Search Results (2,611)

Aerosols emitted by biomass burning represent one of the largest sources of uncertainty in our current understanding of the Earth’s radiative balance. We investigate the climatic influence of biomass burning aerosols emitted from six key regions of biomass burning by using GEOS-Chem coupled with the rapid radiative transfer model. We evaluate our model using AERONET observation, with the model reproducing data with 87% observed spatial and seasonal variability with a low negative bias of 7%. The radiation sensitivity is generally highest for North Asia (NAS) and for North America (NCC); lowest for South America (SAM) and South and Southeast Asia (SSA); and moderate for Africa (AFR) and Oceania (OCE). These regional differences are related to the main burning types of the regions. When we consider the global radiation influence, AFR dominates the global picture due to the comparatively large biomass burned. We estimate the global mean radiation influence of biomass burning aerosol is −0.116 W m⁻². For monthly features, in summer, due to higher incident energy obtained in NAS and NCC, high negative radiation sensitivity of biomass burning, biomass burning aerosols, and biomass burning organic aerosol are shown in these regions. Meanwhile, the radiation sensitivity peak of black carbon for these two regions occurs earlier in late spring (NAS) or early summer (NCC), when large incident energy and large high reflectance snow cover coexist in these two high-latitude regions. A significant yearly difference in radiation influence, rather than radiation sensitivity, is found, with the relative difference between the maximum year and minimum year reaching 90% of the maximum radiation influence year. Specifically, two regions affected by El Niño (OCE and SSA) have the most significant yearly variation in all factors, with anomalies occurring in El Niño years. Full article

TEC disturbances have substantial impacts on communications and global positioning systems. Based on total electron content (TEC) observations from global navigation satellite systems and plasma observations from the Defense Meteorological Satellite Program, global variations in and mechanisms of the differential TEC (dTEC) during three successive substorms, which occurred on 23 December 2014 during the main phase of a geomagnetic storm, were investigated. The results show that TEC disturbances were not globally uniform but exhibited pronounced latitude and local time dependences. One prominent dTEC enhancement, reaching up to 25 TECU within 10 min, occurred over North America from the prenoon to dusk sector at subauroral and auroral latitudes, related to the ionization driven by particle precipitation and storm-enhanced density (SED) driven by an intensified convection electric field. Enhanced dTEC at high latitudes expanded to midlatitudes, forming the broad midlatitude SED, expanding poleward and developing a tongue of ionization (TOI), persisting for 100 min. In addition, over South America at premidnight, decreased dTEC at low latitudes and increased dTEC at equatorial latitudes with amplitudes of around 16 TECU were consistent with suppression of the equatorial ionization anomaly (EIA), driven by substorm-related westward prompt penetration electric fields (PPEFs). These results demonstrate that storm time substorms can simultaneously enhance and deplete TEC in different latitude and local time sectors through the combined effects of particle precipitation, convection electric fields, and PPEFs. Full article

Assessing the contribution of tropical cyclones to regional precipitation variability is essential for understanding the associated hydrometeorological benefits and risks. This study quantifies the contribution of tropical cyclones to annual precipitation in the northernmost part of South America from 2016 to 2025, utilizing data from surface rain gauges. Simulations using the Weather Research and Forecasting (WRF) model, configured with 2 km grid spacing and 38 vertical levels, estimate the influence of relative humidity at 850 hPa and ambient temperature at 500 hPa on precipitation over the continental region when each convective system is nearest to the coastline. During Hurricanes Matthew (2016) and Melissa (2025), contributions to the annual average precipitation reached 51% and 47%, respectively, with the highest values observed near the northern South American coastline. The contributions of Harvey (2017), Iota (2020), Julia (2022), and Beryl (2024) to annual precipitation were 0–26%, 0–18%, 0–12%, and 0–19%, respectively. Precipitation distribution was heterogeneous during the passage of tropical storms. The extent of accumulated precipitation was influenced by the cyclone’s trajectory and proximity to mountainous regions. Patterns of relative humidity at 850 hPa did not correspond to a uniform precipitation distribution. Between 6% and 30% of rain gauges did not record precipitation during the analyzed tropical cyclone events. These findings highlight that tropical cyclone-induced precipitation is strongly influenced by complex interactions between atmospheric dynamics and topography. Future research should assess the contributions of these systems to groundwater and surface reservoirs that support indigenous communities in rural areas. Full article

