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Winds in coastal areas are particularly complex due to the drastic change of roughness and thermal properties between the sea and the land areas. Besides, the coastal topography, the shoreline irregularities, the surface state (land cover/use, soil moisture, sea surface temperature (SST), wind waves), and the interactions with the upper parts of the atmospheric boundary layer (ABL) add more complexity to the final characteristics of the surface winds of these regions.Among coastal winds, coastal breezes are especially common thermally driven flows formed in mid-latitude regions under fair-weather synoptic conditions. Under these situations, the thermal gradient between the sea and the ocean becomes more important, generating pressure gradient forces that lead to onshore winds during the daytime and offshore during the night. The impacts of these winds are broad and varied: they transport humidity, pollutants, and other physical properties in these regions; they can initiate convection (and even trigger the formation of storms), and they also drive the surface coastal currents, among others. From a societal point of view, the coastal breezes are crucial for the wind power industry, air-quality forecasts, maritime sports, and simply for the refreshing impact they cause, an aspect especially important in some areas commonly affected by extreme maximum temperatures and heat waves. Therefore, a correct understanding of the physical characteristics of the coastal breezes is a needed step to correctly forecast them and to be able to investigate their future trends.In this work, we present an observational analysis of the coastal breezes observed in the Gulf of Cádiz. We highlight some differences found between the breezes formed at the sea and at the land areas from observational measurements. Besides, we use the mesoscale Weather Research and Forecasting (WRF) model to simulate key case studies, showing how the interaction with the background synoptic wind is very important for the final characteristics that the breezes have. Related to this, we have observed how the effect of the changes in the surface (SST, soil moisture) on the breeze’s characteristics depend on the wind vertical profile (background wind). That is, surface changes impact the ABL mixing and the momentum transfer from higher levels, which seems to be the main mechanism that impact the breezes at lower levels, even more than the surface thermal gradient effect.

Dense water formation in the Eastern Mediterranean (EMed) is essential in sustaining the Mediterranean overturning circulation. Changes in the sources of dense water in the EMed point to changes in the circulation and the water properties of the Mediterranean Sea. Here we examine with a regional climate system model the changes in the dense water formation in the EMed through the twenty-first century under the RCP8.5 emission scenario. Our results show a shift in the dominant source of Eastern Mediterranean Deep Water (EMDW) from the Adriatic Sea to the Aegean Sea at the first half of twenty-first century. The projected dense water formation reduces by 75 % for the Adriatic Sea, 84 % for the Aegean Sea and 83 % for the Levantine Sea by the end of the century. The reduction in the intensity of deep water formation is related to hydrographic changes of surface and intermediate water, that strengthen the vertical stratification hampering the vertical mixing and thus the convection. Those changes have an impact on the water that flows through the Sicilian Strait to the Western Mediterranean and therefore on the whole Mediterranean system.

Coastal breezes are mesoscale winds formed in mid-latitude regions under fair-weather synoptic conditions, i.e., weak surface-pressure gradient and low winds. They are characterized by a typical wind-direction reversal twice per day, with onshore winds during daytime and offshore during the night. The impacts of these winds are broad and varied: they transport humidity and pollutants (among other physical properties) in the coastal region; they can initiate convection (and even trigger the formation of storms), and they also drive some of the surface oceanic currents formed close to the coast, among others. In this sense, recent surface current observations collected by the Gulf of Cádiz radar system point at the coastal breezes as important contributors to explain the behaviour of the surface currents variability in this region. From a societal point of view, the coastal breezes are crucial for wind power industry, air-quality forecasts, maritime sports, and simply for the refreshing impact that they cause in some warm areas in summer. Hence, a correct understanding of their physical characteristics is needed to correctly forecast them and to be able to investigate their future trends.These phenomena are formed due to the pressure gradient associated with the temperature difference between the sea and the land surfaces. Therefore, both systems (the ocean and the atmosphere) are involved on the final characteristics that specific breeze events will have, impacting on the variability observed in the strength, duration, and vertical/horizontal extension of the breezes. In this work, we use the Weather Research and Forecasting (WRF) mesoscale model to investigate how the changes in the surface affect the features of this phenomenon through the design of different sensitivity experiments. These include artificial changes in the land and sea surface temperature, but also the use of more realistic (and higher resolution) data to initialise the model. Besides, other experiments are designed to investigate the impact of different technical aspects of the model on the correct simulation of the physical processes, such as the use of different vertical and horizontal resolution, the choice of the planetary-boundary-layer scheme, or the activation or not of typical filters (smoothing) within the model.

We analyze the climate change signal in the Mediterranean Sea using the regionally coupled model REMO–OASIS–MPIOM (ROM; abbreviated from the regional atmosphere model, the OASIS3 coupler and the Max Planck Institute Ocean Model). The ROM oceanic component is global with regionally high horizontal resolution in the Mediterranean Sea so that the water exchanges with the adjacent North Atlantic and Black Sea are explicitly simulated. Simulations forced by ERA-Interim show an accurate representation of the present Mediterranean climate. Our analysis of the RCP8.5 (representative concentration pathway) scenario using the Max Planck Institute Earth System Model shows that the Mediterranean waters will be warmer and saltier throughout most of the basin by the end of this century. In the upper ocean layer, temperature is projected to have a mean increase of 2.7 ∘C, while the mean salinity will increase by 0.2 psu, presenting a decreasing trend in the western Mediterranean in contrast to the rest of the basin. The warming initially takes place at the surface and propagates gradually to deeper layers. Hydrographic changes have an impact on intermediate water characteristics, potentially affecting the Mediterranean thermohaline circulation in the future.

