Dataset Information

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

ABSTRACT: 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.

SUBMITTER: Corral-Garcia LS

PROVIDER: S-EPMC10892221 | biostudies-literature | 2024 Jan

REPOSITORIES: biostudies-literature

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

Corral-García Lara S LS Molina María Carmen MC Bautista Luis Fernando LF Simarro Raquel R Espinosa Carlos Iván CI Gorines-Cordero Guillermo G González-Benítez Natalia N

Toxics 20240131 2

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 b ...[more]

PMID: 38393214

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Project description:BACKGROUND:Arapaima gigas (Schinz, 1822) is the largest freshwater scaled fish in the world, and an emerging species for tropical aquaculture development. Conservation of the species, and the expansion of aquaculture requires the development of genetic tools to study polymorphism, differentiation, and stock structure. This study aimed to investigate genomic polymorphism through ddRAD sequencing, in order to identify a panel of single nucleotide polymorphisms (SNPs) and to simultaneously assess genetic diversity and structure in wild (from rivers Amazon, Solimões, Tocantins and Araguaia) and captive populations. RESULTS:Compared to many other teleosts, the degree of polymorphism in A. gigas was low with only 2.3% of identified RAD-tags (135 bases long) containing SNPs. A panel of 393 informative SNPs was identified and screened across the five populations. Higher genetic diversity indices (number of polymorphic loci and private alleles, Shannon's Index and HO) were found in populations from the Amazon and Solimões, intermediate levels in Tocantins and Captive, and very low levels in the Araguaia population. These results likely reflect larger population sizes from less urbanized environments in the Amazon basin compared to Araguaia. Populations were significantly differentiated with pairwise FST values ranging from 0.086 (Amazon × Solimões) to 0.556 (Amazon × Araguaia). Mean pairwise relatedness among individuals was significant in all populations (P < 0.01), reflecting a degree of inbreeding possibly due to severe depletion of natural stocks, the species sedentary behaviour and possible sampling biases. Although Mantel test was not significant (P = 0.104; R2 = 0.65), Bayesian analysis in STRUCTURE and discriminant analysis of principal components (DAPC) showed populations of Amazon and Solimões to be genetically differentiated from Araguaia, with Tocantins comprising individuals from both identified stocks. CONCLUSIONS:This relatively rapid genotyping by sequencing approach proved to be successful in delineating arapaima stocks. The approach and / or SNP panels identified should prove valuable for more detailed genetic studies of arapaima populations, including the elucidation of the genetic status of described discrete morphotypes and aid in delivery of conservation programs to maintain genetic diversity in reservoirs across the Amazon region.

Project description:Spatial and temporal patterns in microbial biodiversity across the Amazon river-ocean continuum were investigated along ∼675 km of the lower Amazon River mainstem, in the Tapajós River tributary, and in the plume and coastal ocean during low and high river discharge using amplicon sequencing of 16S rRNA genes in whole water and size-fractionated samples (0.2-2.0 μm and >2.0 μm). River communities varied among tributaries, but mainstem communities were spatially homogeneous and tracked seasonal changes in river discharge and co-varying factors. Co-occurrence network analysis identified strongly interconnected river assemblages during high (May) and low (December) discharge periods, and weakly interconnected transitional assemblages in September, suggesting that this system supports two seasonal microbial communities linked to river discharge. In contrast, plume communities showed little seasonal differences and instead varied spatially tracking salinity. However, salinity explained only a small fraction of community variability, and plume communities in blooms of diatom-diazotroph assemblages were strikingly different than those in other high salinity plume samples. This suggests that while salinity physically structures plumes through buoyancy and mixing, the composition of plume-specific communities is controlled by other factors including nutrients, phytoplankton community composition, and dissolved organic matter chemistry. Co-occurrence networks identified interconnected assemblages associated with the highly productive low salinity near-shore region, diatom-diazotroph blooms, and the plume edge region, and weakly interconnected assemblages in high salinity regions. This suggests that the plume supports a transitional community influenced by immigration of ocean bacteria from the plume edge, and by species sorting as these communities adapt to local environmental conditions. Few studies have explored patterns of microbial diversity in tropical rivers and coastal oceans. Comparison of Amazon continuum microbial communities to those from temperate and arctic systems suggest that river discharge and salinity are master variables structuring a range of environmental conditions that control bacterial communities across the river-ocean continuum.

Dataset Information

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

Publications

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

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