Navegando por Autor "Santos, Gleice de Souza"
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Item Diversidade do zooplâncton entre hábitats aquáticos de Minas Gerais.(2019) Souza, Vanessa Ferreira de; Sant'Anna, Eneida Maria Eskinazi; Beirão, Marina do Vale; Sant'Anna, Eneida Maria Eskinazi; Bonecker, Cláudia Costa; Santos, Gleice de SouzaEstudos de padrões ecológicos e diversidade β da comunidade zooplanctônica podem ser fundamentais para a compreensão dos padrões de organização dos ecossistemas aquáticos. A organização das comunidades zooplanctônicas responde a vários aspectos dos habitats aquáticos, incluindo conectividade, distúrbios, origem e localização geográfica do corpo d’água. Neste estudo foram utilizados dados publicados sobre a comunidade zooplanctônica das principais bacias hidrográficas do estado de Minas Gerais (MG, Brasil). Foram analisados 31 trabalhos científicos publicados entre os anos de 2005 e 2019 e a riqueza, a composição e a diversidade beta da comunidade zooplanctônica foram avaliadas para quatro variáveis: (I) bacias hidrográficas (variação espacial); (II) tipo de corpo d’água (lagos, lagoas, reservatórios e rios); (III) altitude (menor que 800 m.a.n.m. – baixa – ou maior que 800 m.a.n.m. - alta); e (IV) hidroperíodo (permanente ou temporário). Espera-se que a riqueza, a composição e a contribuição da diversidade beta de zooplâncton de MG podem modificar em relação à todas as variáveis testadas, e que a diversidade β que contribui mais para a diversidade γ. Houve forte influência do efeito espacial sobre a diversidade zooplanctônica, em que sistemas fluviais representaram o tipo de corpo d’água com maior heterogeneidade na comunidade zooplanctônica, acumulando mais espécies que lagos, lagoas e reservatórios. Foi detectada também maior agregação da riqueza em ambientes categorizados como de baixa altitude, com 70,37% mais espécies que de altas altitudes, considerando que houve um esforço amostral de 74,14% para ambientes considerados de baixas altitudes, e apenas 25,86% de alta altitude. Os resultados indicaram que as bacias hidrográficas do Rio Doce, Rio Grande e Rio Pardo contribuem de forma decisiva para a diversidade beta do zooplâncton. O hidroperíodo não representou influência significativa na riqueza, considerando um esforço amostral de 88,8% para ambientes permanentes e apenas 11,2% para ambientes temporários. As análises para diversidade beta mostraram que todas as variáveis contribuíram significativamente para a diversidade γ. O tipo de corpo d’água contribuiu com 50%, a altitude com 29%, o hidroperíodo com 35%, e as bacias hidrográficas exerceram a maior contribuição: 61% da diversidade γ. A decomposição da diversidade beta sugeriu que 97% dos dados da diversidade beta são impulsionados por turnover, enquanto apenas 3% são por aninhamento, reforçando a importância da conservação de ambientes repositórios de espécies. Os resultados obtidos indicam a forte influência do efeito espacial sobre a diversidade zooplanctônica, e também para a necessidade de um maior esforço amostral em bacias hidrográficas pouco estudadas, em ambientes de altitude e temporários, os quais desempenham importantes papeis na estruturação da comunidade zooplanctônica de MG. Essas observações foram corroboradas pela análise de acumulação de espécies, que indica claramente a necessidade de mais pesquisas em bacias ainda muito pouco consideradas nos estudos da diversidade zooplanctônica em Minas Gerais, a despeito de sua importância estratégica para a biodiversidade aquática e desenvolvimento sócio-econômico do estado.Item Diversidade taxonômica e funcional do zooplâncton no Baixo Rio Doce (ES, Brasil) : uma avaliação após o maior acidente com rejeito de mineração de ferro do Brasil.(2021) Paula, Tayenne Luna Tomé de; Sant'Anna, Eneida Maria Eskinazi; Santos, Gleice de Souza; Sant'Anna, Eneida Maria Eskinazi; Melo Júnior, Mauro de; Bonecker, Cláudia CostaO desastre do rompimento da barragem de rejeitos de minério de Fundão, que atingiu a bacia hidrográfica do Rio Doce, teve grande impacto sobre a biodiversidade aquática. Com o objetivo de compreender os possíveis efeitos causados pela onda de rejeito de minério no baixo Rio Doce, sobretudo pela variação das variáveis limnológicas e nas concentrações de metais, foi utilizada a diversidade taxonômica e funcional (análise de grupos funcionais e índices de diversidade funcional) do zooplâncton. Foram encontradas 33 espécies de rotíferos, 22 de cladóceros e 13 de copépodos. A abundância total de espécies foi influenciada pela concentração de clorofila-a. Rotíferos como Conochilus sp. e Keratella cochlearis, estiveram positivamente correlacionados a altas concentrações de ferro e alumínio. Alguns grupos funcionais como G1 (copépodes calanóides), G4 (cladóceros) e G9 (rotíferos) também mostraram ser mais tolerantes à presença de contaminantes associados aos rejeitos de minério. Os índices de diversidade funcional foram negativamente relacionados com o alumínio, ferro e cobre, indicando que a presença do rejeito de minério tem um efeito significativo sobre a estruturação da comunidade zooplanctônica. A organização funcional do zooplâncton pode ser considerada uma métrica sensível na avaliação de impactos ambientais por rejeito de mineração.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 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 The relative importance of regional and local factors in shaping zooplankton diversity in highaltitude tropical shallow lakes.(2020) Sant'Anna, Eneida Maria Eskinazi; Santos, Gleice de Souza; Alves, Natacha Jordania da Silva; Brito, Lorena Aparecida Fortes; Leite, Mariangela Garcia PraçaIn Brazil, although, high-altitude shallow lakes comprise large parts of conservation units and are considered highly important environments for biodiversity studies, little is known about the factors that regulate the zooplankton community. In the present study, we sought to identify the effect of regional (hydroperiod and altitude) and local (lake area and macrophyte cover) factors on the zooplankton communities in eight shallow high-altitude lakes (from 1080 m a.s.l. to lakes above 1200 m a.s.l.) in the Espinhac¸o Mountain Range (Brazil). Of the 116 zooplankton species identified, 66 (56%) showed a high degree of spatial aggregation, occurring in only a few lakes. Accessory species occurred predominantly in small lakes, while rare species were better represented in the larger lakes, suggesting species sorting associated with the niche effect. Zooplankton richness was strongly influenced by hydroperiod, indicating that temporary lakes can congregate species resistant to the environmental filter of the drought, playing an important role in the diversification of the zooplankton community. We identified environmental heterogeneity (macrophyte cover) as the factor that most influenced the species diversity: zooplankton responded positively to increased macrophyte cover, confirming that the presence of aquatic plants constitutes a strong environmental filter to explain the variation of the zooplankton community. Zooplankton species composition and abundance differed among lakes, indicating a certain degree of heterogeneity in assemblage structure, but no influence on zooplankton diversity was observed. Our results provide evidences that altitude did not influence zooplankton diversity and this may affect the regional diversity (ß diversity) of tropical high-altitude lakes, and merits further study.