Scientific Highlights of the 19th International Conference on Harmful Algae Summarizing all of the science from a conference is a huge and perhaps impossible task, but once done, it can serve as a reference for the future. We had five exciting and intensive virtual conference days where all the latest information in our field was presented. Undoubtedly, we cannot include summaries from all talks, and hence this overview focuses on some of the highlights. It would have been impossible to write these highlights without the incredible help of the session chairs and co-chairs. We thank all of them for their support! Word cloud as a summary We start this overview with a word cloud, which is a visual representation of the titles of the abstracts presented in the conference and provides the most prominent terms where larger font size means more counts (Fig. 1). So, the Word Cloud captures the essence of the 19th International Conference on Harmful Algae in one picture! During our meeting, the most common words and the main topics were management, bloom, HABs and toxins, for which the latter came in other terms as well, like toxic and toxicity. Shellfish is also a prominent word, similar in coverage as harmful. The word cloud reveals a focus on dinoflagellate species, specifically on the genera Alexandrium, Gambierdiscus, Dinophysis, Karenia, but diatom genera, such as Pseudo-nitzschia, and freshwater cyanobacteria with Microcystis as prominent group, are also mentioned. The way we are now measuring diversity is using genetic and molecular characterization tools, which clearly also found their way in the titles and abstracts of the meeting. Several other words appear that can be related to each other. For example, management of coastal areas where monitoring of species and events are taking place. Plenary talks The plenary talks covered various topics, ranging from the taxonomy, toxicity, ecology, and management of harmful algal blooms across freshwater and marine habitats around the world. We heard about lessons learned from 40 years of research on the physiology, toxicity, and ecology of Dinophysis (Beatriz Reguera), the phylogeny and taxonomy of unarmed dinoflagellates in the Kareniaceae family (Mitsunori Iwataki), and the impacts of climate change on the eco-physiology of the harmful cyanobacterium Cylindrospermopsis (Michele Burford). Some other talks emphasized the role of species interactions, including gene expression, biosynthesis, and toxicity of HABs in response to copepods (Uwe John), and the intracellular interactions between Fig. 1. Word cloud of the submitted titles and abstracts 4 HARMFUL ALGAE NEWS NO. 69 / 20221 Harmful Algae News An IOC Newsletter on Toxic Algae and Algal Blooms No. 69 - February 2022 https://hab.ioc-unesco.org/ The 19th (1st Virtual) International Conference on Harmful Algae hosted from Mexico The 19th International Conference on Harmful Algae (19 ICHA), was held in a virtual format for Lobby of the virtual ICHA 2021 costs to attend the meeting. The Conference started with two pre-conference sessions of the Young Investigator Networking Session coordinated by Lorena Durán, Carlos Rodríguez, Philipp Hess, and Harry Nelson. Previously, Lorena Durán and Carlos Rodríguez interviewed o The Mexican scientists comprising the Local Organizing Committee special sessions held live on Zoom that covered breakthrough topics on harmful algae from marine and freshwater environments: HAB Early Warning Systems Session, Impacts of HABs on fish farms: Addressing industry and global insurance n Scientific Highlights of the 19th International Conference on Harmful Algae Summarizing all of the science from a conference is a huge and perhaps impossible task, but once done, it can serve as a reference for the future. We had five exciting and intensive virtual conference days where all the late predatorial protists, viruses, and bacteria (Alexandra Worden). Several plenary talks highlighted insights on HAB management, including emergent management strategies for monitoring, biotoxin detection, and human health risks associated with Ciguatera Poisoning (Marie-Yasmine Dechraoui Bottein); com Fig. 2. Long-term history of HABs off Eastern Tasmania, Australia, using sedimentary DNA (courtesy of Linda Armbrecht) French Mediterranean and a French Atlantic