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The Baltic Sea is one of the largest brackish water environments on earth and is characterised by pronounced physicochemical gradients and seasonal dynamics. Although the Baltic Sea has a long history of microscopy-based plankton monitoring, DNA-based metabarcoding has so far mainly been limited to individual transect cruises or time-series of single stations. Here we report a dataset covering spatiotemporal variation in prokaryotic and eukaryotic microbial communities and physicochemical parameters. Within 13-months between January 2019 and February 2020, 341 water samples were collected at 22 stations during monthly cruises along the salinity gradient. Both salinity and seasonality are strongly reflected in the data. Since the dataset was generated with both metabarcoding and microscopy-based methods, it provides unique opportunities for both technical and ecological analyses, and is a valuable biodiversity reference for future studies, in the prospect of climate change., QC 20240115

Växtplankton utgör grunden i den marina näringsväven och används världen överför att bestämma miljöstatus i hav och sjöar. De ingår exempelvis som en kvalitetsfaktor i EU:s vattendirektiv och havsmiljödirektiv. Det finns långa tidsserier avväxtplanktonövervakning där analyserna utförts med mikroskopi. Det sker nu ensnabb internationell utveckling av DNA-metoder för att övervaka växtplankton.Målsättningen med detta projekt var att utveckla en praktisk och robust DNA analysmetod som kan implementeras i svensk marin miljöövervakning.Vårt tillvägagångssätt var att följa med på ordinarie marina miljöövervakningsexpeditioner under ett års tid (2019–2020) och ta parallella havsvattenprov för såkallad DNA-streckkodning av växtplankton. Sammanlagt tog vi prov vid 19 övervakningsstationer som var spridda från Bottenviken i norr till Skagerrak i söder.Provtagningsfrekvensen var cirka 1 gång per månad. Praktiska metoder utarbetadesför fältprovtagning, DNA-extraktion, sekvensering, bioinformatisk analys och taxonomisk annotering. Vi har även tagit fram system för datahantering hos nationelldatavärd och gett förslag på en ny datatyp för nationellt datavärdskap för marinbiologi och oceanografi vid Svenskt Oceanografiskt Datacentrum (https://sharkweb.smhi.se/hamta-data/).En viktig del har varit att jämföra resultaten av DNA-streckkodning och mikroskopi. Resultaten visar att DNA-streckkodning ger ungefär dubbelt så högt biodiversitetsmått än mikroskopering, även om det skiljer sig åt mellan olika grupperav växtplankton. För att undersöka om DNA-streckkodning kan användas förkvantitativ analys tillsatte vi en intern standard till proverna bestående av syntetisktDNA, men eftersom resultatet varierade så behöver man arbeta vidare med detta.Den relativa fördelningen av vanliga eukaryota växtplanktongrupper visade sig harelativt bra överensstämmelse mellan DNA-streckkodning och mikroskopimåttetkolbiomassa, medan biovolym och abundans skiljde sig åt mer. DNA-streckkodningvisade sig ge det, Phytoplankton constitute the base of the marine food web and is used all over theworld to assess the quality status of marine and freshwater systems. Phytoplanktonare for example used in the EU Marine Strategy Framework Directive and in theEU Water Framework Directive. There are long time series of data from monitoringprograms, where phytoplankton are analyzed using microscopy. However, presentlyDNA methods are quickly emerging. The aim of this project was to develop a practical and robust method to analyze phytoplankton that can be implemented inSwedish marine monitoring programs.The project was performed by joining the regular marine monitoring cruisesfor a period of one year (2019–2020). We collected parallel seawater samples forDNA metabarcoding of phytoplankton. Nineteen stations were sampled, all theway from the Bothnian Bay in the northern Baltic Sea to the Skagerrak adjacent tothe North Sea, with a sampling frequency of ~1 sampling per month. Best practiceswere developed for field sampling, DNA extraction, sequencing, bioinformatics andtaxonomic annotation. We also produced a system for data handling at the nationalhost, and provided a new data type for national data host for marine biology andoceanography, the National Oceanographic Data Centre (https://sharkweb.smhi.se/hamta-data/).An important part of the project was to compare results from DNA metabarcoding and microscopy. In general, results of DNA metabarcoding gives about twiceas high biodiversity measures than microscopy, even though it varies betweendifferent phytoplankton groups. We found that the reference databases have shortcomings and need to be further developed. To find out if DNA metabarcoding canbe used quantitatively, we added an internal standard to the samples, composedof synthetic DNA strings. The analysis showed varying results, and therefore furtherdevelopment is needed. The distribution of common eukaryotic groups showedrelatively good agreement between DNA metabarcoding and the carb

