Ecuadorian Amazon Research Articles

Settler urbanism, emotional geographies, and Indigenous planning in Ecuadorian Amazonia

Affects and emotions serve as tools of governance in settler urbanism, facilitating colonial dispossession and control of Indigenous land. Drawing on modernist logics, housing projects in indigenous territory seek to instill fixity and urban orders on mobile Indigenous populations through the management of fear and uncertainty. Here we examine the production of emotions associated with the development of the Pañacocha Millennium Community, a public housing project in the Petroamazonas oilfields of what was once Indigenous Kichwa territory in Ecuadorian Amazonia. We draw on research in Indigenous planning, the geographies of emotion, and critical urban studies to demonstrate the emotional impacts of the imposition of colonial governmental logics of housing production in Indigenous lands. At the same time, we examine the limitations of settler urbanist governance through emotion by documenting the embodied Indigenous relations with land, housing, and mobility captured in the concept territorio cuerpo-tierra, which has led to various forms of resistance and avoidance to the housing project. The case of the Pañacocha Millennium Community illuminates the role of emotion in urban planning and settler urbanism, in particular, and contributes to emerging work in Indigenous and decolonial planning.

Domestic dogs in indigenous Amazonian communities: Key players in Leptospira cycling and transmission?

Leptospirosis is the world's most common zoonotic disease. Mitigation and control rely on pathogen identification and understanding the roles of potential reservoirs in cycling and transmission. Underreporting and misdiagnosis obscure the magnitude of the problem and confound efforts to understand key epidemiological components. Difficulties in culturing hamper the use of serological diagnostics and delay the development of DNA detection methods. As a result, especially in complex ecosystems, we know very little about the importance of different mammalian host species in cycling and transmission to humans. We sampled dogs from five indigenous Kichwa communities living in the Yasuní National Park in the Ecuadorian Amazon basin. Blood and urine samples from domestic dogs were collected to assess the exposure of these animals to Leptospira and to identify the circulating species. Microscopic Agglutination Tests with a panel of 22 different serovars showed anti-leptospira antibodies in 36 sampled dogs (75%), and 7 serogroups were detected. Two DNA-based detection assays revealed pathogenic Leptospira DNA in 18 of 19 dog urine samples (94.7%). Amplicon sequencing and phylogenetic analysis of 16S rRNA and SecY genes from 15 urine samples revealed genetic diversity within two of three different Leptospira species: noguchii (n = 7), santarosai (n = 7), and interrogans (n = 1). The high prevalence of antibodies and Leptospira DNA provides strong evidence for high rates of past and current infections. Such high prevalence has not been previously reported for dogs. These dogs live in the peridomestic environment in close contact with humans, yet they are free-ranging animals that interact with wildlife. This complex web of interactions may explain the diverse types of pathogenic Leptospira observed in this study. Our results suggest that domestic dogs are likely to play an important role in the cycling and transmission of Leptospira. Future studies in areas with complex ecoepidemiology will enable better parsing of the significance of genotypic, environmental, and host characteristics.

Variation in diurnal cortisol patterns among the Indigenous Shuar of Amazonian Ecuador.

The hypothalamic-pituitary-adrenal (HPA) axis and its primary end product, the glucocorticoid cortisol, are major components of the evolved human stress response. However, most studies have examined these systems among populations in high-income settings, which differ from the high pathogen and limited resource contexts in which the HPA axis functioned for most of human evolution. We investigated variability in diurnal salivary cortisol patterns among 298 Indigenous Shuar from Amazonian Ecuador (147 males, 151 females; age 2-86 years), focusing on the effects of age, biological sex, and body mass index (BMI) in shaping differences in diurnal cortisol production. Saliva samples were collected three times daily (waking, 30 minutes post-waking, evening) for three consecutive days to measure key cortisol parameters: levels at waking, the cortisol awakening response, the diurnal slope, and total daily output. Age was positively associated with waking levels and total daily output, with Shuar juveniles and adolescents displaying significantly lower levels than adults (p < .05). Sex was not a significant predictor of cortisol levels (p > .05), as Shuar males and females displayed similar patterns of diurnal cortisol production across the life course. Moreover, age, sex, and BMI significantly interacted to moderate the rate of diurnal cortisol decline (p = .027). Overall, Shuar demonstrated relatively lower cortisol concentrations than high-income populations. This study expands the documented range of global variation in HPA axis activity and diurnal cortisol production and provides important insights into the plasticity of human stress physiology across diverse developmental and socioecological settings.

