ABSTRACT The marine phytoplankton community responds to latitudinal, longitudinal (coast to ocean), and vertical environmental gradients, an important subject in Oxygen minimum zones (OMZ). The phytoplankton structure and the effect of environmental gradients along the central Mexican Pacific, an area within an OMZ, were studied, especially the importance of size fractions and taxonomic groups. A combination of various methods and protocols, such as microscopic analysis, flow cytometer, and pigment analysis, were followed in this study. Oceanographic conditions included thermal gradients along the study area and unreported evidence of a weak upwelling in the southern zone (Acapulco). Vertical distribution of chlorophyll a showed subsurface maxima (SCM, 15-45 m depth) in all stations, and deeper chlorophyll-a maxima (DCM, 85-95 m depth) in more oceanic stations. Chain-forming diatoms dominated in the northern zone stations. Prochlorococcus, Synechococcus, and picoeukaryotes abundances ranged between 0.01 to 21.7 cells×104 mL−1, although most samples showed the highest contribution to biomass (47.95 µg C L−1) by picoeukaryotes. Expected tendencies of Prochlorococcus distribution were observed: highest densities coincided with the DCM and divinyl chlorophyll-a distribution at oceanic stations. Fucoxanthin had the highest concentrations, whereas fucoxanthin and zeaxanthin concentrations were higher at SCM depths. We documented the co-dominance of the pico- and microplankton: picoplankton was important at the DCM, related to oligotrophic and more stratified water column, whereas microplankton prevailed in coastal stations, with mixed water column, high nutrient concentrations, and diatoms as the dominant group. Picoeukaryotes abundances were related to the concentration of prasinoxanthin, which suggests an important mamiellophyte component not previously revealed.

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 A floristic and ultrastructural study on loricated Euglenophyta was made in several freshwater bodies from the Amazonian and Caribbean regions of Colombia. A total of 114 taxa were recorded, 93 belonged to the genus Trachelomonas Ehr., and 21 to Strombomonas Defl. From the total taxa determined, 73 were recorded for the first time for Colombia, 19 for the Amazonian and 52 for the Caribbean region. Besides 43 taxa were examined by scanning electron microscopy (SEM) and details of its ultrastructure are illustrated. Colombia 11 9 Ehr Ehr. 2 Defl determined 7 1 5 region 4 SEM (SEM illustrated

RESUMO Um estudo florístico e ultraestrutural de Euglenophyta loricata de vários corpos de água doce nas regiões amazônica e caribenha da Colômbia foi realizado. Um total de 114 táxons foi registrado, 93 pertencentes ao gênero Trachelomonas Ehr. e 21 ao Strombomonas Defl. 73 táxons foram registrados pela primeira vez na Colômbia, 19 na região amazônica e 52 na região do Caribe. Além disso, detalhes da ultraestrutura de 43 táxons foram examinados por microscopia eletrônica de varredura (SEM). realizado 11 registrado 9 Ehr 2 Defl 7 1 5 Caribe disso 4 SEM. SEM . (SEM) (SEM

