Acta Limnologica Brasiliensia

(631 Artigos indexados)

Adult emergence of Phyllocycla Calvert, 1948 (Odonata: Gomphidae) in artificial environments - (2024)

Carolina Gomes Viana, Lucas Pereira-Moura, Daniel Silas Veras

Volume: 36 - Issue: 0

Resumo. Abstract Aim This study aimed to analyze aspects of adult emergence of Phyllocycla Calvert, 1948 (Odonata: Gomphidae) in artificial environments. Samplings were conducted in Sanharó stream, Caxias municipality, Maranhão State, Brazil. Methods Specimens were examined under a stereomicroscope and identified to the lowest possible taxonomic level. Polystyrene boxes were used as rearing sites, and the following methods were analyzed: a) sand; b) strips of filter paper simulating substrate; c) without substrate. For emergence, the rearing sites had their lids removed and were placed inside larger jars with mesh windows, less water, with most of the substrate exposed above the water level. To verify the difference between treatments, the Log-rank test and Kaplan-Meier survival curves were used. Results The curves indicated that emergences occurred more frequently in the initial days of rearing. There was an absence of statistical difference between groups. Despite that, all treatments showed success in emergence, with larvae without substrate emerging more quickly. Conclusions By exploring the use of different substrates in Odonata rearing, this research provides guidelines for optimizing laboratory conditions, helping to overcome experimental challenges and supporting new studies and inventories.

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Are functional freshwater Nematode traits a good tool for view an early succession on hard artificial substrate in a reservoir of Brazilian semiarid? - (2024)

Fábio Lucas de Oliveira Barros, Sebastião Tilbert, Taciana Kramer Pinto, Maria Cristina da Silva, Francisco José Victor de Castro, Miodeli Nogueira Júnior

Volume: 36 - Issue: 0

Resumo. Abstract Aim The Brazilian tropical semiarid is a biome with small freshwater ecosystems, often intermittent, acting as a mosaic in constant transformation between dry and rainy seasons. Meiobenthic communities play crucial roles in these environments, and understanding their colonization and succession processes is essential to comprehend how these organisms’ structure in a defaunated habitat. In addition to the traditional taxonomic approach, functional traits provide valuable insights into the dynamics of these processes. In this study, we tested the following hypotheses: i) although meiofauna consists of microscopic organisms with limited active dispersion, they quickly colonize new substrates, increasing in abundance, richness, and diversity; ii) functional traits of freshwater Nematoda are a good tool for view an early succession on hard artificial substrate in a lentic reservoir. Methods We placed 27 ceramic plates in a reservoir in the Brazilian semiarid and randomly sampled three replicates each week over nine weeks. Weekly differences in community abundance, richness, and diversity were tested with one-way ANOVA and pairwise PERMANOVA. Results Nematoda predominated in the first week, with Rotifera taking over from the second week of the experiment. No differences were observed in the Nematode taxonomic structure over the weeks. There was an increase in the functional complexity of the Nematoda community over time, as indicated by the maturity index and trophic structure. Colonizers/persistents emerged quickly in the first week. Deposit feeders dominated, but an increase in trophic diversity was observed with the growing presence of chewers over the weeks. Conclusions This study highlights that the functional traits of Nematoda represent a robust tool for assessing ecological succession in freshwater lentic environments in the tropical semiarid.

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Assessing the occurrence of alien species on Brazilian freshwater ecosystems: insights from a comprehensive survey - (2024)

Anderson Oliveira Latini, Daniela Chaves Resende, Daniel Paiva Silva, Dilermando Pereira Lima-Junior

Volume: 36 - Issue: 0

Resumo. Abstract: Aim Assessing the damage caused to natural environments and native biodiversity by alien species is challenging. We tested whether the number of detections of alien species is affected by total alien or total invader alien species richness, considering the importance of predicting which species are more probable future invaders. Methods We summarized a research information survey conducted on alien amphibians, annelids, aquatic macrophytes, cnidarians, crustaceans, fish, microorganisms, mollusks, nemathelminths, platyhelminths, and reptiles, and for Brazilian watersheds. We used linear regressions between detections and total alien species richness and between detections and invader species richness. Results We obtained 1,896 alien detections of 183 aquatic species in Brazil. Fish and mollusk species were the commonest invaders due to their detections being more frequent than expected by chance, considering all the alien species occurring in Brazilian freshwater ecosystems. We also found positive and robust linear relationships between alien species detections and alien species richness. Conclusions Our results illustrate how Brazilian freshwater systems are fragile to alien invasions and highlight the need for effective action to address this question. Scientific uncertainty in Brazil regarding the status of some alien species and their potential harm is high, highlighting the need for a cautionary overview of invaders. Despite this scenario, new policies create opportunities for aquatic parks with exotic organisms to spread further in Brazil, which, in actual Brazilian conditions, is likely to increase the pressure on natural ecosystems and native species. This reinforces the already expressed need by the scientific community for greater attention to the issue.

