How can ocean warming at the NW Iberian Peninsula affect mussel aquaculture?

Understanding and forecasting future consequences of climate change in mussel aquaculture industry require the assessment of changes in physical parameters which may affect mussel growth. The FLOW module of Delft3D model forced with climatic data was validated and calibrated for the Rías Baixas (NW Iberian Peninsula), one of the areas with the highest mussel production in the world. This model was used to perform historical (1999-2018) and future (2080-2099) projections. Temperature and stratification water conditions were compared in order to determine at what extent climate change can affect mussel production. Thermal stress will increase in a non-homogeneous throughout the water column and the comfort level of mussels will be reduced by more than 60% in the upper layers and more than 30% in deep layers in most of the mussel raft polygons. Water column stratification will increase ~ 5-10 cycles h-1 in most of the polygons reducing the vertical exchange of nutrients and oxygen. Hereby changes in water temperature and stratification at the end of the century will not be favorable for mussel growth.publishe

Combined Effects of the North Atlantic Oscillation and the Arctic Oscillation on Sea Surface Temperature in the Alborán Sea

We explored the possible effects of the North Atlantic Oscillation (NAO) and Arctic Oscillation (AO) on interannual sea surface temperature (SST) variations in the Albora´n Sea, both separately and combined. The probability of observing mean annual SST values higher than average was related to NAO and AO values of the previous year. The effect of NAO on SST was negative, while that of AO was positive. The pure effects of NAO and AO on SST are obscuring each other, due to the positive correlation between them. When decomposing SST, NAO and AO in seasonal values, we found that variation in mean annual SST and mean winter SST was significantly related to the mean autumn NAO of the previous year, while mean summer SST was related to mean autumn AO of the previous year. The one year delay in the effect of the NAO and AO on the SST could be partially related to the amount of accumulated snow, as we found a significant correlation between the total snow in the North Albora´n watershed for a year with the annual average SST of the subsequent year. A positive AO implies a colder atmosphere in the Polar Regions, which could favour occasional cold waves over the Iberian Peninsula which, when coupled with precipitations favoured by a negative NAO, may result in snow precipitation. This snow may be accumulated in the high peaks and melt down in spring-summer of the following year, which consequently increases the runoff of freshwater to the sea, which in turn causes a diminution of sea surface salinity and density, and blocks the local upwelling of colder water, resulting in a higher SST.CGL2009-11316 (Ministerio de Ciencia e Innovación, Spain, and FEDER

Analysis of the effect of atmospheric oscillations on physical condition of pre–reproductive bluefin tuna from the Strait of Gibraltar

