research Council Canada, 2004 NRC/4) a Mariona Segura i Noguera. L’estança al Laboratori de Microscopia Electrònica i al Departament de Microbiologia de la Universitat de Bergen ha estat finançada amb una beca del Govern Noruec (Cultural Agreement between Norway and Spain, Norwegian Government Scholarship 2005/2006) concedida a Mariona Segura i NogueraPeer Reviewe

Assessment of the Skill of Coupled Physical-Biogeochemical Models in the NW Mediterranean

18 pages, 13 figures, supplementary material https://www.frontiersin.org/articles/10.3389/fmars.2020.00497/full#supplementary-material.-- Publicly available datasets were analyzed in this study. This data can be found here: http://marine.copernicus.eu/services-portfolio/access-to-products/, http://www.ba.ieo.es/ibamar, http://thredds.socib.es/thredds/catalog.htmlNumerical modeling is a key tool to complement the current physical and biogeochemical observational datasets. It is essential for understanding the role of oceanographic processes on marine food webs and producing climate change projections of variables affecting key ecosystem functions. In this work, we evaluate the horizontal and vertical patterns of four state-of-the-art coupled physical–biogeochemical models, three of them already published. Two of the models include data assimilation, physical and/or biological, and two do not. Simulations are compared to the most exhaustive dataset of in situ observations in the North Western Mediterranean, built ad hoc for this work, comprising gliders and conventional CTD surveys and complemented with satellite observations. The analyses are performed both in the whole domain and in four subregions (Catalan Shelf, Ebro Delta, Mallorca Channel, and Ibiza Channel), characterized by a priori divergent primary production dynamics and driving mechanisms. Overall, existing models offer a reasonable representation of physical processes including stratification, surface temperature, and surface currents, but it is shown that relatively small differences among them can lead to large differences in the response of biogeochemical variables. Our results show that all models are able to reproduce the main seasonal patterns of primary production both at the upper layer and at the deep chlorophyll maximum (DCM), as well as the differential behavior of the four subregions. However, there are significant discrepancies in the local variability of the intensity of the winter mixing, phytoplankton blooms, or the intensity and depth of the DCM. All model runs show markedly contrasting patterns of interannual phytoplankton biomass in all four subregions. This lack of robustness should dissuade end users from using them to fill gaps in time series observations without assessing their appropriateness. Finally, we discuss the usability of these models for different applications in marine ecology, including fishery oceanographyThis work was supported by the European Union’s Horizon 2020 Research and Innovation Program under grant agreement no. 678193 (CERES, Climate Change and European Aquatic Resources). ER-R is grateful for the funding from “Govern de les Illes Balears-Conselleria d’Innovació, Recerca i Turisme, Programa Vicenç Mut.”With the funding support of the ‘Severo Ochoa Centre of Excellence’ accreditation (CEX2019-000928-S), of the Spanish Research Agency (AEI)Peer reviewe

La composició elemental del plàncton

1 page, 1 figureDurant molts anys s’ha estat utilitzant una única estequiometria per descriure la relació entre la composició del plàncton i els cicles dels nutrients. Però estudis recents, especialment sobre cèl·lules fitoplanctòniques individuals, demostren que la composició elemental, i l’estequiometria derivada, poden variar considerablement entre diferents grups de plàncton i d’acord amb les condicions ambientals. L’ús d’aquesta informació permetria fer més bones prediccions sobre el canvi climàtic globalPeer reviewe

Portamuestras para microanálisis de rayos X con microscopía electrónica de barrido

Portamuestras para microanálisis de rayos X con microscopía electrónica de barrido. La invención describe un nuevo portamuestras (1) para microanálisis de rayos X que evita interferencias entre las señales de la muestra y las señales del propio portamuestras (1), y que comprende una base (2) sobre la que se apoyan unas columnas (3a, 3b, 3c) que soportan una estructura (4) de soporte, preferentemente un cilindro cuyo extremo superior tiene una tapa (5) con un orificio central (6) sobre la que se coloca una rejilla que contiene la muestra.Peer reviewedConsejo Superior de Investigaciones Científicas (España)A1 Solicitud de patente con informe sobre el estado de la técnic