Neurogenomic landscape associated with status-dependent cooperative behaviour.

The neurogenomic mechanisms mediating male-male reproductive cooperative behaviours remain unknown. We leveraged extensive transcriptomic and behavioural data on a neotropical bird species (Pipra filicauda) that performs cooperative courtship displays to understand these mechanisms. In this species, the cooperative display is modulated by testosterone, which promotes cooperation in non-territorial birds, but suppresses cooperation in territory holders. We sought to understand the neurogenomic underpinnings of three related traits: social status, cooperative display behaviour and testosterone phenotype. To do this, we profiled gene expression in 10 brain nuclei spanning the social decision-making network (SDMN), and two key endocrine tissues that regulate social behaviour. We associated gene expression with each bird's behavioural and endocrine profile derived from 3 years of repeated measures taken from free-living birds in the Ecuadorian Amazon. We found distinct landscapes of constitutive gene expression were associated with social status, testosterone phenotype and cooperation, reflecting the modular organization and engagement of neuroendocrine tissues. Sex-steroid and neuropeptide signalling appeared to be important in mediating status-specific relationships between testosterone and cooperation, suggesting shared regulatory mechanisms with male aggressive and sexual behaviours. We also identified differentially regulated genes involved in cellular activity and synaptic potentiation, suggesting multiple mechanisms underpin these genomic states. Finally, we identified SDMN-wide gene expression differences between territorial and floater males that could form the basis of 'status-specific' neurophysiological phenotypes, potentially mediated by testosterone and growth hormone. Overall, our findings provide new, systems-level insights into the mechanisms of cooperative behaviour and suggest that differences in neurogenomic state are the basis for individual differences in social behaviour.

The Amazonian Architecture and Challenges Faced in Socio-Spatial Transformation Processes—Shuar and Achuar, Ecuador

This article explores the ties between vernacular architecture, culture and identity in a context of sociocultural change in the Ecuadorian Amazon. The text addresses the loss of a collective cultural identity from a historical, socio-spatial and descriptive perspective. Beliefs and traditions act as a “social glue“ uniting societies around common values, goals and norms, whose disappearance could cause this society to veer off course or to even become fragmented. Fieldwork carried out further supports these data, showcasing cultural changes which are worsened by globalization and contribute to the erosion of common beliefs. Although challenging, this also provides the opportunity to reassess values in search of new forms of local identity and significance. The article highlights the fragmentation between tradition and the beliefs concerning settlements which had been introduced by colonization through an understanding of construction processes and their spatial logic. The transformation of socio-spatial dynamics highlights the challenges faced by the Amazon, as well as attempts to strike a balance between tradition and progresses, without neglecting environmental culture or integrity due to the pressures of globalization. Therefore, understanding the different relationship systems found within a given ecosystem can provide clues on how to aid their preservation.

Biodiversity and Carbon Sequestration in Chakra-Type Agroforestry Systems and Humid Tropical Forests of the Ecuadorian Amazon

Currently, there are several studies related to climate change, carbon sequestration, and floristic composition in different scenarios and land uses. In this context, the objective of this research is: (a) to characterize biodiversity based on ecological indicators and diversity indices and (b) to evaluate carbon sequestration in different components of chakra-type agroforestry systems and secondary tropical humid forests of the Ecuadorian Amazon. For this, temporary sampling plots of 1600 m2 are established on the properties to be investigated. The study found that the structural characteristics and floristic composition vary according to the forest arrangement and the management system. Secondary forests are the most diverse, according to the Shannon (3.49), Simpson (0.96), and Margaleft (9.34) diversity indices, in addition to having the largest carbon stores with 233 (Mg C ha−1), followed by agroforestry systems in association with timber trees (TAFS) and fruit trees (FAFS) with 97.8 and 95.1 (Mg C ha−1) respectively, and cocoa monoculture (CMC) with 90.4 (Mg C ha−1). These results demonstrate the importance of conserving the remnants of tropical forests that still remain, due to the diversity of species, ecosystem services, and the total carbon they contain, as well as the agroforestry systems (AFS), systems analogous to forests, which are gradually becoming important management systems, especially if they are associated with potential species to sequester carbon, such as those documented in this and several other studies that seek solutions to global climate change.