Deep water formation (DWF) in the North Western Mediterranean (NWMed) is a key feature of Mediterranean overturning circulation. DWF changes under global warming may have an impact on the Mediterranean biogeochemistry and marine ecosystem. Here we analyze the deep convection in the Gulf of Lions (GoL) in a changing climate using a regional climate system model with a horizontal resolution high enough to represent DWF. We find that under the RCP8.5 scenario the NWMed DWF collapses by 2040–2050, leading to a 92% shoaling in the winter mixed layer by the end of the century. The collapse is related to a strengthening of the vertical stratification in the GoL caused by changes in properties of Modified Atlantic Water and Levantine Intermediate Water, being their relative contribution to the increase of the stratification 57.8% and 42.2%, respectively. The stratification changes also alter the Mediterranean overturning circulation and the exchange with the Atlantic.

Deep water formation (DWF) in the North Western Mediterranean (NWMed) is a key feature of Mediterranean overturning circulation. Changes in DWF under global warming may have an impact on the region...

Sea breezes are common and recurrent thermally-driven winds formed in coastal areas under conditions of weak synoptic forcing, due to the differential heat capacity of the sea and the land. Their accurate forecast is key because of the impacts on maxima near-surface temperatures, humidity (and then thermal comfort), pollutants distribution, convective-systems formation, etc., being crucial for the wind energy sector and because they develop in areas that are normally densely populated.Some studies have investigated the impacts of the surface conditions in coastal breezes in different regions around the world. Their findings are diverse, mostly attributed to differences in the marine boundary layer stability, which can favour or inhibit the vertical mixing. This is needed to vertically distribute thermal changes in the land or the sea surfaces to deeper atmospheric layers, and thus to modify the horizontal surface pressure gradients. In this work, we use the Weather Research and Forecasting (WRF) model to investigate how the coastal breezes are affected by changes in the surface representation in the Gulf of Cádiz, in the Atlantic coast of the Southwestern Iberian Peninsula. We focus on artificial and realistic changes in land use, soil moisture and sea surface temperature. The analysis is performed for a case study of 20 days in August 2020, characterised by many coastal-breeze events in the area analysed and by a gradual decrease in the sea surface temperature. The model is evaluated with observational data at different coast locations, inland and on the ocean, as well as using wind speed transects from satellite altimetry.

TheTyrrhenian Seaplaysanimportantrole in the winter deep waterformationin the North Western Mediterranean throughthe water thatenters the Ligurian Seavia the Corsica Channel. Therefore, the study of the impact of the changes in the future climate on the Tyrrhenian circulation and its consequences represents an important issue. Furthermore,theseasonally-dependent,richin dynamical mesoscale structures,Tyrrhenian circulationisdominatedby the interplay of local climate and thebasin-wide Mediterranean circulation via thewater transport across its major straitsand an adequate representation of its features represents an importantmodelingchallenge. In this work we examinewith a regionally-coupled atmosphere-ocean modelthechanges in the Tyrrhenian circulationby the end of the 21st century under the RCP8.5 emission scenario, theirdriving mechanisms, as well as their possible impact on winter convection in the NW Mediterranean.Ourmodelsuccessfully reproduces the main features of the Mediterranean Sea and Tyrrhenian basin present-day circulation. We find thattoward the end of the centurythewintercyclonic, along-slope stream around the Tyrrhenian basin becomes weaker. This weakening increases the wind work transferred to the mesoscalestructures, which become more intense than at present in winter and summer. We also find that, in the future, the northward water transport across the Corsica Channel towards theLiguro-Provençal basin becomes smaller than today. Also, water that flows through this channel presents a stronger stratification because of a generalized warming with asalteningof intermediate waters. Both factors may contribute to the interruption ofdeep waterformation in the Gulf of Lions by the end of the century.

A 3-D nonlinear, finite-difference, high-resolution, hydrodynamic model, extended with a direct implementation of the non-hydrostatic pressure, is applied to study the influence of the non-hydrostatic contribution to the generation and propagation of short-period wave fronts (less than 1 h) in the domain of the Gibraltar Strait. The generation, rupture and propagation of these waves and their free surface manifestations are shown. Calculations of the model show its ability to generate surface wave fronts. However, differences in the period and wavelength of the generated baroclinic waves are evident when hydrostatic and non-hydrostatic results are compared. In particular, the non-hydrostatic contribution tends to generate short-period waves with longer wavelengths and periods with respect to the hydrostatic values. An increase of the non-hydrostatic short-period wavelengths from the Camarinal Sill towards the Mediterranean Sea is also plausible. This increase is induced by changes in the thickness of the deeper layer that influences the disintegration of wave fronts into wave trains and the imbalance of non-hydrostatic and non-linear contributions. Sensitivity analyses show that grid resolution is a key factor due to the potential generation of spurious non-hydrostatic processes, including numerical dispersion induced by a low grid resolution. It is shown that this numerical non-hydrostatic process could generate similar results in hydrostatic and non-hydrostatic simulations when the spatial resolution is comparable to the wavelengths. Results also show the ability of the direct implementation of the non-hydrostatic model to reproduce the main features in a real case, such as the Strait of Gibraltar.

The impact of tides on the spreading of the Mediterranean Outflow Waters (MOW) in the Gulf of Cadiz is investigated through a series of targeted numerical experiments using an ocean general circulation model. The full ephimeridic luni-solar tidal potential is included as forcing. The model grid is global with a strong zoom around the Iberian Peninsula. Thus, the interaction of processes of different space and time scales, which are involved in the MOW spreading, is enabled. This is of particular importance in the Strait of Gibraltar and the Gulf of Cadiz, where the width of the MOW plume is a few tens of km. The experiment with enabled tides successfully simulates the main tidal features of the North Atlantic and in the Gulf of Cadiz and the Strait of Gibraltar. The comparison of the fields from simulations with and without tidal forcing shows drastically different MOW pathways in the Gulf of Cadiz: The experiment without tides shows an excessive southwestward spreading of Mediterranean Waters along the North African slope, whereas the run with tides is closer to climatology. A detailed analysis indicates that tidal residual currents in the Gulf of Cadiz are the main cause for these differences.