Abstract This study aimed to analyze the application of the Phytoplankton Community Index-PCI and Functional Groups-FG in determining the water quality of the Guamá River (Pará, Amazônia, Brazil). Samplings occurred monthly for analyses of phytoplankton and physical and chemical parameters, for two years, at the station where water was collected for human supply consumption. Seasonality influenced electrical conductivity, total suspended solids, dissolved oxygen, transparency, winds, true color, and N-ammoniacal. The ebb tide showed high turbidity and suspended solids. The density varied seasonally with the highest values occurring in September and December (61.1 ind mL-1 and 60.2 ind mL-1, respectively). Chlorophyll-a was more elevated in December (21.0 ± 4.7 µg L-1) and chlorophyll-c higher in relation to clorophyll- b indicated the dominance of diatoms. Functional Group P prevailed in the study months. Through the PCI índex the waters of Guamá River varied from reasonable to excellent and the TSI ranged from oligo to mesotrophic. The use of Functional Groups proved to be a promising tool in the determination of water quality since it covered the most abundant species in the Environment, but the PCI is not adequate to characterize Amazonian white-waters rivers, which have diatoms as the leading dominant group. IndexPCI Index GroupsFG FG Pará, Pará (Pará Amazônia Brazil. Brazil . Brazil) parameters years consumption conductivity solids oxygen transparency winds color Nammoniacal. Nammoniacal N ammoniacal. ammoniacal N-ammoniacal 61.1 611 61 1 (61. mL1 mL mL- 602 60 2 60. mL1, 1, respectively. respectively respectively) Chlorophylla Chlorophyll 21.0 210 21 0 (21. 47 4 7 4. L1 L L-1 chlorophyllc chlorophyll c clorophyll months mesotrophic Environment whitewaters white rivers group 61. 6 (61 21. (21 L- (6 (2 (

Abstract: Aim Our goal was to relate the phytoplankton metacommunity to its possible determinants in a micro watershed: (I) determinants related to landscape-scale filtering, (II) determinants referring to local microhabitat filtering, (III) determinants referring to previous colonization, and (IV) determinants representing three different dispersal routes. Methods Eight sampling stations were selected along the Cascavel River watershed, located in the state of Paraná, Brazil. Samples were collected quarterly for three years. All phytoplankton samples were quantitatively analyzed to determine the density of the metacommunity. In addition, it was characterized the landscape in terms of land use and occupation, and environmental characterization in terms of physical and chemical variables of the water. All data underwent relevant statistical analysis, where variance partitioning was carried out using partial RDA models, with prior selection of predictor variables, to estimate the relative role of each predictor in the community. We also compared three possible dispersal routes: “Asymmetric Eigenvector Map” (AEM), “Overland” and “Watercourse”. Results It was found that the metacommunity was best explained by “asymmetric eigenvector mapping” (AEM), indicating that because it is a small spatial scale the high connectivity between the sampling stations enables species to disperse overland as well. The different filters act together and depend on rainfall variation. Besides fluctuating temporally, the influence of these mechanisms is subject to which dispersal hypothesis is being considered. Conclusions At the watershed scale, we argue that small-scale processes should be considered, since they homogenize the landscape and consequently leave the environmental gradient similar between sampling stations. In addition, the connectivity of colonization patches is essential to understand the behavior of microalgae that have a high dispersal capacity and are not restricted only to the river course. Abstract I (I landscapescale filtering II (II III (III IV (IV routes Paraná Brazil years addition occupation water analysis models community Asymmetric Map AEM, AEM , (AEM) Overland “Overland Watercourse. Watercourse . “Watercourse” asymmetric mapping well variation temporally considered smallscale course (AEM “Watercourse

