https://repositorio.ufba.br/handle/ri/1229 Fri, 17 Apr 2026 03:06:17 GMT 2026-04-17T03:06:17Z https://repositorio.ufba.br/handle/ri/44047 Aspectos naturais e antropogênicos associados ao rebaixamento do aquífero cárstico do platô de Irecê, Bahia. Silva, Hailton Mello da Leal, Luiz Rogério Bastos The Hydrogeological Basin of the Verde and Jacaré Rivers, located in the north-central portion of the State of Bahia, is almost entirely overlain by an area of carbonate sedimentary rocks, which constitutes an important karst aquifer in the semi-arid region of Bahia. The clayey soil, with its reddish-yellow hue and high fertility, along with the relatively flat topography, favors agriculture, which is one of the main economic activities practiced in the region. However, given the intrinsic characteristics of a karst environment in a semi-arid climate, the lack of surface water, caused by the existence of rapid percolation zones and sinkholes that absorb rainfall and quickly incorporate it into underground drainage, as well as high evapotranspiration necessitates the search for groundwater as a means of irrigation for cultivated areas. Nevertheless, in recent decades, human occupation in the region has intensified and with the increase in cultivation, there has been a rise in drilling of tubular wells, requiring a disorderly extraction of groundwater, lowering the aquifer and jeopardizing the water potential of that reservoir. Similarly, deforestation for agricultural occupation has led to the extinction of springs responsible for feeding the rivers of this basin, transforming intermittent rivers into ephemeral ones. Likewise, the uncontrolled use of nutrients and pesticides in agriculture has contaminated the aquifer and rendered its waters unsuitable for human consumption. On the other hand, the lack of control over human occupation without adequate infrastructure for solid waste disposal and without appropriate sewage systems has contributed to this contamination due to the great fragility of the karst environment. Thus, this work aims to show that there is an association between anthropogenic and natural factors that are leading to the degradation of the Irecê karst aquifer. This objective was achieved by cross-referencing the karst characteristics of the aquifer, hydrogeological data from tubular wells, land use and occupation data obtained from satellite images and historical rainfall data in the region. It was then possible to conclude that the entire Irecê karst aquifer is subjected to anthropogenic pressure which together with the natural conditions imposed by a semi-arid climate and low rainfall could lead to stagnation of this aquifer. Similarly, this study determined that the central area of the Irecê Karst Aquifer is experiencing the greatest anthropogenic pressure, compromising both the quality and quantity of its groundwater and requiring greater attention from the management bodies in this region. As a result, suggestions were made for implementing actions that, if conducted correctly could assist in the management of the entire Irecê Karst Aquifer, with greater emphasis on the central area, thus helping to control the degradation of this important aquifer in Bahia. Universidade Federal da Bahia Tese Thu, 01 Dec 0012 00:00:00 GMT https://repositorio.ufba.br/handle/ri/44047 0012-12-01T00:00:00Z https://repositorio.ufba.br/handle/ri/43762 Avaliação de atributos físicos como indicadores de qualidade solo e estimativa de propriedades hidrodinâmicas em diferentes pedoambientes e profundidades no Semiárido Brasileiro. Barros, Taíza Nogueira Anjos, José Ângelo Sebastião Araujo dos Soil is a non-renewable natural resource, exhibiting high vulnerability that compromises its physical, chemical, and biological quality. This fragility is even more evident in arid and semi-arid regions, where shallow, sandy, or stony soils predominate, with low water retention capacity and high susceptibility to erosion. In the Caatinga biome, the replacement of native vegetation with extensive pasture systems or conventional agriculture intensifies structural degradation manifested by processes such as soil compaction from animal trampling or machine traffic, the formation of surface crusts, resulting in reduced porosity, increased apparent density, and decreased saturated hydraulic conductivity—factors that limit water infiltration, water availability, and root development of plants. In contrast, Agroforestry Systems (AFS) emerge as a sustainable alternative, promoting a greater input of organic matter, improving soil attributes, and achieving hydrological balance. This thesis aims to