Contrasting complexing capacity of dissolved organic matter produced during the onset, development and decay of a simulated bloom of the marine diatom Skeletonema costatum

Original research articleThe capacity of natural dissolved organic matter (DOM) produced during the onset, development and decay of a simulated bloom of the marine diatom Skeletonema costatum to complex free copper has been followed for a 2 week period. Copper binding capacity of the culture was measured by anodic stripping voltammetry (ASV) with a hanging mercury drop electrode (HMDE). The concentration of dissolved organic carbon (DOC) and two fluorophores, M (humic-like, Ex/Em: 320 nm/410 nm) and T (protein-like, Ex/Em: 280 nm/350 nm), were followed during the course of the incubation. Models using DOC concentrations alone could not accurately predict the complexing capacity of the culture, especially at the end of the bloom, and better predictions were obtained when fluorescence measurements were considered. They were helpful in characterising two types of copper ligands produced in the culture. The first type, traced by the fluorescence of peak T, was related to labile DOC directly exuded by phytoplankton. The second type, traced by the fluorescence of peak M, was the refractory humic-like material presumably produced in situ as a by-product of the bacterial degradation of phytogenic materials. During the onset and development of the bloom (days 0 to 7), the fluorescence of peak T explains 60–80% of the total complexing capacity of the culture, suggesting that exuded “protein-like” compounds among other exuded complexing agents efficiently complexed free copper. On the contrary, during the decay (days 8 to 13), these ligands were replaced by humic substances as the complexing agent for copper.Financial support for this work came from the Spanish ‘Ministerio de Educación y Ciencia’ (MEC), Grant Nos. REN2000-0880-C02-01 MAR and REN2003-00958 MAR and the ‘Xunta de Galicia’, Grant No. PGIDT01MAR40201PN.Versión del editor2,75

New and rare records of teleost fishes from the Cape Verde Islands (eastern-central Atlantic Ocean)

As a result of six exploratory surveys and several opportunistic catches in the Cape Verde Islands from a few metres to about 1000 m of depth, a list of 66 species of teleost fishes is given, six of which are first records from the archipelago: Gnathophis mystax (Congridae), Nezumia africana, Nezumia duodecim (Macrouridae), Ectreposebastes imus (Scorpaenidae), Paraliparis sp. (Liparidae) and Lappanella fasciata (Labridae). Additionally, data on six poorly-known species is also given: Myroconger compressus (Myrocongridae), Myrichthys pardalis, Phaenomonas longissima (Ophichthidae), Sphagemacrurus hirundo (Macrouridae), Gadella imberbis and Physiculus cyanostrophus (Moridae). Data includes distribution, habitat, morphometry and reproduction.Six campagnes exploratoires ainsi que quelques captures opportunistes réalisées de quelques mètres jusqu’à environ 1000 m de profondeur aux îles du Cap-Vert ont permis d’établir une liste comprenant 66 espèces de poissons téléostéens. Six espèces sont signalées pour la première fois aux îles du Cap-Vert : Gnathophis mystax (Congridae), Nezumia africana, Nezumia duodecim (Macrouridae), Ectreposebastes imus (Scorpaenidae), Paraliparis sp. (Liparidae) et Lappanella fasciata (Labridae). La présence de six autres espèces mal connues est confirmée pour cet archipel : Myroconger compressus (Myrocongridae), Myrichthys pardalis, Phaenomonas longissima (Ophichthidae), Sphagemacrurus hirundo (Macrouridae), Gadella imberbis et Physiculus cyanostrophus (Moridae). Les données présentées concernent la distribution, l’habitat, la morphométrie et la reproduction.Postprin

The striped soldier shrimp Plesionika edwardsii (Crustacea:Decapoda:Pandalidae) from the cape Verde Islands