Olive, Olea europaea L. (Oleaceae), cultivation is affected by significant yield losses caused by Palpita persimilis Munroe (Lepidoptera: Crambidae), a defoliating pest in South America. Its control currently relies on synthetic pesticides, which have adverse environmental effects. This study investigated native entomopathogenic bacteria isolated from the rhizosphere of olive trees in Tacna, Peru. A total of 36 bacterial isolates were obtained, of which six strains showing more than 70% larval mortality were selected for further evaluation. Morphological and molecular analyses suggested a tentative affiliation of the isolates with bacterial groups related to the genera Lysinibacillus, Paenibacillus, Priestia, and Bacillus. Bioassays demonstrated that larval mortality depended on the bacterial concentration and exposure time. Strains such as Peribacillus sp. UNM achieved 100% larval mortality after 96 h at a concentration of 1 × 10⁹ CFU mL⁻¹. Analysis using a generalized linear model (GLM) with a binomial distribution confirmed that bacterial strain, concentration, and exposure time significantly influenced larval mortality, indicating that mortality responses varied according to bacterial concentration and exposure time. These findings provide preliminary laboratory evidence of entomopathogenic activity associated with native bacterial isolates against P. persimilis and support future investigations aimed at evaluating these isolates under field conditions in olive agroecosystems. Full article

The systematics of white-tailed deer (Odocoileus virginianus) has been controversial. Some mammalogists consider the white-tailed deer to be a single species, whereas others consider it to consist of multiple species. To help resolve the controversy, we sequenced mitochondrial cytochrome B (mtCyt-b) in samples collected from 83 Neotropical white-tailed deer. Furthermore, we analyzed mitogenomes of samples collected from 19 white-tailed deer. There were five main results, as follows: (1) Phylogenetic analyses with the mtCyt-b dataset showed the existence of eight groups of O. virginianus, three in North and Central America and five in South America. It was hypothesized from different analyses that a Central American O. virginianus population generated the white-tailed deer populations in South America. (2) The haplotype temporal diversification within O. virginianus occurred during the Pleistocene. With the mitogenome dataset, it was dated to have occurred approximately 2.2 mya, using both Bayesian inference and haplotype networks. (3) All of these O. virginianus groups showed elevated levels of mitochondrial genetic diversity for the mtCyt-b dataset, with the exception of the Ecuadorian population (4) Some groups of O. virginianus yielded significant evidence of female population expansions with the mtCyt-b dataset. (5) Although the genetic heterogeneity among these O. virginianus groups was significant, the genetic distances were relatively small. Provisionally, the karyotypic differences between North American and Colombian specimens were very small; therefore, until further karyotypic studies demonstrate otherwise, we consider the existence of a single species of O. virginianus. Because mtDNA genomes have only one quarter of the effective number of autosomal nuclear genes, this generates relatively rapid coalescence times, which can inflate estimates of divergence among populations. Therefore, it is very important to soon sequence the nuclear genes for the different geographic assemblages of O. virginianus found. Full article