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Assessing the taxonomic sufficiency of macroinvertebrate communities and their potential to distinguish the impacts of land use on lowland streams in Uruguay - (2024)

Bárbara Suárez, Margenny Barrios, Franco Teixeira de Mello

Volume: 36 - Issue: 0

Resumo. Abstract: Aim Macroinvertebrates are extensively employed as bioindicators for evaluating how stream ecosystems respond to alterations in physical and chemical habitats caused by human activity. Although family-taxonomic level is usually used to identify macroinvertebrates in biomonitoring programs, coarser taxonomic resolution may provide similar information. We aim to evaluate taxonomic sufficiency by comparing macroinvertebrate communities at the order and family levels to differentiate the effects of different land uses. Methods We conducted colonization experiments using artificial substrates in streams representing three land use types: urban (U, n=3), intensive agriculture - dairy production (AD, n=4), and extensive cattle ranching (CR, n=4). Results We obtained similar results using both taxonomic levels, which effectively distinguished the impacts of different land uses. In the sites examined, the majority of indicator groups exhibited only one family per order, with the exception of Ephemeroptera (Leptophlebiidae, Baetidae, and Caenidae). Notably, Baetidae and Caenidae were more prevalent in streams associated with extensive cattle ranching (CR). Conclusions Although this study provides a clear precedent, further investigation of these systems and other land uses (e.g., afforestation) is needed to validate this pattern. Coarser taxonomic assessment holds potential as a cost-effective method for stream monitoring and assessment in Uruguay.

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Bacterial community dominance in a sewage-driven eutrophic coastal lagoon by next generation sequencing: initial findings - (2024)

Analy Machado de Oliveira Leite, Mauricio Mussi Molisani, Renan Monte de Oliveira, Paula Veronesi Marinho Pontes, Rodrigo Nunes da Fonseca, Jackson de Souza Menezes, Lupis Ribeiro Gomes Neto, Francisco Assis Esteves

Volume: 36 - Issue: 0

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

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Beta diversity of macroinvertebrate assemblages associated with aquatic macrophytes in shallow lakes within a tropical floodplain-dammed river - (2024)

Marcos Callisto, Ricardo Solar, Daiana dos Reis Pelegrine, Marden Seabra Linares

Volume: 36 - Issue: 0

Resumo. Abstract: Aims We assessed the beta diversity of macroinvertebrates associated with aquatic macrophytes in a dam-regulated river floodplain. We tested two hypotheses: (1) macroinvertebrates associated with aquatic macrophytes have higher beta diversity (higher turnover and nestedness components) in the downstream areas closer to the São Francisco River compared to upstream sites; (2) closer lakes share a higher similarity of aquatic macroinvertebrates, disregarding their position relative to the dam. Methods We sampled four lakes, including two upstream (L1- natural and L2- regulated by a Small Hydropower Dam - SHD) and two downstream (L3, L4, unregulated) by the SHD. Results We corroborated our first hypothesis because we found a higher turnover of macroinvertebrates associated with aquatic macrophytes close to the São Francisco River (L4 downstream), where higher non-native mollusk species richness occurs, while we found higher nestedness upstream and downstream of the SHD (L1, L2, L3). We corroborated our second hypothesis, as closer lakes are more similar than distant lakes. Finally, these differences were consistent between lakes for emergent, floating leaf, and submerged aquatic macrophytes. Conclusions Aquatic macrophytes are essential habitats for macroinvertebrates in the Pandeiros River basin, with higher beta diversity in the lake closer to the São Francisco River.

