Genes and genome-resolved metagenomics reveal the microbial functional make up of Amazon peatlands under geochemical gradients.

The Pastaza-Marañón Foreland Basin (PMFB) holds the most extensive tropical peatland area in South America. PMFB peatlands store ~7.07 Gt of organic carbon interacting with multiple microbial heterotrophic, methanogenic, and other aerobic/anaerobic respirations. Little is understood about the contribution of distinct microbial community members inhabiting tropical peatlands. Here, we studied the metagenomes of three geochemically distinct peatlands spanning minerotrophic, mixed, and ombrotrophic conditions. Using gene- and genome-centric approaches, we evaluate the functional potential of the underlying microbial communities. Abundance analyses show significant differences in C, N, P, and S acquisition genes. Furthermore, community interactions mediated by toxin-antitoxin and CRISPR-Cas systems were enriched in oligotrophic soils, suggesting that non-metabolic interactions may exert additional controls in low-nutrient environments. Additionally, we reconstructed 519 metagenome-assembled genomes spanning 28 phyla. Our analyses detail key differences across the geochemical gradient in the predicted microbial populations involved in degradation of organic matter, and the cycling of N and S. Notably, we observed differences in the nitric oxide (NO) reduction strategies between sites with high and low N2 O fluxes and found phyla putatively capable of both NO and sulfate reduction. Our findings detail how gene abundances and microbial populations are influenced by geochemical differences in tropical peatlands.

Landscape-scale consequences of differential tree mortality from catastrophic wind disturbance in the Amazon.

Wind disturbance can create large forest blowdowns, which greatly reduces live biomass and adds uncertainty to the strength of the Amazon carbon sink. Observational studies from within the central Amazon have quantified blowdown size and estimated total mortality but have not determined which trees are most likely to die from a catastrophic wind disturbance. Also, the impact of spatial dependence upon tree mortality from wind disturbance has seldom been quantified, which is important because wind disturbance often kills clusters of trees due to large treefalls killing surrounding neighbors. We examine (1) the causes of differential mortality between adult trees from a 300-ha blowdown event in the Peruvian region of the northwestern Amazon, (2) how accounting for spatial dependence affects mortality predictions, and (3) how incorporating both differential mortality and spatial dependence affect the landscape level estimation of necromass produced from the blowdown. Standard regression and spatial regression models were used to estimate how stem diameter, wood density, elevation, and a satellite-derived disturbance metric influenced the probability of tree death from the blowdown event. The model parameters regarding tree characteristics, topography, and spatial autocorrelation of the field data were then used to determine the consequences of non-random mortality for landscape production of necromass through a simulation model. Tree mortality was highly non-random within the blowdown, where tree mortality rates were highest for trees that were large, had low wood density, and were located at high elevation. Of the differential mortality models, the non-spatial models overpredicted necromass, whereas the spatial model slightly underpredicted necromass. When parameterized from the same field data, the spatial regression model with differential mortality estimated only 7.5% more dead trees across the entire blowdown than the random mortality model, yet it estimated 51% greater necromass. We suggest that predictions of forest carbon loss from wind disturbance are sensitive to not only the underlying spatial dependence of observations, but also the biological differences between individuals that promote differential levels of mortality.

The complete mitochondrial genome of the oleaginous microalgae Ankistrodesmus falcatus strain UCP001 from the Peruvian Amazon.

Ankistrodesmus falcatus strain UCP001 is a native oleaginous microalgae isolated from the Peruvian Amazon basin. In this study we sequenced, de novo assembled, and functionally annotated the complete mitochondrial genome of the native oleaginous microalgae Ankistrodesmus falcatus strain UCP001 (Accesion number MT701044). This mitogenome is a typical circular double stranded DNA molecule of 41,048 bp in total length with G + C content of 37.4%. The mitogenome contains 49 genes, including 18 protein coding genes, 5 ribosomal (rRNA) genes and 26 transfer RNA (tRNA) genes. A phylogenetic analysis of 18 microalgae species indicated that Ankistrodesmus falcatus strain UCP001 was closely related to Ourococcus multisporus and Raphidocelis subcapitata. The complete mitochondrial genome sequence of Ankistrodesmus falcatus strain UCP001 enriches genomic resources of oleaginous native microalgae from the Peruvian Amazon for further basic and applied research.

[River boats as a means of expansion of Aedes aegypti towards border zones of the peruvian amazon]. / Embarcaciones fluviales como medio de dispersión de Aedes aegypti hacia zonas fronterizas de la amazonia peruana.

