ABSTRACT Harmful algal blooms (HABs) can negatively affect coastal water quality, aquatic fauna, and human health from the consumption of toxin-contaminated seafood. Estuaries are especially prone to the incidence of these noxious events and sensitive to the associated damage. This study represents a comprehensive overview of previous investigations reporting the occurrence of harmful algae and/or phycotoxins in the Paranaguá Estuarine Complex (CEP), in Southern Brazil. Secondary data from 2002 to 2021 were combined with new results obtained from widely spaced sampling campaigns performed from 2018 to 2019 to assess the periods and estuarine sectors at greater risk for the incidence of HABs. In total, about 600 water/sediment samples containing harmful microalgae and 675 tissue samples of phycotoxin-contaminated fauna were analyzed. The most frequent and abundant species of potentially toxic microalgae were dinoflagellates belonging to the species complexes Dinophysis acuminata and Prorocentrum lima, producers of diarrhetic shellfish toxins (DSTs), and diatoms of the genus Pseudo-nitzschia, producers of amnesic shellfish toxins (ASTs). Okadaic acid, a DST, was by far the most common toxin in the fauna, reaching higher levels in primary consumers such as bivalve mollusks (mussels, oysters, and clams), zooplankton, and suspension-feeding crustaceans (ghost shrimps), and moderate to low levels in cephalopods, fishes, gastropods, echinoderms, sea turtles, seabirds, and cetaceans. Less rainy periods (winter-early spring) were associated with the highest incidence of DSTs and blooms of their producing algae P. lima and Dinophysis spp., mainly in the middle region of Paranaguá Bay and on the shallow continental platform adjacent to the estuarine mouth. However, certain HAB-forming species may be more successful in inner estuarine areas ( Prorocentrum cordatum) and during different periods, such as late summer—early fall ( Pseudo-nitzschia spp.). Continuous monitoring of harmful algae and toxins is therefore highly recommended to mitigate the effects of HABs in the entire estuary. (HABs quality toxincontaminated contaminated seafood damage andor or CEP, CEP , (CEP) Brazil 200 202 201 total 60 watersediment sediment 67 phycotoxincontaminated phycotoxin analyzed DSTs, (DSTs) Pseudonitzschia, Pseudonitzschia Pseudo nitzschia, nitzschia ASTs. ASTs . (ASTs) acid DST mussels, mussels (mussels oysters clams, clams clams) zooplankton suspensionfeeding suspension feeding ghost shrimps, shrimps shrimps) cephalopods fishes gastropods echinoderms turtles seabirds cetaceans winterearly winter early spring P spp spp. mouth However HABforming HAB forming cordatum summerearly summer spp.. spp.) estuary (CEP 20 6 (DSTs (ASTs 2

Abstract: Background and Aims: The order Gymnodiniales is composed of 11 families, 63 genera and 641 taxonomically valid species. These dinoflagellates are characterized by having a very fragile cell wall. In addition, some species can produce phycotoxins and form dense blooms. In the case of the Mexican Pacific coast, studies focused on knowing the diversity of this group are still limited, despite the economic, social, and ecological importance of these microorganisms. Therefore, the objective of this study was to make a floristic list from a bibliographical review, integrating only the records supported by micrographs, to know the diversity of athecate dinoflagellates of the order Gymnodiniales present in the Mexican Pacific Ocean, with emphasis on those that form harmful algal blooms. Methods: The search for information was carried out in publications (articles and book chapters), from the first record (1943) to the present (November 2022). Each record was confirmed only by the existence of optical and scanning electron micrographs. Key results: The Mexican Pacific is made up of 11 coastal states, where the presence of 10 families, 31 genera and 103 species (which represents 16% of the total number of species recorded worldwide) is currently reported for the order Gymnodiniales. Of the 11 families that make up this order, the Gymnodiniaceae family grouped 29% of the total number of species recorded for the Mexican Pacific, where the genera Gymnodinium and Gyrodinium presented the largest number of species. Conclusions: The evidence presented in this study showed that there is a low diversity for this order in the Mexican Pacific, so it is necessary to implement a greater sampling effort, in addition to venturing into different molecular tools that allow obtaining a better approximation of the diversity in the Mexican coasts.

Resumen: Antecedentes y Objetivos: El orden Gymnodiniales está compuesto por 11 familias, 63 géneros y 641 especies taxonómicamente válidas. Estos dinoflagelados se caracterizan por presentar una pared celular muy frágil. Además, algunas especies pueden llegar a producir potentes toxinas e incluso tienen la capacidad para formar grandes florecimientos. Los estudios enfocados en conocer la diversidad de este grupo, en el caso de las costas del Pacífico Mexicano, siguen siendo limitados, a pesar de la importancia económica, social y ecológica de estos microorganismos. Por lo tanto, el objetivo de este estudio fue realizar un listado florístico a partir de una revisión bibliográfica, que integre únicamente a los registros respaldados por micrografías, para conocer la diversidad de dinoflagelados atecados del orden Gymnodiniales presentes en el Pacífico Mexicano, con énfasis en aquellos formadores de florecimientos algales nocivos. Métodos: La búsqueda de información se realizó en publicaciones (artículos y capítulos de libros), desde el primer registro (1943) hasta la actualidad (noviembre 2022). Cada registro fue confirmado únicamente mediante la existencia de micrografías ópticas y de electrónicas de barrido. Resultados clave: El Pacífico Mexicano está conformado por 11 estados costeros, donde actualmente se tiene reportada la presencia de 10 familias, 31 géneros y 103 especies (16% del total de las registradas a nivel mundial) para el orden Gymnodiniales. De las 11 familias que conforman a este orden, la familia Gymnodiniaceae agrupó 29% del total de especies registradas para el Pacífico Mexicano, donde los géneros Gymnodinium y Gyrodinium presentaron el mayor número de especies. Conclusiones: La evidencia presentada en este estudio demostró que existe una baja diversidad para este orden en el Pacífico Mexicano, por lo que es necesario implementar un mayor esfuerzo de muestreo, además de incursionar en diferentes herramientas moleculares que permitan obtener una mejor aproximación a la diversidad alfa en las costas mexicanas.

