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Oscillating Water Column (OWC)-based power take-off systems are one of the potential solutions to the current energy problems arising from the use of nuclear fission and the consumption of fossil fuels. This kind of energy converter turns wave energy into electric power by means of three different stages: firstly wave energy is transformed into pneumatic energy in the OWC chamber, and then a turbine turns it into mechanical energy and finally the turbogenerator module attached to the turbine creates electric power from the rotational mechanical energy. To date, capture chambers have been the least studied part. In this context, this paper presents an analytical model describing the dynamic behavior of the capture chamber, encompassing the wave motion and its interaction with the OWC structure and turbogenerator module. The model is tested for the case of the Mutriku wave power plant by means of experimental results. For this purpose, representative case studies are selected from wave and pressure drop input-output data. The results show an excellent matching rate between the values predicted by the model and the experimental measured data with a small bounded error in all cases, so that the validity of the proposed model is proven.

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Marine protected areas play an important role in the conservation of marine resources and fisheries management. In the Basque Country (northern Spain), the small (158 ha) Gaztelugatxe Marine Reserve was established in 1998; after 5 years without exploitation, it is considered likely that the goose barnacle Pollicipes pollicipes populations have recovered. This contribution provides information on the standing stock, and of the relationships between biomass, coverage, and density, and environmental factors such as wave height and energy derived from waves received at the coast. Increasing energy levels produce enhanced coverage and abundance, providing a bigger standing stock in the reserve. Numerical models to simulate the energy produced by waves can be used as a tool to predict the potential biomass of the goose barnacle along the coast. Such an approach allows comparison of observed and predicted biomasses, and possibly also determination of the factors involved in the observed differences, e.g. overexploitation and pollution; this will assist in assessing goose barnacle resources along the coast.

The impacts of global climate change on the Basque coast and the pelagic systems within the southeastern Bay of Biscay are reviewed. Climate projections under greenhouse gas emission scenarios indicate that this area will experience changes in climate throughout the 21st century, including warming of surface air (especially heat wave episodes), intensification of extreme daily rainfall (10%), warming of the upper 100 m of the ocean layer (1.5 to 2.05°C), and sea level rise (SLR; 29 to 49 cm). Observations made in the bay throughout the 20th century for air temperature and mean sea level are in agreement with these projections. Trends in ocean-climatic historical observations within the area, including sea temperature, precipitation, upwelling/downwelling, turbulence and wave climate, are also reviewed. The main impacts on the coast are expected to be from SLR, especially in low-lying areas (mostly urbanised) within estuaries. Sandy beaches are also expected to undergo significant mean shoreline retreats of between 25 and 40% of their width. As the sea level rises, the natural migration of saltmarshes and intertidal seagrasses landward will be constrained, in most cases, by existing anthropogenic fixed boundaries. Empirical relationships between the distribution and dynamics of the long-term biological measures (plankton, primary production, benthos, and fisheries) on the one hand, and ocean-climatic variability on the other, indicate that pelagic and coastal water ecosystems will be affected by ocean warming, increased stratification, shifts in anomaly patterns and streamflow regimes. The largest uncertainties are associated with the lack of downscaled projections within the bay on ocean circulation, ocean-meteorological indices, wave climate and ocean acidification.