Structured Equations to Assess the Socioeconomic and Business Factors Influencing the Financial Sustainability of Traditional Amazonian Chakra in the Ecuadorian Amazon

This study focuses on investigating the dimensions of sustainability and their influence on financial-economic sustainability (FES) in traditional agroforestry systems (TAFS) using the case of the Amazonian Chakra. The main objectives were to analyze the dimensions of sustainability and to establish the causal relationships between these dimensions and the FES. To carry out this research, 330 households in Napo Province that use the Amazonian Chakra system to grow cocoa were selected in order to analyze the relationship between the different dimensions of sustainability and FES in this unique context. The results of the study show that practices related to food security (FS) and business factors (BF) have a positive and significant impact on the FES of cocoa-producing households in the Amazonian Chakra system. These findings support the importance of ensuring the availability and quality of food and promoting responsible business practices in these environments. In contrast, the dimensions of environmental resilience (ER) and biodiversity conservation (BC) showed a negative impact on FES, highlighting an economic-financial imbalance in relation to conservation and environmental resilience actions in the Amazonian Chakra. This study contributes to the knowledge needed to promote agricultural practices that include an equal focus on FES, biodiversity conservation, and environmental resilience practices in a globally significant area, providing valuable information for the design of sustainable agricultural policies and practices in the Amazonian Chakra.

Determination of the effectiveness of the electrocoagulation process in the treatment of leachate from the controlled landfill site in Francisco de Orellana canton

The inadequate management of leachate produced in landfill sites, sanitary dumps, or its incomplete treatment generates significant environmental and public health impacts. These conditions are expected in developing countries and are a major concern, especially in sensitive areas like the Amazon. This study investigated the efficiency of electrocoagulation for removing BOD5, COD, TSS, turbidity, and color using a laboratory-scale reactor. Samples of raw leachate from the controlled landfill site in Francisco de Orellana canton, located in the Ecuadorian Amazon, were used. First, the initial conditions of the leachate were determined through a physicochemical characterization, where a reduced presence of heavy metals and high biodegradability were identified, suggesting that it is old leachate. In turn, a reactor with 5 electrodes was installed, where aluminum was used as a cathode and iron as an anode. Finally, electrocoagulation was employed with various operational combinations, where a run using 2.5 V and 20 minutes showed the highest removal efficiency on average, with reductions of 85.23% of BOD5, 98.20% of COD, 11.30% of TSS, 96.52% of turbidity, and 90.73% of color. Keywords: Electrocoagulation; Leachate; Leachate treatment.

Biological nematicides as an alternative for control of Meloidogyne incognita populations in yellow pitahaya (Sselenicereus megalanthus).

Yellow pitahaya in the Ecuadorian Amazon has become one of the most important economic crops in the region. However, the presence of pests (nematodes) in the soil has caused up to 100% of the crop's growth stages to be affected. Faced with this problem, growers use various chemical nematicides that minimize this impact but cause contamination problems. For this reason, the objective of the research was to evaluate microorganisms that control or reduce the population of Meloidogyne incognita in the pitahaya crop at the greenhouse level. The design was DBCA, and the statistical analysis was performed with the statistical package Infostat 2017, using linear mixed models and Fisher's tests at 5%. The results show that root nodules decrease when P. lilacinum + T. asperellum is applied after nematode injection (261). In addition, the lowest number of nodulations (251) was obtained when microorganisms were applied after nematode inoculation (251 nodulations). Still, when microorganisms were used before, aerial biomass growth was stimulated (384.17 g) even when nematodes were present in the root system. Keywords: microorganisms; nematodes; pitahaya.

Determination of the effectiveness of the electrocoagulation process in the treatment of leachate from the controlled landfill site in Francisco de Orellana canton

The inadequate management of leachate produced in landfill sites, sanitary dumps, or its incomplete treatment generates significant environmental and public health impacts. These conditions are expected in developing countries and are a major concern, especially in sensitive areas like the Amazon. This study used a laboratory-scale reactor to investigate the efficiency of electrocoagulation for removing BOD5, COD, TSS, turbidity, and color. Samples of raw leachate from the controlled landfill site in Francisco de Orellana canton, located in the Ecuadorian Amazon, were used. First, the initial conditions of the leachate were determined through a physicochemical characterization, where a reduced presence of heavy metals and high biodegradability were identified, suggesting that it is old leachate. In turn, a reactor with 5 electrodes was installed, where aluminum was used as a cathode and iron as an anode. Finally, electrocoagulation was employed with various operational combinations, where a run using 2.5 V and 20 minutes showed the highest removal efficiency on average, with reductions of 85.23% of BOD5, 98.20% of COD, 11.30% of TSS, 96.52% of turbidity, and 90.73% of color. Keywords: Electrocoagulation; Leachate; Leachate treatment.

