Misión: El Acta Limnologica Brasiliensia es la revista oficial de la Asociación Brasileña de Limnología (ABLimno) cuyo obetivo es publicar trabajos originales en Limnología, incluyendo los aspectos físicos, químicos y biológicos de la Ciencia Ecología de Aguas Continentales.
Brazilian Association of Limnology - ABLimno
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First record of Ceratium furcoides (Levander) Langhans 1925, an invasive dinoflagellate, in a subtropical freshwater coastal lake in Southern Brazil
Ceratium is a planktonic dinoflagellate commonly found in continental waters of temperate regions. In recent decades, Ceratium species have been recorded in tropical water bodies, where they are considered invasive species. These organisms exhibit high dispersal capacity, adaptability, and rapid colonization of new environments. This is the first report of this dinoflagellate in the main lagoon of Florianópolis Island, Peri Lake—a freshwater coastal lake used for public water supply. To identify the species, several Ceratium specimens were analyzed to examine the arrangement of apical plates, a key characteristic for distinguishing Ceratium furcoides from Ceratium hirundinella. The occurrence of Ceratium furcoides was recorded during monthly analyses of the zooplankton community in Peri Lake. Ceratium furcoides is often associated with significant ecological impacts, promoting changes in aquatic communities and contributing to the degradation of water quality. Its uncontrolled growth can affect the trophic structure of ecosystems, influence nutrient availability and compromise local biodiversity. Monitoring and correlation studies between this dinoflagellate and the lake limnological variables are essential to understanding the key factors contributing to the proliferation of Ceratium furcoides and to identifying measures to mitigate potential ecological, social, and economic impacts.
Notas científicas (Short research notes)
Derechos de autor 2025 http://creativecommons.org/licenses/by-nc/4.0
The Caraça Sanctuary as an ecological reference area for water quality in the Upper Rio Doce basin
Aim: Our objective was to evaluate the degree to which reference sites in the Caraça Sanctuary safeguard surface water quality and physical habitat structure. We expected that outside the Caraça Sanctuary, human pressures such as urbanization, untreated domestic sewage discharges, and riparian deforestation would lead to poorer water quality and physical habitat structure. Our hypothesis was that the Caraça Sanctuary preserves streams with high physical habitat condition and water quality. Methods: Data were collected from 28 stream sites, assessing 22 physical habitat structure and 12 water quality parameters. Additionally, land use and land cover in the upstream microbasin were analyzed, and a rapid assessment protocol for riparian vegetation and physical habitat diversity was applied at each site. A Principal Component Analyses (PCA) was used to identify the most important variables explaining variation among sites and to differentiate sites inside and outside the sanctuary. Two PCA biplots were built, one for the habitat structure data and one for the water quality data. Results: The first two PCA axes explained 50% of the variability for physical habitat structure and 48% for water quality, which was most affected at sites near urban and mining areas. Conclusion: The results indicate that the Caraça Sanctuary offers a useful reference area for the upper Rio Doce basin.
Artículos originales (Primary research papers)
Derechos de autor 2026 http://creativecommons.org/licenses/by-nc/4.0
Effects of freezing on the carbon and nitrogen stable isotopic compositions of fish tissues
Stable isotope analysis is a vital tool for elucidating nutrient flow within food chains. Studies utilizing this methodology must consider potential variables that could influence the δ13C and δ15N values of the species being examined. One such variable is the preservation of samples in a frozen state during field studies, particularly when immediate sample processing is not possible. OBJECTIVE: The objective of this study is to investigate the long-term effects of freeze-thaw cycles on the δ13C, δ15N, and C:N ratios in biological samples from three fish species. METHODS: Tissues from three estuarine fish species (Cathorops spixii, Genidens barbus and Chloroscombrus chrysurus) were frozen and subjected to thawing at intervals of 1, 2, 7, 15, 30, 90, and 180 days for sample collection aimed at isotopic determination. MAIN RESULTS: The discrepancies observed in this study were related to the δ13C and C:N ratios in the skin samples of C. spixii and G. barbus, as well as the muscle samples of C. chrysurus. These variations seem to be more closely linked to the potential volatility of the 12C isotope within the samples, resulting in δ13C enrichment and an increase in C:N values. CONCLUSIONS: This suggests that these changes are not solely attributable to the freeze-thaw process, but may also be influenced by other factors within the samples. Our findings suggest that this process significantly influences the δ13C and C:N ratios of skin and muscle tissues. Additionally, we recommend rapid sample processing to mitigate the effects of freezing and thawing. Key words: Marine fish, experiment, preservation of sample, ratios, isotopes.
Quantification and analysis of emerging threats studies on freshwater zooplankton (Copepoda, Cladocera and Rotifera) in Brazil from 2014 to 2023
Objective: This study aimed to quantify and analyze research on emerging threats to freshwater zooplankton (Copepoda, Cladocera, and Rotifera) in Brazil, published between 2014 and 2023. The primary focus was to systematically identify the main environmental stressors studied, knowledge gaps, and methodological trends employed in the research. Method: The analysis was conducted through a systematic literature review in the Web of Science, Scopus, and Scielo databases, using specific terms related to zooplankton and emerging threats. Peer-reviewed articles published within the defined period were included. Each study was categorized based on the type of stressor analyzed (e.g., climate change, microplastic pollution, biological invasions), taxonomic groups addressed, and methodological approaches employed. Results: A total of 50 relevant articles were identified, most of which focused on multiple zooplankton groups (e.g., Cladocera and Rotifera) and utilized laboratory experiments or field studies as their main methodologies. The most analyzed stressors were biological invasions (30%) and climate change (22%), followed by harmful algal blooms and emerging contaminants. Conclusions: The review highlights the need to expand studies on the combined impacts of emerging stressors on zooplankton and to integrate more robust methodologies that better reflect natural conditions.