Metocean modeling resources from an operational oceanography system are applied to assess the hazard of bacterial contamination, resulting from domestic/industrial wastewater discharged into potential bivalve mollusk harvesting areas in Cadiz Bay (Andalusia). The proposed methodology is aimed to at meeting the European Union regulations and best practices for the management and monitoring of this harvesting activity. Modeled current fields, corresponding to scenarios with different wind and tidal conditions, are incorporated in a Lagrangian particle-tracking model, specifically designed to simulate the fate of the bacterial content of wastewaters discharged into the Bay. Numerical results are used to obtain various indices of occurrence and hazard maps of fecal contamination in seawater. The proposed indices also allow estimating fecal contamination fields if appropriate information of discharges and bacterial loads of the wastewater sources are available. Qualitative validation of results shows considerable agreement with measured contamination patterns. The areas with highest exposure to bacterial contamination are the Sancti Petri Channel and the central region of the Inner Bay, although a substantial variability depending on wind conditions is found. Unauthorized occasional wastewater discharges have a considerable impact on local water quality, while regulated wastewater sources are responsible for the larger-scale bacterial contamination pattern. The methodology developed is exportable to other environments and coastal management activities.

The Canary current upwelling is one of the major eastern boundary coastal upwelling systems in the world, bearing a high productive ecosystem and commercially important fisheries. The Canary current upwelling system (CCUS) has a large latitudinal extension, usually divided into upwelling zones with different characteristics. Eddies, filaments and other mesoscale processes are known to have an impact in the upwelling productivity, thus for a proper representation of the CCUS and high horizontal resolution are required. Here we assess the CCUS present climate in the atmosphere-ocean regionally coupled model. The regional coupled model presents a global oceanic component with increased horizontal resolution along the northwestern African coast, and its performance over the CCUS is assessed against relevant reanalysis data sets and compared with an ensemble of global climate models (GCMs) and an ensemble of atmosphere-only regional climate models (RCMs) in order to assess the role of the horizontal resolution. The coupled system reproduces the larger scale pattern of the CCUS and its latitudinal and seasonal variability over the coastal band, improving the GCMs outputs. Moreover, it shows a performance comparable to the ensemble of RCMs in representing the coastal wind stress and near-surface air temperature fields, showing the impact of the higher resolution and coupling for CCUS climate modelling. The model is able of properly reproducing mesoscale structures, being able to simulate the upwelling filaments events off Cape Ghir, which are not well represented in most of GCMs. Our results stress the ability of the regionally coupled model to reproduce the larger scale as well as mesoscale processes over the CCUS, opening the possibility to evaluate the climate change signal there with increased confidence., Open Access funding enabled and organized by Projekt DEAL. Ruben Vazquez was supported through a doctoral grant at the University of Ferrara and University of Cadiz. Dmitry Sein was supported in the framework of the state assignment of the Ministry of Science and Higher Education of Russia (No. 0128-2021-0014). This work used resources of the Deutsches Klimarechenzentrum (DKRZ) granted by its Scientific Steering Committee (WLA) under project ID ba0987.

Sea breezes are common and recurrent thermally-driven wind circulations formed in coastal areas under conditions of weak synoptic forcing. The different heat capacity between the land and the sea causes the thermal contrast needed for their formation. Therefore, the temperature changes at the surface of both the sea and the land influence the breezes characteristics. In this work, we investigate how sensitive are the sea breezes to changes in land cover and soil moisture, which may have a direct impact on the surface temperature inland. This is done through the design of different sensitivity experiments performed with the Weather Research and Forecasting (WRF) model, where we tested the effect of the land use and soil moisture modification. This was done through the simulation of a typical sea-breeze case study in the coastal area of the southwest of the Iberian Peninsula (Gulf of Cádiz). The differences among the experiments are compared spatially and confronted with observations from different meteorological towers at the coast and inland. A special emphasis is made on the changes observed in the area of the National Park of Doñana. This area is characterised by large shallow marshes with varying seasonal status and extensive rice crops. Thus, contrasting conditions of the surface are typically observed, which also depend on the previous hydrological conditions. Preliminary results highlight the importance of the correct representation of the surface inland to obtain a proper simulation of the sea-breeze system. Besides, new lines of research emerge to analyse the impacts caused by other potential modifications in the surface conditions of the land and the ocean (e.g., global change, urbanization, crop modification, changes in precipitation regimes or sea surface temperature, etc).

A catchmentmodel for river basins and a hydrodynamicmodelwere combined in order to simulate the spreading of the turbidity plume produced by sediment discharges from the Guadalquivir River basin within the Gulf of Cádiz under different meteorological conditions. The current fields provided by the hydrodynamic model and a transport-diffusion scheme based on tracking virtual particles tracking released at the river mouth have enabled us to simulate turbidity plumes that show great similarity with the plumes observed in satellite images. The most relevant results of the study show that in the absence of winds, the plume tends to spread very slowly, gradually progressing northwards; this is because of the symmetry between the filling and draining flows at the mouth of the Guadalquivir and low intensity of the tidal currents beyond the mouth. In addition, the transport of the plume towards the Strait of Gibraltar requires wind conditions with a northerly, north-westerly or westerly component. Westwards transport, however, requires winds with an easterly, southerly, or south-easterly component. The periods of heaviest rainfall in the Guadalquivir River basin coincide with winds mainly from the west; therefore, the times ofmaximum discharge at the mouth of the river occurwhen there are wind conditions that favour the transport of the matter suspended in the plume, southwards along the coast, towards the Strait of Gibraltar and the Alboran Sea. Linking the watershed catchment and hydrodynamic models has proved its suitability to predict the evolution and reaching of the sediment plumes fromthe Guadalquivir River discharges and the experience encourages the use of that methodology to be applied in a future prediction systemfor the creation and evolution of those sediment plumes., We would like to thank the Regional Government of Andalusia ( P11-RNM-7722 project), the Spanish Government (TRUCO project RTI2018-100865-B-C22 ), the SUDOE INTERREG AGUAMOD and OCASO projects for supporting this work financially. We are also grateful to NASA for distributing the MODIS data used in this study, and to the AERONET project for the MODIS AQUA RGB True Color Images, especially those from the Malaga-San Jose and Huelva stations.

