https://repositorio.uema.br/jspui/handle/123456789/2172 2026-07-16T10:46:13Z 2026-07-16T10:46:13Z https://repositorio.uema.br/jspui/handle/123456789/6301 2026-07-14T14:39:31Z 2025-12-30T00:00:00Z

Título: Influência da atividade pesqueira na contaminação por plásticos em peixes do Lago Viana, Área de Proteção Ambiental (APA) da Baixada Maranhense Abstact: Plastic pollution in aquatic ecosystems poses a challenge to biodiversity conservation and food security, especially in regions where artisanal fishing is a socially relevant activity. This study evaluated the occurrence and characterized plastic particles in two biomonitor fish species, Pygocentrus nattereri and Hypostomus plecostomus, collected in Lake Viana, Maranhão, during the dry and rainy seasons. Biometric data (weight, total length, and standard length) were recorded, and stomach contents were analyzed to identify plastic particles according to type, color, size, and polymeric composition. Statistical analyses included comparisons between seasonal periods and species, as well as correlations between biometric variables and the number of ingested particles. A total of 79 plastic particles were identified, with an absolute dominance of fibers (94–100%) and a smaller proportion of fragments. The most frequent colors were transparent and blue, varying according to species and season. Infrared spectroscopy revealed a predominance of polyamide (51.9%) and rayon (24.1%), followed by polypropylene, polyester, polystyrene, polyethylene, and polyurethane. No significant differences were found in plastic ingestion between species or seasonal periods. The ecotoxicological risk assessment, based on chemical composition and polymer hazard categories, indicated that most detected polymers are classified as moderate risk, although high- risk materials such as polystyrene and polyurethane were also present. The results indicate that exposure to plastic particles in Lake Viana is more strongly influenced by the environmental availability and persistence of plastic debris than by species-specific traits, highlighting the need for integrated mitigation strategies. This study contributes to advancing knowledge on plastic pollution in tropical freshwater environments and aligns with the goals of the 2030 Agenda, particularly Sustainable Development Goals 3, 12, and 14.

2025-12-30T00:00:00Z https://repositorio.uema.br/jspui/handle/123456789/6293 2026-07-10T13:56:11Z 2024-03-05T00:00:00Z

Título: Avaliação dos impactos ambientais através das respostas bioquímicas em ostras Crassostrea sp. (Bivalvia, Ostreidae) na baía de São José - Maranhão Abstact: The responses of organisms as an environmental monitoring tool have been used by organisms sensitive to changes that occur in the environment. Among the organisms used as biomonitors, oysters stand out, which accumulate large amounts of contaminants in their tissues. In this sense, this research aimed to determine the physical-chemical parameters of seawater at three points in São José Bay, Maranhão - Brazil, perform biometry of oysters of the genus Crassostrea, evaluate the anthropic impact through the quantification of nitrites (NO2) and identify oyster species through molecular analysis. For this, oysters of the genus Crassostrea were collected in the dry season in October 2022 and the rainy season in March 2023 at three points in São José Bay, point S1 (cultivation - Raposa), S2 (extractivism - Paço do Lumiar) and S3 ( urban area- São José de Ribamar). During the time of each collection (low tide), the physical-chemical parameters of the water were recorded at all sampling points and compared with CONAMA Resolution No. 357/2005, 2 ml of seawater was also collected at the three sampling points for NO2 quantification. The nitrite present in the oysters' supernatant was analyzed indirectly through the Griess reaction, which quantifies nitrites. For molecular analysis, DNA extraction techniques using the saline protocol and the Polymerase Chain Reaction were used. Analyzes of the physicalchemical parameters of seawater demonstrated that pH and temperature remained within established limits, except during the rainy season in the extractive area. The concentration of dissolved oxygen remained low at points S2 and S3. In the biometric analysis, it is possible to observe that oysters from extractivism are smaller in all dimensions, especially in the rainy season. The result of nitrite quantification in the oyster supernatant revealed significantly higher concentrations in the extraction area (dry period 0.41 ± 0.7 mg/L and rainy period 0.28 ± 0.11 mg/L), showing that this area is the most impacted. Regarding molecular identification, it was possible to observe a pattern of bands that correspond to Crassostrea gasar and Crassostrea rhizophorae. Therefore, the results found indicate that the quantification of nitrites is an innovative, simple, effective and low-cost tool that can be used in environmental monitoring in addition to the physical-chemical parameters of water and biometric analysis

2024-03-05T00:00:00Z https://repositorio.uema.br/jspui/handle/123456789/6289 2026-07-09T19:37:05Z 2023-01-19T00:00:00Z

