Distributions of three Alexandrium species and their toxins across a salinity gradient suggest an increasing impact of GDA producing A. pseudogonyaulax in shallow brackish waters of Northern Europe

Publication date: July 2019Source: Harmful Algae, Volume 87Author(s): Anke Kremp, Per Juel Hansen, Urban Tillmann, Henna Savela, Sanna Suikkanen, Daniela Voß, Facundo Barrera, Hans Henrik Jakobsen, Bernd KrockAbstractBlooms of Alexandrium spp. are a well-known phenomenon in Northern European waters. While A. tamarense/catenella, and A. pseudogonyaulax have been reported from marine waters, high densities of A. ostenfeldii are mainly observed at lower salinities in North Sea estuaries and the Baltic Sea, suggesting salinity as a driver of Alexandrium species composition and toxin distribution. To investigate this relationship, an oceanographic expedition through a natural salinity gradient was conducted in June 2016 along the coasts of Denmark. Besides hydrographic data, phytoplankton and sediment samples were collected for analyses of Alexandrium spp. cell and cyst abundances, for toxin measurement and cell isolation. Plankton data revealed the predominance of A. pseudogonyaulax at all transect stations while A. ostenfeldii and A. catenella generally contributed a minor fraction to the Alexandrium community. High abundances of A. pseudogonyaulax in the shallow enclosed Limfjord were accompanied by high amounts of goniodomin A (GDA). This toxin was also detected at low abundances along with A. pseudogonyaulax in the North Sea and the Kattegat. Genetic and morphological characterization of established strains showed high similarity of the Northern European population to distan...
Source: Harmful Algae - Category: Environmental Health Source Type: research