Climate simulations for the North Atlantic and Europe for recent and future conditions simulated with the regionally coupled ROM model are analyzed and compared to the results from the MPI-ESM. The ROM simulations also include a biogeochemistry and ocean tides. For recent climate conditions, ROM generally improves the simulations compared to the driving model MPI-ESM. Reduced oceanic biases in the Northern Atlantic are found, as well as a better simulation of the atmospheric circulation, notably storm tracks and blocking. Regarding future climate projections for the 21st century following the RCP 4.5 and 8.5 scenarios, MPI-ESM and ROM largely agree qualitatively on the climate change signal over Europe. However, many important differences are identified. For example, ROM shows an SST cooling in the Subpolar Gyre, which is not present in MPI-ESM. Under the RCP8.5 scenario, ROM Arctic sea ice cover is thinner and reaches the seasonally ice-free state by 2055, well before MPI-ESM. This shows the decisive importance of higher ocean resolution and regional coupling for determining the regional responses to global warming trends. Regarding biogeochemistry, both ROM and MPI-ESM simulate a widespread decline in winter nutrient concentration in the North Atlantic of up to similar to 35%. On the other hand, the phytoplankton spring bloom in the Arctic and in the North-Western Atlantic starts earlier, and the yearly primary production is enhanced in the Arctic in the late 21st century. These results clearly demonstrate the added value of ROM to determine more detailed and more reliable climate projections at the regional scale. Plain Language Summary We downscale present climate and future climate change projections for the North Atlantic and Europe using a regionally coupled Earth System Model including atmosphere, ocean, river runoff, and ocean biogeochemistry components. This approach allows us to attain higher spatial resolution and to a more accurate representation of key physical processes, yielding a better simulation of present climate at regional and local scales when compared to the driving global climate model. Future climate change projections show more detail at regional and local scale, mostly related to the improvement in the representation of orography and bathymetry. These improvements along with a better representation of the interactive ocean-atmosphere coupling lead to other remarkable differences with the driving global climate model: (1) colder Sea Surface Temperature in the Subpolar Gyre region, indicating a local convection collapse and a Atlantic Meridional Overturning Circulation slowdown; (2) a seasonal free-ice Arctic is reached by 2055 under RCP8.5 scenario, well before projected by the driving global climate model; and (3) stronger reduction in nutrients in the North Atlantic by the end of the 21st century. These results clearly demonstrate the added value of the regionally coupled model system to determine more reliable climate projections at the regional scale.

The identification and prioritization of pollution sources is essential to coastal zone management. This task is complicated when a variety of pollution sources are found and by limited data availability, which can result in an inconclusive assessment and differing public perceptions, ultimately hindering the progress of management actions. This is the case in Cartagena Bay (Colombia), a Caribbean hot-spot of pollution, which receives large freshwater discharges from the Magdalena River drained via the Dique Canal along with coastal industrial effluents and untreated domestic wastewater from parts of the coastal population. This study presents a methodology for the integrated assessment of anthropogenic pollution sources discharged into the coastal zone by estimating their loads and comparing their relative contributions to receiving coastal waters. Given the lack of available data on discharges and water quality, an integrated approach is applied by combining various methods of load estimation while emphasizing the importance of calculating confidence intervals for each load value. Pollution loads from nearby sources of domestic wastewater, coastal industrial effluents and continental runoff were assessed with respect to their contributions of coliforms, total suspended solids, nitrogen, phosphorus, and biological oxygen demand (BOD). Loads from the canal's surface runoff were calculated with monthly discharge and water quality data. Domestic loads were computed using GIS analyses of population and sewerage coverage in combination with export coefficients of daily load per capita. Industrial loads were estimated based on previous studies. Results show that each type of land-based source is responsible for different pollution impacts observed in Cartagena Bay. Occasionally, inadequate recreational water quality can be attributed to nearby sources of domestic wastewater, which contribute the highest coliform load (6.7 ± 3.9 × 1015 MPN/day). Continental runoff via the Dique Canal contributes the greatest sediment load (2.5 ± 1.9 × 103 t/day) causing the bay's turbid plumes and related ecosystem issues. Hypoxic conditions in the bay can be attributed to all three pollution sources which all discharge significant BOD loads (2–8 t/day), while the highest total phosphorus load comes from the Dique Canal (3.2 ± 2.4 t/day) and the highest nitrogen loads flow from the canal (3.7 ± 3.1 t·NO3-N/day) and the industrial sector (3.1 ± 4.1 t·N/day). Given that these loads are projected to increase in future years, this study highlights the importance of prioritization and mitigation in coastal pollution management and demonstrates a method that could be applied in other places with similar problems in the Wider Caribbean Region.

The modification of waves by shipwrecks and the resulting scour play important roles in shipwreck site formation, and conservation of archaeological sites. The oscillatory flow induced by waves and its interaction with the hull structure at a historic shipwreck site was analyzed using a two phase 2D model based on the Reynolds averaged Navier-Stokes equations and shear stress transport (SST) k-Omega turbulence model, with inputs from field-based bathymetric survey. The relative importance and seasonal variation in hydrodynamic processes were investigated (flow velocity increase, coherent structures and vortex shedding, turbulence and steady current induced by the non linearity of waves). Results demonstrate that frictional velocity and flow increase dominate morphological change in the low wave energy period (LEP), whereas turbulent shear stress and large coherent structures dominate scouring in the high wave energy period (HEP). Furthermore, flow acceleration around the hull structure and recirculation cells originated by wave non-linearities become more prominent in the HEP, modifying the trajectory of the shedding vortex and increasing its capacity to transport sediment. The results demonstrate, for the first time, that computational fluid dynamics is a valuable tool in assessing the wave structure interaction in full scale and realistic morphological conditions at complex shipwreck sites.

