Resumen Introducción: Las lagunas salobres son ecosistemas de alta diversidad y con posibilidades para uso humano. Por lo que es necesario mejorar el conocimiento del fitoplancton para entender su impacto real. Objetivo: Relacionar el fitoplancton de la Laguna Mandinga con las condiciones limnológicas durante épocas de secas y lluvias. Métodos: El material se recolectó en tres estaciones: Isla Conchas (ICO), Mandinga Chica (MCH) e Isla del Amor (IA) en secas (marzo 2018) y lluvias (septiembre 2017 y 2018). El análisis limnológico incluyó diez variables abióticas, además del fitoplancton mediante el método de Utermöhl. Los datos fueron analizados por el índice de Shannon (H') y Correspondencia Canónica (ACC). Resultados: Análisis de 136 especies; 68.4 % Heterokontophyta, 22.8 % Dinoflagellata, 5.9 % Cyanobacteria; con 40 eurihalinas y 96 estenohalinas. Las especies más abundantes fueron: Bacillaria paxillifera, Chaetoceros compressus, Coscinodiscus rothii y Chaetoceros atlanticus. La mayor abundancia se registró en ICO (secas) y la menor en MCH (lluvias) con 307 x 103 y 76 x 103 cell/ml, respectivamente. El H' osciló entre 1.31 y 0.70 bits/ind. El CCA mostró una relación entre salinidad y oxígeno disuelto con C. rothii y Ceratoneis closterium. Los fosfatos se asociaron con B. paxillifera, C. atlanticus y Podosira stelligera. Los nitratos, temperatura y pH se correlacionaron con Tripos hircus, T. furca, Diploneis bombus y Merismopedia elegans. Mientras, Skeletonema costatum, Cocconeis scutelum y Nitzschia bicapitata no presentaron correlación con las variables limnológicas. Conclusiones: La Laguna Mandinga es un ecosistema somero, eurihalino y bien oxigenado. La dominancia de diatomeas y dinoflagelados se evidenció por su capacidad para sobrevivir en diferentes concentraciones de salinidad y temperatura. Sugerimos monitorear al fitoplancton por la presencia de Microcystis wesenbergii, B. quinquecornis, Pseudo-nitzschia cf. pungens y P. cf. pseudodelicatissima ya que pueden formar proliferaciones dañinas.

Abstract Introduction: The brackish lagoons are ecosystems with great diversity and possibilities for human use. Therefore, the knowledge about phytoplankton needs to be improved to understand its real impact. Objective: To relate the Mandinga’s Lagoon phytoplankton to the limnological conditions during the dry and wet seasons. Methods: The material was collected in three stations: Isla Conchas (ICO), Mandinga Chica (MCH) and Isla del Amor (IA) during the dry (March 2018) and wet (September 2017 and 2018) seasons. The limnological analysis included ten abiotic variables, and the phytoplankton was analyzed by the Utermöhl method. Data was analyzed with the Shannon index (H') and Canonical Correspondence Analysis (CCA). Results: 136 species were identified: 68.4 % Heterokontophyta, 22.8 % Dinoflagellata, and 5.9 % Cyanobacteria; with 40 euryhaline and 96 stenohaline. The most abundant species were: Bacillaria paxillifera, Chaetoceros compressus, Coscinodiscus rothii, and Chaetoceros atlanticus. The highest abundance was in ICO (dry) and the lowest in MCH (wet), with 307 x 103 and 76 x 103 cells/ml, respectively; the H' ranged from 1.31 to 0.70 bits/ind. The CCA showed a relationship between salinity and dissolved oxygen with C. rothii and Ceratoneis closterium. The phosphates were associated with B. paxillifera, C. atlanticus, and Podosira stelligera. The nitrate, water temperature and pH were related to Tripos hircus, T. furca, Diploneis bombus, and Merismopedia elegans. In contrast, Skeletonema costatum, Cocconeis scutelum, and Nitzschia bicapitata did not correlate with the limnological variables. Conclusions: The Mandinga’s Lagoon is a shallow, euryhaline and well-oxygenated ecosystem. The dominance of diatoms and dinoflagellates was evidenced by their ability to survive in different salinities and temperatures. It is recommended monitor phytoplankton, in particular Microcystis wesenbergii, B. quinquecornis, Pseudo-nitzschia cf. pungens, and P. cf. pseudodelicatissima as they are harmful algae.