Växtplankton utgör grunden i den marina näringsväven och används världen över för att bestämma miljöstatus i hav och sjöar. De ingår exempelvis som en kvalitetsfaktor i EU:s vattendirektiv och havsmiljödirektiv. Det finns långa tidsserier av växtplanktonövervakning där analyserna utförts med mikroskopi. Det sker nu en snabb internationell utveckling av DNA-metoder för att övervaka växtplankton. Målsättningen med detta projekt var att utveckla en praktisk och robust DNA analys­metod som kan implementeras i svensk marin miljöövervakning. Vårt tillvägagångssätt var att följa med på ordinarie marina miljöövervakningsexpeditioner under ett års tid (2019–2020) och ta parallella havsvattenprov för så kallad DNA-streckkodning av växtplankton. Sammanlagt tog vi prov vid 19 övervakningsstationer som var spridda från Bottenviken i norr till Skagerrak i söder. Provtagningsfrekvensen var cirka 1 gång per månad. Praktiska metoder utarbetades för fältprovtagning, DNA-extraktion, sekvensering, bioinformatisk analys och taxo­nomisk annotering. Vi har även tagit fram system för datahantering hos nationell datavärd och gett förslag på en ny datatyp för nationellt datavärdskap för marin­biologi och oceanografi vid Svenskt Oceanografiskt Datacentrum (https://sharkweb. smhi.se/hamta-data/). En viktig del har varit att jämföra resultaten av DNA-streckkodning och mikroskopi. Resultaten visar att DNA-streckkodning ger ungefär dubbelt så högt biodiversitetsmått än mikroskopering, även om det skiljer sig åt mellan olika grupper av växtplankton. För att undersöka om DNA-streckkodning kan användas för kvantitativ analys tillsatte vi en intern standard till proverna bestående av syntetiskt DNA, men eftersom resultatet varierade så behöver man arbeta vidare med detta. Den relativa fördelningen av vanliga eukaryota växtplanktongrupper visade sig ha relativt bra överensstämmelse mellan DNA-streckkodning och mikroskopimåttet kolbiomassa, medan biovolym och abundans skiljde sig åt mer. DNA-streckko

The Baltic Sea is one of the largest brackish water environments on earth and is characterised by pronounced physicochemical gradients and seasonal dynamics. Although the Baltic Sea has a long history of microscopy-based plankton monitoring, DNA-based metabarcoding has so far mainly been limited to individual transect cruises or time-series of single stations. Here we report a dataset covering spatiotemporal variation in prokaryotic and eukaryotic microbial communities and physicochemical parameters. Within 13-months between January 2019 and February 2020, 341 water samples were collected at 22 stations during monthly cruises along the salinity gradient. Both salinity and seasonality are strongly reflected in the data. Since the dataset was generated with both metabarcoding and microscopy-based methods, it provides unique opportunities for both technical and ecological analyses, and is a valuable biodiversity reference for future studies, in the prospect of climate change., The Baltic Sea is one of the largest brackish water environments on earth and is characterised by pronounced physicochemical gradients and seasonal dynamics. Although the Baltic Sea has a long history of microscopy-based plankton monitoring, DNA-based metabarcoding has so far mainly been limited to individual transect cruises or time-series of single stations. Here we report a dataset covering spatiotemporal variation in prokaryotic and eukaryotic microbial communities and physicochemical parameters. Within 13-months between January 2019 and February 2020, 341 water samples were collected at 22 stations during monthly cruises along the salinity gradient. Both salinity and seasonality are strongly reflected in the data. Since the dataset was generated with both metabarcoding and microscopy-based methods, it provides unique opportunities for both technical and ecological analyses, and is a valuable biodiversity reference for future studies, in the prospect of climate change.

SMHI har på uppdrag av Länsstyrelsen för Västra Götaland genomfört en utvärdering av marina växtplanktondata och omvärldsparametrar som påverkar växtplankton. Rapporten gäller prover insamlade inom miljöövervakningen längs Västra Götalands kust (Bohuskusten och Göteborgs skärgård) under åren 1986–2021. Prover från centrala Skagerrak har tagits med som jämförelsematerial. Uppdraget genomfördes av Bengt Karlson, Markus Lindh och Ann-Turi Skjevik. Förslag och synpunkter som framförs i rapporten kommer från författarna.

