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 En un experimento a escala piloto desarrollado en Brasil, se cultivaron juveniles de tilapia genéticamente mejorada en efluente de tanque séptico seguido de laguna de alta tasa (LAT). Durante las 22 semanas de la investigación se evaluó la combinación de tres tasas de aplicación superficial de nitrógeno amoniacal total (NAT) (0,6; 1,2 y 2,4 kg NAT.ha-1.d-1) y tres densidades de cultivo (3; 6 y 12 peces.m-2). Los tanques de cultivo funcionaron como unidades de pulimento para tratamiento de las aguas residuales, adicionando (con los mejores resultados, alcanzados con la menor densidad de cultivo y 1,2 kg NAT.ha-1.d-1) las siguientes eficiencias de remoción adicionales a las obtenidas mediante el uso de la LAT: 78,3% para nitrógeno total Kjeldahl; 89,1% para nitrógeno amoniacal; 63,9% para fósforo total; 57,2% para demanda química de oxígeno; 2,36 unidades logarítmicas para E. coli. La productividad de los peces se estimó del orden de 2,67 ton.ha-1 para cultivo durante seis meses por año para climas templados, utilizando la población de plancton natural del agua residual doméstica tratada como la única fuente de alimento.

Abstract In a pilot-scale experiment carried out in Brazil, genetically improved farmed tilapia juveniles were reared in septic tank-high rate algal pond (HRAP) effluent. The combination of three total ammonia nitrogen (TAN) surface loading rates (0.6; 1.2 and 2.4 kg TAN.ha-1.d-1) and three fish stocking densities (3; 6 and 12 fish.m-2) was evaluated during a 22-week research. The fish rearing tanks worked as wastewater treatment polishing units, adding (as the best results, achieved with the lowest fish stocking density and 1.2 kg TAN.ha-1.d-1) the following removal figures on top of those achieved at the HRAP: 78.3% total Kjeldahl nitrogen; 89.1% ammonia nitrogen; 63.9% total phosphorous; 57.2% chemical oxygen demand; 2.36 log units E. coli. Fish productivity was estimated at 2.67 ton.ha-1 for fish culture over six month per year in a temperate climate region, using the domestic treated wastewater natural plankton population as the only food source.

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.

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.

Resumo: Objetivo Este estudo tem como objetivo verificar a contribuição dos ovos de resistência de cladóceros para as comunidades ativas de lagoas temporárias e testar experimentalmente as condições específicas para a eclosão destes ovos de resistência. Métodos Amostras de cladóceros foram obtidas em quatro lagoas temporárias na planície de inundação do rio Turvo (20° 22’S e 49° 16’W), na região noroeste do Estado de São Paulo, Brasil. Amostras de 5 cm de sedimento foram coletadas durante a estação seca, usando um corer de 4,5 cm de diâmetro. Amostras de plâncton foram coletadas antes e depois da estação seca. Para o teste de incubação, foram realizados dois tratamentos a saber, 1. Condições naturais - sem controle de luz e temperatura; 2. Condições controladas - com fotoperíodo e temperatura controlados. A condição da água e a eclosão dos ovos de resistência foram monitoradas por duas semanas. A influência dos parâmetros na eclosão em ambos os tratamentos foi avaliada por meio da Análise de Partição Hierárquica. Resultados A eclosão dos ovos de resistência foi maior no tratamento Condições controladas do que Condições naturais. Trinta por cento das espécies observadas na comunidade ativa após o alagamento eclodiram no teste de laboratório. Condutividade, pH e oxigênio dissolvido foram positivamente correlacionados com a eclosão de algumas espécies como Ephemeroporus hybridus, Leydigiops ornata, Notoalona sculpta e Ilyocryptus spinifer. As primeiras espécies a eclodirem foram aquelas associadas a macrófitas e em ambients com baixas profundidades. Conclusões Nossos resultados mostram que condições constantes de temperatura e fotoperíodo estimulam maior taxa de eclosão dos ovos de resistência de Cladocera. Variáveis como pH, condutividade e oxigênio dissolvido também foram correlacionados com a eclosão de algumas espécies estudadas. Observamos que as primeiras contribuições para a comunidade ativa após a seca vieram da eclosão de espécies geralmente associadas a macrófitas e condições de baixa profundidade. Resumo 20° 20 (20 22S S 22 49 16W, 16W W 16 , 16’W) Paulo Brasil 45 4 4, diâmetro incubação saber 1 2 controlados semanas Hierárquica laboratório Condutividade hybridus ornata spinifer profundidades Cladocera estudadas profundidade (2 16’W (