Resumen Introducción: Las bahías bioluminiscentes en Puerto Rico desempeñan un papel socioeconómico importante y disminuciones del dinoflagelado bioluminiscente dominante Pyrodinium bahamense son preocupantes. Los estudios muestran proliferaciones erráticas débilmente correlacionadas con factores ambientales locales. Objetivos: Cuantificar cambios en la densidad de dinoflagelados a largo plazo en la Laguna Grande de Fajardo (LGF), comprender cómo el ambiente marino modula esos cambios y determinar los impactos de eventos climáticos extremos en la densidad de dinoflagelados. Métodos: Se recolectaron muestras bimestrales del 2016-2021 en tres sitios de la LGF. La densidad se estimó mediante el conteo de células de Sedgewick Rafter. Condiciones ambientales se obtuvieron de la estación Río Fajardo 5007100 y de la boya NOAA 41056. El clima marino y los indicadores bióticos se obtuvieron por mediciones de teledetección. Se utilizaron correlaciones Kruskal Wallis, Spearman y las correlaciones cruzadas en los registros de campo corto y proxy largos para evaluar los controles ambientales en las proliferaciones de dinoflagelados LGF. Resultados: En seis años de monitoreo se encontraron densidades bajas entre el 2016-2017 y proliferaciones frecuentes e intensas en 2018-2021 marcadas por huracanes. Se registraron valores bajos a finales del invierno, en contraste con valores más altos a finales del verano (agosto-noviembre). Vientos ligeros y la respuesta de capas mixtas al calentamiento estacional en forma de mareas altas y baja salinidad, mantienen la reproducción de los dinoflagelados. Conclusiones: Los dinoflagelados bioluminiscentes son vitales para el turismo costero y requieren manejo de los recursos. En general: 1) los recuentos de dinoflagelados fluctúan ampliamente, 2) los dinoflagelados fluorescentes son sensibles a las condiciones ambientales debido a su estacionalidad limitada y estrecho rango fisiológico, 3) los huracanes juegan un rol de rastrillar y refrescar la laguna costera para su posterior reproducción, y 4) fluctuaciones intra-estacionales se relacionan con las condiciones termodinámicas aire-mar, el balance de salinidad y el nivel del mar.

Abstract Introduction: Bio bays in Puerto Rico play an important socio-economic role and declines in dominant bioluminescent dinoflagellate Pyrodinium bahamense are concerning. Studies show erratic blooms with is weak correlation to in situ environmental factors. Our study examines shorter field and longer proxy records on dinoflagellate density at Laguna Grande de Fajardo (LGF). Objectives: To quantify temporal changes in dinoflagellate density in a long-term monitoring study, understand how the marine environment modulates those changes, and determine the wider impacts of a fluctuating climate and extreme events on proxies for dinoflagellate density. Methods: Bimonthly samples were collected from 2016 to 2021 at three sampling sites in LGF. Dinoflagellates density was estimated by Sedgewick Rafter counting cells. Environmental conditions were obtained from Rio Fajardo 5007100 station and NOAA buoy 41056. Marine climate and biotic proxies were obtained from remote sensing measurements. Kruskal Wallis, Spearman correlations and cross-correlations in the shorter field and longer proxy records were used to evaluate environmental controls on LGF dinoflagellate blooms. Results: Six years of field monitoring densities found a low period in 2016-2017, frequent and intense blooms in 2018-2021 punctuated by hurricanes. Generally low values were recorded in late winter in contrast with higher values in late summer (Aug-Nov). Light winds and mixed layer response to seasonal warming in the form of high tides and low salinity, were found to sustain dinoflagellate reproduction. Conclusions: Bioluminescent dinoflagellates are vital to coastal tourism and require resource management. LGF results show that: 1) dinoflagellate counts fluctuate widely, 2) fluorescing dinoflagellates are sensitive to environmental conditions because of limited seasonality and narrow physiological range, 3) hurricanes play a role by ‘raking and refreshing’ the coastal lagoon for subsequent biotic reproduction, and 4) intra-seasonal fluctuations of density and proxies relate to air-sea thermodynamic conditions, the salinity budget and sea level.

