Resumo: Objetivo Neste estudo, nós investigamos a resposta da composição, diversidade e abundância de microcrustáceos (Cladocera e Copepoda) à origem do lago (natural e artificial) e ao estado trófico (mesotrófico e eutrófico, com eutrofização natural e eutrofização artificial). Testamos as seguintes hipóteses: (I) o aumento na abundância de certas espécies de microcrustáceos pode indicar um aumento no nível trófico; (II) a riqueza e a abundância variam entre os lagos e são maiores no lago com eutrofização natural; e (III) a abundância de microcrustáceos está associada à alta produtividade primária, sendo maior no ambiente eutrófico com eutrofização artificial. Métodos O estudo foi realizado em um segmento da bacia do rio Paranapanema, no sudeste do Brasil, com foco em cinco lagos em um trecho de oito quilômetros, para entender as respostas dos diferentes organismos em condições distintas de ambientes aquáticos. A amostragem foi realizada bimestralmente ao longo de um ano. Resultados Uma análise de componentes principais (PCA) separou três tipos de lagos: eutróficos (naturais e artificiais) a mesotróficos. Adicionalmente, 25 táxons foram encontrados. A análise SIMPER filtrou seis espécies com mais de 70% de contribuição de dissimilaridade. Cinco espécies apresentaram diferenças entre os lagos, uma espécie correlacionada com variáveis naturais, como profundidade. A análise de redundância associou a abundância de Bosminopsis deitersi com lagos eutróficos artificiais e com as variáveis condutividade elétrica, fósforo, nitrogênio, clorofila-a e dureza. Altas abundâncias de B. deitersi indicaram eutrofização artificial especialmente em lagos artificiais, enquanto lagos naturais com eutrofização natural não foram ambientes favoráveis para o aumento da abundância de B. deitersi. Conclusões Este estudo destaca os lagos de meandros neotropicais, enfatizando a importância da caracterização físico-química, da amostragem temporal detalhada e da classificação dos lagos por origem e nível trófico.

Abstract: Aim In this study, we investigated the response of microcrustaceans composition, diversity and abundance (Cladocera and Copepoda) to the lake’s origin (natural and man-made) and trophic state (mesotrophic and eutrophic, with natural eutrophication and artificial eutrophication). We tested the following hypotheses: (I) the increase in the abundance of certain microcrustacean species may indicate a rise in the trophic level; (II) the richness and abundance vary amongst lakes and are higher in the lake with natural eutrophication; and (III) the microcrustaceans abundance is associate with high primary productivity, being higher in the eutrophic environment with artificial eutrophication. Methods The study was conducted in a segment of the Paranapanema River basin, in southeastern Brazil, focusing on five lakes spanning an eight-kilometer stretch, to understand the different organisms' responses to distinct conditions of aquatic environments. Sampling was carried out bimonthly over the course of a year. Results A principal component analysis (PCA) separated three types of lakes: eutrophic (natural and man-made) to mesotrophic. Additionally, 25 taxa were found. SIMPER analysis filtered six species with more than 70% dissimilarity contribution. Five species exhibited differences amongst the lakes, one species correlated with natural variables as depth. The redundancy analysis associated the Bosminopsis deitersi abundance with man-made eutrophic lakes and with the variables electrical conductivity, phosphorus, nitrogen, chlorophyll-a, and hardness. High abundances of B. deitersi indicated artificial eutrophication especially in man-made lakes, while natural lakes with natural eutrophication were not favorable environments for the increase of B. deitersi abundance. Conclusions This study highlights the neotropical oxbow lakes, emphasizing the significance of physicochemical characterization, detailed temporal sampling, and lake classification by origin and trophic level.

