The second International Conference on Ostreopsis Development ICOD 2, French Basque Country, June 1011, 2027 Over the last decades increasing attention has been paid to benthic dinoflagellates belonging to the genus Ostreopsis. The presence of these microalgae has been reported in many temperate regions and in some cases their blooms have caused recurrent deterioration in water quality, mortality of benthic invertebrates, and airborne intoxications in humans resulting from exposure to aerosols containing substances produced along the Ostreopsis blooms. Given these impacts, the dynamics of Ostreopsis blooms have been studied in various areas, showing a wide range of variability in terms of intensity, timing and environmental drivers. The Second International Conference on Ostreopsis Development (ICOD 2) will be held on June 1011, 2027 in the French Basque Country. The first conference (ICOD 1) was held in Villefranche-sur-Mer, France, in 2011 bringing together more than 70 international researchers. The conference proceedings were published in the international journal Cryptogamie Algologie and are available online on the RAMOGE International Agreement website (https://ramoge.org/ documents/). ICOD 2 will provide an overview of the current knowledge on the global distribution and proliferation of Ostreopsis species, covering a broad range of topics, including ecological, ecophysiological, phylogenetic, chemical, and toxicological aspects. As was the case for ICOD 1, the contributions may be published in the journal Cryptogamie Algologie (https://sciencepress. mnhn.fr/fr/periodiques/algologie) as part of the conference proceedings. Contributions will be limited to a maximum of five pages and will be subject to a peer-review process. Registration for the conference and Call for Abstracts will be open at https://gis-littoral.communaute-paysbasque.fr/icod-2027/, from October 1st, 2026 to January 31st, 2027. Participants will be inHARMFUL ALGAE NEWS NO. 84 / 2026 vited to indicate their preference for either an oral presentation or a poster. The scientific committee will notify authors of the acceptance of their submission and the type of presentation by March 15th, 2027. Practical information regarding ICOD 2, including dates, venues, transportation, accommodation and other logistical details will be provided in the same webpage. The RAMOGE International Agreement will co-fund some travel costs for participants from Mediterranean countries to attend the conference. ICOD 2 is organized within the framework of and with the support of the European cross-border project Ostreobila (POCTEFA EFA 040/1). The project aims to (1) monitor the abundance of Ostreopsis along the cross-border Basque coastline, (2) describe the environmental conditions that favour the development of these species, (3) understand their impacts and toxicity in relation to human health and biodiversity, and (4) develop management tools for authorities (local authorities responsible for beach management, and health authorities). We hope to welcome approximately 100 researchers from around the world and to bring together current knowledge on species of the genus Ostreopsis. The Organizing Committee: Aurélie Bocquet-Escourrou, GIS (Scientific Interest Group) Littoral Basque/CAPB (Basque Country Urban Community), France Nerea Egia Larrinaga, Irigune Elkargoa (Basque Country Urban Community), Spain Rodolphe Lemée, Villefranche Oceanography Laboratory, France Elvire Antajan, Ifremer Arcachon, France Elisa Berdalet, Institute of Marine Sciences (ICM-CSIC), Barcelona, Spain Sergio Seoane, University of the Basque Country, Spain 15 Harmful Algae News An IOC Newsletter on Toxic Algae and Algal Blooms No. 84 September 2026 https://hab.ioc-unesco.org/ Unveiling biotic controls of Alexandrium minutum in the Ría de Vigo (NW Spain) Understanding biotic interactions that regulate the dynamics of harmful algal bloom (HAB) species r Fig. 2. The study area in the Ría de Vigo (NW Spain). The red dots indicate the locations where the A. minutum strains were isolated. [1]. We propose that such stable abiotic conditions may facilitate the establishment and persistence of key biotic interactions between the