Abstract Introduction: Blooms of cyanobacteria are becoming increasingly common, and understanding their dynamics can be crucial for proposing appropriate management strategies. While physical and chemical parameters influencing blooms have been widely studied, less attention has been paid to the susceptibility of biological communities. Objective: To analyze phytoplankton abundance networks during cyanobacterial blooms at different intensity levels and how they interact and/or affect the phytoplankton community. Methods: We used 22 samplings conducted in El Limón reservoir located in Northern Argentina, known for recurrent cyanobacterial blooms. Each sampling was classified into four levels based on cyanobacteria abundance (cells/ml): Level 1 (10 000-30 000); Level 2 (30 000-50 000); Level 3 (50 000-100 000); and Level 4 (> 100 000). For each level, abundance correlation networks were constructed considering all species. Results: A pattern of decreasing statistically significant abundance correlations was observed as bloom intensity increased: 219 correlations at Level 1; 144 at Level 2; 80 at Level 3, and only 33 at Level 4. Blooming cyanobacteria showed few correlations with other species at all levels, indicating a certain independence from the community. An increase in bloom intensity appears to disconnect the phytoplankton abundance correlation network. Conclusion: The analysis of abundance correlation networks should be a valuable tool for understanding the dynamics and development of cyanobacterial blooms, as well as identifying key species in this process.

Resumen Introducción: Las proliferaciones de cianobacterias están volviéndose cada vez más comunes, y comprender su dinámica puede ser crucial para proponer estrategias de gestión adecuadas. Si bien se han estudiado ampliamente los parámetros físicos y químicos que influyen en las proliferaciones, se ha prestado menos atención a la susceptibilidad de las comunidades biológicas. Objetivo: Analizar las redes de abundancia de fitoplancton durante las proliferaciones de cianobacterias a diferentes niveles de intensidad y cómo las mismas interactúan y/o afectan a la comunidad de fitoplancton. Métodos: Se realizaron 22 muestreos en el embalse El Limón ubicado en el norte de Argentina, conocido por las proliferaciones recurrentes de cianobacterias. Cada muestreo se clasificó en cuatro niveles basados en la abundancia de cianobacterias (células/ml): Nivel 1 (10 000-30 000); Nivel 2 (30 000-50 000); Nivel 3 (50 000-100 000) y Nivel 4 (> 100 000). Para cada nivel, se construyeron redes de correlación de abundancias considerando todas las especies. Resultados: Se observó un patrón de disminución de correlaciones de abundancia estadísticamente significativas a medida que aumentaba la intensidad de las proliferaciones: 219 correlaciones en el nivel 1; 144 en el nivel 2; 80 en el nivel 3 y solo 33 en el nivel 4. Las cianobacterias que forman proliferaciones mostraron tener poca correlación con otras especies en todos los niveles, lo que podría estar asociado a cierta independencia con respecto a la comunidad. Un aumento en la intensidad de la proliferación parece desconectar la red de correlaciones de abundancia del fitoplancton. Conclusión: El análisis de las redes de correlaciones de abundancias debería ser una herramienta valiosa para comprender la dinámica y el desarrollo de las proliferaciones de cianobacterias, así como para identificar especies clave en este proceso.

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 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. 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.

ABSTRACT Toxic cyanobacteria blooms are an increasingly common global problem due to eutrophication, the effects of climate change and increased surveillance efforts in aquatic ecosystems. In Cuba, several ecosystems have been analyzed in the eastern region, demonstrating that this risk occurs to surface and inland waters, due to climatic conditions, mainly in small ecosystems with great human pressures. However, other areas are still unexplored. The objective of this work was to implement a risk management protocol in the San Blas Lagoon, Camaguey, due to the presence of toxic cyanobacteria in the ecosystem, following a community report, with the death of domestic and wild animals; unpleasant odors and dermatological symptoms in humans. A management protocol and community actions were implemented to minimize the impact of toxic cyanobacteria. In this small eutrophic reservoir, the presence of a mixed bloom of toxigenic cyanobacteria was confirmed, being Spherospermopsis torques-reginae the majority, as well as other nine species associated with the production of microcystins, anatoxins and/or cylindrospermopsins were identified. Strategic actions were implemented to contain the risk situation, with the participation of the community and experts, led by the Camagüey Criminalistics Laboratory.

RESUMEN Las floraciones de cianobacterias tóxicas constituyen un problema global cada vez más frecuente, debido a la eutrofización, los efectos del cambio climático y a un mayor esfuerzo de vigilancia en los ecosistemas acuáticos. En Cuba se han muestreado varios ecosistemas en la región oriental, demostrando que este riesgo existe en aguas superficiales e interiores, debido a las condiciones climáticas, principalmente en pequeños ecosistemas con grandes presiones humanas. Sin embargo, otras zonas están aún inexploradas. El objetivo de este trabajo fue implementar un protocolo de gestión de riesgos en la Laguna San Blas, debido a la presencia de cianobacterias tóxicas en el ecosistema, a raíz de un reporte comunitario, con muerte de animales domésticos y silvestres; olor desagradable y síntomas dermatológicos en humanos. Se implementó un protocolo de gestión y acciones comunitarias para minimizar el impacto de las cianobacterias tóxicas. En este pequeño reservorio eutrófico se confirmó la presencia de una floración mixta de cianobacterias toxigénicas, siendo mayoritaria Spherospermopsis torques-reginae, identificándose otras nueve especies asociadas a la producción de microcistinas, anatoxinas y/o cilindrospermopsinas. Se implementaron acciones estratégicas para contener la situación de riesgo, con la participación de la comunidad y expertos, liderados por el Laboratorio de Criminalística de Camagüey.