Avaliando o potencial de crescimento de cianobactérias nocivas em ambientes aquáticos em cenários de mudanças climáticas
Os ambientes neotropicais de água doce enfrentam ameaças severas devido às mudanças climáticas, que representam riscos significativos para a segurança hídrica global. Prevê-se que eventos hidrológicos extremos, como chuvas torrenciais e secas prolongadas, se tornem mais frequentes e intensos. Essas condições aumentarão o tempo de residência de nutrientes, especialmente fósforo e nitrogênio, favorecendo a proliferação de cianobactérias tóxicas (cyanoHABs). Além disso, as cianobactérias possuem uma vantagem competitiva em ambientes com poucos nutrientes e alta concentração de CO2. Isso agrava os desafios ecológicos e de saúde pública, pois essas cianobactérias podem causar florações de algas nocivas que contaminam o abastecimento de água e perturbam os ecossistemas aquáticos. Objetivos: Nosso objetivo é avaliar a vulnerabilidade de regiões específicas à prevalência de três espécies representativas de cyanoHABs. Métodos: utilizamos ferramentas de modelagem de nicho ecológico (ENMs) baseadas em registros de ocorrência de bancos de dados disponíveis para prever a distribuição das três espécies representativas de cyanoHABs mais frequentes. Empregamos três métodos de modelagem diferentes: modelos lineares generalizados (GLM), modelos gaussianos (GAU) e entropia máxima (MXS). Resultados: Nos resultados dos ENMs, as distribuições para o cenário atual foram consistentes com as distribuições conhecidas. Identificamos novas áreas de pesquisa para o cenário futuro. Conclusões: As variações que observamos indicam que os impactos das mudanças climáticas variam regionalmente, afetando a adequação futura das cianobactérias. A curto prazo, elas podem manter uma adequação estável, mas a longo prazo, espera-se uma redução significativa devido às altas temperaturas. Isso destaca a necessidade urgente de ações mitigadoras para proteger os ecossistemas aquáticos.
Distribution of functional feeding groups of aquatic and semi-aquatic insects on macrophytes in an artificial lentic system in southern Brazil
Aim: To understand the distribution of functional feeding groups (FFGs) of aquatic and semiaquatic insects associated with macrophytes in a lentic system, we tested whether the abundance of FFGs varied between sampling periods and analyzed the variation of environmental variables related to FFGs composition. Methods: We assessed the distribution of FFGs in four collections during the months of March, May, July, and September 2022, covering different seasons. The sampling locations were in three sections of Lago da Ponte, located at the Porto Alegre Botanical Garden, Southern Brazil. The relative abundances (%) were calculated for each family and FFGs per period. In this study, each seasonal collection period was considered a sample, and the three points of the lake served as subsamples. A Principal Component Analysis (PCA) and Permutational Multivariate Analysis of Variance (PERMANOVA) were applied to evaluate the variation of environmental variables throughout the study. To verify the significance of variation in FFGs distribution across the sampling periods, a Chi-Square test (χ²) was performed. Results: The PCA on two axes explained 90.47% of the variation; the variables that contributed most to the first axis were temperature, pH, and dissolved oxygen, with positive correlations, while turbidity was the main contributor to the second axis, with a negative correlation. The χ² test confirmed significant differences in FFG abundances across periods. We collected 4,872 specimens, representing 24 families distributed across five orders. Collector-gatherers were the most abundant FFGs in the study (N=3,126) and most prevalent in autumn (N=899), followed by predators (N=1,385) most abundant in summer (N=582), and collector-filterers (N=359) most abundant in summer (N=158). Conclusions: The association with macrophytes is essential because they are complex mesohabitats, containing a diverse community of FFGs in different seasons, and the variation in environmental conditions can affect the availability of food and refuge. Keywords: aquatic macroinvertebrates; aquatic plant; lake; feeding habit.
A record of Pughead condition in Satanoperca jurupari (Heckel 1840) (Teleostei: Cichlidae) from the Lower Tocantins River Basin
The Pughead condition is an abnormality of the upper jaw that results in a shortening of the upper jaw about the lower jaw and is commonly reported in marine species. Here, we present this deformity in a species of Demon eartheater, Satanoperca jurupari from the Lower Tocantins River. We observed that the upper jaw, the suspensory and the anterior portion of the neurocranium are the most affected bone structures. Regarding the causes of this abnormality, the constant pollution by agrochemicals used in the Palm monoculture in areas close to where the specimen was collected may be inducing this abnormality.
