https://repositorio.ufba.br/handle/ri/24090 2026-04-17T11:10:41Z https://repositorio.ufba.br/handle/ri/42612 Título: Os efeitos das mudanças climáticas nas relações tróficas microbianas em diferentes regiões dos oceanos. Autor(es): Barbosa, Felipe Alexandre Santana Primeiro Orientador: Meirelles, Pedro Milet Abstract: The relationships between microorganisms and phytoplankton are the foundation of the planetary carbon cycle. Photosynthesis removes atmospheric carbon, producing energy that is consumed by bacteria. As in other ecosystems, microorganisms are also susceptible to temperature increases. Primary production, the decomposition of organic matter, and the entire carbon cycle can undergo catastrophic changes due to this phenomenon. In this study, we investigated the impact of climate change on microbial and phytoplankton communities using oceanic vortices in the Brazil-Malvinas Confluence (BMC) region as a natural experimental system. To this end, we integrated flow cytometry, metagenomics, phytoplankton abundance and composition, and physicochemical variable data. This experimental system enabled simulations of warming in two ocean regions: one warm, with waters of equatorial origin, and another cold, with waters from polar regions. Our results reveal that warming induces a 50% decrease in phytoplankton abundance and a 60% increase in bacterioplankton abundance. Additionally, we found a change in the structure and composition of the phytoplankton and bacterial communities. For example, we identified a sixfold increase in the abundance of Karlodinium, a toxin-producing dinoflagellate, in the warmed waters. Conversely, we observed a twofold reduction in Minidiscus, an important diatom for oceanic carbon sequestration, in cold waters. These changes, along with observed differences in fluorescence, suggest a reorganization of microbial and phytoplankton communities, with the replacement of primary producers from eukaryotic phytoplankton to bacterioplankton. This shift has the potential to affect nutrient cycling and primary production, possibly impacting the amount of sequestered carbon, the biomass available for other organisms' consumption, and long-term carbon storage. Editora / Evento / Instituição: Universidade Federal da Bahia Tipo: Dissertação 2024-01-01T00:00:00Z https://repositorio.ufba.br/handle/ri/42549 Título: Avaliação dos fatores ambientais associados à soropositividade para Leptospira SPP. em cães residentes de assentamentos urbanos informais em salvador, brasil Autor(es): Baqueiro, Andrea Marcos Primeiro Orientador: Costa, Federico Abstract: This study investigates the environmental factors associated with canine leptospirosis in Salvador, Bahia, Brazil. Canine leptospirosis, caused by spirochetes of the genus Leptospira, is a significant zoonosis for public health due to its potential for transmission to humans. The tropical climate of Salvador, characterized by high humidity and elevated temperatures, along with the rainy season, creates favourable conditions for the proliferation of Leptospira. Deficient urban infrastructure and sanitation conditions, especially in the outskirts and low-income communities, increase the risk of environmental contamination with the urine of infected animals, primarily rodents, which are natural reservoirs of Leptospira. Dogs that come into contact with these contaminated environments can transmit the disease to humans. The study was conducted in the communities of Marechal Rondon and Pau da Lima. Biological samples were collected from dogs residing in these areas to assess the presence of anti-Leptospira antibodies using the microscopic agglutination test (MAT). Of the 279 dogs tested, 89 (31.9%) were positive, with a prevalence of 29.22% in Marechal Rondon and 35.20% in Pau da Lima. The results indicate that factors such as the presence of a backyard, frequency of zoonosis control, contact with rats, and paved access are determinants of seropositivity for canine leptospirosis. Proximity to watercourses was a significant factor, corroborating previous studies indicating that areas with higher accumulation of garbage and water favour the persistence of pathogens. Identifying critical environmental and structural factors, along with promoting preventive practices such as vaccination and environmental control, are essential to reduce the incidence of canine leptospirosis. This study contributes to the understanding of local disease dynamics and the development of effective control strategies in vulnerable urban areas. Editora / Evento / Instituição: Universidade Federal da Bahia Tipo: Dissertação 2024-06-19T00:00:00Z