Abstract In the present work, harmful algal blooms of the dinoflagellate Blixaea quinquecornis (Abé) Gottschling, 2017 are recorded for the first time for coastal waters of the Peruvian sea. The taxonomic determination of this species was done with light microscopy, Scanning Electron Microscopy (SEM), and Differential Interference Contrast (DIC) microscopy. The thecal formula is: pp, 3’, 2a, 7’’, 5c, 5”’ and 2’’’ 4s. Blixaea quinquecornis was recorded in Sechura, Miraflores and Paracas bays between 2014 - 2016, mainly with algal blooms of 3.2 x105 cel.L-1 (Miraflores) and 2.11x105 cel.L-1 (Paracas) and 4.11 x104 cel.L-1 (Paracas) in autumn of 2016. Blixaea quinquecornis was found alternating with algal bloom produced by the athecate dinoflagellate Akashiwo sanguinea. The physicochemical variables associated with the bloom of B. quinquecornis were SST (18.5 to 26.6° C), salinities (34.7 to 35.325), pH (7.32 to 12.5), and dissolved oxygen (3.8 to 12.5 mL/L). The bloom of B. quinquecornis in Miraflores Bay was positively associated with the increase in SST, salinity and negatively with the concentration of nitrates, whereas the algal blooms of A. sanguinea were positively correlated with the concentration of phosphates and oxygen. The record of the bloom of B. quinquecornis in the 3 bays coincided with unusual sea warming event associated with the El Niño phenomenon 2015-2016.

Resumen En el presente trabajo, se registra por primera vez floraciones algales nocivas del dinoflagelado Blixaea quinquecornis (Abé) Gottschling, 2017 para aguas costeras del mar peruano. La determinación taxonómica de esta especie se realizó mediante microscopia de luz, electrónica de barrido y contraste interferencial diferencial (DIC). La fórmula tecal encontrada fue: pp, 3’, 2a, 7’’,5c, 5”’ y 2’’’ 4s. Blixaea quinquecornis fue registrada en las bahías Sechura, Miraflores y Paracas entre el 2014 y 2017, usualmente con altas densidades de 3.2 x105 cel.L-1 (Miraflores) y 2.11x105 cel.L-1 (Paracas) en verano y 4.11 x104 (Paracas) en otoño 2016. Blixaea quinquecornis estuvo alternando con floraciones algales del dinoflagelado atecado Akashiwo sanguinea. El florecimiento de B. quinquecornis se observó con TSM entre 18.5 a 26.6 °C, salinidades entre 34.70 y 35.32 ups, pH entre 7.32 y 8.82 y oxígeno disuelto entre 3.8 y 12.5 mL/L. En Bahía Miraflores, la floración de B. quinquecornis fue asociado positivamente con el incremento de la TSM, salinidad y negativamente con la concentración de nitratos, mientras que las floraciones algales de A. sanguinea se correlacionó positivamente con la concentración de fosfatos y oxígeno disuelto. El registro de la floración de B. quinquecornis en las bahías de Miraflores y Paracas, coincidió con eventos de inusual calentamiento del mar asociado con el evento cálido El Niño 2015-2016.

Resumo O presente estudo relata variações sazonais e espaciais na diversidade, na distribuição e na abundância de dinoflegelados e indica a presença de espécies de HAB nas águas do Paquistão. Um total de 179 táxons, registrados nesse estudo de águas offshore e próximas à costa, pertence a 41 gêneros em 26 famílias e 10 ordens. A alta contagem de espécies (149 espécies) foi registrada na estação offshore da Ilha de Manora (MI-1) e 105 spp., 109 spp. e 115 spp. foram encontrados na estação offshore da vila de Mubarak (MV-1), Manora perto da estação costeira (MI- 2) e estação próxima à costa da Vila de Mubarak (MV-2), respectivamente. Tripos furca foi a espécie dominante e de ocorrência frequente (> 1 x103 a > 25 x103 células L-1 da costa e > 1x 105 células Ll de estações próximas à costa), além de Alexandrium catenella menos abundante, Alexandrium sp., Alexandrium minutum e Prorocentrum micans (> 103 a 25x 103 células/L). Outras 44 espécies ocorreram em números relativamente baixos (< 103 células L-1). Setenta espécies foram encontradas durante o período de estudo em todas as quatro estações. Foi registrado um alto número de espécies em três gêneros (Tripos (38), Protoperidinium (34) e Prorocentrum (20). Potencialmente tóxicos (16 gêneros e 43 espécies) e HAB relacionados (19 gêneros e 30 espécies), táxons de dinoflagelados também foram registrados. A contribuição percentual de dinoflagelados na população fitoplanctônica total geralmente permaneceu abaixo de 20%, exceto em alguns casos. As estações da Ilha de Manora tinham índice de Shannon comparativamente mais alto e equitabilidade e índice de dominância ligeiramente mais baixos. O gráfico de PCA mostrou forte correlação positiva entre concentração de clorofila-a e oxigênio dissolvido, número total de fitoplânctons e dinoflagelados.