Resumen Introducción: los embalses deben ser concebidos como un conjunto de interacciones, donde la inestabilidad física, química y biológica determinan cambios en la densidad de las comunidades planctónicas. Objetivo: Evaluar la inestabilidad del fitoplancton y zooplancton y su interacción con factores ambientales en cuatro embalses tropicales andinos con diferente estado trófico. Métodos: Se analizaron datos de variables físicas y químicas y de las densidades del fitoplancton y del zooplancton, medidas entre 2010-2018, en los embalses oligotróficos Punchiná y San Lorenzo y, entre 2013 y 2015, en el embalse hipereutrófico Porce II y en el embalse eutrófico Porce III (total N = 248). Se empleó el Factor Shaping Community Assemblages (FCA), para calcular la inestabilidad biótica y ambiental y la interacción entre estas. Resultados: En los embalses estudiados hubo una alta inestabilidad ambiental y biológica. El pH, la saturación de oxígeno, el nitrógeno total, la temperatura del agua, los nitritos, el fósforo total (solo para el zooplancton) y los sólidos totales, son las variables abióticas con mayor aporte a la inestabilidad planctónica, independientemente del estado trófico. Particularmente, Cryptomonas sp., Aulacoseira sp., Cyclotella sp., Dinobryon sp., Nephrocytium sp., Tetraëdron caudatum y Oscillatoria sp., tuvieron mayor influencia sobre la inestabilidad de diferentes taxones de rotíferos y de algunos copépodos. Conclusión: Independiente del estado trófico, la dinámica del pH, la disponibilidad de nutrientes, la cantidad de sólidos suspendidos y la disponibilidad de gases como el oxígeno disuelto determinaron principalmente la inestabilidad del fitoplancton, y en menor medida la del zooplancton. En los embalses oligotróficos la inestabilidad del zooplancton es influenciada principalmente por algas altamente apetecibles con toxicidad nula, y en embalses altamente enriquecidos la inestabilidad fue influenciada por algas con baja calidad nutricional y de difícil ingestión y manipulación.

Abstract Introduction: Reservoirs are conceived as a set of interactions in which physical, chemical, and biological instability determines changes in the density of planktonic communities. Objective: To evaluate the instability of phytoplankton and zooplankton, and their interactions with environmental factors in four tropical Andean reservoirs with different trophic status. Methods: Physical and chemical variables and phytoplankton and zooplankton densities were measured between 2010-2018 in the oligotrophic reservoirs Punchiná and San Lorenzo and between 2013 and 2015 in the hypereutrophic reservoir Porce II and in the eutrophic Porce III reservoir (total N = 248). The Factor Shaping Community Assemblages (FCA) was used to calculate environmental and biotic instability as well as their interaction. Results: High environmental and biological instability was observed in the studied reservoirs. Oxygen saturation, pH, total nitrogen, water temperature, nitrites, total phosphorus (only for zooplankton), and total solids were the abiotic variables with the greatest contribution to planktonic instability, regardless of trophic state. Particularly, Cryptomonas sp., Aulacoseira sp., Cyclotella sp., Dinobryon sp., Nephrocytium sp., Tetraëdron caudatum and Oscillatoria sp. had the greatest influence on the instability of various rotifer taxa and some copepods. Conclusions: Regardless of trophic state, pH dynamics, nutrients availability, amount of suspended solids and the availability of gases, such as dissolved oxygen, mainly determined the instability of phytoplankton and to a lesser extent that of zooplankton. In the oligotrophic reservoirs, zooplankton instability was mainly influenced by highly palatable algae with no toxicity, and in reservoirs highly enriched, the instability was influenced by algae with low nutritional quality and difficult to ingest and manipulate.