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Community attributes reflecting the zooplankton secondary production: using field and experimental approaches - (2024)

Juliana Deo Dias, Nadson Ressye Simões, María Rosa Miracle, Thais Xavier de Melo, Claudia Costa Bonecker

Volume: 36 - Issue: 0

Resumo. Abstract Aim We investigated the relationship between ecological attributes of the zooplankton community and its secondary production. Methods Samples were taken from lakes in the floodplain of the Upper Paraná River (Brazil), in low and high-water periods, and in a manipulative experiment realized in mesocosms. Results The highest amount of production was related to the dominance of few species. Secondary production of larger and long-lived organisms, such as copepods, had been most associated with the biomass, whereas smaller ones, such as rotifers, with the abundance. Conclusions These attributes of the zooplankton community (biomass and abundance) can be used as proxies to estimate the zooplankton secondary production in the floodplain, supporting the studies on monitoring and conservation of these ecosystems.

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Comparative analysis of ex situ zooplankton hatching methods - (2024)

Daniel Nino Flores-Mendez, María Florencia Gutierrez

Volume: 36 - Issue: 0

Resumo. Abstract: Aims This study aims to analyze the efficiency of two novel methods for ex situ zooplankton hatching experiments, compared with a traditional one. Both proposed methods were specifically designed to minimize sediment resuspension during the sampling of hatched individuals when no previous egg isolation is performed. Methods Sediment samples were collected from shallow lakes, homogenized, and incubated for 18 days under stable laboratory conditions. The traditional method (1M) involved simple water filtration from incubated sediments. The so called “inverted funnel filtering” method (2M) includes an inverted funnel located above the sediment to trap zooplankton that passes through the funnel aperture, and the “levels filtering” method (3M) involves perforated plates above the sediment. The efficiency of each method was evaluated by analyzing the cumulative abundance and number of taxa in hatched total zooplankton, rotifers, and microcrustaceans, as well as the overall composition. Results The new proposed methods significantly favored higher abundances than 1M for total zooplankton and rotifers. Even more, 3M outperformed 2M in the case of microcrustacean hatching abundances. Conclusions Our findings suggest that despite all analyzed methods being suitable for studying zooplankton hatchings, the newly proposed methods incorporating internal structures to minimize sediment resuspension displayed increased capture efficiency.

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Composition, life-history, and population dynamics of the Chironomidae from a tropical high-altitude stream (Saltana River, Ecuador) - (2024)

Narcís Prat i Fornells, Andrea C. Encalada, Christian Villamarín, Blanca Ríos-Touma

Volume: 36 - Issue: 0

Resumo. Abstract: Aim To study the composition and population dynamics of Chironomidae (Diptera) from a high-altitude tropical stream in Ecuador. Methods Samples were taken at Saltana River between April 2009 and November 2010. Physico-chemical parameters, such as flow, dissolved oxygen, conductivity, pH, and temperature, were measured in each sampling campaign. Larvae and pupae sampling was conducted with a Hess sampler in different substrates. During each sampling campaign, adults were sampled using amphibious emergence traps for 24 hours. All materials collected were separated and classified in the laboratory. The biomass was calculated using the individual weight of the larvae of different instars multiplied by the density of each instar at each sample. Results A total of 18 larval taxa were found in 14 different genera in the benthic samples. The subfamily Orthocladiinae showed the highest richness (12 genera), followed by Podonominae, Diamesinae, and Chironominae, with two genera each. The most frequent taxa were Cricotopus sp.3, C. (Oliveiriella) rieradevallae, and Genus 1 sp.a. Total densities fluctuate very much from one month to another following the changes of the most abundant species, and only one species showed a relationship with the substrates. Biomass values are lower from June to August of both years, which matches the high flow season. Conclusions The Saltana River’s cold temperature (6-7 °C) and the flow variability determine the low richness, density and biomass throughout the year. It is unclear if individuals showed very short or long-life cycles due to constant temperature throughout the year. However, there is a clear asynchrony in life cycles due to the presence of emerging adults throughout the year.

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Concentrations of metals in water, sediments and aquatic macrophytes in a river located in a region with a hot semi-arid climate - (2024)

Camila Tâmires Alves Oliveira, Antonio Fernando Monteiro Camargo, Eulene Francisco da Silva, Gustavo Gonzaga Henry-Silva

