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Lipophilic toxins were investigated in different benthic compartments of Paranaguá Bay, southern Brazil. Relatively low concentrations of okadaic acid (OA) were frequently reported in macrophyte extracts (maximum 0.64 ng g−1), mainly in sheltered estuarine areas, correlated with the cell abundance of toxigenic benthic dinoflagellates, Prorocentrum lima. Non-conjugated OA was also detected in benthic marine animals, mostly during summer-autumn 2016. Higher OA concentrations were found in the viscera of Genidens genidens fish (24.3 ± 3.7 ng g−1) and in soft tissues of Mytella guyanensis bivalves (21.3 ± 2.13 ng g−1), whereas lower levels were less frequently reported in many other benthic feeders, including cephalopods, gastropods, crustaceans and fishes. Although OA concentrations were below the levels associated with acute human intoxication, possible chronic effects to benthic animals and their consumers cannot be disregarded due to the frequent presence of this biotoxin in various fishery resources. Human health risks are substantially enhanced for small-scale fishing communities and other socioeconomically vulnerable populations. [ABSTRACT FROM AUTHOR]

• Benthic Prorocentrum from coastal and oceanic sites of the Southwest Atlantic studied. • Morphology and molecular (LSU rDNA and ITS) data of Prorocentrum species are provided. • Abundance of benthic Prorocentrum species was determined at 14 sites. • Fernando de Noronha is a hotspot of biodiversity, with 10 species registered. • A latitudinal gradient in global benthic Prorocentrum species richness is evident. In the tropical and subtropical South Atlantic Ocean, studies on the taxonomy and abundance of benthic harmful algae are scarce and the region has been largely under investigated. In this study, morphological descriptions, molecular (LSU rDNA and ITS region) and abundance data of benthic Prorocentrum species from the tropical and subtropical Southwest Atlantic and three oceanic islands are presented. Moreover, a review of global benthic Prorocentrum species richness and distribution is presented. Eleven benthic Prorocentrum species were found in Brazil. Morphological and molecular data on P. borbonicum, P. hoffmannianum, P. lima species complex and P. rhathymum were provided. Prorocentrum panamense, P. cf. caipirignum, P. cf. concavum, P. cf. norrisianum, P. emarginatum / fukuyoi / sculptile complex and two not identified species were observed using scanning electron and/or light microscopy, and morphological descriptions are presented. Prorocentrum lima species complex was found at all investigated sites, in abundances up to 2 × 104 cells g−1 FW at the Northeast Brazil, while maximum abundance of all the remaining species did not exceed 1 × 103 cells g−1 FW. The Fernando de Noronha archipelago can be considered a hotspot of benthic Prorocentrum species diversity, with ten species registered. Data compiled in the literature review shows a clear latitudinal gradient with higher species richness in tropical and subtropical regions relative to temperate areas. It is also evident that there is a bias caused by taxonomic impediment and an uneven sampling effort, with many regions still to be investigated using a combined morphological and molecular effort. Therefore, the current knowledge on the global distribution of benthic Prorocentrum species is likely underestimated. [ABSTRACT FROM AUTHOR]

Based on a literature survey, we evaluated the periods of cyanobacterial dominance in Brazil. We hypothesized that variability of environmental forces along the country will promote or facilitate temporal and spatial mosaic in cyanobacterial dominance. The most striking outcomes are related to the dominance of Cylindrospermopsis, Dolichospermum, and Microcystis. Although they share important adaptive strategies (e.g., aerotopes, large size and toxins production), our findings suggest that they have different environmental preferences. Dolichospermum and Microcystis dominated mainly in warm-rainy periods whereas Cylindrospermopsis was more common during dry periods and in mixed systems, or formed perennial dominance. Maximum phosphorus concentrations were observed in reservoirs dominated by Cylindrospermopsis. Although the main genera reached high biomass levels individually, different abilities to form dominance and co-dominance were observed. The number of co-dominance of Chroococales and Nostocales was almost the same as the individual occurrence of the main genera from these groups. This dataset reveals patterns of dominance of these cyanobacteria and also indicates that physiological features will cause differences in the mechanisms of interactions between species. The understanding of these processes and their relationship to environmental conditions will promote better understanding of cyanobacterial dominance and increase our ability to predict and manage these events. [ABSTRACT FROM AUTHOR]

SUMMARYCoscinodiscus wailesii Gran et Angst is a large centric diatom (280–500 μm diameter) from marine phytoplankton, characterized by a cylindrical frustule with flat valvar surface, two marginal rings of rimoportulae on the mantle, and two macrorimoportulae. Cells from cultured and natural populations collected in Paranaguá Bay, Paraná, southern Brazil were observed under light and scanning electron microscopes to verify the populations’ correct identity and morphology. In both populations, a typical central rosette or a hyaline area was found in the valvar center. The species’ distribution in Brazilian waters was revised, and a discussion on possible vectors of transport was made. Blooms of the species occur sporadically in the coast of Paraná, seeming to affect the local trophic chain. [ABSTRACT FROM AUTHOR]