Resumo: Objetivo O objetivo do trabalho foi relacionar a metacomunidade fitoplanctônica com seus possíveis determinantes em uma microbacia hidrográfica: (I) determinantes relacionados à filtragem em escala de paisagem, (II) determinantes referentes à filtragem local de micro-habitat, (III) determinantes referentes a colonização anterior e (IV) determinantes representando três diferentes rotas de dispersão. Métodos Foram selecionadas oito estações de amostragem ao longo da microbacia do Rio Cascavel, localizada no estado do Paraná, Brasil. As coletas foram realizadas trimestralmente durante três anos. Todas as amostras de fitoplâncton passaram por análise quantitativa para averiguar a densidade da metacomunidade. Além disso fizemos a caracterização da paisagem tanto o uso e ocupação do solo e caracterização ambiental quanto as variáveis físicas e químicas da água. Todos os dados passaram por análises estatísticas pertinentes, onde a partição da variância foi realizada utilizando modelos RDA parciais, com seleção prévia das variáveis preditoras, para estimar o papel relativo de cada preditor na comunidade. Ainda comparamos três possíveis rotas de dispersão: Mapa de Autovetores Assimétricos” (AEM), “Terrestre” e “Curso d´água”. Resultados Constatou-se que a metacomunidade foi mais bem explicada pelo “mapa de autovetores assimétricos” (AEM), indicando que por se tratar de uma pequena escala espacial a alta conectividade entre as estações de amostragem possibilita que as espécies se dispersem também por terra. Os diferentes filtros atuam em conjunto e dependem da variação de chuva. Além de flutuar temporalmente, a influência desses mecanismos está sujeita a qual hipótese de dispersão está sendo considerada. Conclusões Na escala da microbacia hidrográfica, argumentamos que os processos de pequena escala devem ser considerados, uma vez que homogeneízam a paisagem e, consequentemente, deixam o gradiente ambiental semelhante entre as estações de amostragem. Além disso, a conectividade das manchas de colonização é essencial para entender o comportamento das microalgas que têm alta capacidade de dispersão, não se restringindo apenas ao curso do rio. Resumo hidrográfica I (I II (II microhabitat, microhabitat micro habitat, habitat micro-habitat III (III IV (IV Cascavel Paraná Brasil anos água pertinentes parciais preditoras comunidade Assimétricos AEM, AEM , (AEM) Terrestre “Terrestre Curso d´água. dágua d´água . d d´água” Constatouse Constatou mapa assimétricos terra chuva temporalmente considerada considerados consequentemente rio (AEM

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 Nitrogen and phosphorus are essential elements for the growth and performance of organisms, and the environmental N:P ratio can determine the biomass and structure of algal communities. We investigated the effects in the N:P molar ratio changes on epipelon and phytoplankton chlorophyll-a under eutrophic conditions. An enrichment experiment was performed in open-bottom mesocosms to simulate P limitation, N limitation, and good N and P availability. Under eutrophic conditions, the combined availability of N and P enhanced phytoplankton bloom, while an increase in P limitation resulted in the loss of phytoplankton biomass. Under conditions of high P limitation, there was significantly loss of epipelon biomass. No change in the N:P ratio led to a significant increase in algal biomass in the epipelon. In conclusion, changes in the N:P molar ratio can affect the growth of phytoplankton and epipelic algae under eutrophic conditions. Our results suggest that photosynthetic biomass increase in the epipelon depends on an optimal relationship between light and P. organisms NP communities chlorophylla chlorophyll openbottom open bottom bloom conclusion

RESUMO Nitrogênio e o fósforo são elementos essenciais para o crescimento e desempenho dos organismos e a razão N:P ambiental pode determinar a biomassa e estrutura das comunidades algais. Nós investigamos os efeitos de mudanças na razão molar N:P sobre a clorofila-a do epipelon e fitoplâncton em condições eutróficas. Em mesocosmos de fundo aberto, realizou-se um experimento de enriquecimento para simular a limitação de P, limitação de N e boa disponibilidade de N e P. Em condições eutróficas, a disponibilidade combinada de N e P intensificou a floração do fitoplâncton, enquanto um aumento na limitação de P resultou em perda na biomassa do fitoplâncton. Sob condições de alta limitação de P, houve perda significativa da biomassa do epipélon. Nenhuma mudança na relação N:P levou a um aumento significativo na biomassa algal no epipélon. Em conclusão, mudanças na razão molar N:P podem afetar o crescimento do fitoplâncton e algas epipélicas em condições eutróficas. Nossos resultados sugerem que um aumento na biomassa fotossintética no epipélon depende de uma relação ótima entre luz e disponibilidade de P. NP algais clorofilaa clorofila eutróficas aberto realizouse realizou se conclusão