ABSTRACT. The Bay of La Paz (BLP) is located in the southwestern portion of the Gulf of California (GC), the largest and deepest coastal environment along the gulf. The BLP is recognized for its high biological diversity and is a place of refuge, growth, and feeding for several emblematic species, some of which are critically endangered. However, what makes the BLP productive? This paper presents a synthesis and review of the physical processes and mechanisms related to planktonic production, which are directly linked to productivity at higher trophic levels, including top predators. This review reveals that the BLP has a high richness and abundance of plankton species. Several hydrodynamic processes at different scales exert a marked influence on these organisms, including internal waves, hydraulic jumps, thermohaline fronts, the presence of a dipole eddy, and a quasi-permanent cyclonic eddy that is confined to the bay, which induces Ekman pumping that determines the availability of nutrients in the euphotic zone. This eddy induces a differential phytoplankton distribution, with a predominance of dinoflagellates in its center and the dominance of diatoms in its periphery. This arrangement is closely linked to that of zooplankton. Herbivorous zooplankton are highly abundant in the periphery of the eddy, while omnivorous zooplankton are dominant in the center. In contrast, carnivorous zooplankton are dominant in the GC. Although significant progress has been made in understanding the dynamics of the BLP over the last two decades, gaps remain unaddressed. This review highlights the areas of opportunity to continue advancing this endeavor, achieve a better scientific understanding of the region, and propose better management and conservation plans for this highly diverse area.

ABSTRACT. This work aims to report the phytoplankton species composition and cell density in the Mazatlán coastal region (eastern entrance of the Gulf of California (GC), Mexico) during the strong El Niño event of 2023. Surface water samples (at 2 m depth) for phytoplankton cell determinations were collected in December of 2023, a month in which the numerical value of the Oceanic Niño Index was 2.0. The results showed a total of 197 species, including 113 diatoms (with a total cell density of 51,444 cells L-1), 76 dinoflagellates (with a total cell density of 31,260 cells L-1), four silicoflagellates (with a total cell density of 420 cells L-1), two cyanobacteria (with a total cell density of 2,020 cells L-1), one Euglenophyta (with a total cell density of 900 cells L-1) and one ciliate (with a total cell density of 7,820 cells L-1). The diatom Dactyliosolen phuketensis (B.G. Sundström) G.R. Hasle, 1996 and the dinoflagellate Gyrodinium fusiforme (Kofoid & Swezy, 1921) presented the highest cell densities with 4,100 and 5,900 cells L-1, respectively, species that have been previously reported in high abundances in Mexican waters in years of warming events, including El Niño. The results presented here contribute to understanding the effects of strong El Niño events on the phytoplankton community structure of the southeastern GC. This topic still needs to be fully addressed. This study also provides an update on the taxonomic lists available for the region of a group of organisms whose nomenclature has been constantly changing in recent years.

Resumen La Reserva de la Biosfera Isla Guadalupe (RBIG) se localiza a 241 km de la costa occidental de México, siendo uno de los territorios insulares más distante del país. Por lo tanto, el estudio de su biodiversidad en el contexto biogeográfico resulta de gran interés. El objetivo del presente estudio fue presentar los primeros registros de dinoflagelados de la RBIG. Se enlistan e ilustran 34 especies y taxones infraespecíficos de dinoflagelados. Todas las especies ya han sido registradas para las aguas costeras mexicanas y dos de ellas, Dinophysis tripos y Phalacroma mitra, se han reportado en la literatura, como productoras de toxinas. Este estudio representa el primer aporte al conocimiento de los dinoflagelados de la RBIG.