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 The present study aimed to evaluate the ecology considering distribution, abundance, population structure, and fecundity of the marine diplostraceans Penilia avirostris and Pseudevadne tergestina in the Veracruz Reef System National Park, southwest Gulf of Mexico. Surface samples were collected with a 300 μm mesh plankton net at 26 sampling sites in June, August, October (2011), May (2012) and June (2013). Temperature, salinity, and dissolved oxygen were measured in situ. The temperature range was 26.53 ± 0.41 and 29.29 ± 0.27°C, salinity between 33.43 ± 0.49 and 35.91 ± 0.09, and dissolved oxygen between 2.92 ± 0.08 and 6.56 ± 0.08 mg L-1. P. avirostris and P. tergestina presented the highest density, with 2200 ind 100 m-3 in June and 5980 ind 100 m-3 in October, respectively. Four stages were determined in P. avirostris. In P. tergestina, there were five instars, with males in August and October. The size of parthenogenic females of P. avirostris was 773.4 ± 20.08 μm. In P. tergestina, it was 637.6 ± 49.28 μm. The number of embryos in P. avirostris was 2 to 7, and in P. tergestina, 2 to 8 embryos. The correlations between body length and the number of embryos in both species were statistically significant under the potential model (r > 0.68 for both species, P < 0.001). The transects with the highest abundance were the northern and the southern zones because they are far from the influence of the Jamapa River. The density of these crustaceans is related to optimal temperature, salinity, and dissolved oxygen values. The low proportions obtained from gamogenic individuals of P. avirostris and P. tergestina suggest that in tropical and subtropical regions, gamogenesis is not crucial for the life cycle of these organisms.

RESUMEN Existe un incremento de publicaciones por conocer la problemática de la contaminación marina por microplásticos (MPs), donde ya se reconocen algunos de los efectos que pueden tener en el zooplancton. Este aumento de publicaciones requiere que se revisen las metodologías para unificar criterios de comparación, por lo que es de gran importancia unificar técnicas para las metodologías de extracción de los microplásticos ingeridos por el zooplancton para determinar la abundancia y las características de los MPs. A partir de una búsqueda en bases de datos, se escogieron cuatro técnicas específicas para la degradación de la materia orgánica representada por el zooplancton. Las técnicas fueron evaluadas en cuatro aspectos: 1) Eficiencia de la degradación de la materia orgánica, 2) Duración y condiciones de temperatura para el procesamiento, 3) Efecto físico de la digestión sobre los microplásticos, 4) cuantificar los MPs a partir de la tasa de ingestión. Se emplearon cincuenta individuos para cada uno de los grupos más abundantes correspondientes a las familias Paracalanidae, Corycaeidae y Oncaeidae, y al filo Chaetognatha. Los resultados obtenidos mostraron que la mejor técnica fue la de Md Amin et al (2020) con modificaciones, en la que no se observaron alteraciones en la integridad de los MPs y la tasa de ingestión fue similar a la que se reporta para estos organismos.

ABSTRACT Marine pollution caused by microplastics (MPs) in the ocean has been very high research in recent years, and their effects over different marine organisms such as zooplankton have been recognized. The crescent literature requires review and harmonization of the methodologies to unify criteria of comparison. Literature on microplastic ingestion in marine organisms is just beginning to be published, so it is of great importance to establish unified techniques for the extraction methodologies of microplastics ingested by zooplankton to determine the abundance and characteristics of MPs. Databases were used to find specific techniques for digestion of organic material from marine organisms, and four specific techniques were chosen for zooplankton degradation. Samples collected at one station in the Corales del Rosario and San Bernardo National Natural Park, Colombia were done. The chosen techniques were evaluated in four aspects: 1) The efficiency of digestions was evaluated on zooplankton samples, 2) The efficiency of digestion different duration and temperature conditions was assessed, 3) Evaluate the effect physics of digestions on microplastics, 4) Quantifying MPs from the ingestion rate. Fifty individuals were chosen from the sample to evaluate each technique. The most abundant groups corresponding to the families Paracalanidae, Corycaedae and Oncaeidae, and the phylum Chaetognatha were used. The best technique obtained was Md Amin et al (2020) with our modifications, this technique uses HNO3 65 % at 80 °C of temperature during one hour, in bottles of 2 mL lid with heat resistant. The organic matter was totally degraded, not changes on the physic integrity of MPs were observed, and the ingestion rates were similarly reported for other authors in these organisms.