Coordinated in situ lake sampling concurrent with satellite acquisition days provides a mechanism for addressing data scarcity: A case study from Lake Yojoa, Honduras
Abstract: Remote sensing is a powerful tool for expanding the temporal and spatial coverage of data collection in inland aquatic systems. Aim: In this study, we present the results of a project which used Landsat Collection 2 Surface Reflectance data and European Centre for Medium-Range Weather Forecasts (ECMWF) Reanalysis v5 (ERA5) data to develop a machine learning model to estimate Secchi depth at Lake Yojoa, Honduras. Methods: Satellite remote sensing data obtained within a five-day window of an in situ measurement were matched with in situ Secchi depth measurements and were partitioned into train-test-validate data sets for model development. Results: The machine learning model had good (R2= 0.62) agreement and reasonable uncertainty (MAE = 0.61 m) between remotely estimated and in situ observed Secchi depth. Application of the machine learning model increased the monitoring record of Lake Yojoa from 6 years of measured data to a 23-year record. Conclusions: This model demonstrates the utility of coordinating in situ sampling schedules of short-term research projects with satellite imagery acquisition schedules in order to increase the temporal coverage of remote sensing derived estimates of water quality in understudied lakes.
Características de História de Vida da tuvira Eigenmannia desantanai (Gymnotiformes: Sternopygidae) no Pantanal Sul, Brasil
Objetivo: Este estudo investigou características de história de vida de Eigenmannia desantanai no Pantanal Sul. Métodos: Os peixes foram coletados sob bancos de macrófitas aquáticas utilizando redes de arrasto e peneiras, com malha de 2 mm, nos rios Paraguai e Amonguijá entre fevereiro de 2009 e janeiro de 2011. Resultados: Um total de 484 indivíduos foi amostrado, incluindo 351 fêmeas, 113 machos e 20 indivíduos de sexo indeterminado. As fêmeas predominaram na população (3,1:1) e não foi observada diferença significativa na distribuição do peso total e comprimento padrão entre os sexos. Ambos os sexos apresentaram crescimento alométrico negativo. As fêmeas atingiram a maturidade sexual com comprimento padrão estimado em 63,06 mm, enquanto os machos em 59,58 mm. A fecundidade absoluta média foi de 305,3 ovócitos (fecundidade relativa média = 0,17), sem correlação significativa com o peso total ou o comprimento padrão das fêmeas. A distribuição da frequência do diâmetro dos ovócitos indicou desova parcelada. As fêmeas tiveram um período reprodutivo prolongado, com dois períodos com valores elevados de Índice Gonadossomático (IGS), sendo o primeiro de janeiro a abril e o segundo incluindo junho, agosto e setembro. O IGS foi correlacionado com o nível do rio e com a temperatura. Em contrapartida, os machos se reproduziram durante o ano todo, sem influência de variáveis ambientais. Conclusões: Os resultados indicam que E. desantanai responde às condições ambientais imediatas e demonstra um alto investimento reprodutivo com um período reprodutivo prolongado. Apresentaram picos de reprodução nos meses que correspondem ao período hidrológico de enchente e cheia, associado à temperaturas elevadas ou em elevação. Além disso, a espécie apresenta baixa fecundidade, desova parcelada e um longo período reprodutivo, caracterizando-se como uma estrategista de equilíbrio
Contribución de los vectores biológicos animales a la dispersión y colonización de amebas testadas (Protista, Amebozoa) en ecosistemas de agua dulce.
Objetivo: El presente trabajo tuvo como objetivo comprender cómo las amebas testadas se propagan en un nuevo ecosistema, evaluando su potencial de dispersión en agua dulce. Métodos: En este contexto, realizamos un estudio de campo durante 33 días entre julio y agosto de 2018. El estudio incluyó cuatro enfoques diferentes: (i) un grupo control expuesto exclusivamente al viento, (ii) adición de propágulos dispersos por Odonata ( insectos acuáticos), (iii) adición de propágulos dispersos por anfibios y (iv) adición combinada de propágulos de ambos animales. El objetivo era evaluar la influencia de estos vectores en la dispersión de las amebas analizadas. Resultados: Detectamos un total de 13 especies de amebas analizadas. En términos de riqueza de especies, observamos un aumento constante durante todo el período experimental. En términos de abundancia se observó una tendencia similar, con valores significativos en el último periodo de muestreo y mayores diferencias en el tratamiento de todos los vectores, lo que indica una posible colonización progresiva de estos organismos en el nuevo medio acuático. En cuanto a la composición de las amebas probadas, no detectamos diferencias significativas entre tratamientos en cada período ni entre diferentes tratamientos a lo largo del experimento. Conclusiones: Estos resultados demuestran la importancia de los vectores animales en el transporte de quistes de amebas probados y contribuyen a la dispersión y estructuración de estos organismos.
