Coast Of South America Research Articles

Atmospheric Rivers in South-Central Chile: Zonal and Tilted Events

The extratropical west coast of South America has one of the largest frequencies of landfalling atmospheric rivers (ARs), with dozens of events per season that account for ~50% of the annual precipitation and can produce extreme rainfall events in south-central Chile. Most ARs form an acute angle with the Andes, but, in some cases, the moist stream impinges nearly perpendicular to the mountains, referred to as zonal atmospheric rivers (ZARs). Enhanced surface-based and upper-air measurements in Concepcion (36.8° S), as well as numerical simulations, were used to characterize a ZAR and a meridionally oriented AR in July 2022. They represent extremes of the broad distribution of winter storms in this region and exhibit key features that were found in a composite analysis based on larger samples of ZARs and tilted ARs. The latter is associated with an upper-level trough, broad-scale ascent, extratropical cyclone, and cold front reaching southern Chile. Instead, ZARs are associated with tropospheric-deep, strong zonal flow and a stationary front across the South Pacific, with ascent restricted upstream of the Andes. Consequently, ZARs have minimum precipitation offshore but a marked orographic precipitation enhancement and exhibit relatively warm temperatures, thus resulting in an augmented risk of hydrometeorological extreme events.

Evaluation of the climate models used by the IPCC based on the position of the ITCZ in the Equatorial South Atlantic

AbstractA number of the uncertainties in climate projections for the end of the century are due to the difficulty of general circulation models (GCMs) to represent large‐scale precipitating systems such as the Intertropical Convergence Zone (ITCZ) in the historical period. In this study, we evaluate the Coupled Model Intercomparison Project Phase 5 and 6 models based on the position of the ITCZ in the South Atlantic during the period in which it is climatologically further south (February–May). This period characterizes the rainy season of the Brazilian semiarid. The models were ranked according to two objective methods and validated through a qualitative analysis. The first method considered a success rate to evaluate the correct position of the areas with maximum precipitation and minimum pressure and meridional wind as representative of the mean position of the ITCZ. Among the 15 coupled GCMs analysed for each CMIP, those that best represented the position of the ITCZ were HADGEM.2‐AO, MIROC5 and CANESM2 from CMIP5 and CESM2 and MIROC6 from CMIP6. These models represented well the following characteristics of the ITCZ in February–May: maximum precipitation near the equator at the height of the coast of South America and with the wind convergence zone sloping north towards the African continent. The most common problem noticed in the other GCMs was to displace the ITCZ to the south of its observed mean position within the period February–May. Also, some GCMs presented a double ITCZ (GISS‐E2‐H, GDFL‐CM3 and IPSL‐CM5A‐LR from CMIP5 and INM‐CM5‐0 from CMIP6) following two high TSM cores. One GCM (ACCESS1‐3 from CMIP5) presented a relatively good performance, but the zone of greater precipitation was shifted to the east, being located in the centre of the Atlantic basin. Knowing how the GCMs represent the ITCZ is a criterion that must be considered when choosing the GCMs for climate change studies.

Population genomic evidence of structured and connected Plasmodium vivax populations under host selection in Latin America.

Pathogen genomic epidemiology has the potential to provide a deep understanding of population dynamics, facilitating strategic planning of interventions, monitoring their impact, and enabling timely responses, and thereby supporting control and elimination efforts of parasitic tropical diseases. Plasmodium vivax, responsible for most malaria cases outside Africa, shows high genetic diversity at the population level, driven by factors like sub-patent infections, a hidden reservoir of hypnozoites, and early transmission to mosquitoes. While Latin America has made significant progress in controlling Plasmodium falciparum, it faces challenges with residual P. vivax. To characterize genetic diversity and population structure and dynamics, we have analyzed the largest collection of P. vivax genomes to date, including 1474 high-quality genomes from 31 countries across Asia, Africa, Oceania, and America. While P. vivax shows high genetic diversity globally, Latin American isolates form a distinctive population, which is further divided into sub-populations and occasional clonal pockets. Genetic diversity within the continent was associated with the intensity of transmission. Population differentiation exists between Central America and the North Coast of South America, vs. the Amazon Basin, with significant gene flow within the Amazon Basin, but limited connectivity between the Northwest Coast and the Amazon Basin. Shared genomic regions in these parasite populations indicate adaptive evolution, particularly in genes related to DNA replication, RNA processing, invasion, and motility - crucial for the parasite's survival in diverse environments. Understanding these population-level adaptations is crucial for effective control efforts, offering insights into potential mechanisms behind drug resistance, immune evasion, and transmission dynamics.