Shoreline evolution studies are mostly performed by comparison of vertical images (e.g. aerial photographs and satellite imagery), being limited to the last decades. However, phenomena such as longer term climatic fluctuations may cause important secular coastal changes which are mostly unknown. The use of archaeological remains as shoreline proxies could overcome this limitation by allowing to expand back in time the historical shoreline record. The present study endorses the effectiveness of the use of shipwrecks and man-made structures as proxy data for analyzing historical shoreline evolution. This was confirmed by the evaluation of nearshore evolution (historical shorelines from 1787 to 1823 and recent changes from 1956 to 2013) and the reconstruction of the palaeobathymetry along Sancti Petri sand spit (SW Spain) by means of the analysis of historical documents, historical maps, modern aerial photographs and a recent bathymetry (2011), along with the archaeological prospection supported by the numerical modelling of the dispersion of archaeological remains. The analysis of historical maps has revealed a significant shoreline retreat over the medium term scale in Sancti Petri sand spit, averaging − 1.2 m·year− 1. Results from historical maps and archaeological remains show slight differences with respect to the most recent retreat rates (− 0.9 m·year− 1) obtained from aerial photographs for the period 1956–2013. Spatial variations in coastal retreat along the sandspit are closely linked to local patterns of wave height and wave-induced currents. Significant temporal variation in rates of shoreline change was observed, probably related to storminess variability in the study area, as indicated by the relation between the rates of coastal change for each analyzed period and the corresponding rate of change of winter NAO index.

The Caribbean Sea provides significant ecosystem services to the livelihood and well-being of countries in the region. Protection of the marine ecosystem requires policy on coastal water quality that considers ecologically-relevant thresholds and has a scientific foundation linking land-based discharges with seawater quality. This study demonstrates a practical method for setting local-scale coastal water quality targets by applying this approach to Cartagena Bay, Colombia, and setting targets for end-of-river suspended sediment loads to mitigate offshore coral reef turbidity. This approach considers reef thresholds for suspended sediments and applies a field-calibrated 3D hydrodynamic-water quality model (MOHID) to link the marine thresholds to fluvial loads. Monitoring data showed that suspended sediments were consistently above the coral reef ecosystem threshold of 10 mg/l, and the model adequately reproduced field observations. It was shown that ecosystem thresholds could be maintained within the extent of the bay by reducing suspended sediment loads in the Dique Canal from current load estimates of 6.4 x 10(3) t/d (rainy season) and 4.3 x 10(3) t/d (transitional season) to target loads of 500-700 t/d, representing reductions of similar to 80-90%. These substantial reductions reflect ongoing issues in the Magdalena watershed which has experienced severe erosional conditions and intense deforestation over the past four decades. The presented method is practical for countries without access to long-term datasets, and could be applied to other parameters or discharge types. The method is particularly beneficial for developing site-specific targets, which are needed considering the natural and anthropogenic variability between different coastal zones and water bodies. International Development Research Centre, Ottawa, Canada [108747-001] EAFIT University, Corporacion Autonoma Regional del Canal del Dique (CARDIQUE) [15601] Erasmus Mundus Doctoral Programme in Marine and Coastal Management (MACOMA) info:eu-repo/semantics/publishedVersion

We assess the role of ocean feedbacks in the simulation of the present climate and on the downscaled climate change signal in the Mediterranean Sea with the regionally coupled model REMO-OASIS-MPIOM (ROM). The ROM oceanic component is global with regionally high horizontal resolution in the Mediterranean Sea. In our setup the Atlantic and Black Sea circulations are simulated explicitly. Simulations forced by ERA-Interim show a good representation of the present Mediterranean climate. Our analysis of the RCP8.5 scenario driven by MPI-ESM shows that the Mediterranean waters will be warmer and saltier across most of the basin by the end of the century. In the upper ocean layer temperature is projected to have a mean increase of 2.73 °C, while the mean salinity increases by 0.17 psu, presenting a decreasing trend in the Western Mediterranean, opposite to the rest of the basin. The warming initially takes place at the surface and propagates gradually to the deeper layers.

Coastal upwelling systems are very important from the socio-economic point of view due to their high productivity, but they are also vulnerable under changing climate. The impact of climate change on the Canary Current Upwelling System (CCUS) has been studied in recent years by different authors. However, these studies show contradictory results on the question whether coastal upwelling will be more intense or weak in the next decades. One of the reasons for this uncertainty is the low resolution of climate models, making it difficult to properly resolve coastal zone processes. To solve this issue, we propose the use of a high-resolution regional climate coupled model. In this work we evaluate the performance of the regional climate coupled model ROM (REMO-OASIS-MPIOM) in the influence zone of the CCUS as a first step towards a regional climate change scenario downscaling. The results were compared to the output of the global Max Planck Institute Earth System Model (MPI-ESM) showing a significant improvement.

Cartagena Bay, one of the Caribbean's hot spots of pollution, is an estuarine system connected to the Caribbean Sea by two straits. Large freshwater discharges from the Dique Canal into the south of the bay produce estuarine conditions strongly related to the seasonal variability of runoff from the Magdalena River watershed. The bay's seasonal conditions may be characterized by three seasons: strong winds/low runoff (Jan.-April), weak winds/intermediate runoff (May-Aug.), and weak winds/high runoff (Sept.-Dec.). This coastal zone is known to be impacted by land-based sources of pollution, including continental runoff, industrial effluents and domestic wastewater. However, previous studies have not sufficiently ascertained the spatio-temporal extent of this pollution. This study addresses the following research question: What is the current extent of water and sediment pollution in Cartagena Bay and which factors control its seasonal variability? Monthly seawater samples (Sept.2014-Aug.2015) were taken from surface and bottom depths at 16 stations in and around Cartagena Bay and analyzed for physical, chemical, and biological parameters. Surface sediments were sampled from the bay's bottom every three months and analyzed for various trace metals. Seasonal variability was observed in nearly all of the water quality parameters, with higher concentrations usually coinciding with the high runoff season. Potential pollution impacts are shown by wet-season averages of total suspended solids (45.0 +/- 89.5 mg/l), turbidity (26.1 +/- 59.7 NTU), biological oxygen demand (1.20 +/- 0.91 mg/l), chlorophyll-a (2.47 +/- 2.17 mu g/l), nitrate (171.1 +/- 112.6 mu g/l), phosphate (43.1 +/- 63.5 mu g/l), total phosphorus (85.3 +/- 77.2 mu g/l), phenol (2.9 +/- 17.4 mg/l), faecal coliforms (798 +/- 714 MPN/100 ml) and enterococci (32 +/- 30 CFU/100 ml) in excess of recommended threshold values for marine conservation and recreational adequacy. The bay's hypoxic conditions are evident with low dissolved oxygen concentrations (