Abstract: Aim We aimed to verify the contribution of cladocerans’ resting eggs to the active communities of temporary lagoons and, through an experiment, identify which conditions induce high hatching rates. Methods Cladocera assemblages were sampled in four temporary lagoons in the Turvo River floodplain (20° 22’S and 49° 16’W), in the northwest region of São Paulo State, Brazil. Sediment samples were taken during the dry season from a depth of 5 cm, using a 4.5 cm diameter corer. Plankton samples were taken from the water column before and after the dry season. For the hatching test, two treatments were performed 1. Natural condition – without light and temperature control; 2. Controlled condition – with controlled photoperiod and temperature. Temperature, pH, conductivity, dissolved oxygen and hatching of resting eggs were monitored for two weeks. The influence of the parameters on hatching in both treatments was evaluated using Hierarchical Partition Analysis. Results Hatching of resting eggs was higher in the Controlled condition than in the Natural one. Thirty percent of species observed in the active community after flooding hatched in the laboratory test. Conductivity, pH, and dissolved oxygen were positively correlated to the hatching of some species, e.g., Ephemeroporus hybridus, Leydigiops ornata, Notoalona sculpta and Ilyocryptus spinifer. The first species to hatch were those living associated with macrophytes and at low depths. Conclusions Our results show that stable temperature and photoperiod with similar light and dark hours stimulate greater hatching of Cladocera resting eggs. Variables such as pH, conductivity and dissolved oxygen were also correlated with the hatching of some species. We observed that the first contributions to activating the community after drought came from hatching of species usually associated with macrophytes and low depth conditions. Abstract cladocerans experiment rates 20° 20 (20 22S S 22 49 16W, 16W W 16 , 16’W) State Brazil 45 4 4. corer test 1 control 2 Temperature pH weeks Analysis one Conductivity eg e g e.g. hybridus ornata spinifer depths (2 16’W e.g (

RESUMO (Spermatozopsis exsultans Korshikov (Chlorophyceae, Dunaliellaceae) em ambientes de água doce do sul do Brasil). Spermatozopsis exsultans Korshikov está distribuída no plâncton de água doce em diferentes países, mas raramente é mencionada em águas brasileiras. O objetivo do nosso estudo foi mostrar a morfologia e preferência ecológica da espécie em dois distintos ambientes em sistema subtropical. Amostragem de fitoplâncton foi realizada mensalmente em seis estações no Lago Guaíba (janeiro de 2021 a abril de 2022) e, em seis estações ao longo do curso superior, meio e inferior do Rio Ibirapuitã, no outono e primavera de 2011 e outono de 2012. Spermatozopsis exsultans é uma microalga curvada espiralada com plastídio parietal sem pirenoide, cerca de 10 µm de comprimento, com quatro flagelos de tamanho igual. A espécie mostrou aumento da densidade na estação de verão, estando positivamente correlacionada com temperatura, transparência e condutividade elétrica da água. Spermatozopsis exsultans demonstrou ser uma espécie que preferiu águas quentes, ricas em nutrientes e alta luminosidade em sistema subtropical. Chlorophyceae, Chlorophyceae (Chlorophyceae Dunaliellaceae Brasil. Brasil . Brasil) países brasileiras subtropical janeiro 202 2022 superior Ibirapuitã 201 2012 pirenoide 1 comprimento igual verão temperatura quentes 20 2