Spaces labeled as ‘extreme’ have long fueled the imagination of those who sought to explore, conquer, and represent them. Framed in colonial narratives as terra incognita or finis terrae, these regions generated diverse forms of textual and visual knowledge while simultaneously arousing curiosity and fear. The polar regions, Amazonian forests, and the seas and mountains of Patagonia played a central role in shaping the epistemologies of modern science and art in South America, functioning as laboratories in which ways of seeing were tested and transformed through processes of encounter. In this paper, we move beyond approaches that treat extreme spaces as fixed geographical entities defined solely by climatic severity or environmental hostility. Drawing on a pedagogical experiment inspired by Warburgian image-based research practices, we argue that extreme spaces are better understood as relational constructs, co-produced through multispecies and intercultural encounters. Through a comparative analysis of European iconographies across South America, we identify two coexisting clusters of meaning: one organised around abundance, intercultural cooperation, and extractivism; the other around scarcity, resistance, and environmental imposition. By tracing the circulation and mobilization of these meanings across different environments, we propose an epistemology of extremes, suggesting a mode of knowledge production that classifies spaces through the lens of radical otherness. Full article

Bacteriophage-based products are gaining attention as effective tools to reduce harmful germs in food and combat antimicrobial resistance throughout the food production process. However, in South America, their use is still limited because of complicated regulations and inconsistent evidence requirements. This review aims to (i) explore the current scientific and technological landscape of using bacteriophages in South American food systems, (ii) identify main regulatory challenges that impact their classification, approval, and use, and (iii) highlight the need for consistent international guidelines, especially from Codex Alimentarius, to help safely and effectively incorporate phage-based products in food. Research on phage-based products is growing, but it is not consistent across different regions. There are more patents and advancements in biotechnology, but they are limited to certain areas. Although progress is being made, the regulatory frameworks are still unclear, especially when it comes to how these products are classified, labeled, and monitored for safety. To address these gaps, risk-based guidelines are needed. These should define product categories and claims, set safety standards, and include rules for tracking products and monitoring them after they hit the market. Creating a new Codex Alimentarius project on phage-based products could help establish global guidelines that promote safe use, reduce uncertainty in regulations, and improve trade in food markets around the world. Full article

El Niño–Southern Oscillation (ENSO) has been identified as a key factor influencing grapevine phenology and harvest timing in South America. Nevertheless, few long-term analyses have explored its varietal impacts in hyper-arid viticultural regions. The goal was to evaluate the effect of ENSO phases on harvest dates and bioclimatic indices in different grapevine varieties cultivated in Northern Chile. The results revealed that Muscat of Alexandria showed little variation in harvest timing across ENSO phases. In contrast, harvest time in Thompson Seedless was delayed under La Niña events, being strongly correlated with the Maximum Spring Temperature Summation (SON_max) Index. Moscatel Rosada and Flame Seedless showed non-statistical significance and high variability on harvest dates. El Niño phases were consistently warmer than La Niña events that showed markedly greater interannual variability on harvest dates and bioclimatic index values. The strength of correlations was improved when the bioclimatic indices were recalculated over adjusted seasonal windows, underscoring the need for phenology-based rather than calendar-based approaches. These results provide new evidence of the heterogeneous responses of table and Pisco grapevine varieties to ENSO events in the hyper-arid regions of Northern Chile, underscoring the varietal differences in sensitivity to early-season climatic anomalies. Full article

The limata species complex of the genus Crematogaster encompasses ants with an elongated petiole that gradually narrows towards the anterior margin (dorsal view), a smooth and shining face, with abundant long erect setae, and well-developed propodeal spines. This complex of species is restricted to the Neotropical Region, and is common in arboreal environments of primary and secondary forests, agricultural ecosystems, and even human-modified environments, where they can be locally abundant. Currently, the complex comprises 20 species from southern Mexico to Paraguay and southern Brazil, nesting mainly in twigs, litter, and under bark. Here, we describe six new species from Colombia: C. labalsa, C. orito, C. protzalezi, C. quipile, C. tequendama, and C. vega, based on the worker caste. Additionally, we provide an identification key and original descriptions, including comparisons with the closest species. Full article

