Seagrass meadows are important ecosystems due to their high productivity and ecological value among tropical ecosystems, because of their high species diversity. In Colombia seagrasses are located around some islands, oceanic coral banks and along the Caribbean shelf, mainly in La Guajira Department, where more than 80% of the seagrass meadows of the country are present. In the world, the delimitation of this ecosystem has been successfully mapped during years, with assistance of remote sensing, using satellite image of different spatial scales. Nevertheless, the specific environmental conditions in La Guajira, such as high water turbidity and reduced light penetration restrict the use of traditional satellite images employed for those seascapes. With the aim of delimiting and establishing the extension of seagrass meadows in La Guajira, based on analyses between July 2013 and February 2014, a methodology of massive image interpretation that included fieldwork fast verification was applied, generating as a result one layer of seagrass habitats in Cabo de La Vela – Dibulla area at 1:100000 scale. Methodology included geometric correction, image fusion, fieldwork information, definition of thematic classes, determining of criteria for spatial delimitation, visual interpretation of images, thematic uncertainty qualification, and final cartography production. The process of cartographic production showed that Landsat 8 OLI satellite sensor images made easier the identification of seagrass meadows in deep areas (>10m). In total, 53621 ha of seagrass meadows were identified, and the largest meadows of Colombia were delimitated, which reach dimensions of up to 6018 ha.

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Los autores proponen un estudio climatológico de la altura significativa del oleaje (Hs) en la cuenca colombiana mediante el análisis de datos de altimetría tomados por los satélites Jason-1, Topex -Poseidón, ERS-2, Envisat and Geosat-2 (GFO), catalogados en la base de datos AVISO Delayed Time Corrected Sea Surface Heights entre septiembre 1992 y abril 2009. La cartografía mensual de la altura significativa media del oleaje analizada en ventanas de 0.5° x 0.5° revela valores de altura importantes para enero y febrero, cuando los vientos alisios son más intensos, seguidos por los valores de junio y julio. Estos últimos debidos a la ocurrencia de vientos del Veranillo. El análisis de la variabilidad interanual sobre cuatro ventanas de 1° x 1°, situadas cerca del Golfo de Urabá, Cartagena, Barranquilla y Riohacha presenta niveles de altura significativa del oleaje, que aumentan en sentido este/oeste. Exceptuando los valores del norte del golfo de Urabá con una posición geográfica más protegida. Por otra parte, no se observó aumento de la altura significativa máxima en el período 1992-2009. La estimación de altura significativa del oleaje para diferentes probabilidades de retorno, permite constatar que para ocurrencias de 10 y 50 años, las alturas correspondientes son de 4.17 y 4.53 m. para Riohacha, 4.75 y 5.11 m. para Barranquilla, 5.23 y 5.51 mts para Cartagena y de 4.83 y 5.43 mts para el norte del golfo de Urabá.

During a baseline survey of the shallow bottoms (10-50 m) of the southern continental shelf  of the Colombian Caribbean, a total of 35 molluscan species belonging to 24 families was collected. Three main molluscan bottom assemblages were recognized according to species composition and abundance, whose distribution seems likely to be controlled rather by depth than by sediment features. Twenty four of the species were not recorded before from this area of the Colombian Caribbean.

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