Evolutionary morphology of haptoral anchors in monogenoids (Dactylogyridae) of marine catfish (Siluriformes: Ariidae) from the Atlantic coast of South America.

Exploring the phylogenetic signal of morphological traits using geometric morphometry represents a powerful approach to assess the relative weights of convergence and shared evolutionary history in shaping species' forms. We evaluated the phylogenetic signal in shape and size of ventral and dorsal haptoral anchors of 10 species of monogenoids (Hamatopeduncularia, Chauhanellus and Susanlimocotyle) occurring in marine catfish (Siluriformes: Ariidae) from the Atlantic coast of South America. The phylogenetic relationships among these species were mapped onto the morphospaces of shape and size of dorsal and ventral anchors. Two different tests (squared change-parsimony and Kmult) were applied to establish whether the spatial positions in the phylomorphospace were influenced by phylogenetic relationships. A significant phylogenetic signal was found between anchor form and parasite phylogeny. Allometric effects on anchor shape were non-significant. Phylogenetically distant species on the same host differed markedly in anchor morphology, suggesting little influence of host species on anchor form. A significantly higher level of shape variation among ventral anchors was also found, suggesting that the evolutionary forces shaping ventral anchor morphology may operate with differing intensities or exhibit distinct mechanisms compared to their dorsal counterparts. Our results suggest that phylogenetic relationships were a key driver of changes in shape (but not size) of anchors of monogenoids of South American ariids. However, it seems that the emergence of the digitiform haptor in Hamatopenducularia and in some species of Chauhanellus played an important role in the reduction in anchor size and may cause secondary losses of anchors in other groups of monogenoids.

Spatial and temporal variability of wave energy resource in the eastern Pacific from Panama to the Drake passage

We analyse the wave energy resource available along the Pacific coast of South America from Panama from the latitude of 8°N to the Drake Passage at 55°S. The analysis is based on wave time series over 63 years (1959–2021) from the European Union Copernicus database constructed using the WAM wave model for the entire Pacific forced by wind information from ERA5. The novel features are the analysis of temporal variations in the wave energy flux, quantification of the contribution of swells and wind-seas into the wave energy potential, establishing properties of the most energy-carrying wave conditions, and evaluation of the role of El Niño and La Niña in the wave energy potential. The annual average wave energy flux increases from about 2 kW/m just to the north of the equator on the Colombian Pacific coast to 20–50 kW/m in the central and southern mainland of Chile and up to 80 kW/m near the Drake Passage. The wave energy resource to the north of latitude 32°S is almost entirely provided by swells. To the south of 44°S wind-seas predominate among the most energetic wave conditions and the maxima of energy flux by wind-seas up to 20 times exceed the already high average energy flux. The temporal variation in the wave energy flux follows the same pattern. It is fairly small at lower latitudes and increases rapidly from the forties. The magnitude of seasonal variation in terms of monthly mean wave energy flux is commonly from −47% to +32% from the long-term mean. The calmest time that contains 1% of the total annual energy flux is 10–20 days, about 10% of energy is contained in the 100 calmest days, while 50% of the annual energy flux arrives during the 100 days with strongest waves in the entire study area. The typical height of waves that provide the largest contribution to wave energy is about 1–1.5 m in the very north, around 1 m near the equator, gradually increases to the South and reaches 3.5–4 m on the shores of southern Chile. The associated wave periods are about 10 s in the entire study area. The wave energy flux has been almost constant over the 63 years near the equator but has increased at a rate up to 0.6 kW/m per year in the nearshore of Chile. For the evaluated time scales in coastal areas of South America, the interchange of El Niño and La Niña does not have detectable impact on the wave energy resource.

Evolutionary Dynamics of American Manatee Species on the Northern Coast of South America: Origins and Maintenance of an Interspecific Hybrid Zone

Evolutionary Dynamics of American Manatee Species on the Northern Coast of South America: Origins and Maintenance of an Interspecific Hybrid Zone

December 8, 2022 Meteotsunami Along the Southeastern Coast of South America: A Case Study

December 8, 2022 Meteotsunami Along the Southeastern Coast of South America: A Case Study

Historical landings and management options for the genus Mesodesma in coasts of South America.