This study is part of the PROACTIVA 1-2 (2009-2012) and MARPROF-CV (2010-2014) projects, in the framework of the Canary Islands Government and UE PCT MAC 2007-2013 programmes respectively. Research has mainly focused on the stock assessment of the striped soldier shrimp, Plesionika edwardsii (Brandt, 1851), because it has shown moderate to high levels of fishing yield and abundances compatible with the development of a new sustainable fishery in the Cape Verde Islands. Cruises took place on board the R/V Prof. Ignacio Lozano. Four 15-day surveys have been conducted to date: Cabo Verde 2010-04 (April 2010), Camar˜ao-1 (November 2011), Camar˜ao-2 (Mars 2012) and Camar ˜ao-3 (July 2012). An innovative fishing gear so-called multiple semi-floating shrimp trap (MSFST) was used. Each fishing line was composed by 40-65 traps operating around 2.4 m above the seafloor, using Decapterus macarellus (Carangidae) as unique bait of the traps. Fishing depth was 66-458 m, and efective fishing time was 16-18 h. Each trap was attached to the main bottom line every 15 m, and the maximum attraction of this bait was established to be 100 or 150 m, according to the experience gained from the local fishery for deep-sea lobsters. So density by area was calculated assuming two different areas of attraction of the fishing gear. Initial biomass was estimated from depletion experiments at different abundance stations by applying the Leslie & Davis (1939) method, modified by Ricker (1975). Each fishing operation was classified according to its yield (CPUE in g/trap/night). The potential fishing planar area was estimated between the isobathymetric lines between 90 and 220 m. Total biomasses (Bt) were calculated from areas (km2) and mean minimum/maximum densities (kg/km2). Maximum sustainable yield (MSY) was estimated from Bt using the Beddington and Cooke (1983) model by entering natural mortality (0.6), growth rate (0.53 year�1) and recruitment age (1.32 year), which are the parameters for this target species published for the Canaries. These parameters estimate a biological exploitation rate ( ) of 0.262. Interpolations were applied to estimate MSY for insular stocks representing lesser than 5% of the total fishing grounds for this species in the archipelago. The MSY estimated by depletion were 30.5 tons/year for the stock of S˜ao Vicente, Santa Luzia, Ilheus and S˜ao Nicolau, 10 tons/year for the stock of Santiago, 138.8 tons/year for the stock of Boa Vista and Maio, and 5.6 tons/year for the stock of Sal. The small stocks estimated by interpolation were: 4.5 tons/year for the stock of Santo Ant˜ao, 1.3 tons/year for the stock of Fogo, and 1.8 tons/year for the stock of Brava and Ilheus. In total, 192.5 tons per year was the total MSY for the striped soldier shrimp around the islands of the Cape Verde archipelago, occupying a total area of 1,918 km2 of new fishing grounds at between 90 and 220 m of depth. In comparison with the traditional bottom trap used in the Canary Islands, the innovative fishing gear MSFST were proved to be more selective for pandalid shrimps, minimizing the gear impact on the seafloor as well as the by-catch by reducing the discards. Depletion methods are based on the assumption of a closed system, that is with minimum or zero immigration between neighbouring areas. The straight forward decline of CPUEs obtained during the depletion experiments seems to confirm that P. edwardsii is a low mobility species, making this assumption valid at least during short-time periods. Because of the bathymetry profile of these islands,the depth range is from very close (few nautical miles in Santiago) to far away (10-12 n.m. in Boa Vista) to the coastline. Fishing effort should be controlled on the basis of quotas, number of fishing vessels and a precautionary approach in order to ensure that catching is commensurate with sustainable levels of exploitation. MSY estimates suggest that this new Capeverdean fishery should be carried out by specialized medium-sized fishing vessels. During the last decades a combination of shrimp trawling and industrial trapping activity has threatened over-exploitation in the Mediterranean fisheries targeting on P. edwardsii; currently the shrimp collapse has conducted to the decline of these fisheries. Can the Cape Verde regulatory bodies and all the stakeholders involved learn the lessons this teaches us about this resource management

By-catch composition of the striped soldier shrimp Plesionika edwardsii (Crustace: Decapoda: Pandalidae) experimental fishery in the Cape Verde Islands