ABSTRACT (Spermatozopsis exsultans Korshikov (Chlorophyceae, Dunaliellaceae) in the freshwater environments from southern Brazil). Spermatozopsis exsultans Korshikov is distributed in freshwater plankton across different countries but rarely is mentioned in Brazilian waters. Our study aimed to show the morphology and ecological preferences of the species in two distinct environments in subtropical system. Phytoplankton sampling was carried out monthly in six stations in Guaíba Lake (January 2021 to April 2022), and in six stations along the upper, middle, and lower course of Ibirapuitã River, autumn and spring 2011 and autumn 2012. Spermatozopsis exsultans is a curved spirally twisted microalgae with parietal plastids without pyrenoid, around 10 µm length, with four flagella of equal size. The species showed an increased density in the summer season, which correlated positively with the water temperature, transparency, and electric conductivity. Spermatozopsis exsultans was shown to be a species that preferred warm waters, rich in nutrients, and high luminosity in the subtropical system. Chlorophyceae, Chlorophyceae (Chlorophyceae Dunaliellaceae Brazil. Brazil . Brazil) waters system January 202 2022, 2022 , 2022) upper middle River 201 2012 pyrenoid 1 length size season temperature transparency conductivity nutrients 20 2

Abstract Bioseston is a heterogeneous assemblage of bacterioplankton, phytoplankton, zooplankton, and planktonic debris. A detailed knowledge of biosestons is essential for understanding the dynamics of trophic flows in marine ecosystems. The distributional features of seston biomass in plankton (micro- and mesoplankton) in the Southwest Atlantic Ocean (Rio de Janeiro State, Brazil) were analyzed using stratified samples gathered to a depth of 2,400 m during night time. The horizontal pattern of biomass distribution was analyzed vis-a-vis station depth during both wet and dry periods, with higher values recorded in the continental shelf than in the slope, confirming the terrestrial contribution of nutrient sources to the marine environment. This horizontal variation reinforces the occurrence of seasonal vortices in Cabo Frio and Cabo de São Tomé on the central coast of Brazil. Environmental variables reflect the hydrological signatures of the water masses along the Brazilian coast. The largest seston biomass was related to high temperatures, salinities, and low inorganic nutrient concentrations in tropical and South Atlantic central waters. The observed distribution patterns suggest that seston biomass in plankton in the region may be structured based on partitioned horizontal and vertical habitats and food resources. bacterioplankton phytoplankton zooplankton debris ecosystems micro (micro mesoplankton Rio State Brazil 2400 2 400 2,40 time visavis vis periods slope environment temperatures salinities waters resources 240 40 2,4 24 4 2,

Resumo O trabalho teve como objetivo conhecer a diversidade de cianobactérias planctônicas de três lagos urbanos de Manaus, no estado do Amazonas, a partir da análise de amostras coletadas com rede de plâncton, mensalmente, de outubro de 2009 a setembro de 2010, excetuando-se março de 2010. Foram identificadas 12 espécies, dentre estas, Anathece cf. minutissima, Aphanocapsa annulata, Ap. stagnalis, Coelomoron microcystoides e Pseudanabaena mucicola foram registradas pela primeira vez na Amazônia brasileira. Florações de cianobactérias potencialmente tóxicas ocorreram nos três lagos, destacando-se os lagos Ceasa e Japiim onde Microcystis aeruginosa e Planktothrix agardhii foram, respectivamente, as espécies predominantes em todas as amostras analisadas. São apresentadas descrições e ilustrações das espécies identificadas, bem como comentários taxonômicos. Adicionalmente, as variáveis ambientais (condutividade elétrica, pH e temperatura da água) foram apresentadas. As águas dos ambientes estudados oscilaram de levemente ácidas a alcalinas com valores de temperatura variando de 23,2 a 30,5 °C. Manaus Amazonas plâncton mensalmente 200 2010 excetuandose excetuando se 1 estas cf minutissima annulata Ap stagnalis brasileira destacandose destacando respectivamente analisadas taxonômicos Adicionalmente condutividade elétrica água 232 23 2 23, 305 30 5 30, C °C 20 201 3