Abstract The Guadalupe Island Biosphere Reserve (RBIG) is located 241 km from Mexico's western coast and is thus one of the most distant island territories in the country. Therefore, studying its biodiversity is of great interest in a biogeographic context. This study aimed to present the first records of dinoflagellates found in the RNIG. Thirty-four dinoflagellate species and infraspecific taxa were reported and illustrated. All species have been previously recorded in Mexican coastal waters, and two of them, Dinophysis tripos and Phalacroma mitra, have been reported in the literature as toxin producers. This study represents the first contribution to the knowledge of dinoflagellates in the RBIG.

Abstract The Brazil-Malvinas Confluence (BMC) is a significant biological frontier where distinct currents meet, fostering optimal conditions for phytoplankton development. In this study we tested the hypothesis that eddys promote an increase in phytoplankton biomass at the Brazil-Malvinas Confluence (BMC), altering species diversity. Phytoplankton were collected with Niskin bottles and nutrient concentrations assessed at two depths (Surface and Deep Chlorophyll Maximum Layer – DCML) in areas outside and under the influence of Cold-Core (CCE) and Warm-Core (WCE) Eddies. Environmental variables were determined in situ using a CTD profiler. Four regions were separated based on environmental variables and phytoplankton species, namely, the Brazil Current (BC), Malvinas Current (MC), CCE, and WCE. Species diversity was higher in the eddies. The conditions of the WCE were different from those of the CCE, with low temperature and salinity and high cell density values in the latter. The phylum Bacillariophyta was predominant in terms of species richness in all regions and was responsible for the higher cell density in the MC, while dinoflagellates were dominant in the BC and eddies. Therefore, eddy activity alters the structure, diversity and biomass of the phytoplankton community in the BMC. BrazilMalvinas BMC (BMC meet development BMC, , Surface DCML ColdCore Cold Core CCE (CCE WarmCore Warm (WCE Eddies profiler namely BC, (BC) MC (MC) eddies latter Therefore structure (BC (MC

Abstract This review summarizes the state of knowledge on athecate dinoflagellates occurring within the South Atlantic Ocean and Atlantic sector of the Southern Ocean. We compiled data from 105 articles and selected 33 addressing any aspect of athecate dinoflagellate studies. Our aim is to discuss the patterns in athecate dinoflagellate distribution by building a thorough species list and an occurrence map based on species recorded in coastal and oceanic waters. We found 69 species totaling 141 occurrences in the entire South Atlantic Ocean basin. Contradicting global trends, most species distributed throughout this region are subtropical. We linked this trend to a higher local effort in dinoflagellate research instead of higher biodiversity, especially when compared to usual hotspots in biodiversity attributed to tropical oceans. The Subantarctic and Antarctic regions had a low number of occurrences, with 12 and 5, respectively. Except for the occurrence of Gyrodinium lachryma in the Antarctic Zone, all records are unique, poorly described and never recorded again for species such as Gymnodinium baccatum and Gymnodinium antarcticum. This demonstrates that the state of knowledge regarding athecate dinoflagellates in the South Atlantic and especially in the Antarctic region is still limited due to a lack of directed investigation. 10 3 studies waters 6 14 basin trends subtropical oceans 1 5 respectively Zone unique antarcticum investigation