Revisão do biomonitoramento de metais em rios utilizando girinos de rã-touro: um estudo de aplicabilidade de animais expostos ao rio Sorocaba
Aim: In this study, the recent bibliography on the use of the bullfrog species (Aquarana catesbeiana, Shaw, 1802) as an environmental bioindicator of pollution was verified, and the total concentration of metals in the skin of bullfrog tadpoles exposed to the waters of the Sorocaba River was evaluated in order to analyze the potential use of the tissue as a tool for environmental biomonitoring and to verify the disponibility of metals in the Sorocaba River to animals. Methods: The recent bibliography was evaluated through the Scopus and Pubmed platforms using the terms ¨Lithobates catesbeianus biomarkers¨ and ¨Rana catesbeiana biomarkers¨. Tadpoles were exposed for 96 hours to the waters of 2 points of the Sorocaba River, with the point Ibiúna (PI) representing the source of the river Sorocaba and the point Ituparanga Reservoir (PIR) representing an important point of water supply to region of the city of Sorocaba-SP and using contaminant-free deionized water as a control. The evaluation of the concentration of metals Ba, Cu, Mn, Sr and Zn in skin samples (n=30) was carried out after digestion of the samples in a closed system using HNO3 and HCl and determination in Microwave Plasma Atomic Emission Spectrometer (MP-AES). Results: The review of bibliographical production over the last 10 years resulted in 35 articles on the topic, where metals were the second most studied contaminant using this species (around 34% of articles), behind only agricultural pesticides (around 43% of articles ). The concentration of Ba and Zn metals in the group PI varied in relation to the control group, and the concentration of Mn in the PIR group varied in relation to the control group and in relation to the group exposed to the waters from group PI. For the metals Cu and Sr there was no significant variation between the groups. Conclusions: The existing literature demonstrates the ability to use various tissues from bullfrog tadpoles as environmental bioindicators. An increase in Ba (12%) and Mn (54%) was identified in the PIR group in relation to the PI group in the tadpoles' skin. For the metals Cu, Sr and Zn there was no difference between the groups. As, Cd, Co, Mo, Ni and Pb had results below the limit of quantification in the groups studied. The increased concentration of Mn in the skin of bullfrog tadpoles exposed to the waters of the PIR in relation to the group PI may indicate the accumulation of this metal, pointing to a worsening of water quality in relation to the initial point of the river's course.
Obituário: Claudio Gilberto Froehlich (1927-2023): Um mentor para múltiplas gerações de pesquisadores em biodiversidade
O Prof. Claudio Gilberto Froehlich, um inspirador zoólogo e limnólogo da Universidade de São Paulo (USP, Brasil), faleceu em 27 de novembro de 2023. Ele começou sua carreira em 1950 e desde então tem contribuído continuamente para uma melhor compreensão da biodiversidade neotropical. Aqui, apresentamos sua vida acadêmica e suas contribuições para a ciência e formação de novos pesquisadores.
Aquatic macrophytes in Amazon: review, knowledge and gaps
Objetivo: A região amazônica apresenta peculiaridades em sua hidrologia e vegetação, essenciais para o equilíbrio climático. Por esta razão, a Amazônia necessita de uma melhor amostragem de sua biodiversidade, aumentando assim o conhecimento dos organismos presentes nesta área. Neste estudo gostaríamos de avaliar os avanços nas pesquisas de teorias ecológicas e verificar as etapas da pesquisa da biodiversidade de macrófitas na Amazônia. Métodos: Foram utilizadas bases de dados disponíveis na Web of Science e Scopus. As palavras-chave utilizadas para a busca foram: amazônia, macrófitas e planta aquática. O período de pesquisa designado foi entre 1970 e 2022. Os dados processados ​​foram agrupados em tipos específicos de acordo com o objeto de estudo. Resultados: Nossos resultados mostraram que a maioria dos estudos abordou a influência das macrófitas aquáticas nos organismos aquáticos, bem como sua influência nas características abióticas dos ambientes aquáticos da floresta amazônica. Os estudos focaram principalmente na relação entre macrófitas e outros organismos e variáveis ​​ambientais. Conclusões: Nesta revisão, identificamos lacunas e perspectivas para estudos que avancem nas ciências aquáticas na Amazônia, especialmente no que se refere a estudos ecológicos e invasão biológica. Aumentar a cooperação internacional e a produção científica são cruciais para preencher lacunas fundamentais de conhecimento para a preservação dos ecossistemas.
Spatial and Temporal Factors Determining the Structure of Ciliate Protist Communities in Neotropical Streams
Abstract: Aim: In this study, we focused on patterns of ciliate protist community composition in urban and rural streams. Methods: We analyzed 12 urban and rural streams during two different periods of the year (rainy and dry seasons) across three different stream mesohabitats (riffles, runs, and pools). We predicted that the species composition of ciliates would differ between types of environments (rural and urban), between basins (Pirapó and Ivaí), between mesohabitats (riffles, runs, and pools), and between seasonal periods. We also expected that ciliate species composition would be similar between streams within the same basin. Results: Contrary to our expectations, our results showed that the richness and abundance of ciliates were higher in urban streams than in rural streams. In the analysis of beta diversity, we observed that this measure was higher in rural environments, but only during one period (dry season). Among the mesohabitats, no significant alterations in ciliate species composition were noted, contrary to our predictions. Conclusions: The results obtained in this study demonstrated the effect of multiple spatial (basin, type of environment) and temporal (rainy and dry seasons) factors on the structure of ciliate protists in the water column of neotropical streams. No differences in ciliate attributes were found among the mesohabitats analyzed in this study.
Efeitos da poluição urbana sobre a diversidade de zooplâncton no Rio Almada (Bahia, Brasil)
Aim: This study aimed to analyze the influence of small cities on the diversity of the zooplankton community along the Almada River, Bahia. Methods: The samples were collected at points upstream (Clean Waters - CW) and downstream (Active Decomposition - DA) of the urban area of three municipalities along the Almada River: Almadina, Coaraci and Itajuípe, in the years 2020 to 2023. Results: Among the physical and chemical variables, only dissolved oxygen and water temperature varied significantly between CW and DA. 90 taxa were identified, of which: 60 from Rotifera, 17 from Cladocera and 13 from Copepoda. It was possible to verify the presence of dominant taxa, characteristic of eutrophic environments, in points downstream of urban areas, namely: Lecane bulla bulla, Bdelloidea, Testudinella patina and Platyias quadricornis. The community attributes with significant variation between CW and DA were: abundance, evenness and the Shannon diversity index. The Jaccard dissimilarity between the CW and DA areas was high, indicating a low rate of species sharing between the CW and DA areas. In the BIOENV analysis, the variables of dissolved oxygen and electrical conductivity associated with variation in community structure were chosen. Conclusions: pollution from urbanized regions in the Almada River reduces the evenness and diversity index of shannon, and increases the abundance of the zooplankton community.