This work compiles and updates Information onthedevelopmentofsurf clams'fisheriesof the genus Mesodesma in the coasts of South America. Landings, pnces and exportation valúes (when available), are analyzed for those countries where the species are present: Brazil, Argentine, Uruguay, Perú and Chile. A marked increase in catches during the 80's was observed in Chile, Perú and Uruguay. Argentine maintains a closed season imposed since 1958, while the lack oí available data preclude us to analyze the evolutionof the Brazilian fishery. A lackof regulatory measures, the prevailing open access-system established in four of the five countries analyzed and the marked increase in demand for the produet by domesticand foreign markets, suggest a serious risk of over-exploitation oí the Mesodesma resource. A dissimilar State oí ecological and fishery knowledge observed in the mentioned countries aggravates the above situation. Implications derived from different management scenarios are discussed. Finally, íuture lines of research that ought to be developed in the región are proposed.

Status of the invasion of Carpobrotus edulis in Uruguay based on citizen science records

Carpobrotus edulis, a highly invasive plant species repeatedly introduced along the Atlantic coast of South America, poses a significant threat to the ecological integrity of coastal dune ecosystems in Uruguay. This study used 15 years of iNaturalist records to assess the magnitude of Carpobrotus invasion, focusing on its distribution, abundance, and reproductive phenology. Through the analysis of georeferenced and dated data, we determined that Carpobrotus has spread extensively, covering a 10-km-wide coastal area and occupying approximately 220 km along the Atlantic coast and the outer Rio de la Plata estuary. Records have increased in the last three years, with a summer prevalence of 52.9%, due to higher activity on the platform. The species exhibited two flowering peaks in spring and autumn, suggesting an extended reproductive period. The widespread presence of this species in both natural and urbanized areas highlights the urgent need for effective management strategies to mitigate its impact on native biodiversity. Utilizing citizen science platforms like iNaturalist has been instrumental in monitoring and documenting processes of invasion. However, further investigations are necessary, particularly in less sampled regions, to fully understand the extent of Carpobrotus invasion. To protect the country’s coastal ecosystems, it is crucial for local authorities to reassess current practices related to non-native species ornamental planting. By addressing the invasion of C. edulis, the ecological integrity of coastal dune ecosystems can be preserved, ensuring the survival of native flora and fauna along Uruguay’s Atlantic coast.

The Russian Archaeological Project in South America: Principal Findings and Prospects

This study outlines the findings of field and laboratory studies by the first Russian archaeological expedition to South America in 2014–2015 and 2017–2018 in collaboration with colleagues from Ecuador and Japan. The project focused on sites of the Archaic (10.8–6.6 ka BP) and Early Formative period (5.5–3.5 ka BP) in the coastal zone of Santa Elena Province, Ecuador. Excavations at Real Alto (Valdivia culture) and Loma Alto (Las Vegas culture) yielded representative archaeological, anthropological, and faunal samples and a large series of AMS dates, providing a basis for a number of novel proposals regarding the chronology and periodization of cultures, their origin, and early pottery-production in South America. Specifically, we have demonstrated that at the very beginning of the Formative period, two early ceramic traditions coexisted—Valdivia and “San Pedro”. We have demonstrated the peculiarity of the “Tropical package” in the stone toolkit, and traced the previously unknown features of the funerary rites of the Las Vegas and Valdivia cultures. Radiocarbon analysis helped to correct the chronology of the late stage of the pre-ceramic Las Vegas culture (8.0–4.8 ka BP) and to estimate the tentative date of the earliest pottery manufacture at 4.8–4.7 ka BP. In conclusion, we outline the top priorities and prospects of Russian archaeological studies on the Pacific coast of South America, underscoring the importance of international cooperation.

Prokaryote communities along a source-to-estuary river continuum in the Brazilian Atlantic Forest.

The activities of microbiomes in river sediments play an important role in sustaining ecosystem functions by driving many biogeochemical cycles. However, river ecosystems are frequently affected by anthropogenic activities, which may lead to microbial biodiversity loss and/or changes in ecosystem functions and related services. While parts of the Atlantic Forest biome stretching along much of the eastern coast of South America are protected by governmental conservation efforts, an estimated 89% of these areas in Brazil are under threat. This adds urgency to the characterization of prokaryotic communities in this vast and highly diverse biome. Here, we present prokaryotic sediment communities in the tropical Juliana River system at three sites, an upstream site near the river source in the mountains (Source) to a site in the middle reaches (Valley) and an estuarine site near the urban center of Ituberá (Mangrove). The diversity and composition of the communities were compared at these sites, along with environmental conditions, the former by using qualitative and quantitative analyses of 16S rRNA gene amplicons. While the communities included distinct populations at each site, a suite of core taxa accounted for the majority of the populations at all sites. Prokaryote diversity was highest in the sediments of the Mangrove site and lowest at the Valley site. The highest number of genera exclusive to a given site was found at the Source site, followed by the Mangrove site, which contained some archaeal genera not present at the freshwater sites. Copper (Cu) concentrations were related to differences in communities among sites, but none of the other environmental factors we determined was found to have a significant influence. This may be partly due to an urban imprint on the Mangrove site by providing organic carbon and nutrients via domestic effluents.