Abstract The exploration of the biodiversity of cyanobacteria and microalgae holds great promise for obtaining pigments of industrial interest. This study focused on the bioprospecting of these organisms to obtain pigments of industrial interest together with enriched biomass. We investigated the impact of photoperiod and concentration of C/N/P nutrient sources in heterotrophic cultures, controlling specific variables such as light intensity, volume, pH, temperature, air flow and time to produce phycobiliproteins in Arthrospira platensis UTEX1926 and total carotenoids in Scenedesmus sp. using a nonfactorial Plackett‒Burman design in STATISTICA 7.0 software. The biomass concentration was determined by dry weight, while the concentrations of phycocyanin and carotenoids were determined spectrophotometrically at specific wavelengths. Heterotrophic cultures demonstrated superior productivity, with phycocyanin and carotenoids achieving percentages of 7% and 0.4% (w/w), respectively, and an R2 value of 0.99. Among the influential parameters, potassium diphosphate and sodium bicarbonate played pivotal roles in the final deposition of carotenoids and phycocyanin, respectively, yielding concentrations of 96.5 mg/L phycocyanin and 6.5 mg/L carotenoids.

Resumen La exploración de la biodiversidad de cianobacterias y microalgas es muy prometedora para la obtención de pigmentos de interés industrial. Este estudio se centra en la bioprospección de estos organismos para obtener pigmentos de interés industrial junto con biomasa enriquecida. Investigamos el impacto del fotoperiodo y la concentración de fuentes de nutrientes C/N/P en cultivos heterótrofos, controlando variables específicas como la intensidad luminosa, volumen, pH, temperatura, flujo de aire y tiempo para la producción de ficobiliproteínas en Arthrospira platensis UTEX1926 y carotenoides totales en Scenedesmus sp. Empleando un diseño Plackett‒Burman no factorial en el software STATISTICA 7.0. La concentración de biomasa fue determinada por peso seco, mientras que la concentración de ficocianinas y carotenoides fueron determinadas espectrofotométricamente a longitudes de onda específicas. Los cultivos heterótrofos demostraron una productividad superior, alcanzando las ficocianinas y los carotenoides porcentajes del 7% y el 0,4% (% p/p) respectivamente, y un notable valor R2 de 0,99. Entre los parámetros influyentes, el difosfato potásico y el bicarbonato sódico desempeñaron papeles fundamentales en la deposición final de carotenoides y ficocianinas, respectivamente, alcanzando concentraciones de 96,5 mg/L de ficocianinas y 6,5 mg/L de carotenoides.

Abstract Background: Nostocales is a widely distributed, monophyletic order of cyanobacteria, whose species are mainly characterized by the presence of specialized structures such as heterocytes and akinetes. Despite being the most diverse group in marine environments, little is known about coastal species in Mexico. Particularly in Veracruz, only 17 species have been recorded, without photographic, morphological references, or ecological data; these records are only mentioned in floristic lists. Questions and / or Hypotheses: The present study aimed to contribute to the knowledge of the diversity of benthic marine Nostocales species in Veracruz, Mexico, as well as to provide detailed descriptions and illustrations of the species found, which can serve as a reference in subsequent studies. Study site and dates: Collect of cyanobacterial growths were made in three locations throughout Veracruz in 2020. Methods: The organisms were isolated from the field material. With the use of specialized taxonomic keys, they were morphologically identified, described and photographed. Results: A total of 20 Nostocales species were obtained, of which 17 were additions to the phycoflora of Veracruz, constituting an increase of 55 %. Taxonomic notes are added highlighting their differences with the literature. One of the species was identified as cf. and seven as sp., because their characteristics fully coincided with the generic morphology, but did not completely concur with the literature. Conclusions: These suggest that several records could correspond to new taxon not yet described that must be confirmed with different molecular markers.

Resumen: Antecedentes: Nostocales es un orden monofilético de cianobacterias, ampliamente distribuido, cuyas especies se caracterizan principalmente por la presencia de estructuras especializadas como heterocitos y acinetos. A pesar de ser el grupo más diverso en ambientes marinos, en México se conoce poco sobre las especies litorales. Particularmente en Veracruz solo se han registrado 17 especies, sin referencias fotográficas, morfológicas, ni datos ecológicos; estos registros solo se mencionan en listas florísticas. Preguntas y / o Hipótesis: El presente estudio tuvo como objetivo contribuir al conocimiento de la diversidad de especies Nostocales marinos bentónicos en Veracruz, México, así como brindar descripciones e ilustraciones detalladas de las especies encontradas, que puedan servir como referencia en estudios posteriores. Sitio y años de estudio: Se realizaron recolectas de crecimientos de cianobacterias en tres localidades de Veracruz en 2020. Métodos: A partir del material de campo se aislaron los organismos. Con el uso de claves taxonómicas especializadas se identificaron morfológicamente, describieron y fotografiaron. Resultados: Se obtuvo un total de 20 especies de Nostocales, de las cuales 17 fueron adiciones a la ficoflora de Veracruz, constituyendo un incremento del 55 %. Se agregan notas taxonómicas destacando las diferencias de estas con la literatura. Una de las especies fue identificada como cf. y siete como sp., debido a que sus características coincidían plenamente con la morfología genérica, pero no lo hacían completamente con la literatura. Conclusiones: Estos sugieren que varios registros podrían corresponder a nuevo taxón aún no descrita que deben ser confirmados con diferentes marcadores moleculares.