Análisis del efecto de las oscilaciones atmosféricas en la condición física del atún rojo del estrecho de Gibraltar antes de su reproducción El objetivo de este estudio fue explorar los posibles efectos de las oscilaciones atmosféricas, la oscilación del Atlántico Norte (NAO) y la oscilación del Ártico (AO), en la condición física del atún rojo (Thunnus thynnus). Para ello, estimamos un índice de condición física para cada clase de talla y año a partir de 3.501 pares de datos de talla–peso de atunes capturados en la pesca de cebo vivo antes de la temporada de desove (enero, febrero y marzo). Con el fin de obtener un valor único del índice de condición física (K–mean) por año calculamos el promedio de todas las clases de talla. Además, calculamos el índice de condición física de Le Cren (KLC). Observamos correlaciones positivas significativas entre las oscilaciones atmosféricas y los dos índices decondición física. En el caso del K–mean, la AO explicó un 75% de la variabilidad observada. En relación con el KLC, la NAO explicó aproximadamente un 73% de la variabilidad observada, mientras que la AO explicó un 70% de la variabilidad observada. El aumento de la prevalencia de fuertes vientos de componente oeste podría intervenir en la mejora de la condición física del atún rojo asociada con una fase positiva de las oscilaciones atmosféricas. Llegamos a la conclusión de que el aumento de la prevalencia de fuertes vientos de componente oeste, ya sea por una AO o una NAO positiva, favorece el viaje de los atunes que llegan desde el Atlántico hasta el Mediterráneo porque, por un lado, reduce los costes energéticos de la migración y, por otro, aumenta la cantidad de nutrientes en superficie al mezclar las capas de agua profundas y superficiales en zonas locales como el estrecho de Gibraltar.The aim of this study was to explore the possible effects of atmospheric oscillations: North Atlantic Oscillation (NAO) and Arctic Oscillation (AO), on the physical condition of bluefin tuna (Thunnus thynnus). We estimated a fitness ratio from 3,501 pairs of length–weight data based on bluefin tuna caught in bait–boat fisheries before the spawning season (January, February and March), for each length class and year. In order to obtain a single fitness ratio (K–mean) per year we determined the average for all length classes. We also evaluated Le Cren’s condition index (KLC). We observed significant positive correlations between the atmospheric oscillations and both physical condition indexes. In the case of K–mean, the AO explained 75% of the observed variability. Regarding KLC, the NAO explained approximately 73% of the observed variability, while the AO explained 70% of the observed variability. The increase in physical conditions of bluefin tuna in association with positive atmospheric oscillations could be mediated by the increase in the prevalence of strong trade winds. We concluded that the increase in the prevalence of strong westerly winds, mediated by a positive AO or NAO, favours the trip from the Atlantic to the Mediterranean by reducing energy costs due to migration and by increasing the supply of nutrients at the surface by the mixing of deep water and surface water in local areas such as the Strait of Gibraltar.Análisis del efecto de las oscilaciones atmosféricas en la condición física del atún rojo del estrecho de Gibraltar antes de su reproducción El objetivo de este estudio fue explorar los posibles efectos de las oscilaciones atmosféricas, la oscilación del Atlántico Norte (NAO) y la oscilación del Ártico (AO), en la condición física del atún rojo (Thunnus thynnus). Para ello, estimamos un índice de condición física para cada clase de talla y año a partir de 3.501 pares de datos de talla–peso de atunes capturados en la pesca de cebo vivo antes de la temporada de desove (enero, febrero y marzo). Con el fin de obtener un valor único del índice de condición física (K–mean) por año calculamos el promedio de todas las clases de talla. Además, calculamos el índice de condición física de Le Cren (KLC). Observamos correlaciones positivas significativas entre las oscilaciones atmosféricas y los dos índices decondición física. En el caso del K–mean, la AO explicó un 75% de la variabilidad observada. En relación con el KLC, la NAO explicó aproximadamente un 73% de la variabilidad observada, mientras que la AO explicó un 70% de la variabilidad observada. El aumento de la prevalencia de fuertes vientos de componente oeste podría intervenir en la mejora de la condición física del atún rojo asociada con una fase positiva de las oscilaciones atmosféricas. Llegamos a la conclusión de que el aumento de la prevalencia de fuertes vientos de componente oeste, ya sea por una AO o una NAO positiva, favorece el viaje de los atunes que llegan desde el Atlántico hasta el Mediterráneo porque, por un lado, reduce los costes energéticos de la migración y, por otro, aumenta la cantidad de nutrientes en superficie al mezclar las capas de agua profundas y superficiales en zonas locales como el estrecho de Gibraltar

Assessing the response of exploited marine populations in a context of rapid climate change: the case of blackspot seabream from the Strait of Gibraltar