In this paper, an LC-MS/MS method for the simultaneous identification and quantification of cyanotoxins with hydrophilic and lipophilic properties in edible bivalves is presented. The method includes 17 cyanotoxins comprising 13 microcystins (MCs), nodularin (NOD), anatoxin-a (ATX-a), homoanatoxin (h-ATX) and cylindrospermopsin (CYN). A benefit to the presented method is the possibility for the MS detection of MC-LR-[Dha7] and MC-LR-[Asp3] as separately identified and MS-resolved MRM signals, two congeners which were earlier detected together. The performance of the method was evaluated by in-house validation using spiked mussel samples in the quantification range of 3.12-200 mu g/kg. The method was found to be linear over the full calibration range for all included cyanotoxins except CYN for which a quadratic regression was used. The method showed limitations for MC-LF (R-2 = 0.94), MC-LA (R-2 <= 0.98) and MC-LW (R-2 <= 0.98). The recoveries for ATX-a, h-ATX, CYN, NOD, MC-LF and MC-LW were lower than desired (<70%), but stable. Despite the given limitations, the validation results showed that the method was specific and robust for the investigated parameters. The results demonstrate the suitability of the method to be applied as a reliable monitoring tool for the presented group of cyanotoxins, as well as highlight the compromises that need to be included if multi-toxin methods are to be used for the analysis of cyanotoxins with a broader range of chemical properties. Furthermore, the method was used to analyze 13 samples of mussels (Mytilus edulis) and oysters (Magallana gigas) collected in the 2020-2022 summers along the coast of Bohuslan (Sweden). A complementary qualitative analysis for the presence of cyanotoxins in phytoplankton samples collected from marine waters around southern Sweden was performed with the method. Nodularin was identified in all samples and quantified in bivalve samples in the range of 7-397 <= g/kg. Toxins produced by cyanoba

This is a technical guide for monitoring the taxonomic diversity of phytoplankton using environmental DNA metabarcoding, together with conventional phytoplankton monitoring techniques in marine and brackish waters. The guidelines focus on the detection of eukaryotic and prokaryotic phytoplankton with 185 and 165 rRNA primers, using high-throughput sequencing. Information and recommendations on sampling, sample processing, molecular biological work, quality control, bioinformatics, data storage and management and cost estimates are included so that the method eon be used to complement standardized light microscopy. Furthermore, the guidelines contain information from scientific literature and a discussion on future perspectives, including reference databases and standardization. The guidelines were developed within the project, lmplementing DNA-based methods in Northem European marine phytoplankton monitoring (/O­NEP), supported by the Nordic Council of Ministers in 2022. These guidelines serve as a status quo to accommodate future advances in molecular methods, international guidelines and standards. Using eDNA metabarcoding to complement standardized light microscopy advances conventional monitoring and research on phytoplankton communities to assess biodiversity and the state of the marine environment.