Summary: Cyanobacteria are oxygenic phototrophic organisms that possess a high adaptive capacity to different environments, allowing them to pioneer terrestrial ecosystems. The objective of this study was to compare the cyanobacterial community in two areas of secondary mountain forest: one seven days after a fire (post-fire soil) and another nearby without fire (control soil). The collected samples were cultivated for 8 weeks under controlled conditions. A total of 35 taxa were identified: 2 unicellular, 24 filamentous without heterocytous, and 9 with heterocytous cyanobacteria; 13 of them represent the first record for soils in Córdoba.Microcoleus vaginatuswas the most frequent taxon, along withScytonema hoffmannii, Desmonostoc muscorum, andNostoc commune, which persisted until the end of the experiment. The presence of exclusive organisms such asCalothrix brevissima, Chlorogloeopsis fritschii,andCylindrospermum muscicolain the control soils highlights their sensitivity to this type of disruptive event in the community. The availability of nitrogen, CO content, and pH are the physicochemical soil variables that define the community structure. This work is contributing to increase our knowledge of soil restoration after forest fires.

Resumen: Las cianobacterias son los organismos fototróficos oxigénicos que poseen una alta capacidad adaptativa a diferentes ambientes, lo cual les permite ser pioneros en los ecosistemas terrestres. El objetivo del trabajo fue comparar la comunidad de cianobacterias en dos zonas de bosque serrano secundario, uno a siete días de ocurrido un incendio (suelo post-fuego) y otra próxima sin incendio (suelo testigo). Las muestras extraídas se cultivaron durante 8 semanas en condiciones controladas. Se identificaron un total de 35 taxones: 2 unicelulares, 24 filamentosas sin heterocitos y 9 con heterocitos; 13 de ellos constituyen primera cita para suelos de Córdoba.Microcoleus vaginatusfue el taxón más frecuente, junto conScytonema hoffmannii, Desmonostoc muscorumyNostoc communepermanecieron hasta finalizar el ensayo. Se destaca la presencia de organismos exclusivos tales como:Calothrix brevissima, Chlorogloeopsis fritschiiyCylindrospermum muscicolaen los suelos testigos, serían los taxones sensibles a este tipo de eventos disruptivos en la comunidad. La disponibilidad de nitrógeno, contenido de CO y pH son las variables físico-químicas del suelo que definen la estructura de la comunidad. Se considera que este trabajo aporta valiosa información para el avance del conocimiento de la restauración de suelos luego de los incendios forestales.

RESUMEN Las investigaciones sobre cianobacterias bentónicas en reservorios de alta montaña en regiones tropicales aún son limitadas, debido a su complejidad y vacíos de conocimiento en relación con su ecología. Este estudio tuvo como objetivo explorar la composición, diversidad y potencial tóxico de estas cianobacterias en sedimentos superiores de dos embalses colombianos, empleando múltiples metodologías, como experimentos de germinación para evaluar su presencia y viabilidad en sedimentos, ensayos de ELISA competitivo para cuantificar toxinas en cultivo, análisis de Unidades Taxonómicas Operativas (OTUs) a partir de submuestras de los cultivos para evaluar su diversidad y riqueza entre los diferentes phylum procarióticos, y análisis filogenético de cianobacterias cultivables. Se confirmó la presencia de poblaciones viables de cianobacterias en los sedimentos mediante mediciones de clorofila-a y la identificación microscópica demostró su capacidad de crecimiento en condiciones controladas de laboratorio. A pesar de los bajos niveles de microcistina en cultivo, la detección previa de genes mcy en muestras directas de sedimento, sugiere un potencial tóxico en las cianobacterias presentes. El análisis de la comunidad reveló una notable diversidad microbiana en los sedimentos de ambos embalses, con una mayor abundancia relativa de cianobacterias en comparación con otros phylum procarióticos. Estos hallazgos respaldan la hipótesis de que los sedimentos superficiales desempeñan un papel fundamental como depósito de cianobacterias que pueden plantear riesgos inherentes a la salud del ecosistema. En conclusión, esta investigación subraya la necesidad de realizar más estudios para lograr una comprensión holística de la dinámica de las cianobacterias bentónicas en reservorios tropicales de alta montaña.

ABSTRACT Benthic cyanobacteria research in high mountain reservoirs remains limited, mainly due to their complexity and knowledge gaps that persist in relation to their ecology in tropical regions. This study aimed to explore the composition, diversity, and toxic potential of cyanobacterial in the upper sediment of two Colombian reservoirs. Our investigation involved multiple methodologies, such as germination experiments, that allowed us to assess the presence and viability of cyanobacteria in upper sediment samples, while the competitive ELISA assay allowed for the quantification of toxins within the cultures. The molecular analysis of Operational Taxonomic Units (OTUs) from subsamples of sediment cultures focused on evaluating cyanobacterial diversity and richness among prokaryotic phyla, and the Phylogenetic analysis of culturable cyanobacteria. Chlorophyll-a measurements confirmed the presence of viable populations in sediment cultures, while microscopic identification demonstrated the growth capacity of cyanobacteria from the orders Nostocales, Chroococcales, Oscillatoriales, and Synechococcales under controlled laboratory conditions. Despite low microcystin levels in culture, the prior detection of mcy genes in direct sediment samples suggests a possible toxic potential of cyanobacterial inhabiting the upper sediments. Community analysis, based on the OTUs abundance, revealed a notably diverse microbial community in both reservoir sediments, with a higher relative abundance of cyanobacteria compared to other prokaryotic phyla. These findings support the hypothesis that surface sediments play a fundamental role as a repository for cyanobacteria that may pose inherent risks to ecosystem health. In conclusion, this research underscores the necessity of further studies to achieve a holistic comprehension of benthic cyanobacteria dynamics in high-mountain tropical reservoirs.