Small, isolated, and fragmented populations often exhibit low levels of genetic diversity as a result of genetic drift, limited gene flow, and inbreeding. Huemul (Hippocamelus bisulcus) is a medium-sized South American deer categorized as endangered by the International Union for Conservation of Nature (IUCN). Huemul in its northernmost range was previously distributed in Central Chile between 36° S and 37° S, but its current distribution and conservation status in the region are poorly documented. We used non-invasive genetic approaches to assess the genetic diversity, population connectivity, and demographic history of the huemul’s northernmost population using nuclear microsatellite markers from fecal samples of wild individuals. Observed nuclear DNA genetic variation (Ho = 0.2958 ± 0.0318) was moderate, and allelic richness was low (Ar = 3.43–4.01), consistent with the theoretical expectation that isolated populations may retain heterozygosity while losing allelic richness more rapidly. However, the estimated nuclear DNA effective population size was low (Ne = 47; 95% CI: 19.2–∞). Demographic simulations project continued loss of genetic diversity under all scenarios modeled. Our results provide a foundation for further study of this population and provide the genetic data necessary to design detailed management plans to ensure the persistence of healthy populations of this rare and elusive deer. Full article

The El Niño–Southern Oscillation (ENSO) is the main driver of interannual climate variability, strongly influencing precipitation, temperature, and extreme events worldwide. In South America, its impacts are well documented. However, studies examining different ENSO types—Eastern Pacific (EP), Central Pacific (CP), and Mixed (MX), defined according to the location of sea surface temperature (SST) anomalies in the tropical Pacific—remain limited, particularly for the Brazilian subtropical climate. This study investigates rainfall variability in the Brazilian subtropical region associated with different ENSO types. Composite analyses of precipitation, wind, and SST anomalies were performed, and monthly rainfall data from 703 stations were used to identify homogeneous regions. The results show the intensity and spatial coherence of rainfall signals vary according to El Niño type, with EP events favoring widespread wet conditions and CP events producing more heterogeneous or locally negative anomalies. For La Niña, the intensity and seasonal distribution of negative rainfall anomalies vary by ENSO type: stronger impacts occur in summer (EP), spring (MX), and autumn (CP). These findings improve the understanding of ENSO-related rainfall variability in the Brazilian subtropical region and provide valuable insights for the management of climate-related risks in an area frequently affected by rainfall extremes. Full article

Atmospheric Motion Vectors (AMVs) from geostationary satellites are a critical observational source for data assimilation, particularly in regions with sparse observations, such as the Southern Hemisphere. This study evaluates the impact of assimilating AMVs from the Geostationary Operational Environmental Satellite (GOES) series into the Numerical Modeling and Assimilation System (SMNA) used at the Center for Weather Forecasting and Climate Studies of the National Institute for Space Research (CPTEC/INPE). The SMNA consists of the Brazilian Global Atmospheric Model (BAM) coupled with the Gridpoint Statistical Interpolation (GSI) data assimilation system. Two experiments were conducted in February 2024: a control experiment that assimilated all conventional observations along with AMVs from GOES-16 and GOES-18 satellites, and a second experiment (data denial), in which the AMVs were excluded. This time period coincided with the formation of the tropical cyclone Akará offshore the southeast coast of Brazil. The diagnostic analysis of the assimilation process indicates a substantial increase in the relative contribution of wind observations to the cost function and a reduction in the differences between the background and the analysis, particularly in the mid and upper troposphere. Forecast verification showed that assimilating AMV data led to a reduction in RMSE and an increase in anomaly correlations for several variables, including wind and temperature at various vertical levels. The positive impact of GOES AMV data on the representation of the tropical cyclone Akará is evident in the improved positioning, intensity, and circulation structure of the cyclone, particularly during its intensification phase. With tropical cyclone events over South America becoming more frequent in recent years, results from this study indicate the critical need to assimilate AMV data to improve forecast skill. Furthermore, the assimilation of GOES AMVs significantly enhances the representation of atmospheric circulation over South America, particularly improving the predictability of large-scale events such as cyclones in the South Atlantic. Full article