analyze and comparatively estimate how the pedoenvironments of the Brazilian Semi-Arid region (preserved caatinga, caatinga replaced by pasture, and caatinga replaced by agroforestry systems) influence the physical quality and hydrodynamic properties of the soil at different depths. To this end, the hypothesis was established that: the replacement of native Caatinga with different land uses alters the physical quality and hydrodynamic properties of the soil at different depths in the Semi-Arid region. Furthermore, the changes are more intense in the surface layers, while the deeper layers are less influenced by land use. In order to answer this hypothesis, two scientific articles were developed and published in the Brazilian Journal of Environmental Management and Sustainability: the first, entitled "Analysis of physical attributes as indicators of soil quality under different land use and depth conditions in the Brazilian Semi-Arid region," and the second, "Use of the Beerkan methodology to estimate hydraulic conductivity and soil sorbency in different land uses and depths in the Brazilian Semi-Arid region." The thesis is organized into four chapters: Chapter I presents an introduction, Chapters II and III correspond to the two published articles. Chapter IV presents the conclusions. The research used disturbed and undisturbed soil samples, in addition to conducting water infiltration tests and soil penetration resistance tests in three areas and at three depths. In the first article, physical attributes were evaluated: soil density; particle density; soil porosity; soil moisture; soil texture; and soil mechanical resistance to penetration. To assess the physical quality of the soil, two indicators with their respective optimal ranges or critical limits were used: Soil Density (Ds) and Soil Penetration Resistance (RP). The results were processed using Excel software to obtain descriptive statistics and the RStudio program for a Bootstrap analysis. Then, the t-test was applied to identify confidence intervals and generate the graphs. The Caatinga biome presented the functioning of the studied physical attributes as a natural reference for conservation. The agroforestry system proved to be a promising strategy for improving and maintaining the physical quality of the soil in the semi-arid region, while the pasture showed conditions of soil compaction, highlighting the need for conservation management practices to mitigate degradation processes and promote soil sustainability. In the second article, water infiltration tests were performed in the soil using a simple ring infiltrometer to estimate, through the Beerkan method, the physical-hydric attributes: saturated soil moisture; soil hydraulic conductivity; and soil sorbency. To evaluate the physical quality of the soil, hydraulic conductivity was used as an indicator chosen from the literature with its respective optimal or critical limit ranges. The results were processed using Excel software to obtain descriptive statistics and the RStudio program for a Bootstrap analysis. Subsequently, the t-test was applied to identify confidence intervals and generate graphs. The preserved Caatinga presented the best values, ensuring greater infiltration and structural quality of the soil. Pastureland shows the lowest results due to compaction and reduced macroporosity; and agroforestry systems occupy an intermediate position, contributing to the partial recovery of hydrological functions. The results obtained in this research will contribute to deepening the knowledge about the effects of land use at different depths in the Semi-arid region. Universidade Federal da Bahia Tese Wed, 29 Oct 2025 00:00:00 GMT https://repositorio.ufba.br/handle/ri/43762 2025-10-29T00:00:00Z https://repositorio.ufba.br/handle/ri/43573 Variações temporais das assembleias de foraminíferos bentônicos recentes produtores de carbonato sedimentar em área sob influência de emissário submarino, Litoral Norte da Bahia. Costa, André Ramos Leão, Zelinda Margarida de Andrade Nery The primary objective of this study was to characterize and assess the ecological status of the sedimentary environment on the continental shelf in an area adjacent to a submarine outfall along the Northern Coast of Bahia, Brazil, through the microfaunal analysis of benthic foraminifera (qualitative and quantitative composition of foraminiferal assemblages). This study aims to provide insights into the health of the ecosystem and the potential effects of pollution and local sediment dynamics in a paleoecological context, also addressing the taphonomy of the foraminiferal tests. For