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

Resumen Se monitorearon las aguas costeras de 6 playas recreativas en la costa de Campeche en el golfo de México de marzo a octubre de 2019. Los rangos de temperatura, salinidad y pH variaron según la temporada y probablemente estuvieron influenciados por la hidrografía local y la poca profundidad del área de estudio. Los taxones nocivos identificados en este estudio incluyeron 3 especies de diatomeas, 5 dinoflagelados y 2 cianobacterias, con abundancias que oscilaron entre 102 y 105 cél·L-1. Dentro de la comunidad de fitoplancton, los fitoflagelados (nanofitoplancton <20 µm) exhibieron una abundancia máxima de 1.6 × 106 cél·L-1 en Boca del Río en Champotón. El microfitoplancton (>20 µm), incluidas diatomeas, dinoflagelados y cianobacterias, fue un componente secundario con densidades que oscilaron entre 103 y 106 cél·L-1. El dinoflagelado Pyrodinium bahamense, identificado como tóxico para los humanos en la costa de Campeche, mostró una abundancia máxima de 2.0 × 105 cel·L-1 en mayo en Boca del Río. La diatomea tóxica Pseudo-nitzschia exhibió una abundancia máxima de 105 cél·L-1 en Payucan en mayo. Los géneros de cianobacterias Anabaena y Trichodesmium exhibieron abundancias que oscilaron entre 102 y 104 cél·L-1. En todas las estaciones y meses se presentaron fitoplancton y cianobacterias potencialmente dañinos, lo que indica que es necesario un monitoreo continuo para evaluar la calidad de las playas y garantizar la seguridad de las playas recreativas.

Abstract The coastal waters of 6 recreational beaches on the coast of Campeche in the Gulf of Mexico were monitored from March to October 2019. Temperature, salinity, and pH ranges varied depending on the season and were likely influenced by the local hydrography and shallow depth of the study area. The harmful taxa identified in this study included 3 diatom, 5 dinoflagellate, and 2 cyanobacteria species, with abundances ranging from 102 to 105 cell·L-1. Within the phytoplankton community, phytoflagellates (nanophytoplankton <20 µm) exhibited a peak abundance of 1.6 × 106 cell·L-1 at Boca del Río in Champotón. Microphytoplankton (>20 µm), including diatoms, dinoflagellates, and cyanobacteria, were a secondary component with densities ranging from 103 to 106 cell·L-1. The dinoflagellate Pyrodinium bahamense, identified as toxic to humans on the Campeche coast, showed a maximum abundance of 2.0 × 105 cell·L-1 in May at Boca del Río. The toxic diatom Pseudo-nitzschia exhibited a peak abundance of 105 cell·L-1 at Payucan in May. The cyanobacteria genera Anabaena and Trichodesmium exhibited abundances ranging from 102 to 104 cell·L-1. Potentially harmful phytoplankton and cyanobacteria were present in all seasons and months, indicating that continual monitoring is needed to assess beach quality to ensure the safety of recreational beaches.

Resumen Se registra por primera vez el género de dinoflagelado Metadinophysis (Dinophyceae: Dinophysales) en la bahía de Buenaventura y el Parque Nacional Natural Uramba- PNN Uramba en Bahía Málaga del Pacífico colombiano central, se analiza su densidad con los cambios de marea. Se registraron células con contorno subtriangular y reniforme en vista ventral, epiteca pequeña. Aleta sulcal izquierda con tres costillas y la derecha muy reducida o ausente, presentando tamaño promedio 43.1 μm de longitud total y 25.0 𝜇m de ancho total, la densidad del género se analizó bajo cuatro factores, la marea alta y la marea baja en la bahía de Buenaventura y en la bahía de Málaga. Se encontraron diferencias significativas entre la densidad en la marea alta y la marea baja para la bahía de Buenaventura, la diferencia entre la marea alta de la bahía de Málaga y la marea baja de la bahía de Buenaventura. Asimismo, se estableció que la distribución de la densidad no tiene ninguna estructura espacial en ninguno de los eventos mareales. Con el presente estudio se registra por primera vez el género de Metadinophysis en el pacífico colombiano, ampliando su distribución a nivel global.