Understanding the composition and spatial distribution of Amazonia’s bioindustry enterprises is essential for sustainable development. Based on an analysis of primary and secondary data, we offer a preliminary overview of biodiversity-based biofactories, which transform raw materials derived from Amazonian biodiversity into industrialized products, in Brazilian Amazonia. Of the 187 biofactories we identified, most operate in the food sector (74%), followed by cosmetics (14%) and organic chemicals (9%). Records identified biofactories in 72 of the study area’s 559 municipalities. Fifty percent of biofactories are in the municipalities of Manaus, Belém, Castanhal, Santarém, Benevides, and Igarapé-Miri, which together hold 18% of the study area’s population. Conversely, none were identified in the consulted sources for 487 municipalities, comprising 62% of the study area’s population—about 14 million people. Statistical modeling among municipalities with identified units revealed a positive association between municipal gross domestic product and biofactory abundance. While some units may be undetected because they operate outside formal networks, the available records suggest that these businesses are geographically unevenly distributed and mostly of low technological intensity. Moreover, a significant portion of the population may lack direct access to local industrial infrastructure for processing biodiversity resources, highlighting potential territorial inequalities in regional processing capacity. Full article

The Monk Parakeet (Myiopsitta monachus) is a psittacid species native to central and eastern South America that was introduced into many countries by traders, for its popularity as caged pets. After escapes or releases, it has been successful in establishing in new territories, capable of reproducing, dispersing, and exhibiting population growth in introduction sites during recent decades. It is considered a pest due to negative impacts, especially for its damage to agriculture and urban infrastructure. Although its global distribution has been previously described, given its high adaptability and effectiveness in colonizing new environments, many of these distribution maps may be outdated. We used eBird, a free online birding database, to locate sightings of this species globally and compared it with the reported range for the species. Additionally, we overlaid compiled data on species distribution with economic data to explore if there is a correlation between the reported parakeet presence in new cities and wealth. We compiled data from 1900 to 2024 and compared reported differences in the Monk Parakeet presence. Our results indicate that Monk Parakeets have invaded at least 31 countries, being present in capital cities, cities, towns, and rural territories. The number of cities where the species was reported as invasive increased significantly since 1985, by an average of 150% by decade. We found a positive pooled association between country-level Gross Domestic Product (GDP) per capita and the number of cities with Monk Parakeet records, although this pattern should be interpreted cautiously, given potential biases from observation effort, country size, and temporal co-variation. We present new evidence on Monk Parakeet’s rapid global expansion and deliver an updated map of the Monk Parakeet global distribution, relevant for planning and implementing control measures. Full article

Seasonal influenza circulation was profoundly disrupted during the COVID-19 pandemic, resulting in an unprecedented global decline in viral activity and genetic diversity. As non-pharmaceutical interventions gradually relaxed, influenza viruses re-emerged in multiple regions in 2022; however, genomic data from Latin America remain limited, particularly for the first post-pandemic season. In this study, we analyzed the epidemiological, genomic, and evolutionary patterns of influenza A and B viruses circulating in Mexico between June 2018 and June 2023, with a specific focus on the first post-pandemic season (June 2022–June 2023). More than 90% of the influenza virus genomes available from Mexico for this post-pandemic period were generated in this study, while data from earlier seasons were used for contextualization. Following a near-complete absence of influenza circulation during 2020–2021, viral activity re-emerged in late 2021 and intensified during 2022–2023. Post-pandemic circulation in Mexico was dominated by influenza A(H3N2), with a lower contribution from A(H1N1)pdm09 and a delayed re-emergence of B/Victoria; B/Yamagata was not detected. Genomic analyses revealed rapid lineage turnover after the pandemic, characterized by the predominance of post-pandemic clades and reduced genetic diversity compared with pre-pandemic seasons. Phylogenetic analyses indicated multiple introductions and strong regional connectivity across North and South America. Full article