Abstract The littoral zone is an essential compartment for lake biota because of its high productivity and diversity. Moreover, phytoplankton is expected to have non-equilibrium dynamics on it. The study’s aimed to explore phytoplankton in the littoral zone of a shallow lake over a short-term scale. Daily sampling was conducted for 25 consecutive summer days in 2016, at two marginal points of a continuously warm, polymictic, and oligo-mesotrophic subtropical lake (Lake Mangueira, Brazil). Cyanobacteria and Chlorophyta contributed 86% of total biomass. We observed high variability in phytoplankton structure, with species turnover over diel cycles. Redundancy analysis indicated spatial differentiation for phytoplankton structure in relation to abiotic conditions. Nutrient dynamics and humic substances were significant drivers for phytoplankton variability. Phytoplankton was positively correlated with SRP and negatively with humic substances. Our results showed a non- equilibrium state for the littoral phytoplankton of Lake Mangueira, given the high variability of abiotic conditions, even at short distances. Due to its high temporal and spatial variability, the littoralzone seems to contribute to the recruitment and maintenance of phytoplankton biodiversity in shallow lakes. Further studies should consider the functional attributes of species and the complex biological interactions of phytoplankton and macrophytes along the littoral zone. diversity Moreover nonequilibrium non it studys study s shortterm term scale 2 2016 warm polymictic oligomesotrophic oligo mesotrophic Mangueira Brazil. Brazil . Brazil) 86 biomass cycles conditions distances lakes 201 8 20

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

Resumo Os padrões espaciais e temporais e a dinâmica da estrutura da comunidade biológica podem ser compreendidos por meio das lentes da teoria de metacomunidades, no qual o efeito dos processos locais (processos determinísticos, teoria do nicho ecológico) e regionais (processos estocásticos, teoria neutra) são destacados como os principais preditores do fitoplâncton. O objetivo deste trabalho foi avaliar o efeito de preditores ambientais locais, espaciais e de paisagem sobre a comunidade fitoplanctônica em lagos da planície de inundação do Rio Araguaia. Avaliamos as seguintes questões: (i) Qual é a importância específica das características físicas e químicas da água (preditores ambientais locais), dos processos dispersivos (preditores espaciais) e do uso e ocupação do solo (preditores de paisagem) na estrutura da metacomunidade fitoplanctônica, tanto para grupos taxonômicos quanto funcionais? (ii) O tamanho do buffer usado na medição do uso e da ocupação do solo ao redor das unidades de amostragem mostra diferenças na previsão da comunidade fitoplanctônica? Todos os preditores explicaram a estrutura do fitoplâncton, mas os espaciais foram os mais importantes. Os buffers mostraram diferentes habilidades preditivas, com a classificação taxonômica sendo relacionada a tamanhos maiores de buffers e grupos funcionais, o oposto. A grande influência dos preditores espaciais pode ser explicada pela dinâmica fonte-sumidouro, em que a dispersão é tão forte que pode diminuir os efeitos dos preditores locais e garantir um grande fluxo de organismos para as comunidades de sumidouros. Em conclusão, foi demonstrado que os processos dispersivos influenciam fortemente a estruturação espacial da metacomunidade de fitoplâncton e destacamos a necessidade de considerar o tamanho dos buffers ao avaliar o efeito da paisagem sobre as comunidades de fitoplâncton. metacomunidades determinísticos ecológico estocásticos neutra Araguaia questões i (i , locais) funcionais ii (ii importantes preditivas oposto fontesumidouro, fontesumidouro fonte sumidouro, sumidouro fonte-sumidouro sumidouros conclusão