Ranges of concentration of "quality controlled" oceanographic data (inorganic nutrients, dissolved oxygen and chlorophyll-a) from the NW Mediterranean

38th CIESM Congress, Istanbul, Turkey.-- 1 page, 1 tableQuality control procedures have been applied to oceanographic data collected at the Catalan Sea, NW Mediterranean Sea. The data sourceranges from historical data from MEDATLAS and MATER databases, inhouse data from CSIC (IIP, ICM and CEAB) from 1982 to 1997,to recent cruises of ICM, from 1999 to 2003. The effects of sample manipulation and chemometrics on the data have been studied. On thisbasis the ranges for each variable have been defined. This “quality controlled”data would be used to study ecological and biogeochemicalprocesses at the Catalan Sea (NW Mediterranean), such as seasonal dynamics of nutrients, dissolved oxygen and chlorophyll-a, as well asstoichiometr

Spawning environmental conditions of Sardinella aurita at the northern limit of its distribution range, the western Mediterranean

10 pages, 4 figures, 1 tableIn the last 20 yr, an increasing abundance and northward expansion of Sardinella aurita has been reported in the western Mediterranean. The present study characterizes the spawning habitat of S. aurita at the northern limit of their geographic distribution and determines the hydrodynamic conditions that could control their northward expansion in the western Mediterranean. Data along the Catalan shelf and slope were obtained in 4 oceanographic cruises conducted in the summers of 2003 and 2004. A clear preference for spawning in coastal areas shallower than 100 m was determined, with larvae showing a wider distribution extending offshore up to the position of the 150 m isobath. The greatest abundance of eggs and larvae was found in the southern half of the area on the wide shelf near the mouth of the Ebro River. This zone was characterized by high values of surface chlorophyll a in association with relatively low salinity waters from the Ebro River. In the northern part of the area, a thermal front across the shelf, with higher sea surface temperatures on its southern side, marked the northern limit of egg and larvae distribution. The northern side of this front was under the direct influence of the shelf–slope current, advecting slope waters from the north, while its southern side was dominated by coastal water. Larvae carried by coastal waters tended to concentrate near the convergence associated with the front. Thus, the thermal front retains and concentrates S. aurita larvae, and could represent one of the limiting factors for the expansion of the species towards the northM.E. was partially funded by contracts 2005SGR00476 and ESP2005-06823-C05-01. This work was supported by the project REN 2002-01339/MARPeer reviewe

An improved energy-dispersive X-ray microanalysis method for analyzing simultaneously carbon, nitrogen, oxygen, phosphorus, sulfur, and other cation and anion concentrations in single natural marine microplankton cells

15 pages, 9 figures, 3 tables.Electron-probe X-ray microanalysis (XRMA) is a technique that can be used to simultaneously quantify C, N, O, Na, Mg, Al, Si, P, S, Cl, K, and Ca present in single cells collected from the sea, with a minimal treatment of the samples. The technique has been used to determine elemental composition in plankton using scanning electron microscopes (SEM) or transmission electron microscopes (TEM). The methodologies used have shown some drawbacks. Here we present an improved methodology focusing on the analysis of the elemental concentration of marine microplankton cells, including light elements, based on the methodology of Norland et al. (1995). The most important modification is the use of a SEM microscope but reproducing TEM conditions by placing the sample grid at a distance from the holder bottom. This modification eliminates the interference of the SEM stub from the analysis of the cells, and improves the limit of detection of elements that are present in low concentrations. Experimental and theoretical data on the beam penetration depth using low incident beam energies (15 kV) are presented. The results show that a 15 kV accelerating voltage, invoked as a limitation in using XRMA for the analysis of samples thicker than 0.1 μm (Twining et al. 2008), is sufficient to analyze whole microplankton cells, and that there is no absorption of X-rays during the analysis. The method has been applied to diatoms and dinoflagellates from the Western Mediterranean Sea. The cell elemental composition results fall within the range of historical data in the literature.This work was supported by project PUDEM (REN2003-06637-C02,MEC) and by an I3P fellowship (CSIC, MEC) to M. Segura-Noguera.Peer reviewe