RESUMEN Las cianobacterias y las microalgas representan fuentes prometedoras para la producción sostenible de biofertilizantes y bioestimulantes, que pueden mejorar el rendimiento, la calidad de los cultivos y contribuir a la seguridad alimentaria. Sin embargo, a pesar de su potencial, su exploración sigue siendo incompleta, obstaculizada por los desafíos técnicos y económicos que surgen cuando se intenta escalar la producción. El objetivo principal de esta revisión es profundizar en los compuestos químicos activos responsables de las funciones de biofertilización y bioestimulación de las cianobacterias y las microalgas. También, explora las operaciones unitarias esenciales involucradas en la transformación de su biomasa en potenciales bioproductos. Además, esta revisión destaca estudios que han empleado cianobacterias y microalgas como fuentes de biofertilizante en diversos cultivos, describiendo su modo de acción y aplicación. Mediante la integración del procesamiento de cianobacterias y microalgas con otras herramientas biotecnológicas avanzadas, se puede mejorar significativamente la viabilidad de estos productos para la agricultura sostenible.

ABSTRACT Cyanobacteria and microalgae represent promising sources for sustainable production of biofertilizers and biostimulants, which can improve crop yield and quality and contribute to food security. However, despite their potential, their exploration remains incomplete, hindered by technical and economic challenges that arise when attempting to scale up production. The primary focus of this review is to delve into the active chemical compounds responsible for the biofertilizing and biostimulating roles of cyanobacteria and microalgae. In addition, it explores the essential unit operations involved in transforming their biomass into potential bioproducts. Moreover, this review highlights studies that have employed cyanobacteria and microalgae as sources of biofertilizer in various crops, describing their mode of action and application. By integrating cyanobacteria and microalgae processing with other advanced biotechnological, the viability of these products for sustainable agriculture can be significantly enhanced.

ABSTRACT Haematococcus pluvialis synthesizes and accumulates astaxanthins, while Spirulina (Arthrospira) platensis produces phycocyanins. The ornamental shrimp Neocaridina davidi is commercially important for its variety and intensity of coloration. We evaluate the effect on the coloration of N. davidi by consuming H. pluvialis and S. platensis as a food supplement to preserve their nutritional quality. H. pluvialis was subjected to stress to obtain aplanospores with astaxanthin. Live microalgae were included in gelled spheres to provide them as a supplement to three-day-old N. davidi juveniles with different phenotypes: wild (NdW), red (NdR), and blue (NdB). The experiment involved the commercial food supply and spheres with or without microalgae for 31 days. Chromatophores present in the uropod of each phenotype were examined, their number and expansion estimated, and the area covered by optical density (OD). Results show that H. pluvialis reached a greater astaxanthin accumulation on day 30. The coloration of the NdR and NdB phenotypes improved by consuming microalgae, increasing the OD in the uropod. NdB phenotype showed better coloration when consuming S. platensis (56.2%), while the NdR phenotype was more favored when consuming H. pluvialis (74.2%). The chromatophores expanded their area by doubling in the NdR and NdB phenotypes, where H. pluvialis increased its intensity four times in NdR. The number of chromatophores was significant only in NdR with S. platensis. In conclusion, gelling is a viable method to preserve the nutritional quality of live microalgae and transfer bioactive compounds that improve the coloration of N. davidi.

Abstract This study aimed to characterize seasonal changes in microphytoplankton composition and abundance on Bahia continental shelf, a region with upwelling events. Semi-annual sampling was conducted during summer and winter from 2017 to 2021 at nine points. Microphytoplankton was sampled using a conical plankton net through horizontal subsurface drags, using a flowmeter coupled to the net, to measure the total volume of filtered water. Temperature and salinity were measured in situ, presenting typical values of tropical waters. In addition, dissolved inorganic nutrient concentration corroborated a tropical marine oligotrophic pattern. A total of 144 taxa were identified in the region, with the phyla Heterokontophyta and Dinoflagellata being the most representative, as is typically recorded in tropical coastal regions. The density ranged from 6.08 × 104 to 3.38 × 108 cells L-1, with higher average values in summer. Although cyanobacteria accounted for only 3.2% of species richness in the region, due to summer blooms of Trichodesmium erythraeum (2018, 2019, and 2021), it was the most abundant group throughout the study. It was observed that upwelling events do not seem to establish favorable conditions for marked seasonal changes in microphytoplankton composition and abundance. Trichodesmium erythraeum blooms are closely related to physiology and ecological capacity of this species. Except for bloom periods, the study area presented a high species richness and diversity throughout the analyzed time series.