Abstract The spatial and temporal patterns and dynamics of biological community structure can be better understood through the lens of metacommunity theory, in which the effect of local (deterministic processes, ecological niche theory) and regional (stochastic processes, neutral theory) processes are evaluated as the main predictors of phytoplankton. The objective of this paper was to evaluate the effect of local environmental characteristics, spatial, and landscape predictors on the phytoplankton community in lakes of the Araguaia River floodplain. We evaluated the following questions: (i) What is the specific importance of physical and chemical water characteristics (local environmental predictors), dispersive processes (spatial predictors), and land use and occupancy (landscape predictors) in the phytoplankton metacommunity structure, both for taxonomic and functional groups? (ii) Does the buffer size used in land use and land cover measurement around the sampling units show differences in phytoplankton community prediction? All the predictors could explain the phytoplankton structure but the spatial were the most important. The buffers showed different predictive abilities, with taxonomic classification being related to larger sizes of buffers and functional groups the opposite. The great influence of spatial predictors can be explained by source-sink dynamics, where dispersal is so strong that it can diminish the effects of local predictors and guarantee a large flux of organisms to sink communities. In conclusion, dispersive processes have been shown to strongly influence the spatial structuring of the phytoplankton metacommunity and we highlight the need to consider buffers’ size when assessing the landscape’s effect on phytoplankton communities. theory deterministic stochastic floodplain questions i (i predictors, , ii (ii prediction important abilities opposite sourcesink source communities conclusion landscapes s

Resumo A utilização de índices é indicada no monitoramento e avaliação permanente de ecossistemas aquáticos, pois eles sintetizam a complexidade técnica do resultado das variáveis e traduzem esses resultados em classes de qualidade, refletindo ações implementadas e apontam caminhos para a recuperação e conservação de recursos. Índices do estado trófico do ambiente fornecem uma visão sobre como nutrientes, disponibilidade de luz e outros fatores estimulam o desenvolvimento da biomassa algal contribui para o aumento do enriquecimento da condição dos sistemas aquáticos. O Índice do Estado Trófico (IET) Lamparelli diferencia ambientes lênticos (menor produtividade fitoplanctônica) e lóticos (maiores concentrações de Fósforo e menores concentrações de Clorofila-a). O Índice de Proteção da Vida Aquática (IVA) reflete a qualidade da água com base no estado trófico do ambiente, determina o grau de toxicidade para a biota e ainda indica deficiência em variáveis e condições essenciais para a proteção da vida aquática. Os índices foram aplicados a uma longa série de dados no monitoramento do Reservatório Guarapiranga, um reservatório urbano, localizado no Estado de São Paulo, sudeste do Brasil, que sofre com ocupação urbana em seu entorno e aporte de efluentes domésticos. A avaliação da série temporal de 1978 a 2021 com esses índices mostrou piora na condição trófica e de preservação da vida aquática no reservatório e em um dos tributários. Considerando que a avaliação conjunta dos dois índices fornece um enfoque de conservação ambiental, sua utilização em longo prazo refletiu alterações e impactos ao ambiente, mostrando ainda os locais mais conservados. Os resultados mostraram que os dois índices são indicados para aplicação em uma rede básica em ambientes subtropicais, aptos a indicar locais para aprimoramento do monitoramento e sensíveis às alterações ambientais. aquáticos recursos nutrientes IET (IET menor fitoplanctônica maiores Clorofilaa. Clorofilaa Clorofila . Clorofila-a) IVA (IVA Guarapiranga urbano Paulo Brasil domésticos 197 202 tributários ambiental conservados subtropicais ambientais Clorofila-a 19 20 1 2