Abstract The aim of this research was to study the diversity of planktonic cyanobacteria in three urban lakes in Manaus, in the state of Amazon, by analyzing samples collected monthly with a plankton net from October 2009 to September 2010 (except March 2010). Twelve species were identified and classified. Anathece cf. minutissima, Aphanocapsa annulata, Ap. stagnalis, Coelomoron microcystoides and Pseudanabaena mucicola were recorded for the first time in the Brazilian Amazon region. Potentially toxic cyanobacteria blooms occurred in all three lakes, especially in Ceasa and Japiim, where Microcystis aeruginosa and Planktothrix agardhii, respectively, were the predominant species in all analyzed samples. Descriptions and illustrations of the identified species are presented as well as comments. In addition, environmental variables were presented (electrical conductivity, pH and water temperature). The waters of the studied environments ranged from slightly acid to alkaline and temperature varied from 23.2 to 30.5 °C. Manaus 200 201 except 2010. . 2010) classified cf minutissima annulata Ap stagnalis region Japiim agardhii respectively comments addition electrical conductivity temperature. temperature) 232 23 2 23. 305 30 5 30. C °C 20 3

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 Piaractus mesopotamicus, is a fish usually farmed in semi-intensive systems with access to natural food and supplementary feed. This study evaluates effects of feed allowance on the productive performance, carbon turnover and proportions of nutrient (carbon) contribution of feed and natural food for the growth of pacu. Juvenile fish were stocked in fiberglass tanks and fed to 100, 75, 50, 25, 0% apparent satiety (ApS), with a practical, extruded (C4 photosynthetic pathway) feed in a randomized design trial (n=3); plankton production for simulated semi-intensive farming system condition was induced by chemical fertilization. A control treatment was set up in tanks devoid of natural food. Data on muscle stable carbon isotope ratios were used to study carbon turnover using a relative growth-based model. Low variation of the δ13C impaired fitting a turnover model curve for the 0 and 25 % ApS treatments. Fish of the 100% and 75% ApS treatments reached circa 95% and 82.85% of the carbon turnover, respectively. Extruded feed was the main nutrient source for the growth of pacu in the semi-intensive, simulated farming condition. The current study contributes to the knowledge of the relationship between feeding rates and carbon turnover rates in the pacu muscle. mesopotamicus semiintensive semi intensive performance (carbon 100 75 50 ApS, , (ApS) practical C4 C (C pathway n=3 n3 n 3 (n=3) fertilization growthbased based δC δ 2 95 8285 82 85 82.85 respectively semiintensive, intensive, 10 7 5 (ApS n= (n=3 9 828 8 82.8 1 (n= 82. (n

ABSTRACT Abstract: Rhithropanopeus harrisii (Brachyura, Panopeidae) is a small euryhaline and eurythermal omnivorous crab native to the Northwest Atlantic. However, it has become an invasive species in various estuaries and coastal areas far from its original habitat, most likely due to intercontinental shipping. Once it establishes itself in one location, it can spread to neighboring regions via maritime currents. In 1982, this species was found in South America, specifically in Lagoa dos Patos, Brazil. In this study, we present the first record of R. harrisii larvae in Uruguay, located in the coastal marine zone of Laguna de Rocha, approximately 300 km south of Lagoa dos Patos. It was discovered during a study that involved 15 plankton samplings, conducted from February 2016 to February 2017. Notably, the observation of R. harrisii larvae was limited to the coastal zone during the summer and autumn of 2016 (February to April). All observed larvae were in the zoeal stage, and their abundance ranged from three to 185 individuals per 100 m3. The temperature and salinity values recorded during sampling surveys with the presence of R. harrisii ranged from 19 to 22.4 °C and 11.8-32.5 ppt, respectively. The discovery of the larval stage suggests that adults of this species may be reproducing in the eastern coastal zone of Uruguay or nearby regions. The area in which they are currently found could potentially serve as a biological corridor, facilitating their spread to other estuaries of great economic and ecological importance, such as the Río de la Plata, as well as other coastal lagoons and subestuaries in Uruguay and Argentina. Further monitoring studies are necessary to determine whether this species became established in the area. Potential ecological consequences in our region derived from its presence are herein discussed. Abstract Brachyura, Brachyura (Brachyura Panopeidae Atlantic However habitat shipping location currents 1982 America Patos Brazil R Rocha 30 1 samplings 201 2017 Notably April. April . April) 18 10 m3 m 224 22 4 22. C 11.832.5 118325 11.8 32.5 11 8 32 5 11.8-32. ppt respectively corridor importance Plata Argentina discussed 198 3 20 2 832 11.832. 11832 118 11. 325 32. 11.8-32 83 11.832 1183 11.8-3 11.83 11.8-