Abstract The present study reports on seasonal and spatial variations in diversity, distribution and abundance of dinoflegellates and indicates the presence of HAB species in Pakistan waters. A total of 179 taxa, recorded in this study from offshore and near-shore waters, belong to 41 genera in 26 families and 10 orders. The high species count (149 species) was recorded from Manora Island offshore station (MI-1) and 105 spp, 109 spp and 115 spp were encountered from the Mubarak village offshore station (MV-1), Manora near shore station (MI-2) and Mubarak Village near-shore station (MV-2) respectively. Tripos furca was the dominant and frequently occurring species (> 1 x103 to > 25 x103 cells L-1 from coastal and >1x 105 cells L-l from near-shore stations) in addition to less abundant Alexandrium catenella, Alexandrium sp., Alexandrium minutum, and Prorocentrum micans (>103 to 25x 103cells/L). Another 44 species occurred in relatively low numbers (<103 cell L-l). Seventy species were found throughout the study period at all four stations. High number of species in three genera (Tripos (38), Protoperidinium (34) and Prorocentrum (20) was recorded. Potently toxic (16 genera 43 species) and HAB related (19 genera and 30 species) dinoflagellate taxa were also recorded. The percent contribution of dinoflagellates in total phytoplankton population generally remained below 20% except for a few instances. Manora Island stations had comparatively higher Shannon index and equitability and slightly lower dominance index. The PCA plot showed strong positive correlation among chlorophyll-a concentration, dissolved oxygen, total number of phytoplankton and dinoflagellates.

Resumen Introducción: Las proliferaciones de cianobacterias en los cuerpos de agua tropicales son cada vez más comunes, debido a la eutrofización y al aumento de las temperaturas. En consecuencia, muchos sistemas de agua dulce se ven afectados por la reducción de la calidad del agua, la biodiversidad y los servicios de los ecosistemas. Con el aumento de la frecuencia de la proliferación de algas nocivas, el desarrollo de herramientas biológicas para mejorar la calidad del agua es urgente. Objetivo: Evaluar los efectos de una macrófita sumergida y un cladócero sobre la cianobacteria productora de microcistina llamada Microcystis aeruginosa (NPLJ-4) y la clorofita Raphidocelis subcapitata (BMIUFRPE-02) en cultivos mixtos. Métodos: Se realizaron dos experimentos paralelos durante diez días para evaluar los efectos de la macrófita sumergida Ceratophyllum demersum y el cladócero Moina micrura sobre las interacciones microalgales. Se cultivaron cepas de microalgas en el medio de cultivo ASM1, en condiciones controladas de laboratorio. El primer experimento presentó cuatro tratamientos: M (C. demersum), Z (M. micrura), MZ (C. demersum y M. micrura) y C (control). El segundo experimento consistió en cinco tratamientos, en el que las microalgas se cultivaron juntas en diferentes proporciones de Microcystis:Raphidocelis: 1:0, 3:1, 1:1, 1:3 y 0:1. La biomasa y las tasas de crecimiento de las cepas se evaluaron cada dos días, y se trataron estadísticamente con ANOVA de medidas repetidas de dos o tres factores. Resultados: En el primer experimento, M. aeruginosa se inhibió significativamente en los tratamientos M y MZ a partir del segundo día, y en Z a partir del cuarto, mientras que R. subcapitata no mostró reducción de su biomasa en ningún tratamiento. Por otro lado, R. subcapitata fue estimulada a partir del octavo y décimo día en el tratamiento M y solo en el octavo día en el tratamiento Z. En el segundo experimento, M. aeruginosa se inhibió significativamente cuando se cultivó con R. subcapitata en proporciones bajas (proporción de Microcystis:Raphidocelis de 1:3) durante todo el experimento, mientras que la clorófita se estimuló en ese tratamiento. Conclusiones: La coexistencia de una cianobacteria con un alga verde no alteró la principal respuesta negativa de M. aeruginosa a la macrófita sumergida y al zooplancton, sino que estimuló al alga verde. En consecuencia, la introducción de macrófitos y cladóceros sumergidos ya adaptados a las condiciones eutróficas, tanto aislados como combinados, resultó ser un buen método para controlar las proliferaciones de cianobacterias sin afectar negativamente a otras especies de fitoplancton coexistentes.