Abstract The use of indices is recommended for continuous monitoring and assessment of aquatic ecosystems, as they summarize the technical complexity of the results of multiple analyzes performed and translate these results into quality classes that reflect the actions taken and indicate ways to recover and conserve the resources. Environmental trophic state indices provide information on how nutrients, light availability and other factors promote the development of algal biomass and contribute to increased enrichment status of aquatic systems. Lamparelli's Trophic State Index (TSI) distinguishes between lentic (lower phytoplankton productivity) and lotic (higher phosphorus concentrations and lower chlorophyll-a concentrations) environments. The Aquatic Life Protection Index (ALPI) reflects water quality based on the trophic state of the environment, determines the degree of toxicity to biota and indicates deficiencies in variables and conditions essential for the protection of aquatic life. The indices were applied to a long data series to monitor the Guarapiranga Reservoir, an urban reservoir in the state of São Paulo in southeastern Brazil, which suffers from the urbanization of its surroundings and the discharge of domestic wastewater. The evaluation of the time series from 1978 to 2021 using these indices showed a deterioration in the trophic status and conservation of aquatic life in the reservoir and in one of its tributaries. Considering that the joint assessment of the two indices provides an approach to environmental conservation, their long-term use reflected changes and impacts on the environment and showed the best-preserved sites. Both indices are suitable for application in a baseline network in subtropical environments. They can pinpoint locations for better monitoring and are sensitive to environmental changes. ecosystems resources nutrients systems Lamparellis Lamparelli s TSI (TSI productivity higher chlorophylla chlorophyll environments ALPI (ALPI Reservoir Brazil wastewater 197 202 tributaries longterm term bestpreserved best preserved sites 19 20 1 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 Objetivo O conhecimento das características hidrológicas é essencial para a compreensão dos processos ecológicos nas planícies de inundação, o que pode subsidiar um gerenciamento sustentável. Nós avaliamos as variações ambientais em uma lagoa rasa de planície de inundação, localizada na Chapada Diamantina, Andaraí, Bahia. Nosso objetivo foi identificar as fases do ciclo hidrológico e sua influência na densidade de desmídias, um grupo de algas conhecido por seu potencial como bioindicador de mudanças tróficas. Métodos Amostragens bimestrais foram realizadas em quatro pontos da lagoa. Foram determinadas as variáveis abióticas (temperatura, condutividade, pH, transparência, profundidade, oxigênio dissolvido, concentração de nutrientes totais e dissolvidos) e bióticas (cobertura de macrófitas, clorofila-a do fitoplâncton e densidade de desmídias). O Índice de Estado Trófico (IET) foi calculado com base na clorofila-a do fitoplâncton e concentração de fósforo total. Resultados A lagoa foi caracterizada por águas bem oxigenadas, levemente ácidas e com baixa condutividade elétrica. De acordo com o IET, a lagoa variou de mesotrófica a hipereutrófica durante o período de estudo. Os meses mais secos (agosto e outubro) foram marcados pela elevada transparência, baixa profundidade, concentração de nitrogênio e cobertura de macrófitas. O maior valor de precipitação acumulada foi registrado em dezembro, quando houve um aumento da profundidade e a diminuição da condutividade elétrica e concentração de PT. Evidenciou-se ocorrência de duas fases limnológicas, as quais foram determinadas pela profundidade e concentração de nutrientes. A maior abundância de desmídias ocorreu no final da época chuvosa, quando a disponibilidade de nutrientes e pH eram elevados e a profundidade reduzida. Conclusões Nossos resultados sugerem que o pulso hidrológico foi o fator determinante da condição limnológica e que, juntamente com as características morfológicas das macrófitas, tenha influenciado na abundância e distribuição das desmídias em uma lagoa de planície de inundação no semiárido. sustentável Diamantina Andaraí Bahia tróficas temperatura, temperatura (temperatura transparência dissolvido dissolvidos macrófitas clorofilaa clorofila desmídias. . desmídias) IET (IET total oxigenadas estudo agosto outubro dezembro PT Evidenciouse Evidenciou se limnológicas chuvosa reduzida semiárido