Resumen El objetivo del presente estudio fue caracterizar los cambios estacionales en la composición y abundancia del microfitoplancton en la plataforma continental de Bahía, una región con presencia de eventos de surgencia. Se realizaron muestreos semestrales durante los veranos e inviernos de 2017 a 2021 en nueve puntos. El microfitoplancton se muestreó utilizando una red cónica de plancton en arrastres horizontales debajo de la superficie, utilizando un medidor de corriente acoplado a la red, para medir el volumen total de agua filtrada. La temperatura y la salinidad fueron medidas in situ, presentando valores típicos de aguas tropicales. Además, las concentraciones de nutrientes inorgánicos disueltos corroboraron el patrón oligotrófico marino tropical. Se identificaron un total de 144 taxones en la región, siendo los phyla Heterokontophyta y Dinoflagellata los más representativos, como se registra típicamente en las regiones costeras tropicales. La densidad varió de 6,08 × 104 a 3,38 × 108 células L-1, con valores promedio más altos en verano. Aunque las cianobacterias representaron solo el 3,2% de la riqueza de especies en la región, debido a las floraciones de verano de Trichodesmium erythraeum (2018, 2019 y 2021), fue el grupo más abundante a lo largo del estudio. Se observó que los eventos de surgencia no parecen establecer condiciones favorables para cambios estacionales marcados en la composición y abundancia del microfitoplancton. Las floraciones de Trichodesmium erythraeum están estrechamente relacionadas con la fisiología y la capacidad ecológica de esta especie. Con excepción de los períodos de floración, el área de estudio presentó patrones de alta riqueza y diversidad de especies a lo largo de la serie temporal analizada.

Abstract Global access to clean and safe drinking water remains a formidable challenge, contributing to a myriad of health issues. This research exposes the existence of waterborne parasites in seemingly pristine spring waters, indicating potential contamination. Daily extensive sampling of Seventeen water sources was conducted in the untarnished freshwater streams of Tehsil Babuzai, District Swat, Khyber Pakhtunkhwa, Pakistan, from February to September 2021. Employing a stringent filtration process, the collected samples were effectively concentrated to detect any waterborne parasites. Subsequent application of the wet mount technique, combined with the capabilities of a compound microscope, revealed a disconcerting reality: all examined samples tested positive for various parasites. Identified parasites included Schistosoma species, Ascaris lumbricoides, Trichiuria trichiuria, Taenia saginata, Entamoeba histolytica, Amoeba, Lacrymana olor, Tintinnids, Paramecium, Dileptus, Euglena, Loxodes striatus, Acanthocyclops lynceus, Spondylosium, Oscillatoria, Cyanobacteria, Cilindros, Cilindros cerro, Commensal amoeba mature cysts,, Filliform larva of Strongyloides, Cercaria larva, Larva of Taenia solium, Egg of Enterobius vermiculais, Egg of Isospora belli, Egg of Tapeworm, Egg of Schistosoma species, Egg of Toxocara, and Egg of Diphyllobothrium latum. These findings clearly demonstrate the presence of a diverse array of parasites in the freshwater springs of Tehsil Babuzai, Swat, Pakistan. Implementing robust water treatment protocols, conducting regular monitoring and testing, and raising awareness about the risks of waterborne parasites are crucial steps to safeguard public health in the region. challenge issues waters contamination Babuzai Swat Pakhtunkhwa Pakistan 2021 process technique microscope reality species lumbricoides trichiuria saginata histolytica Amoeba olor Tintinnids Paramecium Dileptus Euglena striatus lynceus Spondylosium Oscillatoria Cyanobacteria cerro cysts cysts, Strongyloides solium vermiculais belli Tapeworm Toxocara latum protocols testing region 202 20 2

Resumo O acesso global à água potável limpa e segura continua a ser um desafio formidável, e a falta das condições de potabilidade contribui para uma miríade de problemas de saúde. Esta pesquisa expõe a existência de parasitas transmitidos pela água em águas de nascentes aparentemente intocadas, indicando uma possível contaminação. Foram realizadas amostragens extensivas diárias de 17 fontes de água nos riachos de água doce intocados de Tehsil Babuzai, Distrito de Swat, Khyber Pakhtunkhwa, Paquistão, de fevereiro a setembro de 2021. Utilizando um processo rigoroso de filtração, as amostras coletadas foram concentradas de forma eficaz para detectar quaisquer parasitas transmitidos pela água. A aplicação subsequente da técnica de montagem a úmido, combinada com as capacidades de um microscópio composto, revelou uma realidade desconcertante: todas as amostras examinadas testaram positivo para vários parasitas. Os parasitas identificados incluíram espécies de Schistosoma, Ascaris lumbricoides, Trichiuria trichiura, Taenia saginata, Entamoeba histolytica, Amoeba, Lacrymana olor, Tintinnids, Paramecium, Dileptus, Euglena, Loxodes striatus, Acanthocyclops lynceus, Spondylosium, Oscillatoria, Cyanobacteria, Cilindros, Cilindros cerro, Cistos maduros de ameba comensal, Larva filiforme de Strongyloides, Larva de Taenia solium, Ovo de Enterobius vermiculais, Ovo de Isospora belli, Ovo de verme, Ovo de espécies de Schistosoma, Ovo de Toxocara e Ovo de Diphyllobothrium latum. Estes achados demonstram claramente a presença diversificada de parasitas nas nascentes de água doce de Tehsil Babuzai, Swat, Paquistão. Implementar protocolos robustos de tratamento de água, conduzir monitoramento e testes regulares, e aumentar a conscientização sobre os riscos de parasitas transmitidos pela água são passos cruciais para proteger a saúde pública na região. formidável intocadas contaminação 1 Babuzai Swat Pakhtunkhwa Paquistão 2021 filtração úmido composto desconcertante Schistosoma lumbricoides trichiura saginata histolytica Amoeba olor Tintinnids Paramecium Dileptus Euglena striatus lynceus Spondylosium Oscillatoria Cyanobacteria cerro comensal Strongyloides solium vermiculais belli verme latum regulares região 202 20 2