Evaluación de la respuesta de las poblaciones marinas explotadas en un contexto de cambio climático rápido: el caso del besugo de la pinta en el estrecho de Gibraltar Existe una creciente preocupación por la disminución de la pesca y la posibilidad de que esta disminución se acelere debido al cambio climático. Los estudios sobre la pesca a pequeña escala podrían ayudar a mejorar nuestra comprensión de los efectos del clima en la ecología de las poblaciones explotadas. El estrecho de Gibraltar es una importante zona de pesca para la flota artesanal. En esta zona, el besugo de la pinta (Pagellus bogaraveo) es la especie más importante para la pesca artesanal en vista de su volumen de descarga. Los objetivos de este estudio consisten en estudiar los posibles efectos de dos oscilaciones atmosféricas: la oscilación del Atlántico Norte (NAO) y la oscilación del Ártico (AO), en la captura del besugo de la pinta en el estrecho de Gibraltar con objeto de determinar su relación con las condiciones oceanográficas, y mejorar nuestro conocimiento sobre los posibles efectos del cambio climático en la ecología de la pesca, para poder mejorar la gestión de la actividad pesquera. Utilizamos dos tipos de datos de diferentes fuentes: (i) los desembarques por unidad de esfuerzo registrados por un segundo grupo de trabajo entre Marruecos y España sobre el besugo de la pinta en la zona del estrecho de Gibraltar, para el período 1983–2011, y (ii) los desembarques registrados de besugo de la pinta obtenidos de las estadísticas anuales de pesca publicadas por la Junta de Andalucía. Nuestros resultados indican que el desembarque a largo plazo del besugo de la pinta en el estrecho de Gibraltar está íntimamente relacionado con las oscilaciones atmosféricas. Por lo tanto, los períodos prolongados de tendencias positivas en la NAO y la AO podrían favorecer altos rendimientos pesqueros. En contraste, las tendencias negativas de la NAO y la AO reducen drásticamente el rendimiento pesquero.There is a growing concern over the decline of fisheries and the possibility of the decline becoming worse due to climate change. Studies on small–scale fisheries could help to improve our understanding of the effect of climate on the ecology of exploited stocks. The Strait of Gibraltar is an important fishery ground for artisanal fleets. In this area, blackspot seabream (Pagellus bogaraveo) is the main species targeted by artisanal fisheries in view of its relevance in landed weight. The aims of this study were to explore the possible effects of two atmospheric oscillations, the North Atlantic Oscillation (NAO) and the Arctic Oscillation (AO), on the capture of blackspot seabream in the Strait of Gibraltar, to determine their association with oceanographic conditions, and to improve our knowledge about the possible effects of climate change on fisheries ecology so that fishery management can be improved. We used two types of data from different sources: (i) landings per unit of effort reported from a second working group between Morocco and Spain on Pagellus bogaraveo in the Gibraltar Strait area, for the period 1983–2011, and (ii) the recorded blackspot seabream landings obtained from the annual fisheries statistics published by the Junta de Andalucía (Andalusian Regional Government). Our results indicate that the long–term landing of blackspot seabream in the Strait of Gibraltar is closely associated with atmospheric oscillations. Thus, prolonged periods of positive trends in the NAO and AO could favour high fishery yields. In contrast, negative trends in NAO and AO could drastically reduce yield.Evaluación de la respuesta de las poblaciones marinas explotadas en un contexto de cambio climático rápido: el caso del besugo de la pinta en el estrecho de Gibraltar Existe una creciente preocupación por la disminución de la pesca y la posibilidad de que esta disminución se acelere debido al cambio climático. Los estudios sobre la pesca a pequeña escala podrían ayudar a mejorar nuestra comprensión de los efectos del clima en la ecología de las poblaciones explotadas. El estrecho de Gibraltar es una importante zona de pesca para la flota artesanal. En esta zona, el besugo de la pinta (Pagellus bogaraveo) es la especie más importante para la pesca artesanal en vista de su volumen de descarga. Los objetivos de este estudio consisten en estudiar los posibles efectos de dos oscilaciones atmosféricas: la oscilación del Atlántico Norte (NAO) y la oscilación del Ártico (AO), en la captura del besugo de la pinta en el estrecho de Gibraltar con objeto de determinar su relación con las condiciones oceanográficas, y mejorar nuestro conocimiento sobre los posibles efectos del cambio climático en la ecología de la pesca, para poder mejorar la gestión de la actividad pesquera. Utilizamos dos tipos de datos de diferentes fuentes: (i) los desembarques por unidad de esfuerzo registrados por un segundo grupo de trabajo entre Marruecos y España sobre el besugo de la pinta en la zona del estrecho de Gibraltar, para el período 1983–2011, y (ii) los desembarques registrados de besugo de la pinta obtenidos de las estadísticas anuales de pesca publicadas por la Junta de Andalucía. Nuestros resultados indican que el desembarque a largo plazo del besugo de la pinta en el estrecho de Gibraltar está íntimamente relacionado con las oscilaciones atmosféricas. Por lo tanto, los períodos prolongados de tendencias positivas en la NAO y la AO podrían favorecer altos rendimientos pesqueros. En contraste, las tendencias negativas de la NAO y la AO reducen drásticamente el rendimiento pesquero

Characterization of a winter upwelling event in the Northern Galician Rias

II International Symposium in Marine Sciences = II Simposio internacional de Ciencias del Mar, Vigo, 27-30 abril 2009N

Analysis of the effect of atmospheric oscillations on physical condition of pre–reproductive bluefin tuna from the Strait of Gibraltar

Analysis of the effect of atmospheric oscillations on physical condition of pre–reproductive bluefin tuna from the Strait of Gibraltar .— The aim of this study was to explore the possible effects of atmospheric oscillations: North Atlantic Oscillation (NAO) and Arctic Oscillation (AO), on the physical condition of bluefin tuna ( Thunnus thynnus ). We estimated a fitness ratio from 3,501 pairs of length–weight data based on bluefin tuna caught in bait–boat fisheries before the spawning season (January, February and March), for each length class and year. In order to obtain a single fitness ratio (K–mean) per year we determined the average for all length classes. We also evaluated Le Cren’s condition index (K LC ). We observed significant positive correlations between the atmospheric oscillations and both physical condition indexes. In the case of K–mean, the AO explained 75% of the observed variability. Regarding K LC , the NAO explained approximately 73% of the observed variability, while the AO explained 70% of the observed variability. The increase in physical conditions of bluefin tuna in association with positive atmospheric oscillations could be mediated by the increase in the prevalence of strong trade winds. We concluded that the increase in the prevalence of strong westerly winds, mediated by a positive AO or NAO, favours the trip from the Atlantic to the Mediterranean by reducing energy costs due to migration and by increasing the supply of nutrients at the surface by the mixing of deep water and surface water in local areas such as the Strait of Gibraltar.Postprin

Assessing the responses of exploited marine populations in a context of rapid climate change: the case of blackspot seabream from Strait of Gibraltar.