ABSTRACT The semi-permanent coastal upwelling system within the Humboldt Current System (HCS) off northern Chile provides nutrient-rich, oxygen-poor water to the euphotic zone that contributes to high levels of primary production and restricts the vertical distribution of most zooplankton species according to their tolerance to hypoxia within this highly heterogeneous environment. The day/night vertical distributions of two calanoid copepods, Eucalanus inermis and Nannocalanus minor, were studied concerning the presence of oxygen-poor water associated with the Oxygen minimum zone (OMZ) at a coastal and an offshore station off northern Chile (∼20°S), by stratified sampling from the surface to a depth of 600 m. At the coastal station, most of the population of both species remained above the OMZ, whereas at the offshore station, most populations remained at the edge of the OMZ. Both species exhibited reverse diel vertical migration between day and night and were positively correlated with dissolved oxygen and chlorophyll-a, suggesting that both species may prefer oxygenated waters and avoid the OMZ. However, E. inermis and N. minor exhibited distinct behavior, with E. inermis displaying significant variations among stations and strata and N. minor showing differences only among strata, particularly in the upper strata where it was more aggregated. The results helped us understand the behavior and distribution of zooplankton related to OMZ and how they may change as ocean temperature increases worldwide.

ABSTRACT The ecology, distribution, and taxonomy of bopyrid isopod species are often omitted from studies not systematically addressed to crustaceans. From a wider study of zooplankton in coastal and reef waters of the Mexican Caribbean Sea, two bopyrid species were collected, Probopyrinella latreuticola, attached to the branchial chamber of Latreutes fucorum andProbopyrus pandalicola parasitizing the branchial chamber of Palaemon northropi. For both parasite-host associations, these records represent a new locality and the southernmost record in the Mexican Caribbean. A map and a list of the bopyrid species belonging to Bopyridae recorded in the Mexican Caribbean are provided.

RESUMEN: Se determinaron las especies de zooplancton presentes en áreas de cultivo de Argopecten purpuratus “concha de abanico” Vichayo, Sechura, Piura; se relacionaron los parámetros físicos y químicos con la composición del zooplancton; la unidad muestral fue de 100 ml de agua, en la que se evaluó zooplancton, temperatura, pH, oxígeno y salinidad, fueron colectadas 180 muestras en 5 puntos de muestreo elegidos al azar, muestreos por arrastre y vertical durante seis meses; determinándose las especies con el uso de claves taxonómicas y oxímetro, peachímetro y refractómetro para evaluar factores físicos y químicos. Los datos obtenidos fueron analizados mediante estadística descriptiva e inferencial, con decisiones de 95% de confianza. Los resultados indican que en el zooplancton predomina el phyllum Arthropoda y dentro de él, la clase Copepoda; los valores físicos y químicos se hallaron dentro de los rangos establecidos. Concluyéndose que del 100% de las especies de zooplancton presentes en las áreas evaluadas, el 69,84% pertenecen al phylum Arthropoda; y que, la comunidad de zooplancton se mantiene en equilibrio dinámico debido a una baja dominancia y valores elevados de riqueza de especies, diversidad y equitabilidad.

ABSTRACT: The zooplankton species present in Argopecten purpuratus “fan shell” culture areas were determined in Vichayo, Sechura, Piura; The physical and chemical parameters were related to the composition of the zooplankton; The sampling unit was 100 ml of water, in which zooplankton, temperature, pH, oxygen and salinity were evaluated. 180 samples were collected from 5 sampling points, chosen at random, using drag and vertical sampling, for six months. ; species are determined using taxonomic keys and the appropriate equipment to evaluate physical and chemical factors. The data obtained were analyzed using descriptive and inferential statistics, with decisions of 95% confidence. The results indicate that the phyllum Arthropoda predominates in the zooplankton and within it, the Copepoda class; The physical and chemical values were within the established ranges. Concluding that of 100% of individuals of the zooplankton species community present in the evaluated areas, 69.84% of them belong to the Phylum Arthropoda; and that the zooplankton community remains in dynamic equilibrium due to low dominance and high values of species richness, diversity and equitability.

