Is the air-breathing organ a significant route for CO excretion during aquatic hypercapnia in the pirarucu, Arapaima gigas?

The pirarucu is one of the very few obligate air-breathing fish, employing a gigantic, highly vascularized air-breathing organ (ABO). Traditionally, the ABO is thought to serve mainly for O uptake (ṀO), with the gills providing the major route for excretion of CO (ṀCO) and N-waste. However, under aquatic hypercapnia, a common occurrence in its natural environment, branchial ṀCO to the water may become impaired.

Temperature alters antioxidant status and induces cell damage in the Amazonian fish tambaqui.

Since Amazonian fish live close to their maximum thermal limits, this makes them vulnerable to the effects of global warming. The aim of this study was to evaluate the oxidative stress and antioxidant enzymatic and biochemical responses of the plasma, liver and muscle of tambaqui (Colossoma macropomum) exposed to a rising gradient of water temperature. One hundred and twenty (N = 120) juvenile tambaqui were exposed to four temperature levels, these being: the environmental temperature of the season (T - 25.

Fish mortality in the Amazonian drought of 2023: the role of experimental biology in our response to climate change.

Higher temperatures exacerbate drought conditions by increasing evaporation rates, reducing soil moisture and altering precipitation patterns. As global temperatures rise as a result of climate change, these effects intensify, leading to more frequent and severe droughts. This link between higher temperatures and drought is particularly evident in sensitive ecosystems like the Amazon rainforest, where reduced rainfall and higher evaporation rates result in significantly lower water levels, threatening biodiversity and human livelihoods.

Morphological changes in eggs and embryos of Aedes aegypti (Diptera: Culicidae) exposed to predicted climatic scenarios for the year 2100 in the Central Amazon.

According to the IPCC, by the year 2100, rises in global temperature could reach up to 5 °C above current averages. On a planet-wide scale, this is one of the effects of climate changes that could have repercussions on the biological cycle of Aedes aegypti, the main arbovirus vector in urban environments and a transmitter of the arboviruses that cause dengue, Zika, chikungunya and urban yellow fever. The objective of this study was to evaluate morphological changes in Ae.

Amazon tropical fishes of commercial interest show human-cell contamination but no SARS-CoV-2 in a real-life scenario.

Background: Amazonas was one of the most impacted Brazilian states by the COVID-19 pandemic. Mortality rates were high, and the health systems collapsed. It is important to identify possible intermediate reservoirs to avoid animal-to-human contamination.

Simulated climate change and atrazine contamination can synergistically impair zebrafish testicular function.

Elements that interfere with reproductive processes can have profound impacts on population and the equilibrium of ecosystems. Global warming represents the major environmental challenge of the 21st century, as it will affect all forms of life in the coming decades. Another coexisting concern is the persistent pollution by pesticides, particularly the herbicide Atrazine (ATZ), which is responsible for a significant number of contamination incidents in surface waters worldwide.

Effects of climate change and mixtures of pesticides on the Amazonian fish Colossoma macropomum.

Several studies highlighted the complexity of mixing pesticides present in Amazonian aquatic environments today. There is evidence that indicates that ongoing climate change can alter the pattern of pesticide use, increasing the concentration and frequency of pesticide applications. It is known that the combination of thermal and chemical stress can induce interactive effects in aquatic biota, which accentuates cell and molecular damage.

Oil spill in an amazon blackwater environment: Biochemical and physiological responses of local fish species.

The accidental spill of petroleum asphalt cement (PAC) in São Raimundo (SR Harbor, located on the Rio Negro (Manaus, Amazonas, Brazil) was monitored through the analysis of polyciclic aromatic hydrocarbons (PAHs) in water and a set of biomarkers in fishes (exposure biomarkes: PAHs-type metabolites concentrations in bile; the activities of ethoxyresorufin-O-deethylase (EROD), glutathione-S-transferase (GST), catalase (CAT), superoxide dismutase (SOD), and glutathione peroxidase (GPx) in liver. Effect biomarkers: lipid peroxidation concentration (LPO) in liver, acetylcholinesterase activity in brain, and genotoxic DNA damage in erythrocytes). Two fish species, Acarichthys heckelii and Satanoperca jurupari, were collected 10, 45, and 90 days after the PAC spill in São Raimundo.