Abstract Introduction: Cyanobacterial blooms in tropical water bodies are increasingly common, because of eutrophication and rising temperatures. Consequently, many freshwater systems are affected, by reducing water quality, biodiversity, and ecosystem services. With the increased frequency of harmful algal blooms, the development of biological tools to improve water quality is an urgent issue. Objective: To evaluate the effects of a submerged macrophyte and a cladoceran on the microcystin-producing cyanobacteria Microcystis aeruginosa (NPLJ-4) and the chlorophyte Raphidocelis subcapitata (BMIUFRPE-02) in mixed cultures. Methods: Two parallel experiments were carried out for ten days to evaluate the effects of the submerged macrophyte Ceratophyllum demersum and the cladoceran Moina micrura on microalgal interactions. Microalgal strains were cultivated in the ASM1 culture medium, under controlled laboratory conditions. The first experiment presented four treatments: M (C. demersum), Z (M. micrura), MZ (C. demersum and M. micrura), and C (control). Meanwhile, the second experiment consisted of five treatments, in which the microalgae were cultivated together at different Microcystis:Raphidocelis ratios: 1:0, 3:1, 1:1, 1:3, and 0:1. Biomass and growth rates of the strains were evaluated every two days, which were statistically treated with three-way or two-way repeated-measures ANOVA. Results: In the first experiment, M. aeruginosa was significantly inhibited in M and MZ treatments from the second day, and Z from the fourth, while R. subcapitata showed no reduction in its biomass in any treatment. On the other hand, R. subcapitata was stimulated from the eighth and tenth days in M treatment and only on the eighth day in Z treatment. In the second experiment, M. aeruginosa was significantly inhibited when cultivated with R. subcapitata in low ratios (Microcystis:Raphidocelis ratio of 1:3) throughout the experiment, while the chlorophyte was stimulated in that treatment. Conclusions: The coexistence of a cyanobacterium with a green alga did not alter the main negative response of M. aeruginosa to the submerged macrophyte and zooplankton but stimulated the green alga. Accordingly, the introduction of submerged macrophytes and cladocerans already adapted to eutrophic conditions, both isolated and combined, proved to be a good method to control cyanobacterial blooms without negatively affecting other coexisting phytoplankton species.

ABSTRACT The phytoplankton community’s temporal variability associated with environmental factors and harmful algal blooms in Acapulco Bay was analyzed. Phytoplankton samples were taken monthly at three sites (MSL: Morro de San Lorenzo, CDO: Casa Díaz Ordaz, and PP: Playa Palmitas) over 11 months in 2018. The physical and chemical variables of surface water were measured in situ, and the composition and community structure of phytoplankton were analyzed. The physical and chemical characteristics studied varied significantly. The highest temperatures were obtained in September and October (September: 29.6 ± 3.58°C, October: 34.61 ± 1.83°C), whereas the highest salinities and chlorophyll-α concentrations occurred from February to May (salinity: 34.06 ± 0.38, chlorophyll-α: 2.73 ± 0.15 μg L-1). The highest oxygen concentrations were recorded during the rainy season (June 91.8% and December 100%). A total of 201 phytoplankton species were identified: 94 diatoms, 101 dinoflagellates, 4 cyanobacteria, and 2 silicoflagellates. Diatoms dominated during the rainy season, whereas dinoflagellates dominated during the dry season (June to December). A total of 17 harmful species were identified; four toxin-producing species included a diatom genus (Pseudonitszchia sp.) and three dinoflagellate species (Gymnodinium catenatum, Dinophysis caudata, and Phalacroma rotundata). One species that produces oxygen reactive species and hemolysis (Margalefidinium polykrikoides) caused a harmful algal bloom at the CDO and PP stations. The temperature is one of the most critical factors for its bloom in October.

Abstract The objective of this study was to evaluate variations in the composition and abundance of the phytoplankton community after an exceptional harmful bloom of Akashiwo sanguinea that occurred in Todos os Santos Bay (BTS) in early March, 2007. Samples were collected every ten days, between April, 2007 and March, 2008, from the estuarine gradient of the Paraguaçu River to BTS. The physical and chemical variables were measured in situ using a multiparameter sensor. Water samples were collected for analysis of the dissolved inorganic nutrient concentrations and for the study of composition and abundance of the microphytoplankton. Overall, 135 taxa were identified, with a higher richness of diatoms. The total cell density ranged from 2.92 × 103 to 1.16 × 107 (5.47 × 105 ± 1.69 × 106) cells L−1, with higher values in the freshwater zone than in the marine area. Five species showed peaks of abundance throughout the study, forming small blooms. Four of these blooms occurred in the rainy season, formed by the species Guinardia striata (April, 2007), Scrippsiella cf. acuminata (August, 2007), Euglena gracilis (August, 2007), and Skeletonema cf. costatum (September, 2007), while a new bloom of the species Akashiwo sanguinea occurred during the dry season (December, 2007). The environment was typically oligotrophic, with low spatiotemporal variation in the concentrations of dissolved nutrients. Even so, we observed short-term variations in the structure and composition of the phytoplankton community, demonstrated by rapid bloom events, followed by an increase in the total abundance of microphytoplankton, especially during the rainy season. The blooms did not cause any notable changes in the water column and did not present any harmful effects on the system.