Globally, there are 3 400 to 4 000 described species of marine microalgae but only 1 to 2percent are considered to be harmful (Shumway et al., 2018).The generic term “harmful algal bloom”1 (HAB) includes proliferations of microalgaein marine or brackish waters that can cause water discolouration and massive fish kills,contaminate seafood with toxins, or alter ecosystems and services in ways that humansperceive as detrimental.The impacts and mass mortalities of marine species caused by harmful algae are not newand have been recorded for decades (Sellner and Rensel, 2018). However, there is growingconcern that these events will increase due to accelerating global warming, climate changeand anthropogenic activities.Toxin-producing HABs, in particular, can contaminate seafood, drinking and recreationalwaters, or kill fish and wildlife. HAB events related with seafood biotoxins represent 48percent of total HAB events globally (Hallegraeff et al., 2021). Some HABs are responsiblefor potentially deadly food-borne illnesses, and some HAB toxins may be aerosolizedand cause respiratory distress in susceptible or high-exposure populations (for example,aerosolized brevetoxins from Karenia brevis blooms in Florida, United States of America).Six human syndromes are presently recognized to be caused by consumption of seafoodcontaminated with marine algal toxins:• amnesic shellfish poisoning (ASP)• azaspiracid shellfish poisoning (AZP)• ciguatera poisoning (CP)• diarrhetic shellfish poisoning (DSP)• neurotoxic shellfish poisoning (NSP)• paralytic shellfish poisoning (PSP)In addition, cyanobacteria are identified as food-borne poisoning causative organisms.The species considered harmful are catalogued in published texts (for example, in Lassuset al., 2016) and now periodically updated in the IOC-UNESCO Taxonomic ReferenceList of Harmful Micro Algae (Lundholm et al., 2021) and in AlgaeBase (Guiry and Guiry,2021).Non-toxin-producing but high biomass blooms, including proliferations of, Bengt Karlson har författat kapitel 6: Karlson, B., 2023. Early detection and early warning of harmful cyanobacteria blooms, In: FAO, IOC, IAEA (Eds.), Joint FAO-IOC-IAEA technical guidance for the implementation of early warning systems for harmful algal blooms., Fisheries and Aquaculture Technical Paper. FAO, Rome, pp. 186-200.Bengt Karlson är medförfattare till kapitel 5:McKenzie, C.H., Cembella, A., Goes, J., Al Kharusi, A.S., Al Mawaali, A.K., Clément, A., Stumpf, R.P., Dortch, Q., Suddleson, M., Naustvoll, L.J., Karlson, B., 2023. High biomass blooms causing fish kills and other environmental impacts, In: FAO, IOC, IAEA (Eds.), Joint FAO-IOC-IAEA technical guidance for the implementation of early warning systems for harmful algal blooms., Fisheries and Aquaculture Technical Paper. FAO, Rome, pp. 150-185.

The diatom Pseudo-nitzschia H. Peragallo is perhaps the most intensively researched genus of marine pennate diatoms, with respect to species diversity, life history strategies, toxigenicity, and biogeographical distribution. The global magnitude and consequences of harmful algal blooms (HABs) of Pseudo-nitzschia are particularly significant because of the high socioeconomic impacts and environmental and human health risks associated with the production of the neurotoxin domoic acid (DA) among populations of many (although not all) species. This has led to enhanced monitoring and mitigation strategies for toxigenic Pseudo-nitzschia blooms and their toxins in recent years. Nevertheless, human adaptive actions based on future scenarios of bloom dynamics and proposed shifts in biogeographical distribution under climate-change regimes have not been implemented on a regional scale. In the CoCliME (Co-development of climate services for adaptation to changing marine ecosystems) program these issues were addressed with respect to past, current and anticipated future status of key HAB genera such as Pseudo-nitzschia and expected benefits of enhanced monitoring. Data on the distribution and frequency of Pseudo-nitzschia blooms in relation to DA occurrence and associated amnesic shellfish toxin (AST) events were evaluated in a contemporary and historical context over the past several decades from key northern CoCliME Case Study areas. The regional studies comprised the greater North Sea and adjacent Kattegat-Skagerrak and Norwegian Sea, eastern North Atlantic marginal seas and Arctic gateways, and the Baltic Sea. The first evidence of possible biogeographical expansion of Pseudo-nitzschia taxa into frontier eastern Arctic gateways was provided from DNA barcoding signatures. Key climate change indicators, such as salinity, temperature, and water-column stratification were identified as drivers of upwelling and advection related to the distribution of regional Pseudo-nitzschi

We present guidelines for using environmental DNA metabarcoding, together with conventional techniques, to monitor the taxonomic diversity of phytoplankton in marine and brackish waters. The focus is on eukaryotic and prokaryotic phytoplankton using 18S and 16S rRNA primers and high-throughput sequencing. Information and recommendations on sampling, sample processing, molecular biological work, quality control, bioinformatics, data storage and management and cost estimates are included so that the method can be used to complement standardized light microscopy. A scientific literature review, discussion on future perspectives, reference databases and standardization are included. Using eDNA metabarcoding to complement standardized light microscopy advances conventional monitoring and research on phytoplankton communities to assess biodiversity and the state of the marine environment.