Coastal altimetry products are available and are being extensively validated. Their accuracy has been assessed in many coastal zones around the world and they are ready for exploitation near the shore. This opens a variety of applications of the sea level data obtained from the specific reprocessing of radar altimeter signals in the coastal strip. In this work, we retracked altimeter waveforms of the European Space Agency satellites: ERS-2 RA and Envisat RA-2 from descending track (#0360) over the eastern side of the Strait of Gibraltar using the Adaptive Leading Edge Sub-waveform (ALES) retracker. We estimated along-track Sea Level Anomaly (AT_SLA) profiles (RA-2) at high posting rate (18 Hz) using improved range and geophysical corrections. Tides were removed with a global model (DTU10) that displays a good performance in the study area: the mean root square sum (RSS) of the main constituents obtained with DTU10 and 11 tide gauge stations was 4.3 cm in agreement with the RSS using a high-resolution local hydrodynamic model (UCA2.5D) (4.2 cm). We also estimated a local mean sea surface by reprocessing ERS-2/Envisat waveforms (track #0360) with ALES. The use of this local model gave more realistic AT_SLA than the values obtained with the global model DTU15MSS. Finally, the along-track Absolute Dynamic Topography (AT_ADT) was estimated using a local Mean Dynamic Topography obtained with the local hydrodynamic model UCA2.5D. We analysed the cross-strait variability of the sea level difference between the African/Spanish coasts along the selected track segment. This was compared to the sea level cross-strait difference from the records of two tide gauges located in the African (Ceuta) and Spanish (Tarifa) coasts. The sea level differences from altimetry and tide gauges were linked to the zonal component of the wind. We found a positive and significant (>95% c.l.) correlation between easterlies/westerlies and positive/negative cross-strait sea level differences between the southern and northern coasts of the Strait in both datasets (altimetry: r = 0.54 and in-situ: r = 0.82).

Drifting Fish Aggregating Devices (dFADs) are small drifting platforms with an attached solar powered buoy that report their position with daily frequency via GPS. We use data of 9,440 drifting objects provided by a buoys manufacturing company, to test the predictions of surface current velocity provided by two of the main models: the NEMO model used by Copernicus Marine Environment Monitoring Service (CMEMS) and the HYCOM model used by the Global Ocean Forecast System (GOFS).

The ecosystem function of local fisheries holds great societal importance in the coastal zone of Cartagena, Colombia, where coastal communities depend on artisanal fishing for their livelihood and health. These fishing resources have declined sharply in recent decades partly due to issues of coastal water pollution. Mitigation strategies to reduce pollution can be better evaluated with the support of numerical hydrodynamic models. To model the hydrodynamics and water quality in Cartagena Bay, significant consideration must be dedicated to the process of light attenuation, given its importance to the bay’s characteristics of strong vertical stratification, turbid surface water plumes, algal blooms and hypoxia. This study uses measurements of total suspended solids (TSS), turbidity, chlorophyll-a (Chla) and Secchi depth monitored in the bay monthly over a 2-year period to calculate and compare the short-wave light extinction coefficient (Kd) according to nine different equations. The MOHID-Water model was used to simulate the bay’s hydrodynamics and to compare the effect of three different Kd values on the model’s ability to reproduce temperature profiles observed in the field. Simulations using Kd values calculated by equations that included TSS as a variable produced better results than those of an equation that included Chla as a variable. Further research will focus on evaluating other Kd calculation methods and comparing these results with simulations of different seasons. This study contributes valuable knowledge for eutrophication modelling which would be beneficial to coastal zone management in Cartagena Bay.

The evolution of the shallow water wave-dominated Fougueux wreck site in the Gulf of Cadiz was investigated through repeat bathymetric surveys, wave- and current-velocity field measurements, and numerical modeling. This multidisciplinary approach was used to understand the relationships between scouring, morphodynamic change, and hydrodynamic forcing. Field experiments and numerical models indicate that wave processes dominate site evolution. Numerical model outputs indicate current velocity, bed shear stress, orbital velocity, and specially wave fraction breaking (with an increase of 45% and 135% for weak and significant storm conditions, respectively) are all amplified at the site. Scour pits 0.8 m depth inshore and 0.4 m depth offshore of the wreck are developed in response to hydrodynamic forcing. Time-lapse bathymetric surveys quantify seasonal geomorphological change at the Fougueux. Up to 1.2 m of sediment is deposited and 0.7 m of sediment eroded in response to seasonal wave climate variation (an increase of 0.5 m for mean significant wave height, 0.9 m for significant wave height corresponding to 99% of nonexceedance probability, and 0.4 m·s−1 for mean near-bed orbital velocity during winter conditions). A two-dimensional scour model reproduces observed seasonal scour changes. Results have direct applications at all stages of a wreck site investigation.