Abstract Aim Knowledge of hydrological characteristics is essential for understanding ecological processes in floodplains, which can support sustainable management. We evaluated environmental variations in a shallow floodplain lagoon located in the Chapada Diamantina, Andaraí, Bahia. We aim to identify phases of the hydrologic cycle and their influence on desmid density, which is a group of algae known for its potential as bioindicator of trophic changes. Methods Bimonthly samplings were performed at four points in the lagoon. Abiotic (temperature, conductivity, pH, transparency, depth, dissolved oxygen, total and dissolved nutrients) and biotic (macrophyte cover, phytoplankton chlorophyll-a, and desmid density) variables were determined. The Trophic State Index (TSI) was calculated based on phytoplankton chlorophyll-a, and total phosphorus concentration. Results The lagoon was characterized by well-oxygenated, slightly acidic waters with low electrical conductivity. According to the TSI, the lagoon varied from mesotrophic to hypereutrophic during the study period. The driest months (August and October) were marked by high water transparency, low depth, nitrogen concentration, and macrophyte coverage. The highest value of accumulated precipitation was registered in December, when there was an increase in depth and a decrease in electrical conductivity and PT concentration. Two phases of the hydrologic cycle were evidenced and determined by the depth and nutrient concentrations. The highest abundance of desmids occurred at the end of the rainy season when the nutrient availability and pH were higher, and the depth was reduced. Conclusions Our results suggest that the flood pulse was the determining factor of the local environmental conditions and that, together with the macrophyte morphological traits, it influenced desmid abundance and distribution in a floodplain lagoon in the semiarid region. floodplains management Diamantina Andaraí Bahia density changes temperature, temperature (temperature transparency oxygen nutrients cover chlorophylla, chlorophylla chlorophyll a, chlorophyll-a TSI (TSI concentration welloxygenated, welloxygenated well oxygenated, oxygenated well-oxygenated period August October coverage December concentrations higher reduced traits region

ABSTRACT The disposal of domestic effluents without an adequate treatment may increase nitrogen and phosphorus levels in natural water bodies. Bioremediation using microalgae is one of the solutions for treating effluents before disposal. We tested the effect of Scenedesmus acuminatus, Chlorella vulgaris and Planktothrix isothrix, as well as the effect of water dilution, on the nutrient concentration in water eutrophicated by domestic effluent in an urban lake in the Brazilian Amazon. We inoculated the three species in monoculture in undiluted water (PW0), and 50% (PW50) and 90% (PW90) diluted water. The experiment lasted 10 days and every 24 hours we removed a bottle of each treatment for nutrient analysis. The three species were equally efficient in removing ammonia in PW0. Nitrate removal rate was highest for Chlorella vulgaris in PW0, and higher for C. vulgaris and P. isothrix in PW50 and PW90. Orthophosphate removal efficiency was higher for S. acuminatus and C. vulgaris in PW0, equally efficient for the three species in PW50, and higher for C. vulgaris and P. isothrix in PW90. We concluded that the three species of microalgae tested are efficient in removing ammonia. Scenedesmus acuminatus was not an ideal species for nitrate removal. Planktothrix isothrix was efficient in removing nutrients when domestic wastewater is diluted. Chlorella vulgaris was efficient in removing nutrients from domestic wastewater whether diluted or not. bodies dilution Amazon PW0 PW , (PW0) 50 (PW50 90 PW90 (PW90 1 2 analysis C P PW5 S (PW0 5 (PW5 9 PW9 (PW9 (PW

RESUMO O descarte de efluentes domésticos sem tratamento adequado pode elevar os níveis de nitrogênio e fósforo em corpos hídricos naturais. A biorremediação com o uso de microalgas é uma solução para o tratamento de efluentes antes do descarte. Nós testamos o efeito de Scenedesmus acuminatus, Chlorella vulgaris e Planktothrix isothrix e o efeito da diluição da água sobre a concentração de nutrientes da água eutrofizada por efluente doméstico de um lago urbano na Amazônia brasileira. Inoculamos as três espécies em monocultura em água não diluída (PW0) e diluída a 50% (PW50) e 90% (PW90). O experimento durou 10 dias e a cada 24 horas retiramos um recipiente de cada tratamento para análise de nutrientes. As três espécies foram igualmente eficientes na remoção de amônia em PW0. A eficiência de remoção de nitrato foi mais alta com C. vulgaris em PW0, e mais alta com C. vulgaris e P. isothrix em PW50 e PW90. A eficiência de remoção de ortofosfato foi mais alta com S. acuminatus e C. vulgaris em PW0, igualmente eficiente para as três espécies em PW50, e mais alta com C. vulgaris e P. isothrix em PW90. Concluímos que as três espécies de microalgas testadas são eficientes na remoção da amônia. Scenedesmus acuminatus não foi ideal para a remoção de nitrato. Planktothrix isothrix foi eficiente na remoção de nutrientes quando a água residual doméstica é diluída. Chlorella vulgaris foi eficiente na remoção de nutrientes de águas residuais domésticas, estando diluída ou não. naturais brasileira PW0 PW (PW0 50 (PW50 90 PW90 . (PW90) 1 2 C P PW5 S domésticas (PW 5 (PW5 9 PW9 (PW90 (PW9

