69 research outputs found
Are pelagic cephalopods in the Mediterranean as abundant as suggests the stomach contents of their predators?
Final workshop IDEADOS: The wrapping up of the IDEADOS project, International Workshop on Environment, Ecosystems and Demersal Resources and fisheries, 14-16 November 2012, Palma de Mallorca, SpainPeer reviewe
Zooplankton and Micronekton Active Flux Across the Tropical and Subtropical Atlantic Ocean
Quantification of the actual amount of carbon export to the mesopelagic layer by both zooplankton and micronekton is at present a gap in the knowledge of the biological pump. These organisms perform diel vertical migrations exporting carbon through respiration, excretion, mortality, and egestion during their residence at depth. The role of zooplankton in active flux is nowadays partially assessed. However, micronekton active flux is scarcely known and only a few studies addressed this downward transport. Even less is known about the capacity of both communities to export carbon in the ocean. Here, we show the results of zooplankton and micronekton active flux across a productivity gradient in the tropical and subtropical Atlantic Ocean. Biomass vertical distribution from the surface up to 800 m depth by day and night was studied during April 2015 in a transect from 9 degrees S to 25 degrees N, covering from the quite oligotrophic zone off Brazil to the meso- and eutrophic areas of the equator, Guinea Dome, and the oceanic upwelling off Northwest Africa. Zooplankton and micronekton migrant biomass was estimated from day and night catches at different layers of the water column using MOCNESS-1 (1 m(2) mouth area) and Mesopelagos (35 m(2)) nets, respectively. Respiratory flux was assessed by measuring the enzymatic activity of the electron transfer system (ETS) of organisms at depth. Results showed a close relationship between migrant biomass and respiratory flux in zooplankton and micronekton as expected. Using a rather conservative 50% of efficiency for the net used to capture micronekton, respiratory flux resulted in similar values for both communities. Gravitational (passive) flux measured using sediment traps increased from the oligotrophic toward the meso- and eutrophic zones. Total active flux (including respiration and estimated mortality, excretion, and gut flux) by zooplankton and micronekton accounted for about 25% of total flux (passive plus active) in oligotrophic zones. Total active flux also increased toward meso- and eutrophic zones, reaching about 80% of total flux and being at least twofold higher than passive flux. These results alert about an important underestimation of the ocean biological pump using only passive flux measurements
Swimbladder properties of Cyclothone spp. in the northeast Atlantic Ocean and the Western Mediterranean Sea
Non-migratory bristlemouth fishes (Cyclothone spp.) are the most abundant vertebrates on Earth and play an important role in the biological carbon pump by remineralizing organic carbon in deep ecosystems. Acoustic data and net sampling are often used in combination to estimate fish and zooplankton biomass, but this procedure may be subject to several sources of error when applied to mesopelagic species. For instance, the allocation of echoes to species has often been biased by not considering Cyclothone spp. due to the use of nets targeting larger fish. Furthermore, the acoustic properties of the target organisms must be well understood to convert acoustic density into numerical density. The characteristics of a fish’s swimbladder are the most relevant features necessary to assess its acoustic properties. This study provides information on the swimbladder properties of six Cyclothone species inhabiting the meso- and bathypelagic layers in the North Atlantic Ocean and Mediterranean Sea, including swimbladder location within the body, fat tissue content, morphology, morphometry (only available for C. braueri and C. pseudopallida), and fish body-mass density (only available for C. braueri, C. pseudopallida, C. pallida, and C. pygmaea). The studied species showed a functional physoclistous swimbladder, with well-developed gas glands and rete mirabile and numerous capillaries