Sección Temática: II Simposio sobre Zooplancton Neotropical
Microcrustaceans structure determined by the type and trophic state of lakes
Aim: In this study, we investigated the response of microcrustaceans 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). Methods: We tested the following hypotheses: (I) the richness and abundance vary amongst lakes and are higher in the lake with natural eutrophication; (II) the microcrustaceans abundance is associate with high primary productivity, being higher in the eutrophic environment with artificial eutrophication; and (III) the increase in some species’ abundance can indicate increase of the trophic level. 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 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 sheds light on neotropical meander lakes, emphasizing the significance of physicochemical characterization, detailed temporal sampling, and lake classification by origin and trophic level.
Importance of abiotic factors and hydroperiod for the zooplankton community from ponds with different hydrological dynamics
The increase in impacts on natural environments has led to changes in the characteristics of ecosystems. Such changes, when not understood and controlled, can negatively impact the dynamics of aquatic environments, especially the small ones such as temporary ponds. Hydroperiod can change the structure of aquatic ecosystems and the factors that determine the species occurrence in these water bodies. Within this context, studies that assess the influence of the hydroperiod become extremely relevant. In this study we evaluated how zooplankton species are distributed along five ponds with different hydroperiods located in the Restinga de Jurubatiba National Park and the importance of the water retention time for the taxonomic and functional diversity of this community. Methods: We evaluated the water retention time indirectly by daily temperature measurements over three years and the main limnological parameters. The zooplankton community was sampled from the five studied ponds. Its diversity was evaluated through richness (S), Shannon diversity index (H’), functional richness (FRic), functional divergence (FDiv) and functional dispersion (FDis). Major results: We observed that the ponds, even being inserted within the same natural mosaic, can present different characteristics. Abiotic factors such as water salinity and more unstable hydroperiod negatively impacted zooplanktonic diversity. The highest values of taxonomic diversity were found in ponds with intermediary conditions of water retention (seasonal droughts). Conclusion: According to our results, seasonal environments favor the co-occurrence of species from both perennial and ephemeral ponds and presented higher diversity. Furthermore, we observed that even under the same regional species pool, differences in desiccation frequency were sufficient to determine differences in the zooplankton community.
Epistylid ciliates as epibionts on calanoid copepods in an Amazonian floodplain lake (Batata Lake)
This is the first record of peritrichous epibiont ciliates Epistylis sp. colonizing calanoid copepods in Amazonian ecosystems (Lake Batata, Pará, Brazil). The main objective was to investigate changes in the prevalence and infestation intensity of the epibiotic relationship in relation to the impact of bauxite tailings (natural and impacted areas) during two distinct periods of the hydrological pulse (rising and high-water). The hydrological pulse of this system can be characterized with four distinct phases: rising, high-water, falling, and low-water. After degradation by bauxite tailings for ten years (1979-1989), and despite an ongoing long-term ecological restoration process, it is still possible to recognize two distinct regions in the lake: the area impacted by the tailings and the natural area. We sampled zooplankton (calanoids and epibiont ciliates) and limnological variables during the high-water period (March 2015) and rising-water period (June 2019) at twelve sampling points in Lake Batata, six in the impacted area and six in the non-impacted area. We recorded epibiont ciliates in the calanoid copepodite and adult stages, as well as the main location sites on the thorax and abdomen. Our study recorded a significant difference in the prevalence and mean infestation intensity between the natural and bauxite tailings-impacted areas, and in the prevalence of infestation between the rising -water (2015) and high-water (2019) collections. The prevalence of infestation was higher in the impacted area and during the rising-water period. Although the host/epibiont/environment interaction is complex and requires analysis with a larger number of temporal samples, this study records a clear effect of flooding in this Amazonian system on the spatial and temporal dynamics of epibiont ciliates associated with calanoid copepods.
Hatching of Cladocera (Crustacea: Branchiopoda) rest eggs from permanently hydrated and temporarily dehydrated sediments of an Amazon lake
Resumo: Objetivos: i) caracterizar a composição das espécies de Cladocera eclodidas dos ovos de resistência de sedimentos permanentemente hidratados e temporariamente desidratados; e ii) testar se a desidratação periódica afeta a eclosão dos ovos de resistência. Métodos: Os ovos de resistência de Cladocera foram coletados do sedimento do lago Tupé, Amazonas, Brasil. A amostragem foi realizada no período de seca, quando o sedimento é encontrado em duas condições: sedimento permanentemente hidratado (PHS) e sedimento temporariamente desidratado (TDS). Com isso foi realizado um experimento de eclosão, com temperatura de 24 °C (± 2 °C) e fotoperíodo de 12h claro: 12h escuro, durante 20 dias. Resultados: Dos dois tipos de sedimentos foram contabilizados oito táxons de Cladocera. Em PHS foram identificados cinco táxons (um exclusivo) e em TDS ocorreram sete espécies (três exclusivas). Quando comparada a proporção de eclosão dos ovos de Cladocera entre os tipos de sedimento houve maior proporção em TDS (0,36 ± 0,48 %) do que em PHS (0,32 ± 0,49 %), mas sem diferença estatisticamente significativa entre eles (GLM: χ21= 0,012; P > 0,05; Pseudo-R2M= 0.0006). Conclusões: Este estudo foi pioneiro com ovos de resistência de Cladocera na Amazônia Ocidental. Neste foi encontrado oito espécies a partir da eclosão dos ovos de resistência encontrados em PHS e TDS. A hipótese de que a desidratação periódica dos ovos de resistência de Cladocera reduz a eclosão dos ovos foi refutada. Ainda, ocorreu o inverso do que foi predito, uma vez que TDS teve a maior proporção de eclosão.