In vivo exposure to high temperature compromises quality of the sperm in Colossoma macropomum.

Increases in temperature can affect the reproduction of fish by decreasing the quality of gametes for fertilization. Therefore, this study aimed to evaluate the in vivo effect of temperature on the production and sperm quality of Colossoma macropomum, which is an economically relevant species for Brazil, and other countries. Broodstock were exposed for 10 days at temperatures of 29 °C (n = 4) and 35 °C (n = 4).

Gut microbiota of an Amazonian fish in a heterogeneous riverscape: integrating genotype, environment, and parasitic infections.

A number of key factors can structure the gut microbiota of fish such as environment, diet, health state, and genotype. , an Amazonian cichlid, is a relevant model organism to study the relative contribution of these factors on the community structure of fish gut microbiota. has well-studied genetic populations and thrives in rivers with drastically divergent physicochemical characteristics.

Ammonia Increases the Stress of the Amazonian Giant in a Climate Change Scenario.

Ammonia is toxic to fish, and when associated with global warming, it can cause losses in aquaculture. In this study, we investigated the physiological and zootechnical responses of to the current scenarios and to RCP8.5, a scenario predicted by the IPCC for the year 2100 which is associated with high concentrations of environmental ammonia (HEA).

Bacterioplankton Communities in Dissolved Organic Carbon-Rich Amazonian Black Water.

The Amazon River basin sustains dramatic hydrochemical gradients defined by three water types: white, clear, and black waters. In black water, important loads of allochthonous humic dissolved organic matter (DOM) result from the bacterioplankton degradation of plant lignin. However, the bacterial taxa involved in this process remain unknown, since Amazonian bacterioplankton has been poorly studied.

Correlation between caffeine and coprostanol in contrasting Amazonian water bodies.

The evaluation of contamination by domestic sewage is relevant in the Amazon region; however, it has neither been well-developed nor accompanied by research or monitoring programs. In this study, caffeine and coprostanol as indicators of sewage were investigated in water samples from Amazonian water bodies that crisscross the city of Manaus (Amazonas state, Brazil) and cover regions with distinct main land uses such as high-density residential, low-density residential, commercial, industrial, and environmental protection areas. Thirty-one water samples were studied based on their dissolved and particulate organic matter (DOM and POM) fractions.

Genomic and Environmental Factors Shape the Active Gill Bacterial Community of an Amazonian Teleost Holobiont.

Fish bacterial communities provide functions critical for their host's survival in contrasting environments. These communities are sensitive to environmental-specific factors (i.e.

Vitellogenin Ab structure of the amazonian Arapaima gigas.

The vitellogenin is composed by polypeptides that are precursors of egg yolk proteins that provides embryo and larvae nutrition. The mRNA encoding for vitellogenin Ab (Vtg-Ab; 4,536 bp long and 1,512 amino acids) were obtained by RNA-Seq library sequencing of pirarucu gonads. The Vtg-Ab sequences had high homology with Vtgs of other three teleosts species of the order Osteoglossiformes.

Impact of high temperature, CO and parasitic infection on inflammation, immunodepression and programmed cell death in Colossoma macropomum at the transcriptional level.

The production of tambaqui Colossoma macropomum has recently reached a milestone, being considered the main native species produced in South American continental waters. Despite the importance of this fish, its immunity is poorly understood, and global warming could pose severe risks to its health as increasing water temperature leads to an increase in the incidence of parasitic diseases. In an experimental context based on the high-emission scenario of the 5th Intergovernmental Panel on Climate Change (IPCC) report, we evaluated the synergistic effect of exposure to the extreme climate change scenario (RCP8.

Tissue distribution of appetite regulation genes and their expression in the Amazon fish Colossoma macropomum exposed to climate change scenario.

Climate change leads to an increase in water acidification and temperature, two environmental factors that can change fish appetite and metabolism, affecting fish population in both wild and aquaculture facilities. Therefore, our study tested if climate change affects gene expression levels of two appetite-regulating peptides - Neuropeptide Y (NPY) and Cholecystokinin (CCK) - in the brain of tambaqui, Colossoma macropomum. Additionally, we show the distribution of these genes throughout the body.