Abstract The dinoflagellate genus Metadinophysis (Dinophyceae Dinophysales) is recorded for the first time in the Buenaventura Bay and Uramba National Natural Park-PNN Uramba in Málaga Bay in the central Colombian Pacific and its density is analyzed with tidal changes. Cells were recorded with subtriangular and reniform outline in ventral view and small epitheca. Left sulcal fin with three ribs and the right one very reduced or absent, presenting average size 43.1 μm total length and 25.0 μm total width, the density of the genus was analyzed under four factors, high tide and low tide in Buenaventura Bay and in Málaga Bay; significant differences were found between the density at high tide and low tide for Buenaventura Bay, the difference between high tide in Malaga Bay and low tide in Buenaventura Bay. Likewise, it was established that the density distribution has no spatial structure in any of the tidal events. With the present study, the genus Metadinophysis is recorded for the first time in the Colombian Pacific, extending its distribution globally.

ABSTRACT This study analyzes the spatial and temporal variability of phytoplankton biomass and taxonomic composition in the surface waters of Todos Santos Bay, a semi-enclosed bay within the upwelling zone of the Baja California peninsula (México). Two methodological approaches (microscopy and chemotaxonomy [CHEMTAX]) were used to describe the variability of some genera and species (observed under the microscope) and the importance of those groups that cannot be observed microscopically. Phytoplankton biomarker pigments were measured with high-resolution liquid chromatography and used as input to run the CHEMTAX software to determine the contribution of the main phytoplankton groups to chlorophyll-a (Chl-a). The microscopic analyses showed that diatoms and dinoflagellates comprised 65 and 33% of the total cells, respectively. Dinoflagellates were most abundant in the inner bay and during cold months; the most frequent and abundant genera were Tripos, Protoperidinium, and Prorocentrum. Among diatoms, the most frequent genera were Cylindrotheca, Guinardia, Navicula, Pseudo-nitzschia, and Chaetoceros. CHEMTAX indicated that, together with diatoms, the flagellates prymnesiophytes and chlorophytes contributed a median of 80% to Chl-a, with chlorophytes as the most important group (29.9%). The high contribution of these flagellates suggests that they are represented by small-sized cells not visible by the light microscopy used. However, CHEMTAX largely underestimated the contribution of dinoflagellates (due to the presence of many mixotrophic species). Hence, our results emphasize the importance of using both techniques for a more detailed evaluation of the taxonomic composition of phytoplankton in this and other coastal regions.

Resumo Apesar de sua pequena área, a baía do Araçá (AB) possui grande valor cultural, histórico e econômico, e biodiversidade bentônica. Assim, é fundamental monitorar sua saúde ambiental, que inclui conhecer os principais grupos de fitoplâncton e sua variabilidade temporal. As águas rasas da baía do Araçá são continuamente modificadas pela hidrografia complexa do canal de São Sebastião (SSC), desafiando desenhos experimentais convencionais para coleta de fitoplâncton. Aqui relatamos mudanças sazonais na composição do fitoplâncton, em intervalos de 4 a 6 semanas, de setembro de 2013 a agosto de 2014 na baía do Araçá e no SSC, sendo coletadas duas vezes ao dia por três dias consecutivos em cada campanha de amostragem para aumentar a resolução taxonômica. Nosso objetivo foi fornecer um inventário de ocorrência de espécies para auxiliar futuras políticas públicas e gestão ambiental na área. As análises revelaram alta riqueza de espécies e 166 táxons fitoplanctônicos diferentes. Diatomáceas e dinoflagelados foram numericamente dominantes, mas a ocorrência de táxons mudou acentuadamente entre observações. As diatomáceas do gênero Pseudo-nitzschia foram abundantes durante a primavera e o verão concomitantemente às assinaturas da Água Central do Atlântico Sul no CSS, enquanto Thalassiosira ocorreu durante períodos de salinidade relativamente mais baixa. O inventário demonstrou várias espécies potencialmente nocivas de microalgas e cianobactérias, sugerindo fortemente investimentos para programas de monitoramento nesta área que vem registrando aumento populacional contínuo. AB (AB cultural econômico bentônica Assim temporal SSC , (SSC) semanas 201 taxonômica 16 diferentes dominantes observações Pseudonitzschia Pseudo nitzschia CSS baixa cianobactérias contínuo (SSC 20 1 2