Abstract Harmful algal blooms are an increasingly common problem worldwide, causing severe damage to public health, economic losses in aquaculture, damage to tourism and mortality events of natural populations of fish, birds and marine mammals. The toxins are produced by phytoplankton and accumulated in bivalve molluscs that feed on water filtration, being these main vectors of human intoxication. In the Argentine Sea marine toxins of microalgal origin have been reported associated with four shellfish poisoning syn-dromes. The most serious due to their extension, frequency, toxicity and affected organisms are those caused by the dinoflagellate Alexandrium catenella responsible for the Paralytic shellfish poisoning that has caused numerous human deaths. Then, the mildest, in severity and frequency, is the Diarrhetic shellfish poisoning. In contrast, domoic acid, known as Amnesic shellfish toxin, has not produced human intoxications yet. Recently, toxins and dinoflagellate species causing Azaspiracid shellfish poisoning have been re-corded, expanding the range of toxins for the region. In addition, the potentially toxic Yessotoxins and Spirolides have been detected, whose mechanism of action and toxicity is still being evaluated worldwide. These emerging toxins represent a potential risk to public health and socioeconomic activities due to the eventual closure of mollusc exploitation sites. They certainly present a new challenge, since detection and quantification can only be carried out using methods based on HPLC - mass spectrometry, which makes monitor-ing in regional laboratories difficult. Prevention through policies, regulations, and monitoring and control systems of each toxin group is the key management tool. These preventive measures are expected to contribute to reducing the number of poisonings and to ap-plying more efficient fisheries closures, ensuring a balance that protects both public health and the development of the fishing industry.

Resumen Las floraciones de algas nocivas son un problema cada vez más frecuente a nivel mundial que ocasiona severos daños sobre la salud pública, pérdidas económicas en acuicultura, perjuicios al turismo y episodios de mortalidad de poblaciones naturales de peces, aves y mamíferos marinos. Las toxinas son producidas por el fitoplancton y se acumulan en moluscos bivalvos que se alimentan por filtración del agua siendo estos los principales vectores de intoxicación humana. En el Mar Argentino, se han reportado toxinas marinas de origen microalgal asociadas con cuatro síndromes de intoxicación por moluscos. Los síndromes más graves por su extensión, frecuencia, toxicidad y organismos afectados, son los originados por el dinoflagelado Alexandrium cate-nella responsable de la Intoxicación Paralizante por Moluscos la cual ha ocasionado numerosas muertes humanas. Seguidamente, la más leve, en cuanto a gravedad y frecuencia, ha sido la Intoxicación Diarreica por Moluscos. En contraste, el ácido domoico, conocido como toxina amnésica de moluscos, no ha producido hasta ahora intoxicaciones humanas. Recientemente, se amplió el rango de toxinas para la región al registrarse las toxinas y los dinoflagelados productores de la Intoxicación Azaspirácidos por Moluscos. Además, se han detectado las potencialmente tóxicas Yessotoxinas y Espirolidos, cuyos mecanismos de acción y toxicidad están siendo aún evaluados a nivel mundial. Estas toxinas emergentes para la región, representan un riesgo potencial para la salud e inconvenientes socioeconómicos por el cierre de los sitios de explotación de moluscos. Ciertamente presentan un nuevo desafío, pues la detección y cuantificación sólo puede realizarse por medio de métodos basados en HPLC - espectrometría de masas, lo cual dificulta el monitoreo en laboratorios regionales en el país. La herramienta clave de manejo es la prevención, a través de políticas, regulaciones y sistemas de monitoreo y control de cada grupo de toxinas. A través de estas mejoras, se anticipa que no sólo disminuirá el número de afectados por estas intoxicaciones, si no que se podrán realizar vedas más eficientes, asegurando un equilibrio que proteja tanto la salud pública como el desarrollo de la industria pesquera.

Resumen Las floraciones de cianobacterias pueden causar problemas en la calidad del agua por su rápido crecimiento y abundancia. Además de generar biomasa en exceso, causan cambios físicos, químicos y biológicos en el ecosistema. Asimismo, las cianobacterias producen neurotoxinas, hepatotoxinas y dermatotoxinas, entre otras. Los problemas asociados con las floraciones de cianobacterias han aumentado en las últimas décadas y, en consonancia, se ha incrementado a nivel global el número de investigaciones sobre las floraciones tóxicas y su efecto en los ecosistemas y la salud humana; hoy muchos países cuentan con protocolos para su manejo. Los principales factores del cambio climático global asociados con una mayor presencia y duración de las floraciones de cianobacterias son el incremento de temperatura, la eutrofización, las alteraciones hidrológicas, el aumento en la estabilidad física de la columna de agua y los cambios en las redes tróficas. En Colombia la eutrofización y el aumento en la temperatura del agua son problemas crecientes y, a pesar de ello, no existe un registro al respecto ni normas estatales que permitan reportar los casos, hacer seguimiento e implementar medidas de control y manejo. En esta revisión se presenta el estado actual del conocimiento sobre dichas floraciones en el país y las expectativas ante el cambio climático global.

Abstract Cyanobacteria can cause problems in water quality due to rapid increases in their abundance known as cyanobacterial bloom. Besides the increase in biomass, it causes physical, chemical, and biologic changes in ecosystems. Cyanobacteria also produce neurotoxins, hepatotoxins, and dermotoxins. The problems associated with cyanobacterial blooms have increased progressively in the last decades. Globally, more studies on harmful cyanobacterial blooms and their effects on ecosystems and human health are being conducted and many countries have developed protocols for their management. The main factors of climate global change associated with increasing cyanobacterial blooms are the rise in temperature, eutrophication, hydrological alterations, the increase in the physical stability of water columns, and changes in trophic networks. Eutrophication and the increase in water temperature are the main issues in Colombia, but, nevertheless, there is no record of cyanobacterial blooms nor state regulations on case reporting, monitoring or control and management measures. This review presents the current state of knowledge on cyanobacterial blooms in the country and expectations vis a vis the global climate change scenario.

