Navegando por Autor "Silva, Edissa Emi Cortez"
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Item Do metals differentiate zooplankton communities in shallow and deep lakes affected by mining tailings? : the case of the Fundão dam failure (Brazil).(2022) Santos, Gleice de Souza; Silva, Edissa Emi Cortez; Barroso, Gilberto Fonseca; Pasa, Vanya Marcia Duarte; Sant'Anna, Eneida Maria EskinaziThe effects of exposure to mining tailings on water quality and biota of tropical lacustrine ecosystems remain poorly understood. We tested the hypothesis that after mining tailing spills, shallow lakes should retain higher metal concentrations in comparison with deep lakes, which might contribute to differentiating species sorting and community structure of zooplankton in both ecosystems. Surveys were performed in 6 Brazilian lakes af- fected by the Fundão dam failure from October 2018 to September 2019. The shallow lakes showed higher values of turbidity (19.4 ± 12.9 NTU), conductivity (846.5 ± 1727.1 μS.cm-1), total organic carbon (11.6 ± 4.6 mg.L-1), total nitrogen (2688.7 ± 2215.6 μg.L-1), iron (2507.5 ± 726.9 μg.L-1), aluminum (419.9 ± 166.5 μg.L-1) and man- ganese (150.8 ± 146.2 μg.L-1) and lower zooplankton richness (9.2 ± 3.2) compared to the deep lakes (13.4 ± 3.0), which showed higher cyanobacteria density (84.7 103 ± 69.3 103 cel.mL-1). We recorded negative relation- ships between zooplankton richness and turbidity, conductivity, iron, zinc and vanadium, indicating that as well as morphometric characteristics of lakes (area and depth) have an important role in zooplankton richness, the coupling between metals and limnological variables represent decisive environmental filters for species sorting of zooplankton. The variation-partitioning analysis showed that limnological variables and metals explained zoo- plankton composition, highlighting that metals play major influence on zooplankton composition. We suggest that the shallowness of the lakes should had promoted often resuspension of mining tailings that caused in- creases in metal concentrations in water column. The results indicate that the shallow lakes presented higher vulnerability to mining tailings exposure than the deep lakes, which may have substantially contributed for differentiating zooplankton communities in both ecosystems. This study reveals the need for considering shallow lakes as priority target for conservation among freshwater ecosystems affected by mining tailings.Item Egg production and life history of Alona guttata Sars, 1862 (Cladocera, Chydoridae) : implications for colonization of temporary ponds.(2022) Silva, Edissa Emi Cortez; Souza, Vanessa Ferreira de; Santos, Gleice de Souza; Sant'Anna, Eneida Maria EskinaziCladocerans are a diverse group of species that show rapid responses to changes in environmental conditions. This adaptive capacity has important implications for egg production and life cycle, especially in transitory environments such as temporary waterbodies. The present study investigated the life history and egg production of Alona gutatta Sars, 1862 (Crustacea, Cladocera), an abundant and frequent species from a high-altitude temporary pond (Lagoa Seca, Minas Gerais, Brazil). Newly hatched neonates were monitored in relation to time of maturation, number of eggs produced per female and time of survival. Neonates required a mean of 8 days to mature. A. guttata survived for a mean of 30.9 ± 8.1 days and produced 2 eggs per brood, generating a mean of 10.95 ± 6.41 neonates during the entire life cycle. The rapid development, short time to produce eggs and long life cycle are important adaptations to the adverse environmental conditions of temporary aquatic environments, which can contribute to the rapid colonization of Alona guttata in transitory ecosystems.Item Impacts of exposure to mine tailings on zooplankton hatching from a resting egg bank.(2021) Santos, Gleice de Souza; Silva, Edissa Emi Cortez; Balmant, Florinda Moreira; Gomes, Paula Cristine Silva; Sant'Anna, Eneida Maria EskinaziIn the last five years, two colossal envi- ronmental disasters involving iron-enriched mine tailings have occurred in Brazil, affecting many aquatic ecosystems over the short, medium and long- terms. This study investigated whether these iron- enriched mine tailings affect the main biotic strategy to restore zooplankton populations affected by severe stress, i.e., hatching of dormant stages. A 30 day hatching experiment was conducted, using a resting egg bank from a natural lake, exposed to 3 concen- trations of mine tailings: control (0 g), T25 (25 g) and T50 (50 g). A total of 22, 15 and 16 species hatched in the