Volume: 36 - Issue: 0

Resumo. Abstract Aim i) is there a difference in the level of contamination in the different parts of the basin in the water, sediment and aquatic macrophytes compartments? and ii) do the three compartments respond similarly to metal contamination? Methods Samples of water, sediment and aquatic macrophytes (Salvinia auriculata Aubl., Pistia stratiotes L., Ludwigia helminthorrhiza (Mart.) H. Hara and Eichhornia crassipes (Mart.) Solms) were collected at 10 sampling sites in different stretches of a tropical hydrographic basin. We determined the metal concentrations of Fe, Pb, Ni, Zn, Mn, Cr, Cu and Cd, and to the results we applied Principal Component Analysis (PCA), separately for each compartment, to order the sampling sites. Results Fe and Mn had higher concentrations than other metals in plants and sediment. With the exception of Mn, the order of metals was similar between water and sediment. However, the PCAs ordered the sampling sites differently. Our results demonstrated that the ordering of sampling sites by metal concentrations differs among water, sediment and macrophytes. Conclusions We conclude that to evaluate the contamination of aquatic environments by metals and the effects of contamination on the food chain, it is not enough to evaluate them only in water or sediment, but also in an aquatic community.

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Diel dynamics and environmental influences on phytoplankton communities in an Andean lagoon: implications for management and conservation - (2024)

Ivan Edward Biamont-Rojas, Herminio René Alfaro-Tapia

Volume: 36 - Issue: 0

Resumo. Abstract: Aim Lacustrine environments are unique locations to study temporal fluctuations derived from natural and artificial sources within a hydrographic basin. The objective of this study was to analyze the diel cycle of physicochemical parameters and their influence on the phytoplankton community structure in open waters, as well as, to evaluate the total phosphorus and nitrogen contents in the vicinity of fish tanks in the lagoon, and to identify the phytoplankton assemblage in the water column in a diel cycle in an open water area during the rainy and dry seasons. Methods The epilimnion and hypolimnion zones of an open water area were assessed over 24 hours, starting at 10:00 on day one and finishing at 10:00 on day two, obtaining a total of 36 samples (9 samples at 3-hour intervals, in two lake zones, in two seasons). Sampling employed a Van Dorn sampling bottle, and the Morphologically Based Functional Groups (MBFG), Shannon-Weaver and Simpson Indices were employed to describe the identified genera. Results Six of the seven parameters monitored registered higher values during the rainy season; only transparency was higher during the dry season. Fifteen genera distributed in nine classes were identified, with richness and diversity being higher in the rainy season. Conclusions The MBFG and sinking properties of group and genera has influenced the vertical migration of phytoplankton. The daily cycle method effectively captured the fluctuations in physicochemical and phytoplankton parameters over a 24-hour period in both seasons in Chacas Lagoon.

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Distribution of invasive bivalves in Paraguay: filling the gaps in the heart of South America - (2024)

Igor Christo Miyahira, Rebeca Carballo, Héctor Samuel Vera-Alcaraz, Cristhian Clavijo

Volume: 36 - Issue: 0

Resumo. Abstract La Plata Basin is the second largest hydrographic system in South America but the most impacted by invasive species of molluscs in the continent. Paraguay is a land-surrounded South American country with scarce information about malacological fauna. To fill some of these gaps, a large field expedition was conducted to analyze the distribution of invasive freshwater bivalves in Paraguay. The field survey encompassed 41 sampling stations in seven Departments of Paraguay. The mussels were searched using bare hands and feet. All stations were georeferenced and some environmental parameters were measured. Results indicated the presence of three invasive species of freshwater bivalves in Paraguay: Corbicula fluminea, C. largillierti, and Limnoperna fortunei. The Asiatic clam Corbicula fluminea was the most widespread invasive species, covering main rivers and small tributaries in the four freshwater ecoregions of Paraguay. The two remaining invasive species were more restricted. Corbicula largillierti were found at the lower section of the Paraná River, and Limnoperna fortunei inhabits the main river canals of the Paraguay River and the lower section of the Paraná River. The invasive species were found in three protected areas of Paraguay and can represent a threat to the mostly unknown fauna of native mussels. The invasive bivalves are widespread in Paraguay. Mitigation measurements must be taken to avoid the spread of these species and more drawbacks over native fauna.