ABSTRACT Fish-killing algal species are responsible for important global economic losses to the finfish industry. Chile is the world’s second-largest salmon exporter, and fish-killing algal blooms have widely impacted its production in the last decades. The lack of standardized analytical methods to quantify and characterize the so-called “ichthyotoxins” has hindered our understanding of the underlying ichthyotoxic modes of action. The novel application of a highly sensitive and reproducible fish RTgill-W1 cell line-based assay has allowed significant progress in the field. In this study, the ichthyotoxic potency of the main microalgae species, which has been reported in fish-killing events in the historical Chilean monitoring programs, was assessed. The dinoflagellate Karenia selliformis was the most ichthyotoxic species against the RTgill-W1 (cell viability down to 8%), representing the major threat for the local salmon industry. In comparison, the raphidophyte Heterosigma akashiwo and the dinoflagellate Prorocentrum micans were the least toxic (gill cell viability down to 81 and 89%, respectively). Importantly, ichthyotoxic flagellates were more toxic to fish gill cells upon rupture. These results have important implications for the mitigation and management of algal blooms by the salmon industry.

Abstract: Background and Aims: Harmful Algal Blooms (HAB) commonly occur in the Mexican Pacific, being important HABs of Gymnodinium catenatum (Gc) and of Pyrodinium bahamense var. compressum (Pbc) for being saxitoxin-producing dinoflagellates that cause paralytic shellfish poisoning. The latter is a taxon that sporadically occurs in the tropical Mexican Pacific. This study describes the behavior of both taxa throughout the annual cycle and analyzes their morphology, abundance, distribution, and their bloom dynamics, in relation to environmental and climatological parameters. Methods: Phytoplankton collections were made ten times from October 2009 to January 2011 within Acapulco Bay and its surroundings, together with measurements of physicochemical parameters. Climatic data were obtained from Acapulco weather station. Abundance of phytoplankton was evaluated with the Utermöhl method. Statistical analyses were carried out to investigate the relationship of Gc and Pbc abundances with environmental and climatic parameters. Key results: Gc was present throughout the year 2010 in low densities and in November 2010 it reached a maximum of 189×103 cells l-1, associated with several species of diatoms and dinoflagellates, including Pbc. Gc bloom coincided with decrease in ammonium and decrease in water temperature with respect to the average. Pyrodinium bahamense morphometry from Acapulco corresponds to var. compressum. Pbc formed an intense HAB in July 2010 (reaching a maximum abundance of 773×103 cells l-1), causing significant toxicity and had an upturn in November. Conclusions: Pbc HABs in Acapulco require the occurrence of a previous HAB in the central Pacific or Gulf of Tehuantepec, Mexico, horizontal transportation of their cysts, as well as high water temperature conditions, abundant rainfall that increased the concentration of phosphates, which is propitiated in the periods of transition “El Niñoˮ-“La Niñaˮ events. Gc HABs in Acapulco are related to “La Niña” events, with an abrupt change in water temperature and an increase in nitrogenous forms.

Resumen: Antecedentes y Objetivos: Los florecimientos algales nocivos (FAN) ocurren comúnmente en el Pacífico mexicano, siendo importantes los de Gymnodinium catenatum (Gc) y Pyrodinium bahamense var. compressum (Pbc), dinoflagelados productores de saxitoxina que causan envenenamiento paralítico por mariscos. Pbc se presenta esporádicamente en el Pacifico tropical mexicano. El estudio describe el comportamiento de ambos taxa en un ciclo anual y analiza su morfología, abundancia, distribución y dinámica del FAN en relación con parámetros ambientales y climatológicos. Métodos: Se realizaron diez recolectas de fitoplancton (octubre 2009-enero 2011) en la Bahía de Acapulco y zona costera adyacente, y mediciones de parámetros fisicoquímicos. Los datos climáticos se obtuvieron de la estación meteorológica de Acapulco. La abundancia del fitoplancton se evaluó con el método de Utermöhl. Se realizaron análisis estadísticos para investigar la relación de las abundancias de Gc y Pbc con parámetros ambientales y climáticos. Resultados clave: Gc estuvo presente durante todo el año 2010 con densidades bajas; en noviembre de 2010 alcanzó un máximo de 189×103 células l-1, asociado con especies de diatomeas y dinoflagelados, incluyendo Pbc. El florecimiento de Gc coincidió con disminución de amonio y disminución de temperatura del agua con respecto al promedio. La morfometría de Pb de Acapulco correspondió con la var. compressum. Pbc formó un intenso FAN en julio de 2010 (abundancia máxima de 773×103 células l-1), causando una toxicidad significativa y tuvo un repunte en noviembre. Conclusiones: Los FAN de Pbc en Acapulco requieren un FAN previo en el Pacífico central o en el Golfo de Tehuantepec, transporte horizontal de sus quistes, alta temperatura del agua y abundante precipitación que aumente la concentración de fosfatos; condiciones que se propician en los períodos de transición”El Niño”-“La Niña”. Los FAN de Gc en Acapulco están relacionados con eventos “La Niña”, siendo importantes el cambio abrupto de temperatura del agua y el aumento de formas nitrogenadas.