RESUMEN Antecedentes. El reservorio de Valle de Bravo forma parte del sistema Cutzamala que suministra agua potable a la Ciudad de México; por esta razón es fundamental el garantizar su conservación y la calidad de sus aguas. Debido al creciente incremento de contaminantes agroquímicos y la descarga de aguas residuales en el embalse, se ha acelerado la eutrofización de sus aguas, fenómeno que se asocia al desarrollo de florecimientos cianobacteriales nocivos (FCN,s), que pueden afectar a las comunidades acuáticas. Objetivos. El propósito de este estudio fue evaluar la diversidad, riqueza específica y abundancia de cladóceros en el reservorio de Valle de Bravo y determinar el impacto de este ambiente eutrófico sobre estas poblaciones. Métodos. Se realizaron colectas de zooplancton mediante arrastre vertical, en 6 estaciones de muestreo, mensualmente durante un ciclo anual. Resultados. En total se registraron 12 especies de cladóceros de las cuales ocho son nuevos registros para Valle de Bravo. La mayor densidad de cladóceros se presentó en los meses de marzo y junio, con una disminución notable de agosto a noviembre. Los sitios de muestreo S1, S2 y S4 tuvieron densidades de cladóceros mayores a 60 ind. L-1. La especie que tuvo la densidad más alta fue Bosmina longirostris y cinco especies se registraron durante todo el año. El índice de diversidad de Shannon mostró valores bajos (1.0 a 1.48), lo que se asocia con un sistema acuático eutrofizado. Conclusiones. A pesar de que el reservorio de Valle de Bravo tuvo en todo momento florecimientos dominados por cianobacterias, la riqueza de especies fue alta comparada con otros lugares en el país, lo que refleja posiblemente que los esfuerzos de colecta previos no fueron lo suficientemente intensos para reflejar la diversidad y riqueza que registramos. Finalmente, no se pueden descartar los efectos nocivos que los florecimientos cianobacteriales tienen sobre la biota acuática.

ABSTRACT Background. The Valle de Bravo reservoir is part of the Cutzamala system that supplies drinking water to Mexico City. For this reason, it is essential to guarantee its conservation and the quality of its waters. Due to the increased discharge of agrochemical pollutants and domestic wastewater discharges into the reservoir, the eutrophication of its waters has been accelerated. Eutrophication is associated with developing harmful cyanobacterial blooms (HCBs), which can affect aquatic communities. Goals. This study aimed to evaluate the diversity, species richness, and abundance of cladocerans in the Valle de Bravo reservoir and to determine the impact of this eutrophic environment. Methods. Zooplankton samples were obtained at six sampling stations through vertical throws, monthly during an annual cycle. Results. In total, 12 species of cladocerans were recorded, of which eight are new records for Valle de Bravo. The highest density of cladocerans occurred in March and June, with a notable decrease from August to November. Sampling sites S1, S2, and S4 had cladoceran densities higher than 60 ind. L-1. The species with the highest density was Bosmina longirostris, and five species were recorded throughout the year. The Shannon diversity index showed low values (1.0 a 1.48) associated with a eutrophic aquatic system. Conclusions. Even though the Valle de Bravo dam had blooms dominated by cyanobacteria at all times, the species richness was high compared to other freshwater ecosystems in Mexico, possibly reflecting that previous collection efforts were not intense enough to reflect the diversity and richness we recorded. Finally, the harmful effects of cyanobacterial blooms on aquatic biota cannot be ruled out.

RESUMEN Antecedentes: La importancia del puerto Dos Bocas, Tabasco, para la actividad petrolera del sur del Golfo de México, contrasta con la escasa información sobre la comunidad zooplanctónica de su entorno. Objetivos: Generar información de línea base sobre la distribución espacial de la riqueza, abundancia y relación holoplancton/meroplancton (H/M) de los grupos del zooplancton (GZ) en el gradiente de salinidad. Métodos: En octubre de 2016 se realizó un muestreo en 17 estaciones en la zona costera adyacente al puerto Dos Bocas y la laguna Mecoacán. La colecta biológica se realizó con una red cónica de 300 µm, registrando la salinidad y la temperatura del agua. Resultados: La riqueza, la abundancia y la relación H/M decrecieron con la salinidad. La zona costera se caracterizó como un ambiente euhalino, en la que se registraron 26 GZ, con abundancia media de 3,880 ind 100 m-3 y relación H/M = 11.3, siendo los copépodos el grupo dominante, lo que es indicativo de la productividad secundaria asociada al ambiente costero. En la laguna Mecoacán predominó un ambiente meso-polihalino, en el que se registraron 17 GZ, con abundancia media de 409 ind 100 m-3 y relación H/M = 1.8, siendo los huevos de peces el grupo dominante, lo que es indicativo de la importancia de la laguna Mecoacán para especies con importancia comercial o ecológica, antes de su fase adulta. Conclusiones: Los cambios en la riqueza y abundancia de los taxa del zooplancton a través del gradiente de salinidad aporta información de línea base sobre el uso diferencial de la laguna Mecoacán y la costa adyacente por GZ con ciclos de vida distintos, representando la primera contribución al conocimiento del zooplancton en el área de estudio.