The marine dinoflagellate Alexandrium Halim represents perhaps the most significant and intensively studied genus with respect to species diversity, life history strategies, toxigenicity, biogeographical distribution, and global magnitude and consequences harmful algal blooms (HABs). The socioeconomic impacts, environmental and human health risks, and mitigation strategies for toxigenic Alexandrium blooms have also been explored in recent years. Human adaptive actions based on future scenarios of bloom dynamics and shifts in biogeographical distribution under climate-change parameters remain under development and not yet implemented on a regional scale. In the CoCliME (Co-development of climate services for adaptation to changing marine ecosystems) project these issues were addressed with respect to past, current and anticipated future status of key HAB genera and expected benefits of enhanced monitoring. Data on the distribution and frequency of Alexandrium blooms related to paralytic shellfish toxin (PST) events from key CoCliME Case Study areas, comprising the North Sea and adjacent Kattegat-Skagerrak, Norwegian Sea, and Baltic Sea, and eastern North Atlantic marginal seas, were evaluated in a contemporary and historical context over the past several decades. The first evidence of possible biogeographical expansion of Alexandrium taxa into eastern Arctic gateways was provided from DNA barcoding signatures. Various key climate change indicators, such as salinity, temperature, and water-column stratification, relevant to Alexandrium bloom initiation and development were identified. The possible influence of changing variables on bloom dynamics, magnitude, frequency and spatial and temporal distribution were interpreted in the context of regional ocean climate models. These climate change impact indicators may play key roles in selecting for the occurrence and diversity of Alexandrium species within the broader microeukaryote communities. For example, shifts to high

Epibenthic dinoflagellates occur globally and include many toxin-producing species of concern to human health and benthic ecosystem function. Such benthic harmful algal blooms (BHABs) have been well described from tropical and sub-tropical coastal environments, but assessments from north temperate waters, e.g., northern Europe, and polar regions are scarce. The present study addressed the biodiversity and distribution of potentially toxic epibenthic dinoflagellate populations along the west coast of Sweden (Kattegat-Skagerrak) by morphological and molecular criteria. Morphological analysis conducted by light- and electron-microscopy was then linked by DNA barcoding of the V4 region of 18S rRNA gene sequences to interpret taxonomic and phylogenetic relationships. The presence of two potentially toxigenic epibenthic dinoflagellates, Prorocentrum lima (Ehrenberg) F.Stein and Coolia monotis Meunier was confirmed, along with a description of their spatial and temporal distribution. For P. lima, one third of the cell abundance values exceeded official alarm thresholds for potentially toxic BHAB events (>1000 cells gr–1 of macroalgae fresh weight). The same species were recorded consecutively for two summers, but without significant temporal variation in cell densities. SEM analyses confirmed the presence of other benthic Prorocentrum species: P. fukuyoi complex, P. cf. foraminosum and P. cf. hoffmannianum. Analyses of the V4 region of the 18S rRNA gene also indicated the presence P. compressum, P. hoffmannianum, P. foraminosum, P. fukuyoi, and P. nanum. These findings provide the first biogeographical evidence of toxigenic benthic dinoflagellates along the west coast of Sweden, in the absence of ongoing monitoring to include epibenthic dinoflagellates. Harmful events due to the presence of Coolia at shellfish aquaculture sites along the Kattegat-Skagerrak are likely to be rather marginal because C. monotis is not known to be toxigenic. In any case, as a preliminary assess

High-throughput sequencing-based analysis of microbial diversity has evolved vastly over the last decade. Currently, the go-to method for studying microbial eukaryotes is short-read metabarcoding of variable regions of the 18S rRNA gene with <500 bp amplicons. However, there is a growing interest in applying long-read sequencing of amplicons covering the rRNA operon for improving taxonomic resolution. For both methods, the choice of primers is crucial. It determines if community members are covered, if they can be identified at a satisfactory taxonomic level, and if the obtained community profile is representative. Here, we designed new primers targeting 18S and 28S rRNA based on 177,934 and 21,072 database sequences, respectively. The primers were evaluated in silico along with published primers on reference sequence databases and marine metagenomics data sets. We further evaluated a subset of the primers for short- and long-read sequencing on environmental samples in vitro and compared the obtained community profile with primer-unbiased metagenomic sequencing. Of the short-read pairs, a new V6-V8 pair and the V4_Balzano pair used with a simplified PCR protocol provided good results in silico and in vitro. Fewer differences were observed between the long-read primer pairs. The long-read amplicons and ITS1 alone provided higher taxonomic resolution than V4. Together, our results represent a reference and guide for selection of robust primers for research on and environmental monitoring of microbial eukaryotes.