Abstract Aim The aim of this study was to evaluate how phytoplankton community diversity, dominance, and rarity are influenced by different local environmental conditions in urban lakes. We expect that richness will be negatively influenced in lakes with higher nutrient concentrations and high turbidity, while abundance will be positively influenced. Thus, lakes with these conditions will have greater dominance of a few species and lower rarity, and the opposite in lakes with lower nutrient concentrations and less turbidity. Methods Phytoplankton and abiotic variables samples were collected in fourteen lakes distributed in the municipality of Goiânia, Goiás, Brazil, during a rainy period. Results It was possible to identify an environmental heterogeneity among the lakes. We identified a separation of the lakes according to phytoplankton richness and density, especially due to the contribution of green algae, desmids, and cyanobacteria. Most lakes showed high diversity and evenness values, with a predominance of rare taxa and few dominant species. The main variables associated with phytoplankton were water temperature, dissolved oxygen, turbidity, and nutrient concentrations. Conclusions Therefore, the study of species diversity, dominance, and rarity based on phytoplankton richness and abundance and their relationship with different local environmental conditions can be an important model for assessing water quality in urban lakes. turbidity Thus Goiânia Goiás Brazil period density algae desmids cyanobacteria values temperature oxygen Therefore

Resumo Objetivo O objetivo deste estudo foi avaliar como a diversidade, dominância e raridade da comunidade fitoplanctônica são influenciadas por diferentes condições ambientais locais em lagos urbanos. Nós esperamos que a riqueza será influenciada negativamente em lagos com maiores concentrações de nutrientes e maior turbidez, enquanto a abundância será influenciada positivamente. Assim, haverá uma maior dominância de poucas espécies e menor raridade em lagos com essas condições, sendo esperado o contrário em lagos com menores concentrações de nutrientes e menor turbidez. Métodos As amostras do fitoplâncton e das variáveis abióticas foram coletadas em quatorze lagos distribuídos no município de Goiânia, Goiás, Brasil, durante um período chuvoso. Resultados Foi possível identificar uma heterogeneidade ambiental entre os lagos. Nós identificamos uma separação dos lagos em função da riqueza e densidade fitoplanctônica, especialmente devido à contribuição de algas verdes, desmídias e cianobactérias. A maioria dos lagos apresentou altos valores de diversidade e equitabilidade, com predominância de táxons raros e poucas espécies dominantes. As principais variáveis que estiveram relacionadas com o fitoplâncton, foram a temperatura da água, oxigênio dissolvido, turbidez e as concentrações de nutrientes. Conclusões Portanto, o estudo da diversidade, dominância e raridade baseada na riqueza e abundância fitoplanctônica e a sua relação com as diferentes condições ambientais locais pode ser um importante modelo na avaliação da qualidade da água em lagos urbanos. urbanos positivamente Assim Goiânia Goiás Brasil chuvoso verdes cianobactérias equitabilidade dominantes dissolvido Portanto

ABSTRACT Background: Alcoholic liver disease (ALD) and metabolic-dysfunction associated steatotic liver disease (MASLD) are common, and gut microbiota (GM) is involved with both. Here we compared GM composition in animal models of MASLD and ALD to assess whether there are specific patterns for each disease. Methods: MASLD model- adult male Sprague Dawley rats, randomized into two groups: MASLD-control (n=10) fed a standard diet; MASLD-group (n=10) fed a high-fat-choline-deficient diet for 16 weeks. ALD model- adult male Wistar rats randomized: ALD-control (n=8) fed a standard diet and water+0.05% saccharin, ALD groups fed with sunflower seed and 10% ethanol+0.05% saccharin for 4 or 8 weeks (ALC4, n=8; ALC8, n=8). ALC4/8 on the last day received alcoholic binge (5g/kg of ethanol). Afterwards, animals were euthanized, and feces were collected for GM analysis. Results: Both experimental models induced typical histopathological features of the diseases. Alpha diversity was lower in MASLD compared with ALD (p<0.001), and structural pattern was different between them (P<0.001). Bacteroidetes (55.7%), Firmicutes (40.6%), and Proteobacteria (1.4%) were the most prevalent phyla in all samples, although differentially abundant among groups. ALC8 had a greater abundance of the phyla Cyanobacteria (5.3%) and Verrucomicrobiota (3.2%) in relation to the others. Differential abundance analysis identified Lactobacillaceae_unclassified, Lachnospiraceae_NK4A136_group, and Turicibacter associated with ALC4 and the Clostridia_UCG_014_ge and Gastranaerophilales_ge genera to ALC8. Conclusion: In this study, we demonstrated that the structural pattern of the GM differs significantly between MASLD and ALD models. Studies are needed to characterize the microbiota and metabolome in both clinical conditions to find new therapeutic strategies. Background (ALD metabolicdysfunction metabolic dysfunction (MASLD common (GM Methods model MASLDcontrol control n=10 n10 n 10 (n=10 MASLDgroup group highfatcholinedeficient high fat choline deficient 1 ALDcontrol n=8 n8 (n=8 water005 water 0 05 water+0.05 ethanol005 ethanol ethanol+0.05 ALC4, ALC (ALC4 n=8. . n=8) ALC48 ALC4/ 5g/kg 5gkg gkg 5g kg g ethanol. ethanol) Afterwards euthanized Results diseases p<0.001, p0001 p p<0.001 , 001 (p<0.001) P<0.001. P0001 P P<0.001 (P<0.001) 55.7%, 557 55.7% 55 7 (55.7%) 40.6%, 406 40.6% 40 6 (40.6%) 1.4% 14 (1.4% samples 5.3% 53 5 3 (5.3% 3.2% 32 2 (3.2% others Lactobacillaceaeunclassified Lactobacillaceae unclassified Lactobacillaceae_unclassified LachnospiraceaeNK4A136group LachnospiraceaeNKAgroup Lachnospiraceae NK4A136 NK A Lachnospiraceae_NK4A136_group ClostridiaUCG014ge ClostridiaUCGge Clostridia UCG 014 ge Gastranaerophilalesge Gastranaerophilales Conclusion study strategies n=1 n1 (n=1 n= (n= water00 water+0.0 ethanol00 ethanol+0.0 (ALC p000 p<0.00 00 (p<0.001 P000 P<0.00 (P<0.001 55.7 (55.7% 40.6 (40.6% 1.4 (1.4 5.3 (5.3 3.2 (3.2 LachnospiraceaeNK NKA NK4A13 ClostridiaUCG 01 (n water0 water+0. ethanol0 ethanol+0. p00 p<0.0 (p<0.00 P00 P<0.0 (P<0.00 55. (55.7 40. (40.6 1. (1. 5. (5. 3. (3. NK4A1 water+0 ethanol+0 p0 p<0. (p<0.0 P0 P<0. (P<0.0 (55. (40. (1 (5 (3 NK4A water+ ethanol+ p<0 (p<0. P<0 (P<0. (55 (40 ( p< (p<0 P< (P<0 (4 (p< (P< (p (P