A shipwreck site located off Sancti Petri sand spit (Cadiz, Spain) was identified as a Temeraire-class 74-gun French ship. The archaeological deposits relate it to the Fougueux, sunken after the Battle of Trafalgar. The site contains some pieces of the naval structure, 32 iron guns, and a large anchor, but two thirds of the ship is missing. Available information (including ship logbooks of weather observations and other historic documents) establishes that a dismasted French ship ran aground on 22 October 1805 and broke up into pieces on the 25th due to tempestuous weather. Combining that information and a set of numerical models (ocean, atmosphere, and dispersion), we aim to simulate different scenarios in order to determine the most probable areas for finding the shipwreck remains of the Fougueux, taking into account the uncertainty of the information used and the modeling limitations. The probability of finding scattered remains belonging to the Fougueux was calculated using the modeled scenarios. As a result, it was found that the high probability area contained four additional sites comprising 40 guns and 5 anchors whose characteristics and dating are similar to those of the previously known site. The results of our study highlight the value of numerical modeling in underwater archaeology as a tool for the identification and optimization of resources in prospecting scattered shipwreck sites.

A bay's capacity to buffer fluvial fluxes between the land and sea is sensitive to hydrological changes that can affect its water renewal rates. In Cartagena Bay, Colombia, pollution issues have been associated with freshwater fluxes which are projected to increase in future years. This has led to plans to reduce freshwater flows by constructing upstream hydraulic doors. Given the influence of freshwater discharge on coastal water renewal, it is important to assess how these upstream changes will affect the bay's hydrodynamic processes. This study calibrated the 3D MOHID Water model, configured with a high-resolution mixed vertical discretization to capture the bay's characteristic processes of vertical stratification and mixing. A Lagrangian transport model was used to analyze the flow of passive particle tracers and calculate water renewal time scales. Mean residence times of 3-6 days and flushing times of 10-20 days for canal water were found, while mean residence times of 23-33 days and flushing times of 70-99 days were calculated for the bay's complete water volume. An assessment of future scenarios showed that increases in freshwater runoff would result in faster water renewal in the bay, while plans to decrease freshwater discharge would result in slower water renewal in the bay. It is therefore imperative that any plans for reducing fluvial fluxes into the bay be accompanied by the control of local pollution sources, which are abundant and could worsen the bay's water quality issues should water renewal times become longer. International Development Research Centre, Ottawa, Canada [108747-001] EAFIT University Corporacion Autonoma Regional del Canal del Dique (CARDIQUE) [15601] Erasmus Mundus Doctoral Programme in Marine and Coastal Management (MACOMA) Fundacion Hernan Echavarria Olozoga Escuela Naval de Cadetes "Almirante Padilla" University of Wyoming's surface observation service U. Lisboa's Marine Environment Technology Center (MARETEC) info:eu-repo/semantics/publishedVersion

An understanding of the interactions between biological, chemical and physical dynamics is especially important for the adequate conservation of the Underwater Cultural Heritage. However, while physical and chemical processes are relatively well-investigated, the biological communities associated with these habitats are poorly studied. We compared the sessile community developed on panels of different materials placed on two historical shipwrecks, the Fougueux and the Bucentaure, from the Battle of Trafalgar (October 1805). Six materials used at the construction of vessels at the 18th and 19th centuries were selected: copper, brass, cast iron, carbon steel, pine and oak. The sessile community developed on the panels was studied two and 15 months after their immersion at the water to determine the effects of materials and environmental conditions (sediments, waves, hydrodynamic conditions, temperature and salinity) on ecological succession and the possible implications at the conservation of historical shipwrecks. On the Fougueux, the environmental conditions more strongly influenced the biological succession than the material type, with pioneer colonisers dominating the communities in both sampling periods. On the Bucentaure, exposed to more stable environmental conditions, the sessile community showed differences between sampling periods and among materials at the end of the experiment. Under these more stable environmental conditions, the material type showed a higher influence on the sessile community. Species that produce calcareous concretions developed on metallic panels, but were absent on wood panels, where the shipworm Teredo navalis was more abundant. The relationship between environmental conditions, sessile organisms and material type can influence the conservation status of the archaeological sites.

Although numerous methods have been used to extract polyphenols from vegetal sources, these procedures have been rarely compared directly. Herein, four maceration and extraction methods for phenolics from Carmenere (Vitis vinifera L.) skins and seeds are evaluated. Polyphenols were extracted with mixtures of 4:1 (v/v) methanol:water, 4:1 (v/v) acetone:water, 4:1 (v/v) methanol:water, 4:1 (v/v) acetone:water, and 1:9 (v/v) ethanol:water. The extracts were characterized by spectrophotometry for tannins, anthocyanins, total phenols, and color; proanthocyanidin fractionation for monomers, oligomers, and polymers; and high-performance liquid chromatography for anthocyanins and low molecular weight phenols. Seed and skin extracts in methanol/water provided higher polyphenol concentrations compared to the use of acetone/water. Seeds and skins macerated in ethanol/water showed lower concentrations in most polyphenols while seeds and skins that were consecutively macerated in methanol/water and acetone/wat...

Two wrecks related to the Battle of Trafalgar (1805) were studied. Following the guidelines of the UNESCO-2001 Convention for the Protection of the Underwater Cultural Heritage, a holistic and interdisciplinary approach based on the development of four of the thirty-six Rules of this international agreement was applied. A non-destructive survey technique was developed to obtain information from the scattered cannons and anchors without altering their condition (Rule 4). The work performed provided information about the origin of both wrecks, the Fougueux and the Bucentaure, two ships of the line of the French Navy, and allowed to characterize the state of conservation at each site without jeopardizing their future conservation in the marine environment. In addition, measurements of the main physical, chemical and biological variables allowed correlating the conservation status at each site with the marine environmental conditions (Rule 15). Thus, in Fougueux shipwreck large iron objects are corroding at a higher rate (between 0.180 and 0.246 mmpy) due to high sediment remobilization and transport induced by waves at this site, causing damage by direct mechanical effect on metallic material and by removing the layer of corrosion products developed on the artefacts. Meanwhile artillery on Bucentaure site, covered with thick layers of biological concretion, is well preserved, with lower corrosion rates (0.073 to 0.126 mmpy), and archaeological information is guaranteed. Finally, the effectiveness of the cathodic protection as a temporary measure for in situ conservation (Rule 1) was evaluated on a cannon. The use of a sacrificial anode after 9 months reduced the average corrosion rate (from 0.103 to 0.064 mmpy) and the percent of corrosion rate in 37.9%. These results are very useful for developing a decision making system of the Site Management Program, based on predictive models of artefacts permanence and risk factors in the marine environment (Rule 25).