Assessing the response of exploited marine populations in a context of rapid climate change: the case of blackspot seabream from the Strait of Gibraltar.— There is a growing concern over the decline of fisheries and the possibility of the decline becoming worse due to climate change. Studies on small–scale fisheries could help to improve our understanding of the effect of climate on the ecology of exploited stocks. The Strait of Gibraltar is an important fishery ground for artisanal fleets. In this area, b lackspot seabream ( Pagellus bogaraveo ) is the main species targeted by artisanal fisheries in view of its relevance in landed weight. The aims of this study were to explore the possible effects of two atmospheric oscillations, the North Atlantic Oscillation (NAO) and the Arctic Oscillation (AO), on the capture of blackspot seabream in the Strait of Gibraltar, to determine their association with oceanographic conditions, and to improve our knowledge about the possible effects of climate change on fisheries ecology so that fishery management can be improved. We used two types of data from different sources: (i) landings per unit of effort reported from a second working group between Morocco and Spain on Pagellus bogaraveo in the Gibraltar Strait area, for the period 1983–2011 , and (ii) the recorded blackspot seabream landings obtained from the annual fisheries statistics published by the Junta de Andalucía (Andalusian Regional Government). Our results indicate that the long–term landing of blackspot seabream in the Strait of Gibraltar is closely associated with atmospheric oscillations. Thus, prolonged periods of positive trends in the NAO and AO could favour high fishery yields. In contrast, negative trends in NAO and AO could drastically reduce yield.Postprint0,000

Different approaches to analyze the impact of future climate change on the exploitation of wave energy

The increment of the share of renewable energies in the global mix implies that all renewable energies must be exploited. In this sense, it is necessary to make significant research and investment effort in the particular case of wave energy to reach the degree of maturity of other marine energies in the near future. Apart from the inherent factors that hinder the development of wave energy, such as the non-existence of a market-leading type of capturing device, uncertainties about the available future resource also hamper its growth. In this article, a review of the procedures followed in the literature to deal with the future wave energy resources and their subsequent exploitation is described. These procedures include the evaluation of the best future atmospheric models to drive wave models, the different downscaling techniques to evaluate the resource in large regions with high spatial resolution, and the analysis of the variability of the future energy resource and its future exploitability in a certain region taking into account different types of devices. Additionally, the current state of the art of previous studies dealing with future wave energy resources for different locations worldwide is described. Despite the difficulties involved in studying future wave energy resources, the high technological readiness level of the offshore wind industry, the creation of power generation farms with combined technologies, and the growth of marine aquaculture in the coming years could generate synergies that provide the definitive impulse to achieve the necessary technological development.Agencia Estatal de Investigación | Ref. PID2020‐113245RB‐I00Agencia Estatal de Investigación | Ref. TED2021-129479A-I00Xunta de Galicia | Ref. ED431C 2021/44Agencia Estatal de Investigación | Ref. IJC2020-043745-IAgencia Estatal de Investigación | Ref. PRE2021-097580European Cooperation in Science and TechnologyUniversidade de Vigo/CISU

CFD investigation of a complete floating offshore wind turbine

This chapter presents numerical computations for floating offshore wind turbines for a machine of 10-MW rated power. The rotors were computed using the Helicopter Multi-Block flow solver of the University of Glasgow that solves the Navier-Stokes equations in integral form using the arbitrary Lagrangian-Eulerian formulation for time-dependent domains with moving boundaries. Hydrodynamic loads on the support platform were computed using the Smoothed Particle Hydrodynamics method. This method is mesh-free, and represents the fluid by a set of discrete particles. The motion of the floating offshore wind turbine is computed using a Multi-Body Dynamic Model of rigid bodies and frictionless joints. Mooring cables are modelled as a set of springs and dampers. All solvers were validated separately before coupling, and the loosely coupled algorithm used is described in detail alongside the obtained results

Percolation thresholds in chemical disordered excitable media

The behavior of chemical waves advancing through a disordered excitable medium is investigated in terms of percolation theory and autowave properties in the framework of the light-sensitive Belousov-Zhabotinsky reaction. By controlling the number of sites with a given illumination, different percolation thresholds for propagation are observed, which depend on the relative wave transmittances of the two-state medium considered