Valoración de los servicios ecosistémicos del bosque primario de la comunidad Waorani Nampaweno, Orellana, Ecuador.

The Yasuní National Park is the largest protected area in Ecuador; it houses excellent biodiversity of the Amazonian tropical humid forest; it is the home of the Waoranis, an indigenous people in voluntary isolation PIAV, who depend on the resources that the forest has, in this context, this article deals with the assessment of the ecosystem services provided by the tropical humid forest of the Ecuadorian Amazon, the main objective being to determine which of these services is the most important, in addition to showing the ancestral cultural manifestations of this ethnic group; therefore The ecosystem services of the Waorani Nampaweno community, located in the Dayuma parish, Orellana province, were analyzed. In the methodology used, interviews were carried out with the two elders of the community and the inventory sheets of the National Institute of Cultural Heritage INPC, later when applying the Likert scale, the results showed that the cultural ecosystem services obtained 34 points, the highest score, Cronbach's alpha of 0.87 validates the reliability of the research, with the food supply service being the one that allows survival, however, cultural services make visible the vast knowledge and ancestral wisdom that they have treasured. It is transmitted orally by the "pikenanis" (elders) throughout the generations. The highlights of the cards were preparation for the hunt, respect for animals such as eagle and tiger, and the use of annatto as facial ink. Hunting and abundant food are celebrated through dances. The crafts and clothing are made from fibers and seeds from the forest; however, threats such as the invasion of their territory due to colonization and oil exploitation are acculturating young people, ending their way of life, identity and loss. of its ancestral cultural wealth. The Waoranis are the forest's protectors, and their right to their way of life linked to the Amazon rainforest must be strengthened. Keywords: Ecosystemic Services, waorani culture, Amazonian tropical forest, plants from Yasuní Park.

Valoración de los servicios ecosistémicos del bosque primario de la comunidad Waorani Nampaweno, Orellana, Ecuador.

The Yasuní National Park is the largest protected area in Ecuador; it houses excellent biodiversity of the Amazonian tropical humid forest; it is the home of the Waoranis, an indigenous people in voluntary isolation PIAV, who depend on the resources that the forest has, in this context, this article deals with the assessment of the ecosystem services provided by the tropical humid forest of the Ecuadorian Amazon, the main objective being to determine which of these services is the most important, in addition to showing the ancestral cultural manifestations of this ethnic group; therefore The ecosystem services of the Waorani Nampaweno community, located in the Dayuma parish, Orellana province, were analyzed. In the methodology used, interviews were carried out with the two elders of the community and the inventory sheets of the National Institute of Cultural Heritage INPC, later when applying the Likert scale, the results showed that the cultural ecosystem services obtained 34 points, the highest score, Cronbach's alpha of 0.87 validates the reliability of the research, with the food supply service being the one that allows survival, however, cultural services make visible the vast knowledge and ancestral wisdom that they have treasured. It is transmitted orally by the "pikenanis" (elders) throughout the generations. The highlights of the cards were preparation for the hunt, respect for animals such as eagle and tiger, and the use of annatto as facial ink. Hunting and abundant food are celebrated through dances. The crafts and clothing are made from fibers and seeds from the forest; however, threats such as the invasion of their territory due to colonization and oil exploitation are acculturating young people, ending their way of life, identity and loss. of its ancestral cultural wealth. The Waoranis are the forest's protectors, and their right to their way of life linked to the Amazon rainforest must be strengthened. Keywords: Ecosystemic Services, waorani culture, Amazonian tropical forest, plants from Yasuní Park.

Glass Half Full or Half Empty? The Contribution of Cacao in Traditional Agroforestry Systems to the Income of Indigenous Peoples in the Ecuadorian Amazon

Glass Half Full or Half Empty? The Contribution of Cacao in Traditional Agroforestry Systems to the Income of Indigenous Peoples in the Ecuadorian Amazon

Native microalgal-bacterial consortia from the Ecuadorian Amazon region: an alternative to domestic wastewater treatment.