control, T25 and T50, respectively. Conochilussp., Filinia terminalis, Hexartha mira, Bosmina longirostris and Ceriodaphnia silvestrii hatched only in the control, which suggests that these species are sensitive to any concentration of mine tailings. A gradual decrease in richness and hatchling abundance was recorded, from the control (8.0 ± 1.0 SE species and 1597 ± 73.9 hatchlings) to T25 (4.6 ± 1.2 species and 1279 ± 136.5 hatchlings) and then to T50 (2.3 ± 1.2 species and 603.3 ± 61.9 hatchlings). Our results suggest that exposure of zooplankton resting eggs to iron-enriched mine tailings may negatively impact these egg banks in natural ecosys- tems, with potential impacts on the restoration of zooplankton communities after even short-term exposures.Item Interaction between Epistylis sp. and copepods in tropical lakes : responses of epibiont infestation to species host density.(2020) Santos, Gleice de Souza; Ibraim, Vanessa Rezende Cerceau; Silva, Edissa Emi Cortez; Sant'Anna, Eneida Maria EskinaziInteraction between Epistylis sp. and copepods was investigated in 3 tropical lakes. Epibiont load was higher in Thermocyclops minutus compared to Notodiaptomus ssp. at light compensation depth. No difference was found at surface. Infestation of Epistylis sp. seems to respond to copepod species densities. Attaching to more abundant copepods may increase encounter rates of epibionts with its hosts, raising biological efficiency of it even if attaching to smaller hosts when rare larger ones are present.Item A methodological proposal for the analysis of Cladocera (Crustacea, Branchiopoda) subfossils from sediments of temporary aquatic ecosystems.(2019) Silva, Edissa Emi Cortez; Cassino, Raquel Franco; Leibowitz, Zachary William; Sant'Anna, Eneida Maria EskinaziThe main objective of the present study was to promote some adaptations to the standard methodology used in the analysis of Cladocera subfossils. The samples used in this study were collected at Lagoa dos Coutos, a temporary lake located on an outcrop with iron-rich duricrust in the Serra do Gandarela (Minas Gerais, Brazil). The sediment from this pond, typical of temporary ecosystems in the region, is characterized by rigid concretions that are difficult to dissolve in aqueous media, making it difficult to visualize and analyze subfossils taxa. Sediment samples were prepared according to the standard methodology used in paleolimological studies and the methodological adaptations proposed in the present study, which included the addition of 1 mg of Kochia scoparia, a palynological marker used to estimate subfossil density, as well as the addition of hydrofluoric acid (HF) to oxidize silicate materials. The samples prepared according to the new methodological procedure improved Cladocera subfossil visualization, facilitating the taxonomic analysis of the species. The samples submitted to the standard methodological procedure had a significantly higher mean of sediment particles (mean of 84.2 sediment particles) and 70% more residues compared to the samples prepared with the newly proposed methodology (mean of 22.1 sediment particles). Absolute data on the temporal variation of the density of Cladocera subfossils was obtained by using the palinological marker K. scoparia, which showed higher densities of subfossils in more recent, humid periods (112,000 subfossils/cm3 at 5 cm, equivalent to 3,500 years BP). The results indicate that the new methodology can contribute to advances in paleolimnological studies of temporary aquatic ecosystems, whose lake histories are rarely investigated, despite their ecological relevance as ecosystems that indicate environmental and climatic changes.Item O que uma lagoa pode nos contar sobre mudanças ambientais? Uma reconstrução do passado utilizando subfósseis de cladocera.(2018) Silva, Edissa Emi Cortez; Sant'Anna, Eneida Maria Eskinazi; Sant'Anna, Eneida Maria Eskinazi; Kozovits, Alessandra Rodrigues; Bezerra Neto, José FernandesAs mudanças espaciais e temporais de sistemas lacustres podem sem contadas através de estudos paleolimnológicos utilizando proxies como os subfósseis de Cladocera e pólen. Outros indicadores ambientais como a composição isotópica do sedimento (C e N), matéria orgânica e dados geoquímicos são igualmente importantes indicadores de mudanças no pulso hidrológico e variações no clima ocorridas no passado. O objetivo desse estudo foi descrever a evolução ambiental, ao longo do Holoceno, da Lagoa dos Coutos (Serra do Gandarela - MG), uma lagoa temporária de caráter intermitente localizada sob afloramento ferruginoso, contribuindo para as descrições das mudanças paleoecológicas no Quadrilátero