Absorption coefficient of particulate matter on the south-west coast of Europe: a contribution to the validation of the MERIS-Medium Resolution Imaging Spectrometer sensor

Dissolved oxygen (DO) is one of the most important environmental variables of water quality, especially for marine life. Consequently, oxygen is one of the Chemical Quality Elements required for the implementation of European Union Water Framework Directive. This study uses the example of the Ria Formosa, a meso-tidal lagoon on the south coast of Portugal to demonstrate how monitoring of water quality for coastal waters must be well designed to identify symptoms of episodic hypoxia. New data from the western end of the Ria Formosa were compared to values in a database of historical data and in the published literature to identify long-term trends. The dissolved oxygen concentration values in the database and in the literature were generally higher than those found in this study, where episodic hypoxia was observed during the summer. Analysis of the database showed that the discrepancy was probably related with the time and the sites where the samples had been collected, rather than a long-term trend. The most problematic situations were within the inner lagoon near the city of Faro, where episodic hypoxia (<2 mg dm3 DO) occurred regularly in the early morning. These results emphasise the need for a balanced sampling strategy for oxygen monitoring which includes all periods of the day and night, as well as a representative range of sites throughout the lagoon. Such a strategy would provide adequate data to apply management measures to reduce the risk of more persistent hypoxia that would impact on the ecological, important natural resource. economic and leisure uses of this important natural resource.

Contribución al estudio del patrimonio de Cacela: cartografía, arquitectura y paisaje en el contexto del algarve oriental en Portugal

El presente artículo estudia la cartografía de Cacela en el sur de Portugal con el propósito de interpretar su transformación a través del tiempo, considerando la arquitectura, el urbanismo y el paisaje de forma integrada. La lectura de esa transformación se lleva de la mano de las principales cartas de Cacela que coinciden con el inicio del siglo XVII, la aproximación al final del Antiguo Régimen y la transición del siglo XIX al XX, asociando cada uno de estos tiempos a un modo particular de representación. La interpretación de las diferentes cartas está organizada, en términos me- todológicos, a partir del recurso a fuentes escritas de la época, culminando con la elaboración de un dibujo final que contiene la representación del espacio edificado y del paisaje de Cacela a mediados del siglo pasado. Este trabajo se inscribe en una investigación más amplia sobre las aglomeraciones urbanas de pequeña dimensión en las diver- sas subunidades geográficas del sur de Portugal, comprendiendo el paisaje, la morfología urbana y el levantamiento integral de todo el núcleo edificado.