In low-middle income countries (LMIC), wastewater treatment using native microalgal-bacterial consortia has emerged as a cost-effective and technologically-accessible remediation strategy. This study evaluated the effectiveness of six microalgal-bacterial consortia (MBC) from the Ecuadorian Amazon in removing organic matter and nutrients from non-sterilized domestic wastewater (NSWW) and sterilized domestic wastewater (SWW) samples. Microalgal-bacterial consortia growth, in NSWW was, on average, six times higher than in SWW. Removal rates (RR) for NH4 +- N and PO4 3--P were also higher in NSWW, averaging 8.04 ± 1.07 and 6.27 ± 0.66mgL-1 d-1, respectively. However, the RR for NO3 - -N did not significantly differ between SWW and NSWW, and the RR for soluble COD slightly decreased under non-sterilized conditions (NSWW). Our results also show that NSWW and SWW samples were statistically different with respect to their nutrient concentration (NH4 +-N and PO4 3--P), organic matter content (total and soluble COD and BOD5), and physical-chemical parameters (pH, T, and EC). The enhanced growth performance of MBC in NSWW can be plausibly attributed to differences in nutrient and organic matter composition between NSWW and SWW. Additionally, a potential synergy between the autochthonous consortia present in NSWW and the native microalgal-bacterial consortia may contribute to this efficiency, contrasting with SWW where no active autochthonous consortia were observed. Finally, we also show that MBC from different localities exhibit clear differences in their ability to remove organic matter and nutrients from NSWW and SWW. Future research should focus on elucidating the taxonomic and functional profiles of microbial communities within the consortia, paving the way for a more comprehensive understanding of their potential applications in sustainable wastewater management.

Tree Diversity and Its Ecological Importance Value in Silvopastoral Systems: A Study along Elevational Gradients in the Sumaco Biosphere Reserve, Ecuadorian Amazon

This study analyzes tree diversity and its ecological importance value in silvopastoral systems in the Sumaco Biosphere Reserve (SBR), Ecuador, along an altitudinal gradient of 400–2000 masl. Twenty-six plots distributed into low (400–700 masl), medium (701–1600 masl) and high (1601–2000 masl) zones were used. The Shannon index and the importance value index (IVI), based on abundance, dominance and relative frequency, were estimated. The results highlight that in pastures with dispersed trees, the richness of trees decreases with increasing altitude in the elevational gradient; they also show a higher tree density at lower altitudes in contrast to the Andean–Amazonian primary forests. The lower and middle zones showed higher diversity, linked to regeneration and the presence of nearby forests. Species of high commercial value, such as Cedrela odorata and Jacaranda copaia, were common, reflecting knowledge of the local timber market. In the lower and middle zones, the 10 most important species accounted for more than 70% of the trees, with up to 96% in the upper zone. A total of 51 taxa (including 42 species and nine taxa at the rank of genus) were identified, which were mostly native; 64.7% are classified by the IUCN as least-concern (LC) species, 31.4% as not evaluated (NE) species and 3.9% as vulnerable (VU) species, specifically highlighting Cedrela odorata and Cedrela montana. The study concludes with policy recommendations related to the importance of trees in silvopastoral systems for the conservation of species and the livelihoods of local communities, highlighting the need for responsible management of Amazonian pasturelands.

Patterns in the genetic structure of 49 lowland rain forest tree species co‐distributed on opposite sides of the northern Andes

AbstractThe Andes are a major dispersal barrier for lowland rain forest plants and animals, yet hundreds of lowland tree species are distributed on both sides of the northern Andes, raising questions about how the Andes influenced their biogeographic histories and population genetic structure. To explore these questions, we generated standardized datasets of thousands of SNPs from paired populations of 49 tree species co‐distributed in rain forest tree communities located in Panama and Amazonian Ecuador and calculated genetic diversity (π) and absolute genetic divergence (dXY) within and between populations, respectively. We predicted (1) higher genetic diversity in the ancestral source region (east or west of the Andes) for each taxon and (2) correlation of genetic statistics with species attributes, including elevational range and life‐history strategy. We found that genetic diversity was higher in putative ancestral source regions, possibly reflecting founder events during colonization. We found little support for a relationship between genetic divergence and species attributes except that species with higher elevational range limits exhibited higher dXY, implying older divergence times. One possible explanation for this pattern is that dispersal through mountain passes declined in importance relative to dispersal via alternative lowland routes as the Andes experienced uplift. We found no difference in mean genetic diversity between populations in Central America and the Amazon. Overall, our results suggest that dispersal across the Andes has left enduring signatures in the genetic structure of widespread rain forest trees. We outline additional hypotheses to be tested with species‐specific case studies.