The recent development of biological sensors has extended marine plankton studies from conducting laboratory bench work to in vivo and real-time observations. Flow cytometry (FCM) has shed new light on marine microorganisms since the 1980s through its single-cell approach and robust detection of the smallest cells. FCM records valuable optical properties of light scattering and fluorescence from cells passing in a single file in front of a narrow-collimated light source, recording tens of thousands of cells within a few minutes. Depending on the instrument settings, the sampling strategy, and the automation level, it resolves the spatial and temporal distribution of microbial marine prokaryotes and eukaryotes. Cells are usually classified and grouped on cytograms by experts and are still lacking standards, reducing data sharing capacities. Therefore, the need to make FCM data sets FAIR (Findability, Accessibility, Interoperability, and Reusability of digital assets) is becoming critical. In this paper, we present a consensus vocabulary for the 13 most common marine microbial groups observed with FCM using blue and red-light excitation. The authors designed a common layout on two-dimensional log-transformed cytograms reinforced by a decision tree that facilitates the characterization of groups. The proposed vocabulary aims at standardising data analysis and definitions, to promote harmonisation and comparison of data between users and instruments. This represents a much-needed step towards FAIRification of flow cytometric data collected in various marine environments.

The marine dinoflagellate Alexandrium Halim represents perhaps the most significant and intensively studied genus with respect to species diversity, life history strategies, toxigenicity, biogeographical distribution, and global magnitude and consequences harmful algal blooms (HABs). The socioeconomic impacts, environmental and human health risks, and mitigation strategies for toxigenic Alexandrium blooms have also been explored in recent years. Human adaptive actions based on future scenarios of bloom dynamics and shifts in biogeographical distribution under climate-change parameters remain under development and not yet implemented on a regional scale. In the CoCliME (Co-development of climate services for adaptation to changing marine ecosystems) project these issues were addressed with respect to past, current and anticipated future status of key HAB genera and expected benefits of enhanced monitoring. Data on the distribution and frequency of Alexandrium blooms related to paralytic shellfish toxin (PST) events from key CoCliME Case Study areas, comprising the North Sea and adjacent Kattegat-Skagerrak, Norwegian Sea, and Baltic Sea, and eastern North Atlantic marginal seas, were evaluated in a contemporary and historical context over the past several decades. The first evidence of possible biogeographical expansion of Alexandrium taxa into eastern Arctic gateways was provided from DNA barcoding signatures. Various key climate change indicators, such as salinity, temperature, and water-column stratification, relevant to Alexandrium bloom initiation and development were identified. The possible influence of changing variables on bloom dynamics, magnitude, frequency and spatial and temporal distribution were interpreted in the context of regional ocean climate models. These climate change impact indicators may play key roles in selecting for the occurrence and diversity of Alexandrium species within the broader microeukaryote communities. For example, shifts to high

High-throughput sequencing-based analysis of microbial diversity has evolved vastly over the last decade. Currently, the go-to method for studying microbial eukaryotes is short-read metabarcoding of variable regions of the 18S rRNA gene with <500 bp amplicons. However, there is a growing interest in applying long-read sequencing of amplicons covering the rRNA operon for improving taxonomic resolution. For both methods, the choice of primers is crucial. It determines if community members are covered, if they can be identified at a satisfactory taxonomic level, and if the obtained community profile is representative. Here, we designed new primers targeting 18S and 28S rRNA based on 177,934 and 21,072 database sequences, respectively. The primers were evaluated in silico along with published primers on reference sequence databases and marine metagenomics data sets. We further evaluated a subset of the primers for short- and long-read sequencing on environmental samples in vitro and compared the obtained community profile with primer-unbiased metagenomic sequencing. Of the short-read pairs, a new V6-V8 pair and the V4_Balzano pair used with a simplified PCR protocol provided good results in silico and in vitro. Fewer differences were observed between the long-read primer pairs. The long-read amplicons and ITS1 alone provided higher taxonomic resolution than V4. Together, our results represent a reference and guide for selection of robust primers for research on and environmental monitoring of microbial eukaryotes.