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Ecophysiological investigation of the cyanobacteria Anabaenopsis elenkinii and Limnospira platensis: predominant species in saline/alkaline lakes of the Pantanal Wetland - (2024)

Kleber Renan de Souza Santos, Guilherme Scotta Hentschke, Arnaldo Yoso Sakamoto, Luciana Retz de Carvalho, Célia Leite Sant’Anna

Volume: 36 - Issue: 0

Resumo. Abstract: Aim In this study, we investigated the distribution of Anabaenopsis elenkinii and Limnospira platensis in the saline-alkaline lakes of Nhecolândia (Pantanal wetland) and evaluated the impact of pH, temperature, and nitrogen on their growth and development to understand their ecological responses, showing insights into their ecophysiology in both cultured and natural environments. Methods Both species were collected in the subsurface, using a plastic bottle (200 mL) and the parameters temperature, conductivity, and pH were measured in situ. From these samples, the strains A. elenkinii CCIBt1059 and L. platensis CCIBt3335 were isolated and underwent six different cultivation treatments, in triplicate, during 30 days, with daily cell count, photoperiod of 12-12 hours of light-dark, and light intensity between 80-100 µmol photons m-2.s-1, using BG-11 modified medium, as follows: nitrate concentration experiments were performed with a 750 mg.L-1 NaNO3 (50%) and a nitrogen-free condition (0%) (T1 vs T2); temperature experiments were performed with 30 °C and 35 °C (T3 vs T4); pH experiments with 10.5 and 7.0 (T5 vs T6). The adopted control conditions were BG-11m medium (3% NaNO3, 45 mg.L-1), pH adjusted to 9.5, and temperature set at 25 °C. Results We have found that the treatment with the highest nitrogen availability (T1), pH of 9.5, and a temperature of 25 °C, provides the most favorable conditions for the growth of both studied species. In nature, A. elenkinii occurred predominantly between pH 9.04 to 10.4 (average 9.8) and L. platensis at pH 9.22 to 10.23 (mean 9.9), highlighting the alkaliphilic nature of these species. Furthermore, we observed that temperature influences the frequency of heterocyte formation in A. elenkinii. At elevated temperatures (30 and 35 °C), the frequency of heterocytes was higher compared to 25 °C during the exponential growth phase, indicating that increased heterocyte formation is a strategy in response to temperature stress. Conclusions This research provides valuable insights into the ecological aspects and optimization of the cultivation of the two species studied, which hold ecological significance to saline lakes. Further studies are recommended to explore their potential biotechnological applications.

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Environmental monitoring of sediment quality and trace metal status in a tropical perennial river in South India: an exploration using multivariate analysis - (2024)

Dani Benchamin, Sreejai Raghavan, Arya Madhu Sajidevi

Volume: 36 - Issue: 0

Resumo. Abstract: Aim The Kallada River is exposed to several kinds of pollution from domestic, civic, recreational, and agricultural activities and human settlements. The objectives of the study were to assess sediment quality, especially the trace metal concentration and to compare with the previous reports on the sources of pollutants in the Kallada River. Methods A total of 12 sediment variables including the following metals: iron (Fe), manganese (Mn), chromium (Cr), and zinc (Zn) were analyzed. Atomic Absorption Spectrophotometer (AAS) was used to detect trace metal concentration in the sediment samples. Statistical tools such as Pearson’s correlation, Principal component analysis (PCA), and Cluster analysis (CA) were employed to analyze the data and source of pollutants. Results This investigation indicated that Fe was the most accumulated element in the sediments, and the midstream (K6 and K10) and downstream sites (K11 to K15) showed a much higher concentration level than the upstream sites. The concentrations of trace metals in sediment samples followed the order Fe> Mn> Cu>Zn. Conclusions The present study concluded that major sources of pollutants were sewage and civic effluents and agricultural discharges. These may cause a severe threat to the Kallada River and health risk to the local populations, which rely on the river, primarily for drinking purposes. Hence, appropriate conservation policies to reduce pollution are therefore essential.

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Environmental variables as predictors of fish community composition in semiarid aquatic systems - (2024)

Elvio Sergio Figueredo Medeiros, Marcio Joaquim da Silva, Telton Pedro Anselmo Ramos, Robson Tamar Costa Ramos