microalgae and their micr Fig. 4. Abundance of Alexandrium minutum (Am) (A) and bacteria (B) in quasi-axenic monocultures (blue lines) or co-cultures with Alteromonas sp. (Alt) (red lines) with B-vitamins (w B-vit, solid lines) or without B-vitamins (wo B-vit, dashed lines). (C) Taxonomic composition of the bacterial microbi Fig. 5. Box and whisker plot showing the response ratios (RR) of Alexandrium minutum growth to the addition of different Zostera marina exudates at low (200300 μM DOC) and high (500600 μM DOC) concentrations. A total of 14 and 10 response ratios were included for the low and high concentration treat dinoflagellates. It has been suggested that phenolic compounds produced by marine angiosperms, e.g. [25], may play a significant role in the negative interaction between these plants and dinoflagellate growth [56, 21]. However, this hypothesis has not yet been experimentally tested. Acknowledgement Intense algal bloom during the austral summer in Inglesa and Calderilla Bays (Atacama, Chile): phytoplankton monitoring, environmental observations and implications for coastal aquaculture Fig. 1. Seawater discoloration in Inglesa Bay sector, Caldera during the first week of February 2026. (A) and Fig. 3. Dominant dinoflagellate species in the algal bloom. (A) Akashiwo sanguinea and (B) Tripos cf. furca. radically (2005, 2009, 2014, and 2016), including blooms of the toxic dinoflagellate species such as Protoceratium reticulatum, which produces yessotoxins (YTX) and has been detected along t Fig. 5. Abundance of other microplankton groups in February 2026 at the five sampling stations in the Caldera Bay System. 2. Rodríguez L 1978. Noticiario Mensual del Museo de Historia Natural de Chile 22(266):69 3. Rodríguez L 1985. Rev Biol Mar 21:173197. https://hdl.handle. net/20.500.14330/PER01 An overview of the 20182025 monitoring, detection, and control programme for Alexandrium catenella in Southern Chile The frequency, persistence, and geographical extent of harmful algal blooms (HABs) caused by the dinoflagellate Alexandrium catenella have increased in southern Chile over recent deca 3. 4. 5. 6. 7. 8. Fig. 2. Annual number of analysed samples and positive detections between 2018 and 2025. Bars represent the total number of samples collected each year. The red area indicates positive results (number shown at the base of each bar), whereas the blue area corresponds to negative res A mixed bloom of Prorocentrum lima species complex and Aphanocapsa sp. under hypersaline conditions in a mangrove lagoon of the Seaflower Biosphere Reserve, Colombian Caribbean Fig. 1. Old Point Regional Park, San Andrés Island, Seaflower Biosphere Reserve, showing the small mangrove lagoon where t Table 1. Measurements of physicochemical characteristics recorded during the mixed bloom of the Prorocentrum lima species complex and Aphanocapsa sp. Old Point, Colombia Lago delle Nazioni, Italy Paracas Bay, Peru 14 April 2026 December 2019 January 2020 2729 August 2017 4.5 106 4.7 107 2 morphological and molecular identification of benthic Prorocentrum and cyanobacteria with measurements of dissolved inorganic nutrients, dissolved and particulate organic carbon, phycotoxins, microbial community composition, sediment resuspension, and water-exchange and salinity dynamics. Acknowled Forthcoming IOC-FAO IPHAB The Eighteenth Session of the IOC-FAO Intergovernmental Panel on Harmful Algal Blooms (IPHAB-XVIII) will meet on 16-18 March 2027 at FAO Headquarters in Rome. The establishment of an intergovernmental panel on HABs in 1991 was a response to the need to improve the manageria The second International Conference on Ostreopsis Development ICOD 2, French Basque Country, June 1011, 2027 Over the last decades increasing attention has been paid to benthic dinoflagellates belonging to the genus Ostreopsis. The presence of these microalgae has been reported in many temperate re NEW! IOC Toxins database The IOC Toxins database is now on-line. It contains reference information about toxins, some of which are associated with Harmful Algal Events. The IOC Toxin Reference List is work in progress. Some sections are complete, some are partly complete and some are empty. The Lis