• These are the greatest cell abundances ever recorded for toxigenic Dinophysis spp. • Oysters accumulated exceptionally high levels of okadaic acid. • Contaminated bivalves were linked to episodes of diarrhetic shellfish poisoning. • Gastropods, crustaceans, echinoderms, fishes, penguins and dolphins were also affected. • Toxin concentrations in marine consumers were inversely related to their trophic levels. On June 2016, a major bloom of Dinophysis acuminata complex was noticed over the coast of Paraná State (PR), southern Brazil, an area unprotected by any official monitoring program. Here we report the results of an extensive sampling effort that ultimately led PR authorities to issue the first State shellfish-harvesting ban due to multi-species okadaic acid (OA) contamination. During its peak, the bloom covered an area of 201 km2 (∼2.0–3.5 × 54.0 km), attaining unprecedentedly high cell densities along the shallow (<15 m) continental shelf (mean 2.2 × 105, maximum 2.1 × 106 cells L−1) and adjacent sandy beaches (mean 2.8 × 105, maximum 5.2 × 106 cells L−1). Only OA was detected in suspension (max. 188 ng L−1). Toxin levels measured in bivalves were several times greater than the regulatory limit of 160 ng g−1, reaching up to 3600 ng g−1 in Crassostrea gasar , by far the highest OA concentrations ever reported in oysters worldwide, 7700 ng g−1 in brown mussels, Perna perna , and lower levels in clams, Anomalocardia brasiliana , and mangrove mussels, Mytella spp. Nine cases of human intoxication were officially reported and five people were hospitalized with typical symptoms of Diarrhetic Shellfish Poisoning linked to the consumption of contaminated bivalves. All bivalves quickly converted most of the OA into its esterified form, DTX-3, and eliminated the toxins only a few weeks following the bloom, with C. gasar being the slowest-detoxifying species. Lower OA levels were accumulated in zooplankton, gastropods and several novel toxin vectors, including benthic organisms such as sand dollars Mellita quinquiesperforata and the ghost-shrimp Callichirus major , which may act as a good indicator of the presence of toxins in sandy beaches, and pelagic fish species that can serve as potential alternative sources of OA to humans (Chaetodipterus faber and Mugil liza). Monitoring toxin contamination in seafood other than bivalves is thus recommended to ensure comprehensive human health protection during massive Dinophysis blooms. Additionally, since OA was also present at low concentrations in the liver of Guiana dolphins Sotalia guianensis and penguins Spheniscus magellanicus , exposure to biotoxins should be considered in conservation actions involving threatened and near-threatened marine organisms in this region. [ABSTRACT FROM AUTHOR]

Harmful Algae Blooms (HAB) have been documented for at least fifty years in Latin America and the Caribbean (LAC), however, their impacts at social, ecological and economic levels are still little known. To contribute to the impact assessment of HABs in LAC region, the available information in HAEDAT, OBIS, CAREC, and CARPHA databases, and scientific literature was analyzed. This historical analysis allows identification of the main syndromes and causal organisms. Considering the existence of two regional working groups of the Intergovernmental Oceanographic Commission (IOC): Algas Nocivas del Caribe (ANCA) and Floraciones Algales Nocivas en Sudamérica (FANSA), representing Central American/Caribbean and South American countries, respectively, the analysis is presented both globally and subregional. For the FANSA region, the HAEDAT data base listed 249 records from 1970 to 2019, with a total of 1432 human intoxications, including 37 fatalities. The majority of these events comprised Paralytic Shellfish Toxins (49%), Diarrhetic Shellfish Toxins (34%), Cyanotoxins (12%) and 6 % other toxins. The total number of harmful taxa in the OBIS database includes 79 species distributed over 25 genera. The most commonly reported species are Alexandrium catenella/tamarense, Gymnodinium catenatum and the Dinophysis acuminata complex. Two new species Prorocentrum caipirignum Fraga, Menezes and Nascimento and Alexandrium fragae Branco and Menezes were newly described from Brazilian waters. In the ANCA region, HAEDAT listed 131 records from 1956 to 2018. The main problems are PSP and Ciguatera and common HAB taxa are Gambierdiscus, Gymnodinium, Pyrodinium, Alexandrium and Dinophysis. The most reported HAB forming species are Gymnodinium catenatum, Pyrodinium bahamense and Gambierdiscus spp. In recent years Margalefidinium polykrikoides blooms have become frequent, causing fish and invertebrates massive mortalities and impacts on touristic activities. In the LAC region, the greatest economic losses were produced by ichthyotoxic massive events causing salmon deaths associated to Pseudochattonella verruculosa and Alexandrium catenella in Chile and tuna deaths related to Tripos furca and Chattonella spp. in the Mexican Pacific. In the last decade, several studies in LAC have linked HAB events with local mesoscale oceanographic and atmospheric phenomena. Trends analyzed up to 2019 are related to the increasing awareness about presence of toxic species, the geographical expansion of already known species, the detection of new toxins for the region, and HAB events duration and/or impacts., (Copyright © 2020 Elsevier B.V. All rights reserved.)