Genomics of Serrasalmidae teleosts through the lens of microbiome fingerprinting.

Associations between host genotype and host-associated microbiomes have been shown in a variety of animal clades, but studies on teleosts mostly show weak associations. Our study aimed to explore these relationships in four sympatric Serrasalmidae (i.e.

Global change and physiological challenges for fish of the Amazon today and in the near future.

Amazonia is home to 15% (>2700, in 18 orders) of all the freshwater fish species of the world, many endemic to the region, has 65 million years of evolutionary history and accounts for 20% of all freshwater discharge to the oceans. These characteristics make Amazonia a unique region in the world. We review the geological history of the environment, its current biogeochemistry and the evolutionary forces that led to the present endemic fish species that are distributed amongst three very different water types: black waters [acidic, ion-poor, rich in dissolved organic carbon (DOC)], white waters (circumneutral, particle-rich) and clear waters (circumneutral, ion-poor, DOC-poor).

Climate change affects the parasitism rate and impairs the regulation of genes related to oxidative stress and ionoregulation of Colossoma macropomum.

Global climate change represents a critical threat to the environment since it influences organismic interactions, such as the host-parasite systems, mainly in ectotherms including fishes. Rising temperature and CO are predicted to affect this interaction other and critical physiological processes in fish. Herein, we investigated the effects of different periods of exposure to climate change scenarios and to two degrees of parasitism by monogeneans in the host-parasite interaction, as well as the antioxidant and ionoregulatory responses of tambaqui (Colossoma macropomum), an important species in South American fishing and aquaculture.

Involvement of purinergic system and electron transport chain in two species of cichlids from the Amazon basin exposed to hypoxia.

The Amazonian aquatic ecosystem undergoes seasonal variations and daily changes that directly affect the availability of oxygen. During the day the levels of oxygen can reach supersaturation, and at night can drop to zero. In this way, aquatic organisms are exposed daily to physiological challenges regarding the availability of oxygen.

Copper and cadmium impair sperm performance, fertilization and hatching of oocytes from Amazonian fish Colossoma macropomum.

The contamination of aquatic environments by transition metals can have a direct influence on the reproductive process of several organisms in the aquatic biota. This study aimed to evaluate the effect of cadmium and copper on the sperm of tambaqui (Colossoma macropomum). Male (n = 4) and female (n = 4) specimens of C.

Aerobic Metabolism Impairment in Tambaqui (Colossoma macropomum) Juveniles Exposed to Urban Wastewater in Manaus, Amazon.

The main purpose of the present study was to investigate the potential use of metabolic parameters as non-specific biomarkers of pollution. The Igarapé do Quarenta is a small urban river crossing an industrial area in the city of Manaus, Amazon, and receives the city wastewater without treatment. The fish tambaqui (Colossoma macropomum) were exposed to water collected from two different sites of that stretch for 96 h.

Understanding the Science Surrounding Environmental Consequences and Rehabilitation Actions Stemming from Brazil's Fundão Tailing Dam Rupture.

Collapse of the Fundão tailings dam in November 2015 in Minas Gerais, Brazil, resulted in the release of approximately 36 million cubic meters of primarily clay and fine sand-sized particles to the environment. The spill event extended over 600 km of the Rio Doce catchment and affected terrestrial and aquatic ecosystems and compromised socioeconomic activities throughout the watershed. Numerous monitoring programs and research investigations in the catchment since that time contribute to better understanding of the environmental consequences and plans for rehabilitation of the landscape.

Disturbance of oxidant/antioxidant status and impairment on fillet fatty acid profiles in Brycon amazonicus subjected to acute heat stress.

Amazon fish are vulnerable to climate change. Current temperature increases in Amazonian rivers are likely to continue in the coming years. Elevated temperatures impair homeostasis and subject fish to oxidative stress; nevertheless, the effects of elevated temperature on plasma and muscle oxidative stress as well as fillet fatty acid composition in matrinxã (Brycon amazonicus) remain unknown.