Título: Colonização de organismos incrustantes em diferentes tipos de substratos artificiais na Baía de São Marcos, São Luís - MA Abstact: This study had as objective to invertigate the occurrence of fouling organisms in diferente types of substrates the area of São Marcos Bay, under port influence. For the study, three sampling points were defined, which were accessed on four dates between the periods of December/2020 to September/2021, quarterly. The specimens were sampled with recruitment panels composed of four different substrates (acrylic, polyethylene, metal and wood). In situ abiotic variables were also measured, in order to understand the communities tolerances. Appraising the average values of the abiotic parameters, it was observed that there were no significant differences between the stations sampled, except for the metals: boron, copper and zinc with their respective values (p-value = 0.04; 0.004 and 0.015). The values (mg/L) obtained for all metals are above the recommended by CONAMA Resolution no 357/2005. Tukey's test revealed that density was higher in P1 than in P2 and P3, while equity was significantly lower in P1 compared to the other areas. The richness in metal and wood substrate were significantly higher than that found in polyethylene. The non-metric multidimensional analysis (nMDS) showed a grouping in the density of species at point P1, however for the substrates it did not show an ordering of densities, showing few comparisons of efficiency between substrates and a good balance of similarity at P2. The Canonical Correspondence Analysis (CCA) explained 92.12% of the observed data in the add of the two axes, revealing that the zinc concentration negatively influenced four species in P1. Three taxa represent new records for Brazil, namely: Lagis sp., (Polychaeta); Cerapus cf. bumbumiensis (Amphipoda); Natica cf. vitellus (Gastropod) that need to have their studies expanded to determine whether their occurrences indicate bioinvasion events. Studies reveal that chemical components may be influencing the density of encrusting organisms in P3. Therefore, the results of this study indicate that the anthropic processes generated by the port complex influence the distribution of native diversity, as well as attracting exotic species through port activities.

2023-01-19T00:00:00Z https://repositorio.uema.br/jspui/handle/123456789/6281 2026-07-08T19:44:59Z 2026-02-02T00:00:00Z

Título: Uso do hábitat e padrão de estruturação das assembléias de aves Charadriiformes (Charadriidae, Scolopacidae e Laridae) na Ilha de São Luís, zona costeira maranhense Abstact: The coastal ecosystem of São Luís Island harbors a diverse array of habitats utilized by Charadriiform birds during parts of their life cycle. These habitats are selected during the overwintering period based on food availability, refuge from predators, and suitability as stopover sites during migration. This study investigated the structure, diversity, and habitat preferences of Charadriiform bird assemblages in the coastal zone of São Luís Island across four distinct areas—Porto do Itaqui, Praia do Cajueiro, Ferry Boat, and Canal da Raposa—using 500-meter transects surveyed on foot and by boat between March 2023 and July 2025. Direct counting and bioacoustic methods were employed for species identification, and comprehensive statistical analysis was conducted using Generalized Linear Mixed Models (GLMMs). A total of 31 species were recorded, eight of which are classified as threatened at the national level. The Raposa area exhibited the highest species richness (31), followed by Porto do Itaqui (22), Cajueiro (19), and Ferry (18). Regarding maximum abundance across the areas, *C. pusilla* showed the highest count (8,000) at Cajueiro, while *Calidris minutilla* showed the lowest count (2) at Raposa. Of the 36 models generated, the GLMM accounting for the interaction between area and habitat—including time as a factor and a zero-inflated component—was identified as the most competitive model for explaining bird diversity. Porto do Itaqui stood out in pairwise comparisons of diversity indices among the areas, demonstrating greater evenness between diversity and abundance. Regarding habitat preference, *C. pusilla* was primarily associated with "Lavado" (LAV) and mangrove (MAN) habitats, while *C. semipalmatus* and *A. interpres* preferred dune habitats with temporary lagoons (DLT). *C. cirrocephalus* in Sea and River (MR) and Sandy Intertidal Zone (ZIA) habitats; *P. simplex* in Beach (PRA) habitat; *L. atricilla*, *G. nilotica*, *S. superciliaris*, and *S. antillarum* in Sea and River (MR) habitats; *C. canutus*, *T. acuflavidus*, *S. hirundo*, and *R. niger* in Beach (PRA) and Sandy Intertidal Zone (ZIA) habitats. The results underscore the importance of coastal environments in Maranhão in the face of anthropogenic threats to habitat quality at migratory bird wintering and stopover sites, contributing relevant information to conservation policies for the study areas—such as the National Coastal Management Plan (PNGC) and the Coastal Management Law (Law No. 7.661/1988)—given that these habitats are crucial for population continuity during migration, particularly for species experiencing population declines, such as *C. pusilla*, *S. antillarum*, and *C. wilsonia*; the study also supports monitoring efforts for the National Action Plan (PAN) for the Conservation of Migratory Birds.

2026-02-02T00:00:00Z