Acta Limnologica Brasiliensia

Experimental approach on the contribution of wind and animal vectors in the dispersal and colonization of testate amoebae (Protista, Amoebozoa) in freshwater ecosystems

2025-01-31T21:41:04.508000Z

Matos, Matheus Henrique De Oliveira De; Oliveira, Felipe Rafael De; Lansac-Tôha, Fernando Miranda; Progênio, Melissa; Meira, Bianca Ramos De; Santana, Loiani Oliveira; Cochak, Crislaine; Velho, Luiz Felipe Machado;

Abstract: Aim We aimed to understand how testaceous amoebae spread in new sites, assessing their dispersal potential by wind and animals in freshwater ecosystems. Methods We conducted a field experiment over 33 days between July and August 2018. The study included four different approaches: (i) a control group exposed exclusively to wind, (ii) the addition of propagules dispersed by Odonata (aquatic insects), (iii) the addition of propagules dispersed by amphibians, and (iv) the combined addition of propagules of both animals. Results We detected a total of 13 species of testate amoebae. Regarding species richness, we observed a steady increase throughout the experimental period. In terms of abundance, a similar trend was observed, with differences in the treatment of all vectors combinated, when comparing the treatments with only wind, and the combination of wind and vectors alone, indicating a possible progressive colonization of these organisms in the new aquatic environment. Regarding the composition of testate amoebae, we did not detect significant differences between treatments within each period or between different treatments throughout the experiment. Conclusions Our results demonstrate the importance of animal vectors in the transport of testate amoebae cysts.

Ichthyofauna of the Brazilian semiarid region reservoirs: a scientometric analysis of publications from the last 50 years

2025-01-31T21:41:04.508000Z

Pinto, Ana Luisa Eufrasio; Pereira, Juan Alves; Terra, Bianca De Freitas;

Abstract: Aim The construction of reservoirs in the Brazilian semiarid region is a predominant practice aimed mainly at water supply. Introducing fish in these ecosystems has generated environmental and social consequences. We analyzed articles on the ichthyofauna found in reservoirs from this region over the past 50 years. Methods This qualitative-quantitative scientometric analysis considered the scientific impact of the articles, the origin of the species studied, the main topics covered, and women´s participation in the authorship. The articles were collected from the leading research databases: Google Scholar, SciELO (Scientific Electronic Library Online), and Web of Science. Results We found 60 scientific papers on the subject. Most had low impact and visibility, and the state that contributed the most was Rio Grande do Norte (RN). The three most studied reservoirs made up almost half of the articles found (28). Research has only advanced considerably in the last decade, and the most discussed topics are related to the cultivation of commercial fish species, emphasizing pisciculture, reproductive biology, and fish nutrition. Conclusions Despite the significant number of women participating, their visibility in the scientific community remains limited, which affects the community as a whole. Besides, it is crucial to continue promoting research on fish taxonomy, phylogenetics, and functional ecology in the reservoirs of the Brazilian semiarid region.

Coordinating in situ lake sampling with satellite acquisition days provides a mechanism for addressing data scarcity: a case study from Lake Yojoa, Honduras

2025-01-31T21:41:04.508000Z

Fadum, Jemma; Steele, Bethel; Ross, Matthew; Groff, Mia; Hall, Ed;

Abstract: 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 in Lake Yojoa, Honduras. Methods Satellite remote sensing data obtained within a 7-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= 0.57) agreement and reasonable uncertainty (MAE = 0.58 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.

Microcrustaceans structure determined by the type and trophic state of lakes

2025-01-31T21:41:04.508000Z

Nogueira, Bharguan Pizzol; Moreira-Silva, Camila; Marigo, Thaís Coimbra; Perbiche-Neves, Gilmar;

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

Environmental heterogeneity in wetlands increases alpha and beta diversity of cladocerans (Crustacea, Branchiopoda) at local and regional scale

2025-01-31T21:41:04.508000Z

Sousa, Francisco Diogo Rocha; Elmoor-Loureiro, Lourdes Maria Abdu; Mendonça-Galvão, Luciana; Simões, Nadson Ressyé;

Abstract: Aim The goal of this study was to investigate the effect of habitat heterogeneity on diversity on a local and regional scale. We tested two hypotheses: (i) the habitat diversity, given by quantity of microhabitat by macrophytes richness, 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 macrophytes 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 was correlated with the number of microhabitats and the variability between microhabitats in wetlands.

Effects of urban pollution on zooplankton diversity along the Almada River (Bahia, Brazil)

2025-01-31T21:41:04.508000Z

Santos, Jovenilson Ferreira Dos; Nascimento, Jaielle Rodrigues; Simões, Nadson Ressyé;

Abstract: 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 cities: Almadina, Coaraci and Itajuípe, between the years 2020 and 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 zones was high, indicating a low rate of species sharing between the CW and DA zones. 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.