This paper summarizes the research conducted by the partners of the EU co-funded CoCliME project to ascertain the ecological, human health and economic impacts of Ostreopsis (mainly O. cf. ovata) blooms in the NW Mediterranean coasts of France, Monaco and Spain. This knowledge is necessary to design strategies to prevent, mitigate and, if necessary, adapt to the impacts of these events in the future and in other regions. Ostreopsis proliferations in the Mediterranean have been related to massive mortalities of benthic organisms and to symptoms of respiratory and cutaneous irritation in humans. A six-year epidemiologic study in a Ostreopsis hot spot in Catalonia and the accumulated experience of the French Mediterranean National Ostreopsis Surveillance Network confirm the main effects of these blooms on human health in the NW Mediterranean. The impacts are associated to direct exposure to seawater with high Ostreopsis cell concentrations and to inhalation of aerosols containing unknown irritative chemicals produced under certain circumstances during the blooms. A series of mild acute symptoms, affecting the entire body as well as the ophthalmic, digestive, respiratory and dermatologic systems have been identified. A main remaining challenge is to ascertain the effects of the chronic exposure to toxic Ostreopsis blooms. Still, the mechanisms involved in the deletereous effects of Ostreopsis blooms are poorly understood. Characterizing the chemical nature of the harmful compounds synthesized by Ostreopsis as well as the role of the mucus by which cells attach to benthic surfaces, requires new technical approaches (e.g., metabolomics) and realistic and standardized ecotoxicology tests. It is also necessary to investigate how palytoxin analogues produced by O. cf. ovata could be transferred through the marine food webs, and to evaluate the real risk of seafood poisonings in the area. On the other hand, the implementation of beach monitoring and surveillance systems in th

This presentation summarizes the research conducted by the CoCliME project to ascertain the impacts of Ostreopsis (mainly O. cf. ovata) blooms in the NW Mediterranean beached and to design strategies to prevent, mitigate and, if necessary, adapt to the impacts of these events in the future. Noxious effects of Ostreopsis proliferations in the Mediterranean include massive mortalities of benthic organisms. Still, the involved deleterious mechanisms are poorly understood, requiring standardized ecotoxicology tests. Also, the chemical nature of the harmful compounds synthesized by Ostreopsis is unknown. There is a need to understand the toxin transfer through the marine food webs, and to evaluate the real risk of seafood poisonings in the area. The main effects on human health are, by now, associated to direct exposure to seawater with high Ostreopsis cell concentrations and to inhalation of aerosols containing unknown irritative chemicals produced under certain circumstances during the blooms. A six-year epidemiologic study confirmed the mild acute symptoms, affecting mainly the ophthalmologic, digestive, respiratory and dermatologic systems but the risk of chronic exposure as well. Beach monitoring and surveillance systems in summer (such as the surveillance Network on the French Mediterranean coast since 2006) constitutes an effective strategy to prevent Ostreopsis impacts on human health. Nowadays, the general public has a poor knowledge about the occurrence of Ostreopsis blooms. However, considering hypothetical future scenarios of increased Ostreopsis blooms, a large part of coastal rcreational and tourist activities could be negatively impacted. Tourist and residents might continue to go to the beaches during Ostreopsis proliferations, and this be exposed to associated health risks

The Global Harmful Algal Blooms (GlobalHAB, www.global hab.info) Program is aimed at fostering international cooperative research directed toward improving the prediction of harmful algal bloom (HAB) events in aquatic ecosystems, and providing sound knowledge for policy- and decision-making to manage and mitigate HAB impacts in a changing planet. GlobalHAB is sponsored by the Intergovernmental Oceanographic Commission (IOC) of UNESCO and the Scientific Committee on Oceanic Research (SCOR). GlobalHAB was launched in 2016 and will last for 10 years. The GlobalHAB scientific objectives are focused on the research of taxonomic, ecological and toxicology knowledge gaps, on the effects of climate change on HABs and their biogeographic distribution, the implementation of HABs observing systems, and overall, to promote aquatic food and water safety and security. The GlobalHAB program has an international nature, and collaborates with international entities and programs that share objectives on HABs research, management and mitigation, as was already done by the former program GEOHAB. In particular, scientists from Latin America were active participants in GEOHAB and today Latin America is key in the implementation of GlobalHAB. Extreme HAB events affecting aquaculture sites and natural environments, Sargassum beachings, HABs monitoring programs, ciguatera fish poisoning, toxin transfer through the food webs, are examples of topics where scientists in Latin America are very active and thus, contribute to the implementation of GlobalHAB. Scientists are invited to participate in GlobalHAB by designing and endorsing scientific activities linked to the goals of GlobalHAB, and by participating in other international activities