in the case of the shallower species C. braueri and C. pseudopallida (mainly distributed from 400 to 600 m depth), and a fat-invested swimbladder in species with deeper vertical distribution (C. livida, C. microdon, C. pallida, and C. pygmaea). The fat content in the swimbladder (C. pallida and C. microdon) increased with depth and latitude, reducing the space in the swimbladder that could contain gas. Changes in swimbladder size and volume during growth were analyzed for shallower species, where swimbladder volume and equivalent radius followed negative allometric growth in relation to body length. Finally, values of body-mass density (ρ) and gas content required for neutral buoyancy (VG) were estimated for C. braueri and C. pygmaea collected between 350 and 550 m (ρ = 1.052–1.072 g·cm−3, VG = 2%–4%; ρ = 1.052–1.062 g·cm−3, VG = 3.6%), and for C. pallida and C. pseudopallida sampled in the 450–700 m layer (ρ = 1.052–1.062 g·cm−3, VG = 2.6–3.1%; ρ = 1.052–1.062 g·cm−3, VG = 2.8%–3.25%). Results in this study highlight the change in scattering behavior of Cyclothone species from gas-bearing organisms (those that contain gas in their swimbladder) in the upper mesopelagic zone to the fluid-like scattering (with fat-filled swimbladders) of the deeper and northern individuals. The data presented in this manuscript are important for parametrizing acoustic backscattering models built to estimate the echo of Cyclothone species, although further work is needed, particularly for individuals with partially invested swimbladders with an irregular fat-free shape
Carbon remineralization by small mesopelagic and bathypelagic Stomiiforms in the Northeast Atlantic Ocean
The organic carbon resulting from photosynthesis in the upper ocean is transferred downward through the passive sinking of organic particles, physical mixing of particulate and dissolved organic carbon as well as active flux transported by zooplanktonic and micronektonic migrants. Several meso- and bathypelagic organisms feed in shallower layers during the nighttime and respire, defecate, excrete and die at depth. Recent studies suggest that migrant micronekton transport similar amounts of carbon to migrant zooplankton. However, there is scarce information about biomass and carbon flux by non-migratory species in the mesopelagic and bathypelagic zones. The non-migratory bristlemouth fishes (Cyclothone spp.) and partial migrator (A. hemigymnus) remineralise organic carbon at depth, and knowledge about this process by this fauna is lacking despite them having been referred to as the most abundant vertebrates on Earth. Here we show the vertical distribution of biomass and respiration of non-migratory mesopelagic fishes, during day and night, using the enzymatic activity of the electron transfer system (ETS) as a proxy for respiration rates. The study is focused on five Cyclothone species (C. braueri, C. pseudopallida, C. pallida, C. livida and C. microdon) and Argyropelecus hemigymnus. The samples were taken on a transect from the oceanic upwelling off Northwest Africa (20° N, 20° W) to the south of Iceland (60° N, 20° W). Cyclothone spp. showed, by far, the largest biomass (126.90 ± 86.20 mg C·m⁻²) compared to A. hemigymnus (0.54 ± 0.44 mg C·m⁻²). The highest concentrations of Cyclothone spp. in the water column were observed between 400 and 600 m and from 1000 to 1500 m depths, both during day and night. For the different species analysed, ETS activity did not show significant differences between diurnal and nocturnal periods. The total average specific respiration of Cyclothone spp. (0.02 ± 0.01 d⁻¹) was lower than that observed for A. hemigymnus (0.05±0.02 d⁻¹). The average carbon respiration of Cyclothone spp. was 2.22 ± 0.81 mg C·m⁻²·d⁻¹, while it was much lower for A. hemigymnus (0.04 ± 0.03 mg C·m⁻²·d⁻¹). The respiration of Cyclothone spp. was lower in the bathypelagic than in the mesopelagic zone (0.84 ± 0.48 vs 1.36 ± 1.01 mg C·m⁻²·d⁻¹, respectively). These results, to our knowledge, provide the first account of remineralisation by this community in the meso and bathypelagic zones of the ocean.En prens
Segundos resultados de la evaluación de la ansiedad ante el Trabajo Fin de Grado (TFG).