ABSTRACT Background: The importance of the port of Dos Bocas, Tabasco, for the oil industry in the southern Gulf of Mexico, contrasts with the scarce information on the zooplankton community in its surroundings. Objectives: Generate baseline information on the spatial distribution of richness, abundance and holoplankton/meroplankton (H/M) ratio of zooplankton groups (ZG) along the salinity gradient. Methods: In October 2016, one sampling was conducted at 17 sites in the coastal area adjacent to the Dos Bocas port and the Mecoacan Lagoon. The biological samples were obtained using a plankton net with a 300 µm filtering mesh, recording water salinity and temperature. Results: The richness, abundance, and H/M ratio decreased with salinity. The coastal zone was characterized as a euhaline environment, where 26 ZG were recorded, with a mean abundance of 3,880 ind 100 m-3 and H/M ratio = 11.3, with copepods being the dominant group, which is indicative of the secondary productivity associated with the coastal environment. In the Mecoacan Lagoon, a meso-polyhaline environment predominated, where 17 ZG were recorded, with a mean abundance of 409 ind 100 m-3 and H/M ratio = 1.8, with fish eggs being the dominant group, which is indicative of the importance of the Mecoacan Lagoon for species with commercial or ecological importance, before their adult stage. Conclusions: The changes in the richness and abundance of zooplankton taxa along the salinity gradient provide baseline information on the differential use of the Mecoacan Lagoon and the adjacent coast by ZG with distinct life cycles, representing the first contribution to the knowledge of zooplankton in the study area.

Resumen Los cladóceros son crustáceos utilizados como alimento vivo para larvas de peces debido a su aporte nutricional y fácil cultivo. El objetivo fue identificar las especies de cladóceros presentes en ambientes acuáticos temporales y permanentes del estado de Morelos. Se tomaron algunos parámetros físicos y químicos, además de las recolectas del zooplancton, en un total de 130 cuerpos de agua. Se determinaron un total de 33 especies comprendidas en las familias Bosminidae, Chydoridae, Daphniade, Ilyocryptidae, Macrothricidae, Polyphemidae, Sididae y Moinidae, donde sobresalen por su abundancia y frecuencia las especies de la familia Daphnidae. Se reporta que en estos sistemas acuáticos se presentan las especies que son utilizadas como alimento vivo, como es el caso de Moina cf. micrura, Diaphanosoma birgei, Daphnia laevis y Daphnia cf. mendotae. Se registró a Moina wierzejski como especie que habita tanto en lagos, presas y embalses, la cual es utilizada como alimento para larvas de peces.

Abstract Cladocerans are microscopic crustaceans widely used as live food for fish larvae due to their nutritional value and easy culture. The objective was to identify the species of cladocerans present in the temporary and permanent aquatic environments of the state of Morelos. Some physical and chemical parameters were taken, in addition to zooplankton collections, in 130 bodies of water. A total of 33 species included in the families Bosminidae, Chydoridae, Daphniade, Ilyocryptidae, Macrothricidae, Polyphemidae, Sididae, and Moinidae were identified, where the species of the Daphnidae family stand out for their abundance and frequency. It was reported that in these aquatic systems lie the species that are generally used as live food, such is the case of Moina cf. micrura, Diaphanosoma birgei, Daphnia laevis, and Daphnia cf. mendotae. Moina wierzejski is recorded as a species that inhabits in lakes, dams, and reservoirs and which is used as food for fish larvae.

