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

Study of the efflux velocity induced by two propellers

Present analysis is related with seabed erosion caused during docking and undocking maneuvering. Twin propellers without rudder were studied using a physical model with a fixed clearance distance and three different rotating velocities. Experimental results were compared to theoretical expressions of the efflux velocity, axial velocity and finally maximum bed velocity. Efflux velocity equations overestimate the experimental results, whereas axial velocity computed using the Dutch method fits reasonably well the experimental data. However, when maximum bed velocity expressions are compared to experimental results, German method behaves better with an over estimation if a quadratic superposition of the single jets is used.Postprint (published version

Boundary conditions generated by dynamic particles in SPH methods

Smoothed Particle Hydrodynamics is a purely Lagrangian method that can be applied to a wide variety of fields. The foundation and properties of the so called dynamic boundary particles (DBPs) are described in this paper. These boundary particles share the same equations of continuity and state as the moving particles placed inside the domain, although their positions and velocities remain unaltered in time or are externally prescribed. Theoretical and numerical calculations were carried out to study the collision between a moving particle and a boundary particle. The boundaries were observed to behave in an elastic manner in absence of viscosity. They allow the fluid particles to approach till a critical distance depending on the energy of the incident particle. In addition, a dam break confined in a box was used to check the validity of the approach. The good agreement between experiments and numerical results shows the reliability of DBPs

Modeling dam break behavior over a wet bed by a SPH technique

Dam break evolution over dry and wet beds is analyzed with a smoothed particle hydrodynamics model. The model is shown to accurately fit both experimental dam break profiles and the measured velocities. In addition, the model allows one to study different propagation regimes during the dam break evolution. In particular, different dissipation mechanisms were identified: bottom friction and wave breaking. Although breaking dominates over wet beds at the beginning of the movement, bottom friction becomes the main dissipation mechanism in the long run

Historical and future naturalization of Magallana gigas in the Galician coast in a context of climate change

Financiado para publicación en acceso aberto: Universidade de Vigo/CISUGMagallana gigas is a naturalized species on the north coast of Galicia (Rías Altas, Northwest Iberian Peninsula), where it was unintentionally introduced. In recent decades, a greater abundance of M. gigas has been observed on the Galician coast, expanding towards the south, reaching the Artabro Gulf (Rías Centrales, NW Galician coast), probably due to ocean warming. Although this species has been cultivated in the Rías Baixas since the early 1990s and spawning has been reported, recruitment was never observed, which is likely due to the cold water upwelled during the spawning months. The future rise in seawater temperature may favor the naturalization of the non-indigenous species M. gigas southwards, in the Rías Baixas. Thermally, the Ría de Arousa seems to be the most favorable estuary for the future settlement of M. gigas, which may occur in the next decades. The extent of thermally favorable zones within estuaries is projected to increase rapidly by mid-century, and reaching 100 % of the estuarine area by the end of the century. As has already happened in other areas of the world, the expansion and naturalization of the Pacific oyster on the Galician coast will likely affect the native communities and economic activities, making it necessary to implement monitoring and management strategies to mitigate its effect.Xunta de Galicia | Ref. ED481B-2021-103Xunta de Galicia-FEDER | Ref. ED431C 2021/44Fundação para a Ciência e a Tecnologia | Ref. UIDP/50017/2020Fundação para a Ciência e a Tecnologia | Ref. UIDB/50017/2020Fundação para a Ciência e a Tecnologia | Ref. LA/ P/0094/202

Coastal warming under climate change: global, faster and heterogeneous

The assessment of expected changes in coastal sea surface temperature (SST) on a global scale is becoming increasingly important due to the growing pressure on coastal ecosystems caused by climate change. To achieve this objective, 17 Global Climate Models from CMIP6 were used, with data from historical and hist-1950 experiments spanning 1982-2050. This analysis highlights significant warming of coastal areas worldwide, with higher and more variable rates of warming than observed in previous decades. All basins are projected to experience an increase in coastal SST near 1 °C by mid-century, with some regions exhibiting nearshore SST anomalies exceeding 2 °C for the period 2031-2050 relative to 1995-2014. Regarding the Eastern Upwelling Boundary Systems, only the Canary upwelling system and the southern part of the Humboldt upwelling system manage to show lower-than-average SST warming rates, maintaining, to a certain extent, their ability to buffer global warming.publishe

Differences in coastal and oceanic SST trends north of Yucatan Peninsula

The coastal area north of Yucatan has experienced a cooling SST trend from 1982 to 2015 during the upwelling season (May–September) that contrasts with the warming observed at the adjacent ocean area. Different drivers were analyzed to identify the possible causes of that unusual coastal cooling. Changes in coastal upwelling and in sea-atmosphere heat fluxes are not consistent with the observed coastal cooling. The eastward shift of the Yucatan Current observed over the last decades is hypothesized as the most probable cause of coastal cooling. This shift enhances the vertical transport of cold deeper water to the continental shelf from where it is pumped to the surface by upwelling favorable westerly winds.publishe

Projections of wind energy resources in the Caribbean for the 21st century

The Caribbean has suitable conditions for a significant wind energy development, which makes a good planning for the future renewable energy mix essential. The impact of climate change on Caribbean wind power has been analyzed by means of an ensemble of CORDEX regional climate models (RCMs) under the RCP8.5 warming scenario. The offshore wind energy resource was classified for the historical period and for the future considering wind energy factors, environmental risk factors and cost factors whose weights were estimated by a Delphi method. Future projections show a maximum annual wind increase, ∼0.4 ms−1 (8%), in most of the Caribbean, except in the Yucatán Basin. This increment occurs mainly during the wet season, ∼0.5 ms−1 (∼10%), associated with changes in the extension of the North Atlantic Subtropical High, which will strengthen the Caribbean low-level jet. Additionally, the moderate wind increase, ∼0.2 ms−1 (∼4%), projected during the dry season is restricted to the southeastern coast and it is associated with an increment in the land-ocean temperature difference (∼1 °C), which will intensify local easterly winds. The low-level jet region was classified as the richest wind energy resource in the Caribbean for the future with a larger extension compared to the historical period.publishe