El fitoplàncton i els elements de la vida

3 pages, 2 figures[EN] Living organisms are composed mostly of six elements which are present in the oceans as dissolved gases and nutrient salts: hydrogen (H), carbon (C), nitrogen (N), oxygen (O), phosphorus (P) and sulphur (S). Phytoplankton organisms, both microalgae and cyanobacteria that are being drifted away by marine currents owing to their small size, incorporate these elements and use solar energy to build organic matter to live and reproduce while producing oxygen. The growth of phytoplankton therefore depends on the combination of light availability –restricted to surface waters– and nutrients from the deep waters of the continents or oceans. […][ES] Los organismos vivos están compuestos principalmente de seis elementos: hidrógeno (H), carbono (C), nitrógeno (N), oxígeno (O), fósforo (P) y azufre (S) que, en los océanos, se encuentran disueltos en forma de gases y de sales nutritivas. Los organismos fitoplanctónicos, microalgas y cianobacterias, que debido a su pequeño tamaño son arrastrados por las corrientes marinas, incorporan estos elementos y utilizan energía solar, mediante la fotosíntesis, para construir materia orgánica para vivir y reproducirse, a la vez que producen oxígeno. El crecimiento del fitoplancton, por lo tanto, depende de la combinación de la disponibilidad de luz –restringida a las aguas superficiales– y de nutrientes, procedentes de los continentes o de aguas profundas de los océanos. […][CAT] Els organismes vius estan compostos majoritàriament de sis elements: hidrogen (H), carboni (C), nitrogen (N), oxigen (O), fòsfor (P) i sofre (S) que, en els oceans, es troben dissolts en forma de gasos i de sals nutritives. Els organismes fitoplanctònics, microalgues i cianobacteris, que degut a la seva petita mida són arrossegats pels corrents marins, incorporen aquests elements i utilitzen energia solar, mitjançant la fotosíntesi, per construir matèria orgànica per a viure i reproduir-se, alhora que produeixen oxigen. El creixement del fitoplàncton, per tant, depèn de la combinació de la disponibilitat de llum –restringida a les aigües superficials– i de nutrients, procedents dels continents o d’aigües profundes dels oceans. […]Peer reviewe

Les aigües dels canons submarins a la nit

Peer reviewe

An improved energy-dispersive X-ray microanalysis method for analyzing simultaneously carbon, nitrogen, oxygen, phosphorus, sulfur, and other cation and anion concentrations in single natural marine microplankton cells

15 pages, 9 figures, 3 tablesElectron-probe X-ray microanalysis (XRMA) is a technique that can be used to simultaneously quantify C, N, O, Na, Mg, Al, Si, P, S, Cl, K, and Ca present in single cells collected from the sea, with a minimal treatment of the samples. The technique has been used to determine elemental composition in plankton using scanning electron microscopes (SEM) or transmission electron microscopes (TEM). The methodologies used have shown some drawbacks. Here we present an improved methodology focusing on the analysis of the elemental concentration of marine microplankton cells, including light elements, based on the methodology of Norland et al. (1995). The most important modification is the use of a SEM microscope but reproducing TEM conditions by placing the sample grid at a distance from the holder bottom. This modification eliminates the interference of the SEM stub from the analysis of the cells, and improves the limit of detection of elements that are present in low concentrations. Experimental and theoretical data on the beam penetration depth using low incident beam energies (15 kV) are presented. The results show that a 15 kV accelerating voltage, invoked as a limitation in using XRMA for the analysis of samples thicker than 0.1 μm (Twining et al. 2008), is sufficient to analyze whole microplankton cells, and that there is no absorption of X-rays during the analysis. The method has been applied to diatoms and dinoflagellates from the Western Mediterranean Sea. The cell elemental composition results fall within the range of historical data in the literatureThis work was supported by project PUDEM (REN2003-06637-C02,MEC) and by an I3P fellowship (CSIC, MEC) to M. Segura-NogueraPeer reviewe