This work focuses on the by-catch composition of Plesionika edwardsii experimental fishery in the Cape Verde Islands. Obtaining information on abundance, composition and lifecycle of species involved in this potential fishery is useful, in order to ensure its sustainable development under an ecosystem approach. The first step towards this goal is the description of catches. Four 15-day research surveys were conducted on board the R/V Prof. Ignacio Lozano: April 2010 (S˜ao Vicente and Santa Luzia islands), November 2011 (Santiago island), March 2012 (Boa Vista island,) and July 2012 (Sal and S˜ao Nicolau islands). The working depths were between 66 and 458 m depth. A standardized innovative fishing gear was used, so-called multiple semi-floating shrimp traps. Each fishing line was composed by 40-65 traps operating around 2.4 m above the seafloor, using Decapterus macarellus (Carangidae) as unique bait of the traps. Multiple semi-floating shrimp traps is a passive fishing system that allows catch and release sea significant part of the unwanted catches, as in the case of Chondrichthyes or Anguilliformes, reducing the fishing impact on non-target species. The main by-catch was composed of 53 species belonging to three groups including Chondrichthyes (three families and three species), Crustacea (11 families and 19 species) and Osteichthyes (15 families and 29 species). Plesionika edwardsii, the target species of this fishery, represented 97.8% of the catch in terms of abundance and 40.1% in biomass. By-catch represented 59.9% of total catch in terms of biomass. Osteichthyes (87.5%) were the dominant group and was represented by the following main families; Sparidae (33.9%), Moridae (32.5%), Muraenidae (32.5%), Scorpaenidae (9.9%) and Tetraodontidae (9.8%). Chondrichthyes (11.6%) were composed by Centrophoridae (65.3%) and Triakidae (34.1%). Finally, Crustacea (1.9%) were chiefly composed by Pandalidae (79.1%). However, different families represented by specific species were found to be dominant around each island. Sparidae were the dominant family represented by Pagellus acarne (46.2% of total by-catch) at S˜ao Vicente, and by Dentex macrophthalmus (42.6%) at Boa Vista. Tetraodontidae with Sphoeroides pachygaster (25.9%) and Sparidae with P. acarne (25.1%) were the co-dominant families in the by-catch around Santa Luzia. Muraenidae were the dominant family represented by Gymnothorax polygonius (69.4%) at Sal, and by Muraena helena (63.4%) at S˜ao Nicolau. Finally, Scorpaenidae with Pontinus kuhlii (22.3%) and Moridae with Physiculus cyanostrophus (22.1%) were the co-dominant families of the bycatch around Santiago. Acknowledgements: This study is part of the PROACTIVA 1-2 (2009-2012) and MARPROF-CV (2010-2014) projects, in the framework of the Canary Islands Government and UE PCT MAC 2007- 2013 programmes respectively

Respuesta hipofisaria y ovulatoria de conejas nulíparas alimentadas con dietas suplementadas con ácidos grasos poliinsaturados n-3.

Veinte conejas nulíparas se alimentaron ad libitum desde las 10 a las 16 semanas de edad con dos piensos isofibrosos, isoenergéticos e isoproteicos suplementados con dos fuentes de grasa diferentes: 0,75% de manteca para la dieta control (grupo C; n=10) ó 1,5% de un suplemento (Optomega-50; Optivite International Ltd., España) que contenía un 50% de extracto etérero y 38% de ácidos grasos poli-insaturados n-3 (AG n-3) para la dieta experimental (grupo P; n=10). A las 16 semanas de edad se determinó el consumo de pienso, así como la tasa de ovulación y las concentraciones plasmáticas de progesterona y LH a 0, 60 min, 5, 7 y 9 días post-inducción de ovulación con 20 μg de Gonadorelina (Inducel-GnRH, Lab. Ovejero). El consumo de pienso (150,5 g/d), el pico preovulatorio de LH (149,7±10,9 ng/ml), la tasa de ovulación (95%) y el número de cuerpos lúteos (9,8±0,7) fueron similares entre tratamientos. Las concentraciones plasmáticas de progesterona aumentaron a los 60 minutos (7,13±19 ng/ml) y 5 días (13,3±1,9 ng/ml) con respecto al día 0 (0,7±1,9 ng/ml; P<0.05), permaneciendo elevadas el día 9 en ambos grupos (19,4±1,9 ng/ml). Además, el día 5 y 7 post-inducción, las hembras alimentadas con la dieta P tendieron a tener niveles más elevados de progesterona en sangre que las alimentadas con la dieta C (16,6±1,9 vs.12,6±1,8 y 19,0±1,8 vs. 15,5±2,1 ng/ml, P=0,068 y P=0,082; respectivamente) que coinciden con el momento de la implantación embrionaria en esta especie. Por lo tanto, la suplementación con AG n-3 podría mejorar los niveles de progesterona en sangre y por lo tanto reducir la mortalidad embrionaria en este punto