Volume: 36 - Issue: 0

Resumo. Abstract Aim To understand the distribution of fish species and their use of habitat, a range of environmental variables were evaluated as predictors of fish assemblage composition and richness in tropical semiarid aquatic systems. Methods We surveyed the species composition of fish assemblages in semiarid aquatic systems and established their degree of association with the structure of the aquatic habitat. Sites consisted of stream reaches with surface water flow, isolated temporary pools, and man-made reservoirs. Fish sampling was conducted on four occasions during the wet (April and June 2006) and dry seasons (September and December 2006). The correlation between richness and abundance with the habitat structure was evaluated using stepwise multiple regression. Patterns of variation in fish assemblage composition across sites were evaluated using Nonmetric Multidimensional Scaling, and the Indicator Species Analysis was used to determine which species were significant indicators of sites. To establish multivariate correlations and test the hypothesis of local fish composition being associated with the environmental variables we used a Canonical Correspondence Analysis. Results Morphometric variables, stream reach width, stream length and elevation explained 75.6% of the variation in fish richness. Macrophyte cover and overhanging vegetation added to the predictive power of the model equation, where the final model explained 86.9% of the variation in fish richness. Canonical Correspondence Analysis showed a significant relationship between fish composition data and site morphology (altitude, bank slope and littoral depth). Among the water quality, habitat composition and substrate variables, temperature, sand, and gravel showed higher correlation with the CCA axes. Conclusions These results indicated that fish communities assume different structures and compositions across different habitat types following the environmental heterogeneity in dryland aquatic systems.

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Epistylid ciliates as epibionts on calanoid copepods in an Amazonian floodplain lake (Batata Lake) - (2024)

Wésley Altino Flores, Pedro Mendes de Souza, Iollanda Ivanov Pereira Josué, Roberto Júnio Pedroso Dias, Reinaldo Luiz Bozelli

Volume: 36 - Issue: 0

Resumo. Abstract Aim The main objective was to investigate changes in the prevalence and infestation intensity of the epibiotic relationship (ciliates/calanoids) in relation to the impact of bauxite tailings (natural and impacted areas) during two distinct periods of the hydrological pulse (rising and high-water). Methods 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. Results This is the first record of peritrichous epibiont ciliates Epistylis sp. colonizing calanoid copepods in Amazonian ecosystems (Lake Batata, Pará, Brazil). 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. Conclusions 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.

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Experimental studies on freshwater zooplankton in Brazil: a scientometric analysis from 1978 to 2023 - (2024)

Jorge Laço Portinho, Larissa Ferreira Brandão, Marco Antonio Azevedo Machado, Clarice Casa Nova, Maiby Glorize da Silva Bandeira, Juliana Deo Dias, Amanda Costa Ferreira, Reinaldo Luiz Bozelli

Volume: 36 - Issue: 0

Resumo. Abstract Aim This study aims to contribute to elucidating the importance of experimental research on freshwater zooplankton communities in Brazil through a scientometric analysis. Methods Web of Science, SciELO, and Scopus databases were used to compile 249 scientific papers published between 1978 and 2023. The extracted data 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. Results 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 conducted with greater frequency 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 investment and more researchers prepared and interested in studying with experiments in certain regions. Addressing the gaps identified in this review, such as metapopulation dynamics and dispersion, along with emerging threats like invasions, microplastics, pathogens, cumulative stressors, emerging contaminants, and nanomaterials, will be essential for generating scientific knowledge to inform effective management strategies to preserve freshwater zooplankton biodiversity amidst ongoing environmental changes. Conclusions This review underscores the importance of expanding experimental research across diverse regions and underexplored topics to enhance our ecological understanding and better manage freshwater zooplankton biodiversity in Brazil.

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Factors stimulating the hatching of resting eggs and their contribution to the composition of cladoceran assemblages in tropical temporary lagoons - (2024)

Wesley Luiz Guimarães, Eliana Aparecida Panarelli, Natan Guilherme dos Santos, Maria Stela Maioli Castilho-Noll

Volume: 36 - Issue: 0

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

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First record of the Southern Platyfish, Xiphophorus maculatus (), (Cyprinodontiformes: Poeciliidae) in coastal streams of Venezuela and implications for conservation - (2024)

Douglas Rodríguez-Olarte, Críspulo Julián Marrero, Donald Charles Taphorn, Jorge Luis Coronel