RESUMO Contexto: A doença hepática alcoólica (DHA) e a doença hepática esteatótica associada à disfunção metabólica (MASLD) são comuns, e a microbiota intestinal (MI) está envolvida em ambas. Aqui, comparamos a composição da MI em modelos animais de MASLD e DHA para avaliar se existem padrões específicos para cada doença. Métodos: Modelo de MASLD - ratos machos adultos da linhagem Sprague Dawley, randomizados em dois grupos: MASLD-controle (n=10) alimentados com uma dieta padrão; grupo MASLD (n=10) alimentados com uma dieta rica em gordura e deficiente em colina por 16 semanas. Modelo de DHA - ratos machos adultos da linhagem Wistar randomizados: DHA-controle (n=8) alimentados com uma dieta padrão e água+0,05% de sacarina; grupos DHA alimentados com semente de girassol e 10% de etanol+0,05% de sacarina por 4 ou 8 semanas (DHA4, n=8; DHA8, n=8). DHA 4/8 no último dia receberam binge alcoólico (5 g/kg de etanol). Posteriormente, os animais foram sacrificados, e as fezes foram coletadas para análise da MI. Resultados: Ambos os modelos experimentais induziram características histopatológicas típicas das doenças. A diversidade alfa foi menor na MASLD em comparação com a DHA (P<0,001), e o padrão estrutural foi diferente entre elas (P<0,001). Bacteroidetes (55,7%), Firmicutes (40,6%) e Proteobactérias (1,4%) foram os filos mais prevalentes em todas as amostras, embora com abundâncias diferenciadas entre os grupos. DHA8 teve uma maior abundância dos filos Cyanobacteria (5,3%) e Verrucomicrobiota (3,2%) em relação aos outros. A análise de abundância diferencial identificou Lactobacillaceae_unclassified, Lachnospiraceae_NK4A136 e Turicibacter associados ao grupo DHA4, e os gêneros Clostridia_UCG_014_ge e Gastranaerophilales_ge associados ao DHA8. Conclusão: Neste estudo, demonstramos que o padrão estrutural da MI difere significativamente entre os modelos de MASLD e DHA. Estudos são necessários para caracterizar a microbiota e os metabólitos ativos em ambas as condições clínicas, a fim de encontrar novas estratégias terapêuticas. Contexto (DHA (MASLD comuns (MI Aqui Métodos Dawley MASLDcontrole controle n=10 n10 n 10 (n=10 1 DHAcontrole n=8 n8 (n=8 água005 água 0 05 água+0,05 etanol005 etanol etanol+0,05 DHA4 (DHA4 n=8. . n=8) 48 4/ 5 ( gkg g kg etanol. etanol) Posteriormente sacrificados Resultados doenças P<0,001, P0001 P P<0,001 , 001 (P<0,001) P<0,001. 55,7%, 557 55,7% 55 7 (55,7%) 40,6% 406 40 6 (40,6% 1,4% 14 (1,4% amostras 5,3% 53 3 (5,3% 3,2% 32 2 (3,2% outros Lactobacillaceaeunclassified Lactobacillaceae unclassified Lactobacillaceae_unclassified LachnospiraceaeNK4A136 LachnospiraceaeNKA Lachnospiraceae NK4A136 NK Lachnospiraceae_NK4A13 ClostridiaUCG014ge ClostridiaUCGge Clostridia UCG 014 ge Gastranaerophilalesge Gastranaerophilales Conclusão estudo clínicas terapêuticas n=1 n1 (n=1 n= (n= água00 água+0,0 etanol00 etanol+0,0 P000 P<0,00 00 (P<0,001 55,7 (55,7% 40,6 (40,6 1,4 (1,4 5,3 (5,3 3,2 (3,2 LachnospiraceaeNK LachnospiraceaeNK4A13 NKA NK4A13 Lachnospiraceae_NK4A1 ClostridiaUCG 01 (n água0 água+0, etanol0 etanol+0, P00 P<0,0 (P<0,00 55, (55,7 40, (40, 1, (1, 5, (5, 3, (3, LachnospiraceaeNK4A1 NK4A1 Lachnospiraceae_NK4A água+0 etanol+0 P0 P<0, (P<0,0 (55, (40 (1 (3 LachnospiraceaeNK4A NK4A água+ etanol+ P<0 (P<0, (55 (4 P< (P<0 (P< (P