Abstract Zooplankton plays a crucial role as the primary consumers in the Southern Ocean and its ecological processes, particularly in the Antarctic Peninsula, influenced by regional glaciological and oceanographic changes. To assess the overall composition of these communities, vertical samples were collected at various depths using a Multinet at oceanographic stations in the Antarctic Peninsula during the XXXV OPERANTAR expedition in summer 2017. Abiotic data (temperature, salinity and chlorophyll-a) were collected using a CTD and a fluoremeter. Organisms were identified to a higher level, with Chaetognatha and Euphausiacea identified to species whenever possible. Copepoda were the most abundant (73.4%), with Calanoida present in all samples and more abundant at 300m. Salpidae ranked as the second most abundant taxon (16.6%) up to 100m. Three species of Chaetognatha were identified, with Eukrohnia hamata being the most abundant, particularly at 300m. Two species of Euphausiacea were found, Euphausia superba and Thysanoesa macrura, with low abundances. Abiotic parameters showed significant relationships with the taxa. The region exhibits complex oceanography associated with zooplankton communities. The recorded data align with the zooplankton characterization of this region, uncovering a prevalence of Copepoda and surface abundant Salpidae, along with Chaetognatha (particulary E. hamata) and Euphausiacea. processes changes communities 2017 temperature, temperature (temperature chlorophylla chlorophyll chlorophyll-a fluoremeter level possible 73.4%, 734 73.4% , 73 4 (73.4%) 300m m 16.6% 166 16 6 (16.6% 100m found macrura abundances taxa particulary E 201 73.4 7 (73.4% 16.6 1 (16.6 20 73. (73.4 16. (16. 2 (73. (16 (73 (1 (7 (

Resumo: Objetivo A comunidade zooplâncton é utilizada como bioindicador de mudanças ambientais e pode ser um indicador do estado trófico em ambientes aquáticos através de mudanças na composição da comunidade. O objetivo deste trabalho foi estudar a variação de sistemas de reservatórios rasos em um parque urbano, avaliando as relações entre variáveis físicas, químicas e biológicas. Métodos As coletas foram realizadas mensalmente durante um ano na superfície dos reservatórios. As variáveis físicas e químicas da água foram medidas por meio de sonda multiparamétrica na superfície. A análise dos nutrientes foi realizada por espectrofotometria em laboratório. O zooplâncton foi coletado com rede de plâncton (malha de 60 µm). A Análise de Coordenadas Principais (PCoA) foi utilizada para verificar se os três reservatórios apresentam diferenças na composição da comunidade zooplanctônica. Resultados Ao todo foram coletados 43 táxons pertencentes a 16 famílias. Rotifera foi o grupo mais representativo, com 27 táxons, Cladocera teve 13 táxons e Copepoda teve apenas três táxons. As variáveis ambientais indicaram diferentes estados tróficos entre os reservatórios, demonstrando maior eutrofização nos reservatórios 1 e 3. Foi verificada associação entre a composição da comunidade zooplanctônica e o estado trófico dos reservatórios. Conclusões A composição da comunidade zooplanctônica apresenta diferenças entre três dos reservatórios urbanos rasos estudados. O reservatório 1 exibiu Filinia terminalis e Asplanchna herrick como espécies indicadoras. Já no reservatório 2, com menor status trófico, as espécies indicativas foram Bosmina freyi e Diaphanosoma polyspina, correlacionadas com menores concentrações de nitrato, nitrito, fósforo total, pH e menores valores de condutividade elétrica. O reservatório 3 exibiu Brachionus angularis e Brachionus calyciflorus como espécies indicadoras, demonstrando perfil nutricional semelhante ao R1, mas com maiores concentrações de nitrato. Resumo urbano biológicas laboratório malha 6 µm. µm . µm) PCoA (PCoA 4 famílias representativo 2 estudados indicadoras polyspina nitrato nitrito total elétrica R1 R