Mapping species richness and evolutionary regions of the genus Myrcia

AbstractAimMyrcia is a plant genus exclusive of the Neotropical region and one of the most important components of the tree diversity in the Cerrado and Atlantic Forest domains. However, no mapping of its taxonomic diversity for this region exists. Our aim was to describe the spatial patterns of diversity and biogeographical history for Myrcia in the Neotropical region based on a phylogenetic regionalization.LocationNeotropics.TaxonGenus Myrcia (Myrtaceae).MethodsWe derived distributions for 307 species from occurrence records using buffering and species distribution modelling. We used stacked distributions to generate a richness map of the genus and its clades (sections). In addition, we used phylogenetic regionalization methods to define evolutionary regions (evoregions) and ancestral area reconstruction to reveal the biogeographical history across these evoregions.ResultsWe found high species richness in the Atlantic Forest and Cerrado, with some sections restricted to the East coast of South America, while others were widespread across the Neotropics. We defined five evoregions, named A–E; the ancestral reconstruction revealed that Myrcia originated in evoregion B, under a tropical climate, with further specialization of distant‐related lineages to the colder environmental condition in evoregion A.Main ConclusionsHigh species richness of Myrcia in South America eastern coast and in the Brazilian highlands coincides with the evoregions with most diversification. Our genus‐specific regionalization together with the ancestral area reconstruction showed that evoregions A and B were the main evolutionary regions where diversification took place. In addition, the biogeographical history of the group suggests that some lineages have adaptations to deal with colder environments, that probably evolved in response to cooling periods since the mid‐Miocene.

Qualitative Study of the Transport of Microplastics in the Río de la Plata Estuary, Argentina, through Numerical Simulation

Information about the sources, sinks, dynamics, and how environmental variables affect the transport of microplastics (MPs) from continental deposits to marine systems is still limited. Most of the knowledge about the distribution of plastic in the oceans comes from the use of numerical models to understand the routes of MPs moving in aquatic systems. The Río de la Plata (RdP) is an estuary located on the eastern coast of South America and is one of the most anthropized watercourses in the region. In this study, the trajectory of MPs in the RdP was examined through the implementation, for the first time for the region, of numerical simulation models. The impact of the estuary’s hydrodynamic characteristics, winds, and MP morphological properties on their trajectory was investigated. The simulations produced demonstrated a high correlation between the hydrodynamics of the Río de la Plata and the trajectory of positively buoyant MPs. The wind was identified as a significant driving force in the simulation of MP motion dynamics. Modifications in the size of the MPs have more influence on the trajectory than their morphology. The results constitute an initial step toward understanding the dynamics of these emerging pollutants in one of South America’s most important basins.

The use and context of fiber plants during the middle preceramic: evidence from La Yerba II and III, south coast of Peru

Bast fiber artifacts from the Pacific coast of South America are among the earliest evidence of fabric manipulation and the foundation of the millennial Andean textile tradition. Recent examinations of plant macro remains and plant fiber artifacts from La Yerba II (7570–6674 cal BP) and La Yerba III (6485–5893 cal BP) sites provide insight into how plant fabric technologies and pre-loom textile traditions unfolded over the Middle Preceramic (or Middle Archaic; 8000–5000 BP) on the south coast of Peru. Using light microscopy and scanning electron microscopy (SEM), we conduct comparative analyses of modern and archaeological plants to assess the taxonomy and morphological distinctions between them to discriminate species. We identify materials from wild-gathered plants in the Cyperaceae, Typhaceae, and Apocynaceae families and show how they were used to make fishing nets, looped bags, mats, and other artifacts. Evidence from tools and cut marks also enabled us to reconstruct parts of the chaîne opératoire of the fiber production. We discuss the significance of plants from wetland and estuarine habitats in the interrelated dimensions of fabric manufacture and food consumption among these coastal hunter-gatherers.