Environmental heterogeneity in wetlands increases alpha and beta diversity of cladocerans (Crustacea, Branchiopoda) at local and regional scale
Aim: The goal of this study was to investigate the effect of the different levels of habitat heterogeneity on diversity on a local and regional scale. We tested two hypotheses: (i) the habitat diversity, given by quantity of microhabitat, increases the alpha diversity of organisms that live in those environments; (ii) the habitat heterogeneity, given by compositional difference of microhabitat, increases the beta diversity of organisms that live in those environments. Methods: Samples contained cladocerans and specimens of microphytes were collected in six wetlands from the Brazil Central during dry and rainy seasons, in Brazilian National Park (BNP) and Formosa Instruction Field (FIF). Results: In local scale (wetlands) the number of macrophyte morphospecies shows the positive effect on alpha diversity of cladoceran; the compositional difference of the microhabitat positively affected the beta diversity in three wetlands studied. In regional scale, the number of macrophyte morphospecies showed the positive effect on alpha diversity; the beta diversity was higher in the BNP than in the FIF. Conclusions: Our findings suggest that the species richness and dissimilarity of aquatic macrophytes increased to alpha and beta diversity of cladocerans on the local and regional scales. Thus, cladocerans richness is correlated the number of microhabitats and the variability between microhabitats in wetlands.
Seasonal variation of the diversity of zooplankton communities in ponds of the Atlantic Forest
This study analyzed the structure and seasonal variation of the zooplankton community in five ponds in a preserved Atlantic forest environment, the Betary Reserva (24º35'16"S; 48º37'44"W). Sampling took place in March and September 2022and January and July 2023, covering the summer and winter seasons. Vertical trawls were carried out with a 45μm plankton net and, at the same points, physical and chemical parameters of the water were measured with a multi-parameter probe. 59 taxa were recorded, distributed inCopepoda (1), Cladocera (5) and Rotifera (53). Among them, the families Lecanidae, Brachionidae and Trichocercidae were the most representative in terms of number of species. Some of them were present in all samples (Mesocyclops longisetus, Ceriodaphnia cornuta, Brachionus quadridentatus, many species of the genus Lecane and others), but there were also less abundant and rare species that were exclusive to one season. The highest richness was observed in January/23, while the other summer month showed the lowest value. There was a difference in the composition of the assemblage (F= 2.00; p= 0.045), which showed variation in the occurrence and relative abundance of species between seasons. Conductivity and temperature were structuring factors for some populations in the periods studied. The results show the richness found in the pools and demonstrate the importance of protected areas in maintaining the biodiversity of this biome, which is under threat. Further studies are needed to understand the distribution pattern of zooplankton species, the seasonal variation of their communities and their relationship with the physico-chemical parameters of the water.
Diversidade beta de insetos aquáticos (Ephemeroptera, Plecoptera e Trichoptera) em microhabitats de riachos
Objetivo: O objetivo deste estudo foi avaliar como a combinação de características ambientais afeta a diversidade beta da comunidade EPT (Ephemeroptera, Plecoptera e Trichoptera) no nível de habitat e como a singularidade ecológica do habitat se reflete na contribuição local para a diversidade beta (LCBD). Métodos: As amostras foram coletadas em 12 riachos, todas as microbacias amostradas pertencem à Bacia Hidrográfica do Paraná 3. Quatro tipos de substratos foram amostrados em tréplica com o auxílio de um amostrador Surber. As amostras foram classificadas em CSD (areia e argila) e STO (cascalho, seixos e pedregulhos). O substrato composto de pacote de folhas (folhas e galhos) foi dividido em RLP (pacote de folhas de corredeira) e BLP (pacote de folhas de remanso). Resultados: Assim, encontramos o maior valor de diversidade beta na categoria CSD (areia e argila) e a maior contribuição do componente de substituição. Registramos um efeito significativo na mudança de composição entre os microhabitats avaliados e na associação dos gêneros com cada categoria. No entanto, a diversidade beta não diferiu significativamente entre os microhabitats. O LCBD foi maior em pontos de maior degradação, independentemente do tipo de microhabitat amostrado, e exibiu uma relação significativamente negativa com a riqueza no microhabitat BLP (pacote de folhas de remanso). Conclusões: A partição da diversidade beta em seus componentes, combinada com a abordagem LCBD, auxiliou na compreensão de padrões ecológicos em escalas locais, provando ser uma ferramenta eficaz na avaliação da biodiversidade e na tomada de decisões relacionadas à definição de áreas prioritárias para conservação.