Abstract Despite its small area, Araçá Bay (AB) holds cultural, historical, and economic value and displays great benthic biodiversity. Thus, it is crucial to monitor its environmental health, including knowing the main groups of phytoplankton and their temporal variability. The shallow waters of Araçá Bay are continuously modified by the complex hydrography of the adjacent São Sebastião channel (SSC), challenging standard experimental designs for phytoplankton collection. Here we report changes in phytoplankton composition at intervals of five to six weeks from September 2013 to August 2014 in both Araçá Bay and SSC. Samples were collected twice daily for three consecutive days to increase taxonomic resolution. Our goal was to provide an inventory of species occurrences to aid future public policies and environmental management of the area. Analyses revealed high species richness and 166 different phytoplankton taxa. Diatoms and dinoflagellates were always numerically dominant, but taxa occurrence changed markedly. Diatoms of the genera Pseudo-nitzschia were abundant during spring and summer concurrently to signatures of South Atlantic Central Water in the SSC, while Thalassiosira occurred when waters displayed relatively lower salinity. The inventory demonstrated several potentially harmful species of microalgae and cyanobacteria, strongly suggesting investments in monitoring programs in this area that currently experience an increase in population. AB (AB cultural historical biodiversity Thus health variability SSC , (SSC) collection 201 resolution 16 dominant markedly Pseudonitzschia Pseudo nitzschia salinity cyanobacteria population (SSC 20 1 2

Abstract We evaluated the seasonal phosphorus (P) status of the plankton community in the Ombla Estuary (OE) by using its specific alkaline phosphatase activity (sAPA). Microphytoplankton (MICRO) indicated a substantially higher P deficiency than nanophytoplankton (NANO) and picoplankton (PICO). We found that the prolonged increase in the temperature of the surface estuarine water supported a notable growth of the dinoflagellate Prorocentrum spp. in late spring-early summer (June). In the summer (August), we found the maximum microphytoplankton sAPA (MICRO sAPA) (307.8 nmol μg C-1 h-1) in the surface water, in which (84%) dinoflagellates predominated within MICRO with the maximum alkaline phosphatase activity (APA) in all size fractions, including free enzymes. Persistently low discharge of Ombla during summer-early autumn caused a transition from phosphorus- to potentially nitrogen-limited MICRO in the surface water in early autumn (October). Nutrient stress disappeared in winter, in which a significant amount of dissolved orthosilicate, dissolved inorganic nitrogen (DIN), and soluble reactive phosphorus (SRP) enriched the estuary via maximal river discharge and inflow of nutrient-rich coastal waters. MICRO (coccolithophorids and diatoms) had very low APA (surface water) and quantitatively undetectable APA (bottom water) in the nutrient-rich water column in January. This study shows a more significant impact of nutrient concentrations on MICRO than other size classes of the plankton community. Because of the similarity in seasonal hydrological features, we assume that the general pattern of switching from P- to N-limitation of phytoplankton growth also occurs in other highly stratified estuaries along the coastal karst of the eastern Adriatic Sea during the lowest river discharges and groundwater activities in summer-early autumn before the rainy season. This study indicates that a common highly stratified estuary on the eastern Adriatic coast can serve as a natural laboratory to explore connections between nutrient limitations and phytoplankton successions.

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: 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.

