Description: From the German Bight along Jutland to the western Skagerrak, we found representatives of almost all groups of phycotoxins known to occur in North Sea plankton. Identification was by liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) in plankton size fractions, with domoic acid and 20-me G the most abundant toxins. The dominance of 20-me G in the spirolide (SPX) composition of plankton from the Jutland current system matched very well with that of an isolate of the dinoflagellate Alexandrium ostenfeldii . The SPXs of the A. ostenfeldii strain S6_P12_E11, previously isolated from the western North Sea along the Scottish coast, comprised 100% 20-me G, suggesting toxin homogeneity among North Sea populations of this species. We detected highest amounts of azaspiracid-1 in the 3–20-µm size fraction at offshore stations, where the Jutland coastal current converges with the westward North Sea flow off Skagerrak. Azadinium spinosum was subsequently identified by clonal isolation from crude cultures established from these stations. Except for lipophilic toxins usually produced by the dinoflagellate Dinophysis spp., dinophysistoxin-1 (DTX-1) and DTX-2, we detected no other phycotoxins in plankton from the southern German Bight. The spatial distribution of the phycotoxins in the eastern North Sea was apparently related to the hydrographical conditions, identified from salinity and coloured dissolved organic matter profiles. The biogeographical distribution of phycotoxins indicates a strong association with the northward advection by the Jutland current and the mixing of German Bight and North water masses along the northwest Danish coast towards the Skagerrak.

Description: Molecular probes were developed for the dinoflagellate genus Azadinium to discriminate among three taxa difficult to differentiate by light microscopy. This genus contains azaspiracid toxin-producing Azadinium spinosum , but also non-toxigenic species. Quantitative polymerase chain reaction (qPCR) and fluorescence in situ hybridization (FISH) assays were applied to cultured isolates and Azadinium -spiked field plankton. Molecular methods were highly specific and sensitive in the unambiguous detection of Azadinium , and thus are valuable for routine plankton, biogeographic and phylogenetic investigations.

Description: As part of the activities of the Global Ecology and Oceanography of Harmful Algal Blooms (GEOHAB)programme, Open Science Meetings (OSMs) have been organized to discuss and synthesize research efforts on various aspects of harmful algal blooms (HABs), and to plan future collaborative activities relevant to the research theme. Within this framework, the steering committee of the GEOHAB Core Research Project on HABs in Fjords and Coastal Embayments has organized two OSMs. The first OSM was held in 2004 in Santiago, Chile; the major goals were to identify the primary research priorities and to initiate an agenda to further our understanding of HAB dynamics in these small-scale coastal systems. The second OSM was held in May 2012 in Victoria,Canada to highlight the progress accomplished since the first OSM and to focus attention on the importance of a comparative approach in conducting ecosystem studies to improve our understanding of HABs. This second OSM addressed four major themes for which significant advances have been made in recent years, with particular focus on their application to semi-enclosed basins linked to coastal ecosystems: (1) Life history of HAB species; (2) Chemical ecological and toxin interactions; (3) Genetic diversity and (4) Transport and mixing of blooms in small-scale, mesoscale and semi-confined systems. This Report presents the major outcomes of this OSM, followed by recommendations for future collaborative studies. These recommendations include the maintenance of international activities on the ecology and oceanography of HABs after the end of the GEOHAB programme in December 2013. A future agenda should focus on a few key questions with clearly identifiable deliverables. These questions should include the development of (i) improved methods to determine the rates of cyst formation and germination in the field, and (ii) coupled biological-physical-chemical models more appropriate to small-scale environments and which incorporate the role of allelochemicals and toxins, as well as the pelagic and benthic coupling components. Research devoted to life history stages should be continued, particularly with respect to fish-killing algal species that cause particular damage in coastal environments. The influence of aquaculture activities on the development of HABs is poorly understood and should be of greater concern in future research on HABs. The influence of climate change, which may be exacerbated in coastal environments, also should be a focus of future research. Long-term ecological research should be encouraged in this respect, in order to make better predictions in the future concerning the development of HABs in coastal environments.

Description: The paralytic shellfish toxin (PST) profiles of Gymnodinium catenatum Graham have been reported for several strains from the Pacific coast of Mexico cultured under different laboratory conditions, as well as from natural populations. Up to 15 saxitoxin analogues occurred and the quantity of each toxin depended on the growth phase and culture conditions. Previous analysis of toxin profiles of G. catenatum isolated from Mexico have been based on post-column oxidation liquid chromatography with fluorescence detection (LC-FLD), a method prone to artefacts and non-specificity, leading to misinterpretation of toxin composition. We describe, for the first time, the complete toxin profile for several G. catenatum strains from diverse locations of the Pacific coast of Mexico. The new results confirmed previous reports on the dominance of the less potent sulfocarbamoyl toxins (C1/2); significant differences, however, in the composition (e.g., absence of saxitoxin, gonyautoxin 2/3 and neosaxitoxin) were revealed in our confirmatory analysis. The LC-MS/MS analyses also indicated at least seven putative benzoyl toxin analogues and provided support for their existence. This new toxin profile shows a high similarity (〉 80%) to the profiles reported from several regions around the world, suggesting low genetic variability among global populations.