This study examined the spatial and temporal variability of the phytoplankton communities and their physicochemical variables in three stations at Pescadores Artesanales beach, located in Chorrillos (Lima, Peru). In situ measurements of temperature and pH were made every month for a year, while salinity and dissolved oxygen for half a year. Surface water samples were collected to determine the phytoplankton composition. A total of 120 phytoplanktonic taxa were identified, belonging to 46 families and 66 genera. Phytoplankton species were dominated by diatoms (59.2%) and dinoflagellates (35.6%). Phytoplankton abundance was dominated by the Raphidophyceae (73.72%) followed by dinoflagellates (11.75%), and nanoflagellates (11.53%). Algal blooms were formed by Thalassionema nitzschioides, Skeletonema costatum, Akashiwo sanguinea, Heterosigma akashiwo, Prorocentrum gracile, P. balticum, P. minimum, Scrippsiella acuminata, Dictyocha fibula, Leucocryptos marina and some nanoflagellates (< 20 µm). The highest phytoplankton abundance was observed in summer and autumn. Significant correlations were found between phytoplankton communities and physicochemical variables. Abiotic factors such as dissolved oxygen, temperature, salinity and pH favored the presence of algal blooms. Existence of potentially toxic / harmful phytoplankton species suggests a higher monitoring frequency of harmful algal blooms (FAN) at Pescadores Artesanales beach.

Este estudio examinó la variabilidad espacial y temporal de las principales comunidades del fitoplancton en tres estaciones de la playa de Pescadores Artesanales de Chorrillos, Lima, Perú, en relación con las variables fisicoquímicas. Se realizaron mediciones in situ de temperatura y pH todos los meses durante un año y salinidad y oxígeno disuelto durante medio año. Se colectaron muestras de agua superficial para determinar la composición del fitoplancton. Se identificcaron un total de 120 taxa de organismos fitoplanctónicos, pertenecientes a 46 familias y 66 géneros. Las especies de fitoplancton fueron dominadas por las diatomeas (59.2%) y dinoflagelados (35.6%). La abundancia del fitoplancton estuvo dominada por Raphidophyceae (73.72%), seguido de dinoflagelados (11.75%) y nanoflagelados (< 20 µm) (11.53%). Asimismo, se registraron floraciones algales originadas por las especies, Thalassionema nitzschioides, Skeletonema costatum, Akashiwo sanguinea, Heterosigma akashiwo, Prorocentrum gracile, P. balticum, P. minimum, Scrippsiella acuminata, Dictyocha fibula, Leucocryptos marina y nanoflagelados (< 20 µm) durante todo el periodo de estudio. La mayor abundancia de fitoplancton se observó en verano y otoño. Se encontraron correlaciones significativas entre las comunidades del fitoplancton y las variables fisicoquímicas. Se determinó que los factores abióticos como: oxígeno disuelto, temperatura, salinidad y pH favorecieron la presencia de las floraciones algales. La existencia de especies de fitoplancton potencialmente tóxico/nocivo sugiere un monitoreo frecuente de las floraciones de algas nocivas (FAN) en la playa de Pescadores Artesanales de Chorrillos.

RESUMEN En las últimas décadas, las floraciones de algas nocivas (FAN) y los eventos tóxicos, como la ciguatera, parecen haber aumentado en frecuencia e intensidad, afectando negativamente la salud humana, la economía y los ecosistemas marinos. En Colombia, estos eventos han causado una serie de consecuencias que van desde la muerte de peces y aves hasta efectos tóxicos en los seres humanos. Aunque algunas especies de dinoflagelados que producen toxinas son comunes en el Caribe, su dinámica es poco conocida, lo que dificulta la adopción de cualquier regulación. Para determinar la composición y abundancia de dinoflagelados asociados con los pastos marinos, recolectamos 18 muestras en Isla de Barú durante 2015. Encontramos diez géneros de diatomeas y tres géneros de dinoflagelados, Prorocentrum, Ostreopsis y Gambierdiscus, que incluyen especies toxigénicas relacionadas con la ciguatera y la intoxicación diarreica por mariscos. Prorocentrum lima fue el dinoflagelado más abundante, con densidades celulares promedio de 52 ± 48 células / g de peso húmedo de sustrato. La hipótesis de la temperatura gana fuerza como uno de los principales moduladores de la abundancia de dinoflagelados observados en el Caribe, especialmente con respecto a las especies de Prorocentrum y algunas diatomeas como Mastogloia corsicana y Actinocyclus normanii. Este supuesto está respaldado por la alta correlación positiva entre la Oscilación Sur de El Niño y la temperatura de la superficie del mar en el Caribe durante 2015.

ABSTRACT In the last decades, harmful algal blooms (HAB) and toxic events such as ciguatera seem to have increased in frequency and intensity, negatively impacting human health, economy, and marine ecosystems. In Colombia, these events have caused a series of consequences ranging from the death of fish and birds to toxic effects on humans. Although some toxin-producing dinoflagellate species are common in the Caribbean, their dynamics are poorly understood, making the adoption of any regulations difficult. To determine the composition and abundance of dinoflagellates associated with seagrasses we collected 18 samples on Isla de Barú, during 2015. We found ten diatom genera and three dinoflagellate genera, Prorocentrum, Ostreopsis, and Gambierdiscus, that include toxigenic species related to ciguatera and diarrheic shellfish poisoning. Prorocentrum lima was the most abundant dinoflagellate, with average cell densities of 52±48 cells/g substrate wet weight. The temperature hypothesis gains strength as one of the main modulators of dinoflagellate abundance observed in the Caribbean, especially regarding Prorocentrum species and some diatoms such as Mastogloia corsicana and Actinocyclus normanii. This assumption is supported by the Since high positive correlation between El Niño Southern Oscillation and the sea surface temperature in the Caribbean during 2015.