Abstract The present work characterizes the water quality during the culture of shrimp Litopenaeus vannamei in an open system, using fresh well water (0.3 ‰ salinity). The water extracted from the subsoil contained 0.3 ‰ salinity, 0.0115 mg L-1 phosphate (P-PO4), 0.003 mg L-1 nitrite (N-NO2), 0.029 mg L-1 nitrate (N-NO3), < 0.010 mg L-1 ammonium N-NH4, 300 mg L-1 total hardness and 210 mg L-1 alkalinity. The study includes the analysis of the acclimation process of 20-day-old L. vannamei post-larvae and its further development in an open culture system. During acclimation, ammonium concentration increased from non-detect to 1.2 mg L-1 on the second day, and then to 1.5 mg L-1 on the eighth day. Survival of post-larvae upon reaching the freshwater point was 51 %. During 8 weeks of culture in the 2 earthen ponds, the nutrient concentration fluctuated between 0.01 - 0.03 mg L-1 for nitrite, 0.02 - 0.03 for nitrate, 0.07 - 0.09 for ammonium and 0.19 - 0.21 mg L-1 for phosphate. The most representative phytoplankton groups were chlorophyte, diatoms, dinoflagellates and euglenoids, with about 50.6, 25, 14 and 9.2 %, respectively in average for both ponds. The cyanophyte group was represented in the 1% of the phytoplankton community. Spirogyra sp. was the most dominant species. The total heterotrophic bacteria concentration was around 1100 CFU mL-1, while Vibrio sp., Pseudomonas sp. and total coliforms reached an average concentration of 47, 72 CFU mL-1, and 59 CFU/mL-1 respectively. The average weekly growth of L. vannamei was 0.9 g, survival was 45.9 %, and production was around 1088 kg/ha. The nature of the well water in southern Ecuador provides the necessary nutrients for the cultivation of L. vannamei shrimp at extremely low salinity.

Resumen El presente trabajo caracteriza la calidad del agua durante el cultivo del camarón Litopenaeus vannamei en un sistema abierto, con el uso de agua dulce de pozo (0.3 ‰ salinidad). El agua subterránea contenía 0.3 ‰ de salinidad, 0.0115 mg L-1 de fosfato (P-PO4), 0.003 mg L-1 de nitrito (N-NO2), 0.029 mg L-1 de nitrato (N-NO3), < 0.010 mg L-1 de amonio N-NH4, 300 mg L-1 de dureza total y 210 mg L-1 de alcalinidad. El estudio comprende el análisis del proceso de aclimatación de post-larvas de L. vannamei de 20 días de edad y posterior desarrollo en un sistema abierto de cultivo. Durante la aclimatación la concentración de amonio se incrementó desde no detectada a 1.2 mg L-1 al segundo día, y luego a 1.5 mg L-1 al octavo día. La supervivencia de post-larvas al llegar al punto de agua dulce fue del 51 %. Durante 8 semanas de cultivo en los 2 estanques de tierra, la concentración de nutrientes fluctuó entre de 0.01 - 0.03 mg L-1 para nitrito, 0.02 - 0.03 para nitrato, 0.07 - 0.09 para amonio y 0.19 - 0.21 mg L-1 para fosfato. Los grupos fitoplanctónicos más representativos fueron las clorofitas, diatomeas, dinoflagelados y euglenoideos, con alrededor del 50.6, 25, 14 and 9.2 %, respectivamente en promedio para los dos estanques. El grupo de las cianofitas estuvo representado en el 1% de la comunidad de fitoplancton. Spirogyra sp., fue la especie más dominante. La concentración total de bacterias heterótrofas estuvo alrededor de 1100 UFC mL-1, mientras que Vibrio sp., Pseudomonas sp., y coliformes totales, alcanzaron una concentración promedio de 47, 72 UFC mL-1, y 59 UFC/mL-1 respectivamente. El crecimiento promedio semanal de L. vannamei fue de 0.9 g, la supervivencia de 45.9 %, y una producción alrededor de 1088 kg/ha. La naturaleza del agua de pozo en el Sur del Ecuador dispone de los nutrientes necesarios para el cultivo del camarón L vannamei a extrema baja salinidad.