RESUMEN El fitoplancton constituye uno de los componentes más importantes de los ecosistemas dulceacuícolas lenticos, ya que representa el recurso basal para el crecimiento y supervivencia de los demás organismos asociados con estos ecosistemas. Además, aporta información relevante para el diagnóstico del estado de conservación de un cuerpo de agua, por su sensibilidad a un amplio rango de tensores, reflejado en variaciones en su composición y estructura. A pesar de varios estudios sobre la riqueza y dinámica del fitoplancton en sistemas lenticos de zonas tropicales, el conocimiento en humedales someros de zonas bajas es escaso. En el presente estudio se planteó determinar la composición y estructura del fitoplancton y su relación con variables fisicoquímicas, en el humedal El Silencio (Tolima, Colombia), un sistema acuático somero (profundidad < 1 m). Se realizaron ocho muestreos durante un ciclo hidrológico, colectando cuatro muestras en la zona limnética con red de plancton (23 µm). Se encontró que la comunidad fitoplanctónica está compuesta principalmente por el phylum Euglenozoa (78,9 %), seguido de Chlorophyta (17,5 %) y en menor proporción por los phyla Cyanobacteria (2 %), Bacillariophyta (0,92 %), y Charophyta (0,10 %). Las variables fisicoquímicas que más incidieron en la composición de la comunidad fitoplanctónica fueron alcalinidad y fósforo total. Asimismo, la dinámica del fitoplancton estuvo influenciada por los cambios climáticos y los niveles de precipitación. La presencia de Lepocinclis, Actinastrum, Trachelomonas, Phacus y Euglena mostraron una representatividad mayor del 90 %, lo que se asocia con un alto grado de eutrofía en el humedal.

ABSTRACT Phytoplankton constitutes one of the most important components of lentic freshwater ecosystems, due it represents the basal resource for the growth and survival of the other organisms associated with these ecosystems. In addition, it provides relevant information for the diagnosis of the state of conservation of a waterbody, due to its sensitivity to a wide range of stressors, reflected in variations in its composition and structure. Despite several studies on the richness and dynamics of phytoplankton in lentic systems of tropical zones, knowledge of shallow wetlands in lowland zones is scarce. In the present study, it was proposed to determine the composition and structure of phytoplankton and its relationship with physicochemical variables, in the El Silencio wetland (Tolima, Colombia), a shallow aquatic system (depth <1 m). Eight samplings were carried out during a hydrological cycle, collecting four samples in the limnetic zone with a plankton net (23 µm). The phytoplankton community was mainly composed of the phylum Euglenozoa (78,9 %), followed by Chlorophyta (17,5 %) and to a lesser percentage by the phyla Cyanobacteria (2 %), Bacillariophyta (0,92 %), and Charophyta (0,10 %). The physicochemical variables that most influenced the composition of the phytoplankton community were alkalinity and total phosphorus. Likewise, the dynamics of phytoplankton were influenced by climatic changes and precipitation levels. The presence and representativeness greater than 90 % of Lepocinclis, Actinastrum, Trachelomonas, Phacus, and Euglena was associated with a high degree of eutrophication in the wetland.