The main features of the surface currents in the Strait of Gibraltar and Algeciras Bay are analyzed from the numerical results of three-dimensional hydrodynamic modeling, complemented and validated through observational data. The relative contributions of the main processes affecting the surface current patterns (i.e. mean background flows, barotropic tide, baroclinic internal waves, and wind regime) are described and interpreted, focusing on their effects on surface transport-dispersion processes, with special attention paid to the simulation and prediction of the evolution of oil spills and other marine pollutants in this sensitive environment in the context of coastal management. In general, the mean background surface flow promotes eastward transport in the Strait and re-circulation patterns within Algeciras Bay, with inflows and outflows mainly near the western and eastern coasts, respectively. The barotropic tide produces periodic reversals of water transport (and hence higher persistence and re-entrance processes) on the western side of the Strait and within the Bay, while its effects are generally weaker than the mean eastward flow in the eastern region. Baroclinic, tide-induced, short-period internal waves are responsible for occasional local high-divergence of the current field, with effects on the surface transport-dispersion processes. Finally, the wind regimes commonly present in this environment (mainly easterlies and westerlies) generally modulate the transport intensity in the Strait, while affecting more strongly the surface transport patterns within Algeciras Bay. Outputs from the developed metocean modeling system fed a Lagrangian particle-tracking model, validated by drifting-buoy data, to reproduce past oil spill events: the tanker Sea Spirit in the western Strait of Gibraltar (1990), and the ships Fedra and Tawe in Algeciras Bay (2008), each well documented and characterized by different metocean conditions and spill quantities. The predicted time-spatial distribution of the oil slicks and affected coasts were compared with available reports and photographs, showing that the strongly baroclinic oceanographic regime of the Strait of Gibraltar and Algeciras Bay demands a fully 3-D approach to simulate properly the behavior of surface pollutant spills in these environments, in order to achieve an efficient management by supporting risk assessment, contingency planning and palliation activities.

Coastal food services are an important segment within &lsquo, sea and sun&rsquo, tourism. They have a direct impact on the environment from liquid and solid waste generation, air contamination, and excessive energy and water consumption. Mass tourism and the contemporary threat of climate change enhance the anthropogenic intrusion, especially in vulnerable coastal zones. To prevent overexploitation of the coastal zones, the adaptation of the sustainable principles by coastal stakeholders is an urgent matter. Thus, this study aims to design a model of sustainable development for restaurants and to examine the level of its adoption by seaside restaurant owners in two touristic beach areas of Cadiz province, Spain. A questionnaire was performed during the high summer season in 2018. The obtained data was analysed by IBM SPSS software. The survey results showed that the model of sustainable development has been poorly adopted by restaurant managers. Foreign managers of international restaurants are less involved in the adoption of the sustainable model in comparison to Spanish restaurant owners. Moreover, restaurants that have been opened more than 10&ndash, 20 years provide a more sustainable way of business operation in comparison with newly established food service organizations.

[1] The M2 tidal circulation in Algeciras Bay (Strait of Gibraltar) is analyzed using a 3-D, nonlinear, baroclinic, hydrodynamic model, in conjunction with observed data series. Results show the influence of the density stratification on the vertical structure of the M2 currents in Algeciras Bay, although its tidal dynamics shows major differences with respect to the Strait of Gibraltar. Whereas the M2 currents in the Strait present mainly barotropic behavior, the baroclinic effects prevail in Algeciras Bay. A notable finding is the presence of a tidal M2 counter-current system between the upper Atlantic and the lower Mediterranean water layers within the Bay, with amplitudes of up to 25 cm s−1. The interface between the two layers oscillates in antiphase relation with respect to the free-surface elevation, with amplitudes of almost 20 m. The presence of the submarine Algeciras Canyon was found to be determinant in the three-dimensional structure of tidal currents within the Bay, strengthening the baroclinic tidal regime of currents. This situation has quantitative consequences for the flow-exchange processes between Algeciras Bay and the outer Strait, with rates 20 times higher than those obtained when considering only the barotropic behavior, as well as inflow/outflow lateral recirculation volumes during half a tidal cycle that account for more than 20% of the net accumulated volume. This flow-exchange system was found to be affected by the nonlinear interaction processes between the first baroclinic period of resonance of Algeciras Bay and the M2 tide.

The output of a two-layer hydrodynamic model along a west–east section of the Gibraltar Strait is used to estimate tidal induced mixing between the Mediterranean and Atlantic water layers and to simulate the effects of mixing processes on biogeochemical fluxes and the pelagic community of the area. The hydrodynamic model is used to estimate interfacial mixing and water advection which drive the dynamics of the pelagic community. The model was run for 13 months, in order to analyse the effect of annual modulations in tidal amplitude on mixing. Incorporation of a third intermediate layer leads to a significant improvement in the model results, showing the necessity for a three layer circulation scheme when modelling biogeochemical processes in the Strait of Gibraltar. Pelagic processes are modelled using a simple Nutrient–Phytoplankton–Zooplankton (NPZ) model. The intense physical mixing and advection in the channel are the main influence on plankton dynamics in the area. It is found that residence times within the channel are so short that phytoplankton communities cannot grow appreciably during their transit. As a consequence, the use of a more sophisticated biogeochemical model does not lead to significant changes in the results obtained. According to the model, mixing over the Camarinal Sill causes an average of 16% of the out-flowing nutrients to be returned back to the Mediterranean. This fraction varies between 4% and 35% as a function of the tidal amplitude. The comparison of the model results with field data suggests that in order to obtain an accurate simulation of the plankton ecosystem dynamics in the strait, it is necessary to take into account the full horizontal flow, as recirculation and coast-channel interactions seems to be very important processes in explaining the biological patterns in the area.