Este proyecto pretende identificar el grado de ansiedad que genera para el estudiante el sistema actual de evaluación del TFG. Con ello, se pretende sensibilizar a la comunidad universitaria sobre la importancia del desarrollo de las competencias transversales en el marco del EEES, impulsando espacios de colaboración docente en el sistema universitario, promoviendo e impulsando la reflexión personal sobre los procesos de evaluación de la actividad docente, especialmente durante la tutela del TFG, promoviendo buenas prácticas. Se evaluará el grado de ansiedad de los estudiantes de 4º curso de los Grados matriculados en la asignatura de TFG de manera longitudinal (evaluación 1: durante la realización del TFG, evaluación 2: antes de la defensa del TFG) con el instrumento que, conforme a la literatura previa, se muestre más válido y fiable. Como resultado último, se ofrecerá a los futuros estudiantes que defenderán su TFG unas instrucciones fundamentadas sobre lo que puede ayudarles en la preparación de su defensa, para disminuir su ansiedad. Estas conclusiones serán asimismo útiles para los docentes (tutores y tribunales de TFG) para su labor de tutela y de evaluación
Primeros resultados de la evaluación de la ansiedad ante el Trabajo Fin de Grado (TFG)
Este proyecto pretende identificar el grado de ansiedad que genera para el estudiante el sistema actual de
evaluación del TFG. Con ello, se pretende sensibilizar a la comunidad universitaria sobre la importancia del desarrollo de
las competencias transversales en el marco del EEES, impulsando espacios de colaboración docente en el sistema
universitario, promoviendo e impulsando la reflexión personal sobre los procesos de evaluación de la actividad docente,
especialmente durante la tutela del TFG, promoviendo buenas prácticas. Se evaluará el grado de ansiedad de los
estudiantes de 4º curso de los Grados matriculados en la asignatura de TFG de manera longitudinal (evaluación 1: durante
la realización del TFG, evaluación 2: antes de la defensa del TFG) con el instrumento que, conforme a la literatura previa,
se muestre más válido y fiable. Como resultado último, se ofrecerá a los futuros estudiantes que defenderán su TFG unas
instrucciones fundamentadas sobre lo que puede ayudarles en la preparación de su defensa, para disminuir su ansiedad.
Estas conclusiones serán asimismo útiles para los docentes (tutores y tribunales de TFG) para su labor de tutela y de
evaluación
Mejora de las competencias personales y profesionales del profesor tutor del Trabajo Fin de Grado (TFG)
Durante este curso hemos continuado la labor que comenzamos el curso pasado. Hemos constatado la relevancia del tema que estamos trabajando en los foros a los que hemos asistido. Después de llevar a cabo la revisión bibliográfica acerca de las competencias personales y profesionales que debe tener un buen profesor de educación superior, llegamos a la conclusión de que existen tres dimensiones fundamentales: las competencias personales, las pedagógicas y las técnicas. Sobre estas dimensiones hemos construido un cuestionario de evaluación de competencias, lo hemos cribado con la ayuda de un grupo de expertos nombrado “ad hoc” y lo hemos digitalizado . Nos encontramos en la fase de pilotaje, en que se va a aplicar el cuestionario a profesores y alumnos para llevar a cabo el trabajo psicométrico. Una vez que tengamos estos primeros resultados realizaremos el muestreo a gran escala, con el objeto de diseñar el protocolo de actuación que mejore la actuación docente de los profesores que dirigen un TFG
Coordinación y colaboración interdisciplinar entre profesorado y asignaturas para mejorar la calidad de la docencia universitaria
Innovación EducativaLa Universidad necesita nuevas formas de organización docente y establecer lazos con instituciones externas dedicadas a la práctica laboral para proporcionar a nuestro alumnado aprendizajes interdisciplinares y competenciales que les permitan una formación de calidad para el desempeño de su futura vida laboral. En este Proyecto de Innovación Docente (PID) hemos realizado una primera aproximación al conocimiento de las diferentes formas de coordinación y colaboración docente a través de la revisión bibliográfica y posteriormente hemos analizado el nivel de coordinación y colaboración de una muestra de docentes (n=18) de nuestra Universidad mediante la realización de una encuesta. En el marco de este PID se han establecido nuevos vínculos de coordinación y colaboración tanto entre profesores y asignaturas como con instituciones externas a la Universidad. Finalmente se ha llevado a cabo un análisis del impacto de la implementación de nuevas formas de coordinación y colaboración interdisciplinar, tanto desde el punto de vista del profesorado como del alumnado.Departamento de Psicologí
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