OBJECTIVES.: To assess the entomological risk of Aedes aegypti in boats traversing border river routes in Loreto. MATERIALS AND METHODS.: The study population consisted of mosquitoes present in three boats covering border routes in Loreto. The entomological risk of Aedes was determined through ovitraps, the inspection of breeding sites, and the collection and taxonomic identification of adult mosquitoes. RESULTS.: The entomological risk varied according to the route and the season. A medium to very high entomological risk was identified in the high-water season and on the outward route to the border areas. The predominant vector population in the low-water season was Mansonia sp. (74.8%), Culex sp. (12.8%), and Aedes aegypti (0.4%); in the high-water season, Culex sp. (45.1%), Mansonia sp. (26.8%), and Aedes aegypti (19.7%). In no case did we find Aedes albopictus. CONCLUSIONS.: There is moderate to high entomological risk during the high-water season in riverboats traveling from Iquitos to the border areas of Loreto. Our results show that river boats are a means of expansion of Aedes aegypti.

OBJETIVOS.: Evaluar el riesgo entomológico de Aedes aegypti durante el recorrido fluvial en embarcaciones con rutas fronterizas de Loreto. MATERIALES Y MÉTODOS: . La población de estudio fueron los mosquitos presentes en tres embarcaciones con rutas fronterizas en Loreto. El riesgo entomológico de Aedes se determinó mediante ovitrampas, revisión de criaderos, colecta e identificación taxonómica de mosquitos adultos. RESULTADOS: . El riesgo entomológico varió según trayecto y época. Se identificó un riesgo entomológico medio a muy alto en época de creciente y en la ruta de ida hacia las zonas fronterizas. La población vectorial predominante en época de vaciante fue Mansonia sp. (74,8%), Culex sp. (12,8%) y Aedes aegypti (0,4%); en creciente predominó Culex sp. (45,1%), Mansonia sp. (26,8%) y Aedes aegypti (19,7%). En ningún caso se evidenció Aedes albopictus. CONCLUSIONES.: Existe riesgo entomológico de moderado a alto durante la etapa de creciente en las embarcaciones fluviales que viajan desde Iquitos hacia las zonas fronterizas de Loreto. Nuestros resultados evidencian que las embarcaciones fluviales son un medio de dispersión de Aedes aegypti.

Embarcaciones fluviales como medio de dispersión de Aedes aegypti hacia zonas fronterizas de la amazonia peruana / River boats as a means of expansion of Aedes aegypti towards border zones of the peruvian amazon

RESUMEN Objetivos. Evaluar el riesgo entomológico de Aedes aegypti durante el recorrido fluvial en embarcaciones con rutas fronterizas de Loreto. Materiales y métodos . La población de estudio fueron los mosquitos presentes en tres embarcaciones con rutas fronterizas en Loreto. El riesgo entomológico de Aedes se determinó mediante ovitrampas, revisión de criaderos, colecta e identificación taxonómica de mosquitos adultos. Resultados . El riesgo entomológico varió según trayecto y época. Se identificó un riesgo entomológico medio a muy alto en época de creciente y en la ruta de ida hacia las zonas fronterizas. La población vectorial predominante en época de vaciante fue Mansonia sp. (74,8%), Culex sp. (12,8%) y Aedes aegypti (0,4%); en creciente predominó Culex sp. (45,1%), Mansonia sp. (26,8%) y Aedes aegypti (19,7%). En ningún caso se evidenció Aedes albopictus. Conclusiones. Existe riesgo entomológico de moderado a alto durante la etapa de creciente en las embarcaciones fluviales que viajan desde Iquitos hacia las zonas fronterizas de Loreto. Nuestros resultados evidencian que las embarcaciones fluviales son un medio de dispersión de Aedes aegypti.

ABSTRACT Objectives. To assess the entomological risk of Aedes aegypti in boats traversing border river routes in Loreto. Materials and Methods. The study population consisted of mosquitoes present in three boats covering border routes in Loreto. The entomological risk of Aedes was determined through ovitraps, the inspection of breeding sites, and the collection and taxonomic identification of adult mosquitoes. Results. The entomological risk varied according to the route and the season. A medium to very high entomological risk was identified in the high-water season and on the outward route to the border areas. The predominant vector population in the low-water season was Mansonia sp. (74.8%), Culex sp. (12.8%), and Aedes aegypti (0.4%); in the high-water season, Culex sp. (45.1%), Mansonia sp. (26.8%), and Aedes aegypti (19.7%). In no case did we find Aedes albopictus. Conclusions. There is moderate to high entomological risk during the high-water season in riverboats traveling from Iquitos to the border areas of Loreto. Our results show that river boats are a means of expansion of Aedes aegypti.