RESUMO O pirarucu, Arapaima gigas é um peixe de grande importância econômica e social na Amazônia, onde é comumente produzido em viveiros. A produção de peixes em tanques-rede tem crescido no Brasil, e este sistema poderia ser uma alternativa para a produção do pirarucu, reduzindo custos e melhorando os parâmetros produtivos. Nós avaliamos a contribuição do alimento natural na produção em sistema semi-intensivo (viveiros) e intensivo (tanques-rede) e seus efeitos sobre os aspectos produtivos e econômicos do pirarucu na fase de recria. Quatro viveiros (300 m2) e quatro tanques-rede (4,0 m3) foram estocados, respectivamente, com 120 (0,4 peixes m-2) e 160 (40 peixes m-3) juvenis de pirarucu (28,03 ± 6,34 g e 11,75 ± 0,80 cm). O estudo foi conduzido por 105 dias e os peixes foram alimentados com ração comercial extrusada. Crescimento e ingestão de plâncton pelos peixes foram avaliados quinzenalmente. Sobrevivência, comprimento padrão, ganho de peso e peso final foram maiores nos peixes cultivados em viveiros. A conversão alimentar nos viveiros (0,96 ± 0,06) foi menor que nos tanques-rede (1,20 ± 0,11). Mesmo sendo ofertada ração, os pirarucus consumiram alimento natural nos dois sistemas de produção. A abundância relativa de zooplâncton e insetos nos estômagos foi diretamente proporcional ao ganho de peso nos viveiros, e inversamente proporcional nos tanques-rede. Um índice de eficiência econômica mais alto e custo médio de produção mais baixo foram calculados para os viveiros escavados. Nossos resultados indicam que o custo-benefício do cultivo de A. gigas durante a fase de recria é melhor em viveiros. Amazônia tanquesrede tanques rede Brasil semiintensivo semi (viveiros (tanques-rede 300 (30 m2 m 4,0 40 4 0 (4, m3 estocados respectivamente 12 0,4 04 (0, 2 m-2 16 (4 3 m-3 28,03 2803 28 03 (28,0 634 6 34 6,3 1175 11 75 11,7 080 80 0,8 cm. cm . cm) 10 extrusada quinzenalmente Sobrevivência padrão 0,96 096 96 (0,9 0,06 006 06 1,20 1 20 (1,2 0,11. 011 0,11 0,11) tanquesrede. rede. escavados custobenefício benefício 30 (3 4, 0, (0 m- ( 28,0 280 (28, 63 6, 117 7 11, 08 8 0,9 09 9 0,0 00 1,2 (1, 01 0,1 28, (28 1, (1 (2

ABSTRACT Pirarucu, Arapaima gigas is a fish species of great social and economic importance in the Amazon region, where they are often farmed in earthen ponds. Intensive cage aquaculture has been growing in Brazil, which could be an alternative means to farm pirarucu, reducing costs and increasing productivity. We evaluated the contribution of natural food organisms in semi-intensive (ponds) and intensive (cages) production systems, and their effect on pirarucu growth and economic performance during the first phase of grow-out. Four ponds (300 m2) and four cages (4.0 m³) were stocked, respectively, with 120 (0.4 fish m-²) and 160 (40 fish m-³) juvenile pirarucu (28.03 ± 6.34 g, 11.75 ± 0.80 cm). The study was conducted for 105 days and fish were fed with commercial feed. Fish growth and plankton intake were evaluated every two weeks. Survival rate, standard length, weight gain and final weight were higher in fish reared in earthen ponds than in cages. Feed conversion of fish kept in ponds was lower (0.96 ± 0.06) than in cages (1.20 ± 0.11). The consumption of natural food organisms was observed, despite artificial feed being fed in both systems. The relative abundance of zooplankton and insects in stomachs was directly proportional to fish weight gain in ponds, and inversely proportional in cages. Higher economic efficiency rate and lower average production cost were calculated for earthen ponds. Our results indicate that the cost-benefit of the first phase grow-out of A. gigas is better in earthen ponds. Pirarucu region Brazil productivity semiintensive semi (ponds (cages systems growout. growout grow out. out 300 (30 m2 m 4.0 40 4 0 (4. m³ stocked respectively 12 0.4 04 (0. m² ² m-² 16 (4 ³ m-³ 28.03 2803 28 03 (28.0 634 6 34 6.3 g 1175 11 75 11.7 080 80 0.8 cm. cm . cm) 10 weeks length 0.96 096 96 (0.9 0.06 006 06 1.20 1 20 (1.2 0.11. 011 0.11 0.11) observed costbenefit benefit A 30 (3 4. 0. (0 m- ( 28.0 280 2 (28. 63 3 6. 117 7 11. 08 8 0.9 09 9 0.0 00 1.2 (1. 01 0.1 28. (28 1. (1 (2