Predictive capacity of phytoplankton functional groups in a tropical wetland (Pantanal, Brazil)
Aim: Considering the prediction capacity of the phytoplankton community, this study analyzed the environmental factors that influenced the distribution patterns of species and Reynolds Functional Groups (RFG) in hydrological period (dry, rising, flood and ebb) and the type of environment (river and lake), in the Pantanal wetland (Brazil). We expect environmental variability to reflect in the predictive ability of phytoplankton to describe habitat types and flood-pulse periods, where the seasonality (high and low water) are the main drivers of phytoplankton distribution, biovolume and functional groups. Methods: We collected environmental variables and phytoplankton quarterly in 2018 from 18 points in the flood, rising, dry and ebb. Results: recorded 425 taxa distributed into 13 taxonomic groups and 20 RFGs, of which nine groups (D, F, J, G, K, MP, N, S1, and P), represented by green algae, cyanobacteria, and diatoms, had the highest predictive value, characterizing lentic environments as rich in nutrients and light, and the Paraguay River as having a lower availability of these resources for phytoplankton. The variation in biovolume was related to the phases of the flood pulse, being higher in low waters in floodplain lakes and smaller in high waters in the river. Conclusions: Thus, the predictability of the phytoplankton community structure was directly associated with the environment types in the Pantanal wetland and with the homogenization or isolation of the systems promoted by the flood pulse that acted as drivers of phytoplankton distribution, biovolumes and functional groups.
Patricia Fernanda dos Santos de Loureiro Nunes
Experimental studies on freshwater zooplankton in Brazil: A scientometric analysis from 1978 to 2023
This study aims to contribute to elucidating the importance of experimental research on freshwater zooplankton communities in Brazil through a scientometric analysis. The Web of Science, Scielo, and Scopus databases were used to compile 249 scientific papers published between 1978 and 2023. Data extracted from the papers included the year of publication, geographical location, experiment characteristics (type, scale, duration), species or taxa studied, and research topics. Quantitative and qualitative syntheses were performed to provide a systematic understanding of experimental studies on freshwater zooplankton. The analysis revealed a significant increase in the number of experimental papers over time, with a higher concentration of studies in the southeastern region of Brazil. Laboratory experiments were more commonly conducted than field experiments, mainly microcosms. Predation, chemical pollutants, and eutrophication emerged as frequently addressed research topics. On the other hand, certain topics, such as metapopulation dynamics and microplastics, were relatively underrepresented in the literature. Despite the crucial role of experimental research on freshwater zooplankton in advancing ecological understanding in Brazil, there is an unequal distribution of these studies across the country, indicating the need for investments and more researchers prepared to work with experiments in certain regions. Addressing gaps identified in this review, such as metapopulation dynamics and the role of microplastics in zooplankton ecology, will be essential for generating scientific knowledge to inform effective management strategies to preserve freshwater zooplankton biodiversity amidst ongoing environmental changes.
Derechos de autor 2024 http://creativecommons.org/licenses/by-nc/4.0
Substrate influence on Perlidae (Plecoptera) nymph shape in Parque Nacional da Serra dos Órgãos, Teresópolis, Rio de Janeiro, Brazil.
Aim: Ecological studies on Plecoptera in Brazil are still in their initial stages, as is morphometric knowledge on Plecoptera nymphs. In this study, we determined whether Perlidae found in leaf litter were morphometrically distinct from those found in stony substrates. Methods: Specimens were collected in Parque Nacional da Serra dos Órgãos, Teresópolis, Rio de Janeiro, Brazil. Each insect was assigned to a morphotype and was subsequently measured. Data was logarithmically transformed and subjected to a size-free discriminant analysis. Analysis of variance tests were made to assess the relationship between shape, genus and substrate choice. Major results: We collected 562 insects belonging to two genera of Perlidae, Kempnyia Klapálek, 1914 and Anacroneuria Klapálek, 1909. Perlidae occurred primarily in leaf litter. We found significant morphometric differences among genera and substrates. Insects occurring in leaf litter were shown to have wider heads and longer fore femurs than those found in stones, likely indicating a bigger need for anchoring to the substrate and resisting stronger water currents. Conclusions: This study shows the complex relationship between body shape and substrate choice in neotropical Perlidae. Considering that different substrates bear varying ecological pressures on aquatic insects, morphometrics are a capable tool for assessing ecological relationships between these insects and their environment.
Willian Fernandes de Azevedo Cunha de Moura
Use of submerged trunks by stream fishes in the Lower Negro River, Amazon
Fish make use of different microhabitats, such as submerged trunks, branches, foliage, crevices and between stones, with different purposes, whether in search of shelter, refuge, food and even as a substrate for reproduction. The present study aimed to increase the knowledge about fish species that make use of the micro-habitat of trunks on the banks of streams in the conservation unit (CU) known as the Tupé Sustainable Development Reserve, Lower Negro River region, Amazonas. The data analyzed come from two days of collections, carried out in the falling water periods of 2020 in the Central stream. Six species, Pseudanos trimaculatus, Tatia strigata, Trachelyopterichthys taeniatus, Trachelyopterichthys sp. "negro", Ancistrus dolichopterus and A. hoplogenys were captured inside the submerged trunks. The order Siluriformes was the most abundant and represented (83.33%) of the sample. The most abundant species were T. strigata (N=46), followed by A. dolichopterus (N=35). Although most species are of the order Siluriformes, it is worth mentioning the encounter of a species of Characiforme, P. trimaculatus (N=1). In addition, an individual of A. hoplogenys was found in association with eggs deposited and fixed within a trunk, performing the behavior of care and protection. The finding of these species inside trunks may be associated with their foraging site, refuge and parental care in order to increase the chances of survival of the offspring. Therefore, the conservation of these microhabitats is important for the maintenance of aquatic organisms.