Volume: 36 - Issue: 0

Resumo. Abstract Several fishes of the family Poeciliidae are commonly produced in ornamental aquaculture and also used for pest control, leading to their introduction in numerous countries. Many of these species exhibit tolerance and invasiveness, as exemplified by Xiphophorus maculatus (Günther, 1866). This report documents the presence of X. maculatus in a Caribbean coastal stream in Venezuela. Quizandal Creek has experienced significant human intervention in its lower drainage and channel area. In the final segment of the creek the fish were captured using hand nets and beach seines. The specimens were transported alive to the laboratory for evaluation and subsequently preserved according to standard methods and later were cataloged in the fish collection. 16 males ♂ and 8 females ♀ (16.6-29.4 mm SL. CPUCLA-3630) from the Quizandal Creek, part of the coastal drainage of the Borburata River, were analyzed. This is the first report on the occurrence of Xiphophorus maculatus in natural environments of Venezuela. These coastal streams are situated in a zoogeographic transition zone between regional freshwater ichthyofaunas that have a limited number of species, primarily secondary and amphidromous, which could be susceptible to the presence of introduced species. Xiphophorus fish demonstrate the ability to thrive in highly degraded environments, promoting their dispersion and amplifying the impact on the habitat and local fish, particularly small endemic fish, such as the Rivulidae and Poeciliidae.

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First report of harmful Microcystis sp. and microcystin in two tributaries of Paraná River in Misiones, Argentina - (2024)

María de los Angeles Kolman, María Laura Miño, Isaias Emanuel Kunz, Pedro Dario Zapata

Volume: 36 - Issue: 0

Resumo. Abstract Aim Characterize cyanobacterial accumulations detected for the first time from November 2020 to February 2022 along the coastal zone of the Paraná River and in the Zaimán and Mártires streams in Posadas (Misiones, Argentina), by identifying the dominant species, determining their potential toxicity, and monitoring their progression using satellite images. Methods This work analyzes the presence of cyanobacteria by optical microscopy, the production of microcystin (MCY) by molecular and analytical methods, and the detection of these cyanobacterial accumulations by satellite image analysis. Results Optical microscopy analysis revealed the presence of Microcystis spp. colonies in all collected samples and Dolichospermum sp. in the Mártires stream. Using PCR amplification of a conserved region of the mcyE gene we confirmed the presence of MCY-encoding genes in all samples and MCY in the Zaimán stream using UPLC MS/MS analysis. Complementary satellite image analysis showed blooms in the Zaimán and Mártires streams were detectable during all the sampling periods. The presence of Microcystis spp., and MCY could affect the population, as well as the flora and fauna in the streams and the ecosystems along the Paraná River basin. Conclusions In this study, we successfully characterized cyanobacterial accumulations along the Paraná River coast and in the Zaimán and Mártires streams, revealing the presence of Microcystis spp. colonies and MCY-encoding genes, with potential implications for local populations and ecosystems.

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Fish parasites from a neotropical tidal river within a biodiversity hotspot - (2024)

Luddy Searom Carias de Moraes, Ana Paula Lula Costa, Ricardo Massato Takemoto, Andre Andrian Padial

Volume: 36 - Issue: 0

Resumo. Abstract: Aim We investigated the ichthyofauna parasite component community across a gradient of anthropogenic pressures of the Guaraguaçu River, south Brazil, a Neotropical river of central importance for biodiversity conservation. Methods After fish sampling, all fish were identified, measured, weighed and eviscerated. The viscera and gills were inspected for parasite screening and subsequent identification. Parasite diversity estimators were calculated for the most abundant host species. Results A total of 159 host specimens from 12 species were examined, being 140 (88.05%) found to be infected with at least one parasite, including 14 new parasite occurrences. The most widely distributed parasite was the nematode Contracaecum sp., found in 8 host species. The highest mean infection intensity and mean abundance was observed for the monogenean Aphanoblastella mastigatus, infecting the Silver catfish Rhamdia quelen. The Shannon-Wiener, Jost and Simpson indexes were higher for the more abundant fishes, except for the Trahira Hoplias malabaricus. Most host species harbored parasites in poorly aggregated distribution, according to the discrepancy index. The Berger-Parker index showed monogenean dominance in all hosts except for H. malabaricus. We found little evidence for parasite infracommunity changes across the gradient of the river. Conclusions We described the infection patterns in an important Neotropical river. The new parasite occurrences highlight the contribution of our study. Fish-parasite interactions changed throughout the river stretches, and we argue that it does not necessarily means changes in diversity and abundance of parasite within species, but the rearrange of interactions. Moreover, it seems that parasites are more abundant in most impacted sites, another reason to continue the monitoring.