Two Types of Mid-High-Latitude Intraseasonal Oscillations in the Southern Hemisphere during Austral Summer

Abstract Using NCEP–NCAR reanalysis data, the atmospheric intraseasonal oscillation (ISO) over the mid-high latitudes in the Southern Hemisphere during austral summer is studied. Two types of 10–30-day eastward- and westward-propagating ISO at mid-high latitudes are extracted by extended empirical orthogonal functions. The analysis of wave activity flux reveals that the energy sources of the eastward-propagating wave train are in the southwest Pacific and southern Indian Ocean, and the westward-propagating wave train is over the east coast of South America. The diagnosis of geopotential height tendency shows that the zonal gradient of ISO relative vorticity guided by mean zonal wind plays a major role in the eastward propagation of the wave train, while the meridional gradient of mean relative vorticity and geostrophic vorticity guided by ISO meridional wind plays a major role in the westward propagation of the wave train. Energy analysis shows that the amplitude enhancement over the South Pacific is due to the ISO disturbance gaining energy from the mean flow. The eastward-propagating ISO obtains energy from the mean flow through kinetic and potential energy conversion, while the westward-propagating ISO cannot obtain energy through potential energy conversion. The surface air temperature and precipitation in South America are affected by the circulation and propagation corresponding to both types of ISO. The useful forecasting skills by the subseasonal-to-seasonal forecasting project for eastward- and westward-propagating types can reach to 17 days, while the potential forecasting skills improve to 20 and 19 days, respectively. Significance Statement The intraseasonal oscillation (ISO) has important effects on regional weather and climate, and we focus on the ISO over mid-high latitudes in the Southern Hemisphere, which has been paid little attention. We reveal two leading types of the mid-high-latitude ISO during austral summer, namely, the eastward- and westward-propagating types. Also, the characteristics and effects of the two types are explored. To understand their dynamical process, the geopotential height tendency and energy conversion are diagnosed. It is also found that the two ISO types can be predicted up to 17 days in advance by the subseasonal-to-seasonal project, which may provide guidance for the extended-range forecasts.

Deciphering Permanent Uplift Along the Pacific Coast of South America Through Signal Analysis of Various Tectonic Processes

AbstractThe tectonically active South American margin is characterized by the accumulation of deformation contributing to uplift of the Andean forearc at millennial time scales. However, the mechanisms responsible for permanent coastal uplift are debated, mainly because methodologically consistent, continental‐scale analyses of uplifted terraces have not yet been carried out for South America. Uplifted marine terraces are generally used to infer permanent coastal deformation and uplift; we used almost 2,000 measurements of last‐interglacial marine terraces to calculate an uplift‐rate signal on which we performed a wavelength analysis. The same spectral analysis was applied to tectonic and subduction parameters associated with accumulation of permanent deformation to detect possible links with the uplift‐rate signal. The uplift‐rate signal displays a constant background‐uplift rate along the margin, perturbed by changes at variable wavelengths. Similarities between its wavelength spectrum and the spectra of tectonic parameters suggest potential correlations pointing toward underlying processes. For example, crustal faulting is mainly responsible for short‐wavelength deformation; intermediate‐wavelength to long‐wavelength tectonic features indicate various extents of locked areas on the megathrust that relate to its long‐term seismotectonic segmentation. We suggest that moderate, long‐term background uplift is caused by major, deep earthquakes near the Moho, although records of such events are sparse. Due to their disparate occurrence, we infer accumulation of permanent deformation over millennial time scales through multiple, distinct uplift phases that are spatially and temporally distributed. Our study highlights the application and utility of a signal‐analysis approach to elucidate the mechanisms driving surface deformation in subduction zones at a continental scale.

Marine invertebrates as proxies for early kelp use along the western coast of South America

Coastal societies have lived at the seaward edge of the Atacama Desert since at least 12,000 years ago. Kelp forest ecosystems provide evidence for important subsistence activity along the entire Chilean coast through fishing and gathering. Despite their importance, especially in hyperarid contexts with limited plant abundance, there is scarce evidence of kelp in archaeological contexts, hampering the study of kelp use in the past. In the present study, we use the presence of small marine invertebrates, inhabitants of stipes and holdfasts of macroalgae, as proxies that indicate past kelp presence. We analyze samples of three species of snails (Tegula atra,Tegula tridentata,andDiloma nigerrima) and one limpet (Scurria scurra) from nine archaeological sites dated between 7,000 and 500 cal years before present located around the area of Taltal (25°Lat S). Modern samples of these species were collected to reconstruct the size of fragmented archaeological shells and subsequently estimate the size of harvested kelps. Through this approach, we estimated the size and relative abundance of kelp used by coastal groups that inhabited the southern part of the Atacama Desert for around 6,500 years. Our results are a contribution to the scarce information on the presence and use of kelp in the prehistory of the Americas and contribute to comparative perspectives with other areas of the world where the use of kelp by humans in the past has already been explored.