Respuesta hipofisaria y ovulatoria de conejas nulíparas alimentadas con dietas suplementadas con ácidos grasos poliinsaturados n-3

Twenty rabbit does were fed ad libitum from 10 to 16 weeks of age two isofibrous, isoenergetic and isoproteic diets (n=10) supplemented with two different fat sources: 0.75% lard for diet C (control) or 1.5% of a supplement (Optomega-50; Optivite International Ltd., Spain) containing a 50% of EE and 38% of n-3 polyunsaturated fatty acids for diet P (PUFA n-3). Does feed intake, ovulation rate and plasma progesterone and LH concentrations at 0, 60 min, 5, 7 and 9 days post-induction of ovulation with 20 μg of Gonadorelina (Inducel-GnRH, Lab. Ovejero) at 16 weeks of age were assessed. Average daily intake (150.5 g/d), ovulation rate (95%), preovulatory peak of plasma LH (149.7±10.9 ng/ml ng/ml) and number of corpora lutea (9.8±0.7) were similar between dietary treatments. Plasma progesterone concentrations increased at 60 minutes (7.13±1.9 ng/ml) and 5 days (13.3±1.9 ng/ml) after induction with respect to day 0 (0.7±1.9 ng/ml; P&lt;0.05), remaining constant afterward in both groups (19.4±1.9 ng/ml). Moreover, plasma progesterone of does fed diet P tended to be higher than for diet C on day 5 and 7 post-induction (16.6±1.9 vs.12.6±1.8 and 19.0±1.8 vs. 15.5±2.1 ng/ml, P=0.068 and P=0.082; respectively). Therefore, PUFA n-3 supplementation in does rabbit diets might be related with high progesterone levels and reduced early embryo mortality.Veinte conejas nulíparas se alimentaron ad libitum desde las 10 a las 16 semanas de edad con dos piensos isofibrosos, isoenergéticos e isoproteicos suplementados con dos fuentes de grasa diferentes: 0,75% de manteca para la dieta control (grupo C; n=10) ó 1,5% de un suplemento (Optomega-50; Optivite International Ltd., España) que contenía un 50% de extracto etérero y 38% de ácidos grasos poli-insaturados n-3 (AG n-3) para la dieta experimental (grupo P; n=10). A las 16 semanas de edad se determinó el consumo de pienso, así como la tasa de ovulación y las concentraciones plasmáticas de progesterona y LH a 0, 60 min, 5, 7 y 9 días post-inducción de ovulación con 20 μg de Gonadorelina (Inducel-GnRH, Lab. Ovejero). El consumo de pienso (150,5 g/d), el pico preovulatorio de LH (149,7±10,9 ng/ml), la tasa de ovulación (95%) y el número de cuerpos lúteos (9,8±0,7) fueron similares entre tratamientos. Las concentraciones plasmáticas de progesterona aumentaron a los 60 minutos (7,13±19 ng/ml) y 5 días (13,3±1,9 ng/ml) con respecto al día 0 (0,7±1,9 ng/ml; P&lt;0.05), permaneciendo elevadas el día 9 en ambos grupos (19,4±1,9 ng/ml). Además, el día 5 y 7 post-inducción, las hembras alimentadas con la dieta P tendieron a tener niveles más elevados de progesterona en sangre que las alimentadas con la dieta C (16,6±1,9 vs.12,6±1,8 y 19,0±1,8 vs. 15,5±2,1 ng/ml, P=0,068 y P=0,082; respectivamente) que coinciden con el momento de la implantación embrionaria en esta especie. Por lo tanto, la suplementación con AG n-3 podría mejorar los niveles de progesterona en sangre y por lo tanto reducir la mortalidad embrionaria en este punto