Ferrífero. Foram realizadas analises multi-proxy, juntamente com os dados de subfósseis de Cladocera, com o intuito de identificar padrões mais precisos sobre a evolução temporal dessa lagoa e da região. Com a extração dos subfósseis de cladóceros oito espécies foram identificadas no total, sendo possível observar que a distribuição e a presença dessas espécies estão diretamente relacionadas com a variação temporal lagoa, sendo possível diferenciar três zonas paleoambientais, as Zonas 1 e 3 apresentaram períodos mais secos, sendo compostos por uma variedade e número menor de espécies e a Zona 2 apresentou características úmidas, apresentando um riqueza e abundância maior na composição das espécies. Os outros proxies utilizados (isótopos de C e N, Matéria Orgânica, N e C do sedimento lacustre, geoquímica e pólen) corroboraram com os dados de Cladocera, sendo essenciais para confirmar a evolução temporal da lagoa dos Coutos.Item Response of cladoceran assemblages to restoration of riparian vegetation : a case study in a tropical reservoir of Brazil.(2020) Silva, Edissa Emi Cortez; Santos, Gleice de Souza; Leite, Mariangela Garcia Praça; Sant'Anna, Eneida Maria EskinaziIn recent decades, riparian vegetation has been removed from important ecosystems around the world, in spite of its high ecological importance for aquatic biota. Nevertheless, the effects of catchment land use on zooplankton have been little studied. The present study investigated if replanting riparian vegetation in a tropical reservoir influences the richness and abundance of cladoceran communities, by addressing the question of whether cladocerans show differences in richness and abundance among four levels of riparian vegetation conditions: 1) native forest (NF); 2) 30 years after forest replanting (R1); 3) 10 years after forest replanting (R2); and 4) no forest (No-F). Zooplankton samples were obtained from 9 stations in the Volta Grande Reservoir, Minas Gerais, Brazil. Cladocerans in zones NF and R1 showed higher levels of richness and abundance than in zones No-F and R2. Ceriodaphnia reticulata, Ceriodaphnia laticaudata, and Diaphanosoma spinulosum showed higher abundances in zones NF and R1. Cladoceran community structure was influenced by the different levels of riparian vegetation. This study showed that the presence and age of riparian forest positively influence the abundance, richness and diversity of cladoceran assemblages. Furthermore, our results indicated that C. reticulata, C. laticaudata and D. spinulosum are more efficient than other cladocerans in exploiting allochthonous resources provided by riparian forest. Functional diversity was higher in zones NF and R1, suggesting that the trait composition of cladoceran assemblages responds positively to recovery of riparian forest. Overall, our research suggests that cladocerans are good indicators of riparian vegetation conditions and that restoration of riparian forest positively affects cladoceran assemblages of tropical reservoirs.Item A review of 121 years of studies on the freshwater zooplankton of Brazil.(2023) Castilho Noll, Maria Stela Maioli; Meira, Bianca Ramos de; Silva, Edissa Emi Cortez; Sant'Anna, Eneida Maria Eskinazi; Diniz, Leidiane Pereira; Simões, Nadson RessyéA review was carried out on the freshwater zooplankton in Brazil, between 1900 and 2021, based on 1014 studies, and the main trends were pointed. There was an increase of studies from the 1990 s onwards, especially between 2016 and 2020. Most of them addressed ecological research, followed by taxonomical research in the past (mid-1970 s). Field studies were also more numerous than experimental and review ones, but the latter type also increased between 2016 and 2020. Most studies were developed in limnetic regions and in artificial and natural lakes, in contrast to littoral regions, streams and wetlands. Studies on cladocerans were the most numerous in all environments, followed by Copepoda and Rotifera. Protozooplankton was the least studied group, with a predominance of testate amoebae, followed by ciliates, flagellates and naked amoeba studies. We also discuss some aspects of the ecological traits, such as life cycles and life history, population and community dynamics, interactions with the environment, influence of environmental and anthropogenic factors and interspecific interactions. Studies on populations biomass, secondary production, functional ecology, long term duration and molecular analyzes were the main gaps and the next challenges. Finally, it is also necessary to understand the diversity and related variables in different environments that have few or never been studied.