Cladocerans (Crustacea, Branchiopoda) from Mount Roraima, Venezuela, with new species record for this country and the Neotropical region
Introduction and Objectives: Venezuela, located in the north of South America, has ecosystems with great potential for diversity. Among these ecosystems, Mount Roraima located at the border of Venezuela, Brazil, and Guyana, stands out. Its true biodiversity is underestimated, especially for microcrustaceans of the Superorder Cladocera. Mount Roraima is considered a conservation unit, and understanding its fauna is an important tool for species preservation. This study presents a preliminary inventory of the cladocerans of this mountain. Methodology: Samples were collected from two ponds located in the upper part of Mount Roraima using a conical plankton net. The specimens were then analyzed, photographed, and identified. The richness and relative abundance were evaluated. Main results: Three species were recorded for the first time in Venezuela. There is a possibility that the Orinoco Basin endemic species Streblocerus superserricaudatus occurs in Brazil and Guyana, since the ponds are very close to the border of both countries. There is a co-occurrence of three Flavalona species in the territory of Roraima, a fact so far only known for Brazil. Adding the new records to the previously known lists, the cladoceran richness for Venezuela is now 105. Discussion: Samplings in peculiar and remote environments have the potential to reveal new species and records. Further samplings are suggested on Mount Roraima to reduce potential sampling biases. Keywords: altitude, biogeography, Chydoridae, sampling effort, Tepui.
Sandbar breaching promotes long lasting changes on limnological dynamics along the water column of a tropical coastal lagoon
Aim: In this study, we investigated the impact of an episodic marine intrusion on the water column characteristics of Jurubatiba lagoon, a tropical coastal ecosystem, for 12 months following a sandbar breaching event to elucidate the duration of its effects. Methods: Monthly, we sampled the physical, chemical and biological characteristics along the water column for one year after a sandbar breaching event and seawater inflow. We assessed the temporal (monthly) and spatial (along depth profiles) associations among these variables and the temporal correlation among vertical heterogeneities in these variables and environmental drivers of stratification. Results: Marine intrusion resulted in salt wedges formation in the short-term, leading to stratification in dissolved oxygen, pH, salinity, and chlorophyll-a concentration along the water column for at least four months. However, rainfall and temperature also emerged as crucial factors associated to vertical heterogeneity in limnological variables, influencing water density, pH, and turbidity throughout the study period. Wind speed had marginal effects on thermal stratification, probably due to the lagoon’s orientation in the landscape. Conclusions: Our data unveiled that, despite their shallowness and wind exposure, coastal lagoons can exhibit considerable vertical heterogeneities in limnological variables due to various climatic and hydrodynamic aspects. Notably, the effects of marine intrusions on salinity and ectogenic column stratifications can persist for several months, affecting water quality and, probably, biotic communities and ecosystem functioning. Once human activities and climate change may intensify marine intrusions on coastal lagoons, understanding these dynamics and their drivers is fundamental to anticipating their effects and conserving such vulnerable ecosystems.
Ichthyofauna of the Brazilian semiarid region reservoirs
The construction of reservoirs in the Northeast is a prevalent practice intended mainly for water supply, and with the introduction of fish as a widely practiced activity, it generates environmental and social consequences. Aim: This study analyzed articles on the ichthyofauna found in reservoirs in the Northeast over the last 50 years. Methods: It considered the scientific impact of these publications, the origin of the species studied, the main topics covered, and the participation of women in the authorship of these works. Results: A few publications on ichthyofauna were found, most of them of low impact and low visibility. This scenario highlights a concern about research promotion policies and reveals a gap in this area of knowledge. Conclusions: There are still regional asymmetries in publications, a reflection of the disparity in the distribution of incentives and funding actions. Investment in research in this area reflects directly on how research is carried out and viewed in Northeast Brazil. In addition, female participation has been significant in numbers but not visibility. It also reverberates in the scientific community as a whole.
Phytoplankton functional groups associated with the trophic state of tropical reservoirs
Abstract: Aim: The present study investigated functional groups representing reservoirs of different trophic states, identifying indicators of eutrophication. Methods: Water samples were collected to evaluate physical and chemical characteristics and the phytoplankton composition in five reservoirs during dry and rainy periods. Results: Low concentration of dissolved nutrients (nitrite, orthophosphate, and total dissolved phosphorus) and total phosphorus described the oligotrophic and mesotrophic reservoirs, and the opposite the eutrophic and hypertrophic reservoirs. Twenty-four functional groups were identified, eight of which were considered reservoir descriptors due to high biomass. Functional groups were influenced by the trophic state, and secondarily by seasonality. Typical functional groups represented the hypertrophic, eutrophic, and mesotrophic reservoirs. However, an oligotrophic reservoir was represented by a functional group commonly associated with environmental eutrophic. Conclusions: The functional groups were representative of the trophic state of systems and detected signs of early eutrophication.