Surf-diatoms from sandy beaches on the Eastern Coast of South America (Brazil): the identification ofAnaulusEhrenberg andAsterionellopsisRound

Abstract“Surf diatoms” can form high biomass in the surf zone of sandy beaches around the world,AsterionellopsisandAnaulusbeing the main genera of this group in Brazil.Asterionellopsis glacialiswas considered a cosmopolitan species, and taxonomic studies using molecular and morphological tools showed thatA. glacialisis a complex with cryptic and semicryptic species. So, it would be plausible to suppose thatAnaulus australis, another surf zone patch-forming diatom with wide latitudinal occurrence could also be part of a species complex. We collected and identifiedAnaulusandAsterionellopsisstrains from tropical, subtropical and warm temperate sandy beaches on the east coast of South America (Brazil) based on genetic divergence, phylogeny, single-locus automated species delimitation methods (both genera), and frustule ultrastructure (Anaulus).AnaulusandAsterionellopsisshowed contrasting diversity patterns and spatial distribution: a single species ofAnaulus australiswas registered in tropical and subtropical beaches, while at least three species ofAsterionellopsis:A. tropicalis,A. thurstoniiandA. guyunusaewere observed at different latitudes, indicating thatAsterionellopsisspecies have distinct ecological requirements.Asterionellopsis thurstoniiwas previously reported in Europe and it is documented here for the first time in the Southern Hemisphere. The different diversity patterns between these two surf diatom genera suggest that they are likely to have distinct ages, and dispersion and/or speciation processes.

The Diversification of Adaptive Strategies for Karst-Adaptable Plants and the Utilization of Plant Resources in Karst Ecosystems

Karst landforms, which account for approximately 15% of the world’s total land area, are mainly concentrated in low latitudes, including Southeast Asia, the European Mediterranean, the east coast of North America, the west coast of South America, and the marginal areas of Australia [...]

Molecular Changes in the Brain of the Wintering Calidris pusilla in the Mangroves of the Amazon River Estuary.

Migrant birds prepare differently to fly north for breeding in the spring and for the flight to lower latitudes during autumn, avoiding the cold and food shortages of the Northern Hemisphere's harsh winter. The molecular events associated with these fundamental stages in the life history of migrants include the differential gene expression in different tissues. Semipalmated sandpipers (Calidris pusilla) are Arctic-breeding shorebirds that migrate to the coast of South America during the non-breeding season. In a previous study, we demonstrated that between the beginning and the end of the wintering period, substantial glial changes and neurogenesis occur in the brain of C. pusilla. These changes follow the epic journey of the autumn migration when a 5-day non-stop transatlantic flight towards the coast of South America and the subsequent preparation for the long-distance flight of the spring migration takes place. Here, we tested the hypothesis that the differential gene expressions observed in the brains of individuals captured in the autumn and spring windows are consistent with the previously described cellular changes. We searched for differential gene expressions in the brain of the semipalmated sandpiper, of recently arrived birds (RA) from the autumnal migration, and that of individuals in the premigratory period (PM) in the spring. All individuals were collected in the tropical coastal of northern Brazil in the mangrove region of the Amazon River estuary. We generated a de novo neurotranscriptome for C. pusilla individuals and compared the gene expressions across libraries. To that end, we mapped an RNA-Seq that reads to the C. pusilla neurotranscriptome in four brain samples of each group and found that the differential gene expressions in newly arrived and premigratory birds were related with neurogenesis, metabolic pathways (ketone body biosynthetic and the catabolic and lipid biosynthetic processes), and glial changes (astrocyte-dopaminergic neuron signaling, astrocyte differentiation, astrocyte cell migration, and astrocyte activation involved in immune response), as well as genes related to the immune response to virus infections (Type I Interferons), inflammatory cytokines (IL-6, IL-1β, TNF, and NF-κB), NLRP3 inflammasome, anti-inflammatory cytokines (IL-10), and cell death pathways (pyroptosis- and caspase-related changes).