Abstract: Aim To explore the short-term effects of rainfall events on the biomass, density, and richness of the phytoplankton community during dry and rainy periods, as well as on the selection and response of Morphology-Based Functional Groups (MBFG). Methods The phytoplankton community and abiotic environmental variables were sampled over a short period in a subtropical urban lake during the dry and rainy seasons (2018-2019). Generalized Linear Models (GLMs) were generated to analyze the relationship between phytoplankton biovolume, density, and richness with abiotic variables. The predictability of phytoplankton functional groups was assessed using Redundancy Analysis (RDA). Results There was an increase in the density and biovolume of the phytoplankton community during the rainy period. Species richness decreased with increased rainfall. The lake exhibited a high dominance of Cyanobacteria (MBFG VIII), mainly represented by Raphidiopsis raciborskii (Woloszynska) Aguilera in both periods studied. Conclusions We found evidence supporting the hypothesis that rainfall events increase the density and biovolume of phytoplankton. Morphology-based functional groups served as efficient indicators of the lake's environmental conditions. Abstract shortterm term biomass MorphologyBased Morphology Based MBFG. MBFG . (MBFG) 20182019. 20182019 2018 2019 (2018-2019) GLMs (GLMs RDA. RDA (RDA) VIII, VIII , VIII) Woloszynska (Woloszynska studied Morphologybased based lakes s conditions 2018201 201 (2018-2019 (RDA 201820 20 (2018-201 20182 2 (2018-20 (2018-2 (2018- (2018 (201 (20 (2 (

Resumo: Objetivo Explorar os efeitos a curto prazo de eventos de chuva na biomassa, densidade e riqueza da comunidade fitoplanctônica durante os períodos seco e chuvoso, bem como na seleção e resposta de Grupos Funcionais Baseados na Morfologia (MBFG). Métodos A comunidade fitoplanctônica e as variáveis ambientais abióticas foram amostradas em um curto período em um lago urbano subtropical durante as estações seca e chuvosa (2018-2019). Modelos Lineares Generalizados (GLMs) foram gerados para analisar a relação entre o biovolume, a densidade e a riqueza do fitoplâncton com as variáveis abióticas. A previsibilidade dos grupos funcionais de fitoplâncton foi avaliada usando Análise de Redundância (RDA). Resultados Houve um aumento da densidade e do biovolume da comunidade fitoplanctônica no período chuvoso. A riqueza de espécies diminuiu com o aumento da pluviosidade. O lago exibiu uma alta dominância de Cyanobacteria (MBFG VIII), principalmente representadas por Raphidiopsis raciborskii (Woloszynska) Aguilera nos dois períodos estudados. Conclusões Encontramos evidências que sustentam a hipótese de que eventos de chuva aumentam a densidade e o biovolume do fitoplâncton. Os grupos funcionais baseados na morfologia serviram como indicadores eficientes das condições ambientais do lago. Resumo biomassa chuvoso MBFG. MBFG . (MBFG) 20182019. 20182019 2018 2019 (2018-2019) GLMs (GLMs RDA. RDA (RDA) pluviosidade VIII, VIII , VIII) Woloszynska (Woloszynska estudados 2018201 201 (2018-2019 (RDA 201820 20 (2018-201 20182 2 (2018-20 (2018-2 (2018- (2018 (201 (20 (2 (