Abstract: Aim The zooplankton community is used as a bioindicator of environmental changes and can be an indicator of trophic status in aquatic environments through changes in the composition of the community. The objective of this work was to study the variation of shallow reservoir systems in an urban park, evaluating the relationships between physical, chemical, and biological variables. Methods The collections were conducted monthly for a year in the surface of reservoirs. The physical and chemical variables of the water were measured using a multiparametric probe on the surface. Nutrient analysis was performed using spectrophotometry in the laboratory. Zooplankton was collected using a plankton net (60 µm mesh size). Principal Coordinate Analysis (PCoA) was used to verify whether the three reservoirs present differences in zooplankton community composition. Results Altogether, 43 taxa belonging to 16 families were collected. Rotifera was the most representative group, with 27 taxa, Cladocera had 13 taxa, and Copepoda had only three taxa. The environmental variables indicated different trophic status between the reservoirs, demonstrating greater eutrophication in reservoirs 1 and 3. An association between the composition of the zooplankton community and the trophic state of the reservoirs was verified. Conclusions The composition of the zooplankton community shows differences among three of the shallow urban reservoirs studied. Reservoir 1 exhibited Filinia terminalis and Asplanchna herrick as indicator species. As for reservoir 2, with a lower trophic status, the indicative species were Bosmina freyi and Diaphanosoma polyspina, correlated with lower concentrations of nitrate, nitrite, total phosphorus, pH, and lower values of electrical conductivity. Reservoir 3 exhibited Brachionus angularis and Brachionus calyciflorus as indicator species, demonstrating a similar nutrient profile to R1, but with higher nitrate concentrations. Abstract park laboratory 60 (6 size. size . size) PCoA (PCoA Altogether 4 group 2 verified studied polyspina nitrite phosphorus pH conductivity R1 R 6 (

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 Functional traits, short life cycles, and the pivotal role in the ocean make copepod diversity a solid foundation for assessing the effect of global changes in marine food webs and ecosystem functioning. Climate change and extreme events, particularly El Niño, can affect coastal ecosystems. The Arvoredo Marine Biological Reserve (MPA), located in highly productive coastal waters of the Southern Brazilian Bight, presents complex climate and oceanographic conditions. This study investigates the influence of oceanographic processes and El Niño 2015-2016 on the copepod functional diversity from 2014 to 2016 in the Arvoredo MPA. Horizontal tows were performed using a WP2 net with a mesh size of 200 µm. The 41 species accounted for 19 functional entities and four functional groups. Our findings reveal that the seasonal intrusion of water masses influenced copepod functional diversity. During summer, the upwelling of South Atlantic Central Water increased nutrient availability and favored large herbivore-omnivores and carnivores. The Plata Plume Water enrichment during winter coincided with a decline in functional richness and abundance, leading to the predominance of the Oithona nana, a small-sized omnivore. Compensatory mechanisms were observed as functional equivalence and species composition shifts. Acartia lilljeborgii and Temora turbinata exhibited functional equivalence and compensated for each other in response to salinity changes associated with upwelling and El Niño. The copepod assemblage demonstrated the ability to maintain functional diversity despite changes in copepod abundance. However, the decline in functional diversity and abundance during the intense winter indicated potential disruption in trophic dynamics and ecosystem functioning. Maintaining balance and compensating for disturbances such as El Niño is crucial for marine food web resilience. The functional trait approach provided a comprehensive understanding of the copepod assemblage in Arvoredo MPA, contributing to a broader knowledge of the impact of oceanographic processes intensification. Monitoring functional diversity and abundance is crucial for evaluating the effects of copepod assemblage changes in ecosystem functionings. traits cycles functioning events ecosystems MPA , (MPA) Bight conditions 20152016 2015 2015-201 201 WP 20 µm 4 1 groups summer herbivoreomnivores herbivore omnivores carnivores nana smallsized small sized omnivore shifts However resilience intensification functionings (MPA 2015201 2015-20 2 201520 2015-2 20152 2015-