Resumo O uso de satélites para o monitoramento de florestas é uma prática conhecida e comum. Entretanto o monitoramento remoto da qualidade da água ainda é escarça. Nos Estados Unidos da América (EUA), o uso deste tipo de dado está começando a ser utilizado para o monitoramento da floração de cianobactérias tóxicas (FCTs). Essa ferramenta poderosa pode ser utilizada para gerar avaliações espaciais e temporais das FCTs. Entretanto, a falta de informação sobre a sua acurácia ainda é um desafio – especialmente em países tropicais e equatoriais. Esta perspectiva discute as vantagens e desafios de iniciativas atuais que utilizam dados de Observação da Terra para o gerenciamento de FCTs como por o exemplo o “Lake Erie’s HAB Bulletin” e o “Project CYAN” – ambos nos EUA. Adicionalmente, também foi discutido a aplicação de técnicas de sensoriamento remoto para o monitoramento de FCTs em águas continentais brasileiras.

Abstract The use of satellites for monitoring forests is common and well-known practice. However, the operational remote monitoring of water quality from space is still under development. In the United States of America (USA), the use of this type of data is just now being applied to operationally monitor cyanobacterial harmful algal blooms (CHABs). This powerful tool can be used to generate temporal and spatial assessments of CHABs, however the validation of the retrieved information is still a challenge - especially in tropical and equatorial countries. This commentary discusses the advantages and challenges of current initiatives that use Earth Observation data for managing CHABs such as “Lake Erie’s HAB Bulletin” and “Project CYAN” - both in the USA. Additionally, it was also discussed the application of remote sensing techniques to monitor CHABs in Brazilian inland waters.

Abstract: Coastal systems in Mexico shelter a variety of wildlife, the distribution of phytoplankton will depend on the relationship of physicochemical parameters, availability of nutrients and the presence of phytoplankton species that control primary productivity. The objective of this work was to determine the abundance of diatoms and dinoflagellates, and their relationship with physicochemical parameters, such as nitrates, phosphates, silicates and chlorophyll-a in the lagoon system of Mandinga, located on Mexico’s coast. Sample collection was performed monthly at five sites during North winds and dry seasons, showing the following results: maximum temperature values of 29.1±0.8 °C, salinity of 31.0±2.2 psu, dissolved oxygen levels 9.3±1.3 mg L-1. Plus, the concentration of chlorophyll-a was 14.6±5.6 mg m-³ in April, 2012; maximum monthly means for nitrate, silicate and phosphates were of 20.3±44.9, 256.2±25.2 and 2.9±4.2 µM, respectively. In regards of the physicochemical parameters, they were mainly recorded during March and April, 2012. Where forty-seven microalgae, thirty-one genera and sixteen species were identified; sorting in that time four dinoflagellates and twenty-seven diatoms. Given the above, it is important to mention that, some genera were known to produce Harmful Algal Blooms (HABs), including Pseudo-nitzschia. Canonical-Correlation Analysis (CCA) showed that the abundance and distribution of phytoplankton in the lagoon system of Mandinga accounted for 62.67 % of the variance (p = 0.0001) in the physicochemical parameters, such as silicates, dissolved oxygen, salinity and temperature.

Resumen: En México, los sistemas costeros albergan una gran variedad de vida silvestre, la distribución del fitoplancton dependerá de la relación de los parámetros fisicoquímicos, donde la disponibilidad de nutrimentos controla la productividad primaria. El objetivo de este trabajo fue determinar la abundancia de diatomeas y dinoflagelados, y en relación con los parámetros fisicoquímicos, tales como nitratos, fosfatos, silicatos y clorofila-a en el sistema lagunar Mandinga, en la costa de México. La toma de muestras se realizó mensualmente en cinco sitios, durante la temporada de nortes y estiaje, y se obtuvieron los siguientes resultados: valores máximos de temperatura de 29.1±0.8 °C, salinidad de 31.0±2.2 psu, y niveles de oxígeno disuelto de 9.3±1.3 mg L-1. Además, una concentración de clorofila-a de 14.6±5.6 mg m-³ en abril de 2012; las medias máximas mensuales de nitratos, silicatos y fosfatos fueron 20.3±44.9 , 256.2±25.2 y 2.9±4.2 µM, respectivamente. Las cuales se registraron, principalmente, durante los meses de marzo y abril de 2012. Se identificaron 47 microalgas, 31 géneros y 16 especies; clasificando cuatro dinoflagelados y 27 diatomeas. Algunos géneros son conocidos por producir Florecimeintos de Algales Nocivos (HABs), e incluyen Pseudo-nitzschia. El Análisis de Correspondencia Canónica (CCA) mostró que la abundancia y distribución de fitoplancton en el sistema lagunar de Mandinga representa el 62.67 % de la varianza (p = 0.0001) en los parámetros fisicoquímicos: silicatos, oxígeno disuelto, salinidad y temperatura.