K. veneficum strain induced over 50% loss of cell viability. A high level of intra-specific variability of ichthyotoxic activity was obse pacificum and Durusdinium trenchii) to be successfully frozen and revived with high viability (Joseph Kihika). This highlights the potential to have a microalgae diversity bank in the future. Several presentations were focused on the intimate association between hosts and their microbiomes (Chri Fig. 4. Example from a weekly HAB bulletin reporting HAB events along the Irish coast (courtesy of Dave Clarke) harvested along the coast. Analysis of seawater and oyster samples confirmed high levels of PSP toxins (Margarita Fernández-Tejedor). The design, implementation, and contents of HAB bulle for lake ecosystem services and selection of environmental measures together with local farmers, which may reduce overall costs (Claudia Wiegand). A special session on the new WHO book Toxic cyanobacteria in water provided advice and guidelines for the management of freshwater cyanobacterial blooms, ISSHA's Corner The International Society for the Study of Harmful Algae (ISSHA) convened the 19th (1st Digital) International Conference on Harmful Algae (19 ICHA), held in La Paz, México, from 10th to 15th October 2021. The ISSHA Council had monthly meetings on-line between May and October to plan molecular probes targeting HAB species (including their different life cycle stages), difficult to identify with conventional microscopy methods. More information about Lindas biography and publications can be found here. Nomination letter of Linda Medlin to the ISSHA Council There are many, many re waters of the South China Sea, a marginal sea of the Western Pacific (Teng et al. 2013, 2014). Sing Tung Teng has demonstrated his training and dissemination skills by introducing a taxonomic grouping of Pseudo-nitzschia based on frustule morphology, which eventually developed into an interactive ke from some species of Rhodophyta to the cultures significantly enhanced the growth of the two Gambierdiscus species that occur in Japan. He is now starting an investigation to clarify the effect of bacteria on Gambierdiscus growth in an attempt to elucidate the growth characteristics of Gambierdiscus ISSHA President goodbye Dear ISSHA members: As many of you know, at the general glection held prior to the International Conference on Harmful Algae (ICHA2021) from 11-15 October 2021 (La Paz, Mexico), I stepped down as the president of the International Society for the Study of Harmful Algae (ISSHA UNESCO Taxonomic Reference List of Harmful Micro Algae Editors Workshop 2021 On November 18-19th 2021, the nine thematic editors responsible for the UNESCO Taxonomic Reference List of Harmful Micro Algae and Henrik Enevoldsen from IOC-UNESCO gathered together in a hybrid format workshop, to discuss Book Review: A Catalogue of Phytoplankton from the Mexican CentralPacific (in Spanish) Authors: Hernández-Becerril, D.U., Barón-Campis, S.A., Ceballos-Corona, J.G.A., Alonso-Rodríguez, R., RinconesReyes, K.M., Becerra-Reynoso, R.T. & Arce-Rocha, G. 2021. Catálogo de fitoplancton del Pacífico central Forthcoming Events 2022 UN Ocean Conference GLOBAL ONLINE STAKEHOLDER CONSULTATION Inputs to concept papers of interactive dialogues Contribute your inputs to the concept papers of the interactive dialogues for the 2022 UN Ocean Conference! (see back page) Deadline: 21 February 2022 Contribute your GlobalHAB symposium on automated in situ observations of plankton Aims and background Harmful Algal Blooms (HABs) are affecting aquatic ecosystems and human societies. Biotoxin-producing HABs species and species causing fish mortalities are problems for aquaculture, fisheries and also for tourism. H www.neiwpcc.org/events/ushab11 #USHAB2022 For logo contest rules, please visit our conference website. We are pleased to announce that the 11th U.S. Symposium on Harmful Algae will be held on October 23-28, 2022 in Albany, New York, at the Hilton Albany. Local coordination is being led by NEIWPCC, Eds-in-chief Beatriz Reguera, IEO (CSIC), Vigo, Spain Eileen Bresnan, Marine Scotland, UK Regional Editors Caribbean: Ernesto Mancera jemancerap@unal.edu.co Atlantic Europe: Maud Lemoine Maud.Lemoine@ifremer.fr Mediterranean Sea: Adriana Zingone zingone@szn.it India: K.B. Padmakumar kbpadmakumar