This special volume, dedicated to the outstanding contribution to oceanography of Prof. Fernando Fraga, contains 9 articles on marine biogeochemistry, ecotoxicology and contamination of coastal systems. These articles were selected from the scientific contributions at the XV Seminario Ibérico de Química Marina, which was held in Vigo from 22 to 24 February 2010. During the symposium, recent advances in marine sciences –including physical and chemical oceanography, contamination, biogeochemical processes, climate change, ecology and ecotoxicology– were presented by researchers from Spain and Portugal. This seminar, which began in the 1980’s and is held every two years, serves as a meeting point for marine scientists from Spain and Portugal with the aim of presenting their recent findings stimulating the discussion, exchange of ideas and identification of new challenges in the field, advancing our knowledge of the global ocean from a multidisciplinary perspective.