this purpose, grain size and foraminiferal fauna analyses were carried out at ten sites during the seasonal cycles (dry and rainy) of 2010 and 2018. In the first approach (Article 1), the results indicated homogeneity in the sedimentary environment, with sediments being predominantly biogenic and nutrient-poor, reflecting moderate to high hydrodynamic activity and the stability of the physicochemical parameters of seawater. The microfaunal analysis identified 96 species of foraminifera, revealing the dominance of symbiont-bearing species such as Amphistegina gibbosa, Peneroplis carinatus, and Archaias angulatus, which are bioindicators of good environmental quality, particularly in coral reef ecosystems. The spatiotemporal distribution of foraminiferal assemblages was consistent in both qualitative and quantitative composition, as well as in diversity estimates (H') and the FORAM Index (FI), suggesting a satisfactory ecological status for the studied portion of the continental shelf. A high rate of test anomalies was observed in symbiontbearing species, especially in areas closer to the outfall. These findings suggest the influence of anthropogenic pollution, as the study recorded the highest deformity rates near the diffuser structures. Nonetheless, the possibility that these alterations result from species regeneration in response to local hydrodynamic stress cannot be ruled out. The study confirmed that, despite the region's moderate to high hydrodynamic energy, the composition of foraminiferal assemblages and the temporal continuity of ecological patterns demonstrate the stability and resilience of the environment, even in the face of industrial activity. The second approach (Article 2) focused on the spatial-temporal distribution of the foraminiferal assemblages, their ecological characteristics, and the taphonomy (wear and coloration) of foraminiferal tests, relating these to the sedimentary environmental processes in the area. The persistent spatialtemporal patterns in the species composition and taphonomic characteristics suggest that, despite the moderate to high hydrodynamic energy typical of shallow tropical shelf environments, it does not significantly affect the distribution of foraminiferal assemblages, reflecting the uniformity in faunal composition and the clear temporal continuity observed. Universidade Federal da Bahia Tese Fri, 05 Sep 2025 00:00:00 GMT https://repositorio.ufba.br/handle/ri/43573 2025-09-05T00:00:00Z https://repositorio.ufba.br/handle/ri/43283 Caracterização da morfodinâmica das praias da Ilha da Trindade. Nascimento, Thayná Pelição Machado, Arthur Antônio Trindade Island, located in the South Atlantic Ocean, represents a tropical insular environment of high scientific and environmental relevance, yet remains poorly investigated regarding its coastal morphodynamics. This study aimed to characterize the morphodynamic behavior of six sandy beaches — Calheta, Cabritas, Tartarugas, Príncipe, Andrada, and Vermelha — through the analysis of topographic profiles collected during five field campaigns conducted between 2013 and 2024. Data were processed using Matlab®, allowing the calculation of volumetric variation (m³/m), beach mobility parameters (mean width, standard deviation, and coefficient of variation), and the identification of seasonal erosion and progradation patterns. The results revealed contrasting morphodynamic behaviors among the beaches. Critical erosion prevailed at Calheta, Cabritas, and Príncipe, reflecting their greater exposure to storm waves and limited geological protection. Conversely, Andrada and Tartarugas showed a stronger tendency toward progradation, related both to sediment supply and to biogenic disturbances, particularly sediment reworking caused by nesting green turtles. Vermelha Beach exhibited an intermediate response, influenced by reef structures and rip-current dynamics. Temporal variations in beach mobility highlighted the combined influence of cold fronts and southern swells, as well as possible indirect anthropogenic effects. The integrated approach combining long-term field surveys enabled the identification of the most erosion-prone sectors and provided valuable insights into sediment transport processes in Brazilian oceanic islands. These findings underscore the importance of continuous monitoring as a basis for conservation and coastal management strategies in vulnerable insular systems, particularly in the face of climate change and projected sea-level rise. Universidade Federal da Bahia Dissertação Mon, 25 Jul 0007 00:00:00 GMT https://repositorio.ufba.br/handle/ri/43283 0007-07-25T00:00:00Z