Combinación de Prácticas de Simulación y Reales para un Curso Anual de Arquitectura de Computadores

Se presenta un programa de prácticas para un curso anual de la asignatura Arquitectura de Computadores del Segundo Ciclo de la Ingeniería Informática, que trata de conseguir un equilibrio entre la simulación y las prácticas reales de laboratorio

Fertilidad, desarrollo embrionaria y prolificidad de conejas nulíparas alimentadas con piensos enriquecidos en ácidos grasos poliinsaturados n-3.

Un total de 105 conejas nulíparas se alimentaron ad libitum un mes antes y durante su primera gestación con dos piensos isofibrosos, isoenergéticos e isoproteicos suplementados con dos fuentes de grasa diferentes: 0,75% de manteca para la dieta control (grupo C; n=53) ó 1,5% de un suplemento (Optomega-50; Optivite International Ltd., España) que contenía un 50% de extracto etéreo y 38% de ácidos grasos poli-insaturados (AG n-3) para la dieta experimental (grupo P; n=52). A los 4,5 meses de edad se determinó la fertilidad después de ser inseminadas artificialmente y tratadas con 20 μg de Gonadorelina (Inducel-GnRH, Ovejero) para inducirles la ovulación. Al parto se determinó la duración de la gestación, el número y peso de los gazapos nacidos vivos y muertos. Se escogieron 16 conejas al azar, 8 de cada grupo, y se realizaron ecografías a los 8, 15 y 22 días de gestación en las que se determinó las dimensiones del embrión y de los anejos fetales. La suplementación con AG n-3 no afectó a los resultados productivos determinados ya que se trata de parámetros que en nulíparas son difíciles de mejorar y suelen ser altos. Tampoco se observaron diferencias en las determinaciones ecográficas pero se han podido definir medidas fisiológicas de los fetos y anejos placentarios de gran utilidad para futuros estudios en esta especie

Digestibilidad y respuesta ovárica de conejas reproductoras alimentadas con dietas suplementadas con ácidos grasos poliinsaturados n-3

Aumentar el número de gazapos destetados por coneja y parto es un objetivo importante para incrementar la rentabilidad del sector cunícola industrial con efectos directos. La mejora genética de la prolificidad en las líneas de madres ha demostrado ser una estrategia eficaz para alcanzar este objetivo; sin embargo otras vías, como la influencia de diferentes fuentes de grasa en las dietas de conejas reproductoras, han sido muy poco estudiadas. Los ácidos grasos (AG) n-3 interfieren en la fisiología reproductiva porque pueden modular las enzimas involucradas en el metabolismo de las prostaglandinas y del colesterol que es el precursor de los esteroides como la progesterona (revisado en Gulliver et al., 2012). El objetivo de este trabajo es estudiar si la suplementación con AG poliinsaturados (PUFA) n-3 de las dietas de conejas durante la recría puede afectar a la tasa de ovulación y a la síntesis esteroidogénica ovárica determinada mediante las concentraciones de progesterona plasmática

Climate, irrigation, and land cover change explain streamflow trends in countries bordering the northeast Atlantic

Attribution of trends in streamflow is complex, but essential, in identifying optimal management options for water resources. Disagreement remains on the relative role of climate change and human factors, including water abstractions and land cover change, in driving change in annual streamflow. We construct a very dense network of gauging stations (n = 1,874) from Ireland, the United Kingdom, France, Spain, and Portugal for the period of 1961–2012 to detect and then attribute changes in annual streamflow. Using regression‐based techniques, we show that climate (precipitation and atmospheric evaporative demand) explains many of the observed trends in northwest Europe, while for southwest Europe human disturbances better explain both temporal and spatial trends. For the latter, large increases in irrigated areas, agricultural intensification, and natural revegetation of marginal lands are inferred to be the dominant drivers of decreases in streamflow