http://repositorio.ufc.br/handle/riufc/324 2026-06-18T21:21:50Z http://repositorio.ufc.br/handle/riufc/86788 Título: Calibração pólen-vegetação e reconstituição paleoambiental dos últimos 7.500 anos de sedimento lacustre no ecótono cerrado-caatinga (NE, Brasil) Autor(es): Silva, Maria Virgínia Oliveira da Tipo: Tese 2025-01-01T00:00:00Z http://repositorio.ufc.br/handle/riufc/86611 Título: Potencial dendrocronológico e relações clima-crescimento em espécies de manguezal Autor(es): Silva, Mateus de Oliveira Tipo: Dissertação 2026-01-01T00:00:00Z http://repositorio.ufc.br/handle/riufc/86435 Título: Análise geoquímica de micronutrientes metálicos e aplicação de índices de risco ecológico em solos de áreas suscetíveis à desertificação no Jaguaribe, Ceará Autor(es): Oliveira, Eryc Jefferson Alves de Abstract: This study evaluated the availability of metals and the associated ecological risk in soils withdifferent degrees of degradation in a desertification-prone region in the municipality ofJaguaribe, Ceará State, Brazil. Three areas representing distinct stages of degradation wereselected: control area (CA), recovering area (RA), and degraded area (DA). In each area, threecomposite soil samples were collected at a depth of 0–20 cm, totaling nine samples. Eachsample was analyzed in triplicate in the laboratory to determine its physicochemical propertiesand the concentrations of B, Cu, Fe, Mn, Mo, Ni, and Zn. Metal concentrations were obtainedby partial acid digestion according to the EPA 3051A method and expressed as pseudo-totalconcentrations. Potential ecological risk was assessed using quantitative indices:Geoaccumulation Index (Igeo), Pollution Index (PI), Enrichment Factor (EF), and PollutionLoad Index (PLI). Statistical analyses were performed to evaluate the influence of independentvariables (soil degradation degree: DA, RA, and CA; and soil physicochemical attributes, suchas pH and organic matter) dependent variables corresponding to metal concentrations. Thisanalysis included normality tests, ANOVA, Kruskal-Wallis, and Spearman correlation. Ingeneral, soils from the degraded area showed lower concentrations of essential metals, exceptfor Fe, which presented higher levels in the degraded area, possibly due to the accumulation ofiron oxides in the clay fraction. Ecological risk indices indicated the absence of significantanthropogenic contamination, with values classified as non-polluted or minimally enriched.Significant correlations between Cu and B with organic matter, and between Ni and Zn withpH, suggest that the dynamics of these metals are strongly influenced by these soil attributes,affecting their availability and retention. The results obtained may support decision-makingregarding the management and recovery of degraded areas in semi-arid regions susceptible todesertification. Tipo: Dissertação 2025-01-01T00:00:00Z http://repositorio.ufc.br/handle/riufc/85766 Título: Atividade e diversidade da biota do solo em agroecossistemas regenerativos e convencionais Autor(es): Silva, Hugo Felipe da Abstract: Sustainability of agroecosystems requires changes in agricultural practices that integrate soil biodiversity as a central component, with regenerative (conservationist) practices representing an alternative for coffee production systems. In this context, the present study evaluated biological diversity and its association with coffee production systems under conventional, organic and regenerative management, in areas with contrasting levels of yield: low (LY: 2,148- 3,372 kg ha⁻¹) and high (HY: 2,520-5,360 kg ha⁻¹) in the Cerrado. In this study, indicators of soil microbiota, carbon (C) and nutrients were evaluated, as well as metataxonomic analyses of bacteria and fungi. In addition, soil fauna was assessed using pitfall traps during the dry and rainy seasons. Conventional management showed higher microbial activity and β-glucosidase activity, as well as greater microbial biomass and microbial quotient, whereas regenerative management showed higher urease activity. Bacterial richness in the rhizosphere was higher under conventional management compared with regenerative management and was greater than that observed in Cerrado vegetation and in bulk soil. In contrast, fungal richness and soil macrofauna were higher in natural vegetation, and regenerative management showed greater soil fauna richness than conventional management, which presented the lowest diversity values. With regard to coffee yield under regenerative management, high positive correlation coefficients were found between yield and the microbial quotient, acid phosphatase activity and the rhizosphere C:N ratio, as well as between the Z score of surface soil biological activity and the rhizosphere effect. Conversely, yield showed high negative correlation coefficients with soil carbon and nitrogen contents and with labile carbon. Areas with lower yield showed reduced fungal richness in the rhizosphere and in bulk soil, whereas increased yield was associated with denser and more connected networks, in contrast to the pattern observed for bacterial networks. Differences in yield levels were also reflected in soil fauna, with higher richness and diversity of arthropods and greater abundance of predators (Opiliones and Araneae), and lower abundance of Formicidae, in areas of high coffee yield. Biodiversity (bacteria, fungi and arthropods) was affected by management and was associated with higher and lower levels of coffee yield in the Cerrado. Tipo: Tese 2026-01-01T00:00:00Z