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Flood did not cause the taxonomic and functional homogenization of Chironomidae (Diptera) community in a Neotropical floodplain - (2024)

João Pabllo Silva da Silva, Danielle Katharine Petsch

Volume: 36 - Issue: 0

Resumo. Abstract: Aim We investigated the hypothesis that flood decreases the taxonomic and functional beta diversity of Chironomidae (Diptera) larvae among floodplain lakes, causing biotic homogenization. Methods We collected benthic samples using a modified Petersen grab in 18 lakes in a flood period (March 2011) and a drought period (September 2011) in the Upper Paraná River floodplain. We compared the taxonomic and functional beta diversity of Chironomidae among lakes in flood and drought periods using a multivariate dispersion analysis (PERMDISP). Results We found similar taxonomic and functional beta diversity of the Chironomidae between hydrological periods. Conclusions We did not find evidence of biotic homogenization due to flood pulse. Our findings suggest other mechanisms besides increasing connectivity and environmental similarity due to flood pulse that may structure the benthic community, such as variation in the identity of flood-tolerant morphospecies across lakes.

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Hatching of Cladocera (Crustacea: Branchiopoda) resting eggs from permanently hydrated and temporarily dehydrated sediments of an Amazon lake - (2024)

Camila de Araújo Couto, Raize Castro-Mendes, Renan Gomes do Nascimento, Alexander Armando Flores Arzabe, Luis Geraldes Primeiro, Maiby Glorize da Silva Bandeira, Edinaldo Nelson dos Santos-Silva

Volume: 36 - Issue: 0

Resumo. Abstract: Aim i) to characterize the composition of the Cladocera species hatched from the resting eggs of permanently hydrated and temporarily dehydrated sediments; ii) to test whether periodic dehydration reduces the hatching of the resting eggs. Methods Cladocera resting eggs were collected from the sediment of Tupé lake, Amazonas, Brazil. Sampling was performed in the dry season, when the sediment was found in two conditions: Permanently Hydrated Sediment (PHS) in the lake main channel and Temporarily Dehydrated Sediment (TDS) on the margin. Hatching was experimented through a temperature of 24 °C (± 2 °C) and a photoperiod of 12h light: 12h dark, for 20 days. Results Eight Cladocera taxa were counted among the two sediments. In PHS five taxa (one exclusive) were identified and seven taxa (three exclusive) occurred in TDS. The comparison of the hatching rate of Cladocera eggs between TDS (0.36 ± 0.48%) and PHS (0.32 ± 0.49%) was not significant (GLM: χ21= 0.012; P > 0.05; Pseudo-R2M= 0.0006). Conclusions The hypothesis that periodic dehydration of Cladocera resting eggs reduces egg hatching has been refuted. This leads us to conclude that natural periodic dehydration does not affect the hatching of resistance eggs, therefore, resistance eggs, as already reported in the literature are an important mechanism for the maintenance and success of organisms in environments, even undergoing profound changes caused due to the large variation in water levels that occur in Amazon rivers and associated environments.

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Hydrologic cycle influence on desmid abundance in a shallow floodplain lagoon in the Brazilian semiarid region - (2024)

Maria Aparecida dos Santos, Carla Ferragut, Daniela Mariano Lopes da Silva, Carlos Wallace do Nascimento Moura

Volume: 36 - Issue: 0

Resumo. 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.

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Ichthyoplankton distribution set by different environments shapes in a coastal freshwater lagoon - (2024)

Carolina Antonieta Lopes, David Augusto Reynalte-Tataje, Alex Pires de Oliveira Nuñer

Volume: 36 - Issue: 0

Resumo. Abstract Aim This study aimed to evaluate the spatial and temporal distribution of ichthyoplankton in the Peri Lagoon, a coastal freshwater lagoon in Brazil. Methods Ichthyoplankton samples were collected every two months from June 2008 to April 2010 with 500 µm conical-cylindrical planktonic nets at five sampling stations. Results In total, 181 fish eggs and 1,315 larvae, representing estuarine and freshwater species, were captured. The most representative species were Awaous tajasica, Ctenogobius sp1, and Platanichthys platana. Significant differences were found in temporal egg distribution and larval spatiotemporal distribution (Kruskal-Wallis test, p < 0.05). Eggs were predominantly captured during the autumn, winter, and spring Neotropical seasons. Geospatial analysis demonstrated spatial segregation in the distribution of larval assemblages, with higher abundances in areas adjacent to riparian forests, following stream mouths, and deeper areas with rocky substrates. Conclusions Proximity to streams and areas surrounded by dense forests is crucial for the spawning and development of fish species in the Peri Lagoon. The findings of this study provide valuable insights into the conservation of the ichthyofauna in this unique environment.

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