Abstract: This study investigates the presence of bacterial dominance in one of the most studied sewage-driven eutrophic coastal lagoons, the Imboassica Lagoon in Macaé (RJ), Brazil, utilizing high-throughput sequencing of 16S rDNA. Water samples were collected from three sites within the lagoon. Total microbial DNA was extracted, and the V3-V4 region of the 16S rRNA gene was amplified and sequenced on the Illumina MiSeq platform. A total of 744,879 partial 16S rRNA sequences were clustered, revealing the absence of a single bacterial dominance in the sewage-driven eutrophic coastal lagoon. The prominent phyla detected in the lagoon were Cyanobacteria (27.8%), Proteobacteria (23.7%), and Actinobacteria (14.6%). Proteobacteria emerged as the most abundant phylum in the sewage-impacted lagoon site, whereas Cyanobacteria dominated the other two sampling sites. Among families, Synechococcaceae predominated with genus Synechococcus exhibited the highest prevalence. Families of potentially toxic Cyanobacteria represented less than 1% of the total families. The sewage-impacted lagoon section displayed greater bacterial diversity and richness. The dominance of bacterial communities associated with raw sewage, such as members of the Enterobacteriaceae family, was not confirmed, constituting only 0.75% of the families in the most affected site. This study presents the initial analysis of the bacterial community in the Imboassica Lagoon and suggests that dominance in the lagoon responds to the eutrophication and sewage discharge. Abstract sewagedriven driven lagoons RJ, RJ , (RJ) Brazil highthroughput high throughput S rDNA extracted V3V4 VV V3 V4 V V3-V platform 744879 744 879 744,87 clustered 27.8%, 278 27.8% 27 8 (27.8%) 23.7%, 237 23.7% 23 7 (23.7%) 14.6%. 146 14.6% . 14 6 (14.6%) sewageimpacted impacted site prevalence 1 richness family confirmed 075 0 75 0.75 discharge (RJ V3V 74487 74 87 744,8 27.8 2 (27.8% 23.7 (23.7% 14.6 (14.6% 07 0.7 7448 744, 27. (27.8 23. (23.7 14. (14.6 0. (27. (23. (14. (27 (23 (14 (2 (1 (

Resumo: Este estudo investiga a dominância bacteriana em uma das mais estudadas lagoas costeiras eutróficas contaminadas por esgoto, a Lagoa Imboassica em Macaé (RJ), Brasil, utilizando sequenciamento massivo do gene codificador do RNAr 16S. Foram coletadas amostras de água de três locais na lagoa. O DNA microbiano total foi extraído e a região V3-V4 do gene RNAr 16S foi amplificada e sequenciada na plataforma Illumina MiSeq. Um total de 744.879 sequências parciais do gene RNAr 16S foram agrupadas, revelando a ausência de uma dominância bacteriana única na lagoa costeira eutrófica influenciada por esgoto. Os filos predominantes detectados na lagoa foram Cyanobacteria (27,8%), Proteobacteria (23,7%) e Actinobacteria (14,6%). Proteobacteria emergiu como o filo mais abundante no local da lagoa impactado pelo esgoto, enquanto Cyanobacteria dominou os outros dois locais de amostragem. A família de maior prevalência encontrada foi a Synechococcaceae, sendo representada pelo gênero Synechococcus. Famílias do filo Cyanobacteria consideradas potencialmente tóxicas representaram menos de 1% do total de famílias. A região da lagoa impactada pelo esgoto exibiu maior diversidade e riqueza bacteriana. A dominância de comunidades bacterianas associadas ao esgoto bruto, como membros da família Enterobacteriaceae, não foi confirmada, a qual representou somente 0,75% das famílias no local mais afetado. Este estudo apresenta a análise inicial da comunidade bacteriana na Lagoa Imboassica e sugere que a dominância responde a eutrofização e descarga de esgoto. Resumo RJ, RJ , (RJ) Brasil S V3V4 VV V3 V4 V V3-V MiSeq 744879 744 879 744.87 agrupadas 27,8%, 278 27,8% 27 8 (27,8%) 23,7% 237 23 7 (23,7% 14,6%. 146 14,6% . 14 6 (14,6%) amostragem Synechococcaceae Synechococcus 1 bruto Enterobacteriaceae confirmada 075 0 75 0,75 afetado (RJ V3V 74487 74 87 744.8 27,8 2 (27,8% 23,7 (23,7 14,6 (14,6% 07 0,7 7448 744. 27, (27,8 23, (23, 14, (14,6 0, (27, (23 (14, (27 (2 (14 ( (1