Analysis of Mercury in Aquifers in Gold Mining Areas in the Ecuadorian Amazon and Its Associated Risk for Human Health.

Gold mining activity is a source of supply in many areas of the world, and especially in developing countries, it is practiced illegally and by applying unsafe techniques. Particularly in Ecuador, artisanal and small-scale gold mining (ASGM) is widespread, and it is based on the use of toxic substances, such as mercury (Hg), in gold recovery. Hg is a heavy metal that is water-insoluble, which, once mobilized, poses a threat to both the environment and human health. This study analyzes Hg concentrations in the six provinces of Napo, Sucumbíos, Orellana, Pastaza, Morona Santiago, and Zamora Chinchipe of the Ecuadorian Amazon region to conduct a human health risk assessment. Significant differences in Hg levels were found between provinces, but concentrations were below MPL imposed by Ecuadorian regulations everywhere. Nevertheless, a worrisome picture emerges, especially with regard to the most vulnerable receptors represented by the child population. There are multiple factors of incidence that may affect the possible future development of the phenomenon, and with reference to the social, economic, and environmental context of the region, it can be concluded that it may be appropriate to plan further investigation to arrive at a more comprehensive assessment. The results of this study can be used by decision makers to plan further investigation and to implement monitoring networks, risk mitigation strategies, and groundwater protection measures.

A new species of the genus Octomeria (Orchidaceae: Pleurothallidinae) from Ecuador

A new species of Octomeria was found during an orchid research expedition in the southern Ecuadorian Amazon. Octomeria jimenezii is described and illustrated, and information on its distribution, habitat and conservation status is provided. The newly proposed taxon is morphologically similar to O. pacii, from which it differs by the lower lateral lobes, with an obtuse to subacute angle to the anterior margin.

“They study for six years. We study for generations”: Renegotiating birth, power, and interculturalidad in the Ecuadorian Amazon

AbstractThis article explores how kichwa midwives negotiate interculturality as both cultural knowledge‐holders and clinical practitioners. Kichwa midwives in the Ecuadorian Amazon face a dynamic set of barriers in their position as healers, birth care givers, and indigenous activists, including intercultural government policies aimed to delegitimize them, consistent othering in relationship to biomedicine, and shifting generational involvement in kichwa health practices. Midwives engage in a complex set of relationships with the state, relying on it for the “rights” to practice their knowledge, while simultaneously being undermined by the state's promise of interculturality. I demonstrate how kichwa midwives practice “strategic entanglement” as a form of resistance and argue for a renegotiation of the definition and role of interculturalidad in the context of state‐controlled birth care.

Bacterial Diversity in Old Hydrocarbon Polluted Sediments of Ecuadorian Amazon River Basins.

The Ecuadorian Amazon rainforest stands out as one of the world's most biodiverse regions, yet faces significant threats due to oil extraction activities dating back to the 1970s in the northeastern provinces. This research investigates the environmental and societal consequences of prolonged petroleum exploitation and oil spills in Ecuador's Amazon. Conducted in June 2015, the study involved a comprehensive analysis of freshwater sediment samples from 24 locations in the Rio Aguarico and Napo basins. Parameters such as water and air temperature, conductivity, soil pH, and hydrocarbon concentrations were examined. Total petroleum hydrocarbon (TPH) concentrations ranged from 9.4 to 847.4 mg kg-1, with polycyclic aromatic hydrocarbon (PAH) levels varying from 10.15 to 711.1 mg kg-1. The pristane/phytane ratio indicated historic hydrocarbon pollution in 8 of the 15 chemically analyzed sediments. Using non-culturable techniques (Illumina), bacterial analyses identified over 350 ASV, with prominent families including Comamonadaceae, Chitinophagaceae, Anaeromyxobacteraceae, Sphingomonadaceae, and Xanthobacteraceae. Bacterial diversity, assessed in eight samples, exhibited a positive correlation with PAH concentrations. The study provides insights into how microbial communities respond to varying levels of hydrocarbon pollution, shedding light on the enduring impact of oil exploitation in the Amazonian region. Its objective is to deepen our understanding of the environmental and human well-being in the affected area, underscoring the pressing need for remedial actions in the face of ongoing ecological challenges.