ENSO effects on the relationship between aerosols and evapotranspiration in the south of the Amazon biome.

The effects of the El Nino-Southern Oscillation (ENSO) events have local, regional, and global consequences for water regimes, causing floods or extreme drought events. Tropical forests are strongly affected by ENSO, and in the case of the Amazon, its territorial extension allows for a wide variation of these effects. The prolongation of drought events in the Amazon basin contributes to an increase in gas and aerosol particle emissions mainly caused by biomass burning, which in turn alter radiative fluxes and evapotranspiration rates, cyclically interfering with the hydrological regime. The ENSO effects on the interactions between aerosol particles and evapotranspiration is a critical aspect to be systematically investigated. Therefore, this study aimed to evaluate the ENSO effect on a site located on the southern portion of the Amazonian region. In addition to quantifying and testing possible differences between aerosols and evapotranspiration under different ENSO classes (El Niño, La Niña and Neutrality), this study also evaluated possible variations in evapotranspiration as a function of the aerosol load. A highly significant difference was found for air temperature, relative humidity and aerosol load between the El Niño and La Niña classes. For evapotranspiration, significant differences were found for the El Niño and La Niña classes and for El Niño and Neutrality classes. Under the Neutrality class, the aerosol load correlated significantly with evapotranspiration, explaining 20% of the phenomenon. Under the El Niño and La Niña classes, no significant linear correlation was found between aerosol load and evapotranspiration. However, the results showed that for the total data set, there is a positive and significant correlation between aerosol and evapotranspiration. It increases with a quadratic fit, i.e., the aerosol favors evapotranspiration rates up to a certain concentration threshold. The results obtained in this study can help to understand the effects of ENSO events on atmospheric conditions in the southern Amazon basin, in addition to elucidating the role of aerosols in feedback to the water cycle in the region.

Major Regional-Scale Production of O3 and Secondary Organic Aerosol in Remote Amazon Regions from the Dynamics and Photochemistry of Urban and Forest Emissions.

The Amazon rainforest suffers increasing pressure from anthropogenic activities. A key aspect not fully understood is how anthropogenic atmospheric emissions within the basin interact with biogenic emissions and impact the forest's atmosphere and biosphere. We combine a high-resolution atmospheric chemical transport model with an improved emissions inventory and in-situ measurements to investigate a surprisingly high concentration of ozone (O3) and secondary organic aerosol (SOA) 150-200 km downwind of Manaus city in an otherwise pristine forested region. We show that atmospheric dynamics and photochemistry determine a gross production of secondary pollutants seen in the simulation. After sunrise, the erosion of the nocturnal boundary layer mixes natural forest emissions, rich in biogenic volatile organic compounds, with a lofted pollution layer transported overnight, rich in nitrogen oxides and formaldehyde. As a result, O3 and SOA concentrations greater than ∼47 ppbv and 1.8 µg m-3, respectively, were found, with maximum concentrations occurring at 2 pm LT, 150-200 km downwind of Manaus city. These high concentrations affect a large primary forested area of about 11,250 km2. These oxidative areas are under a NOx-limited regime so that changes in NOx emissions from Manaus have a significant impact on O3 and SOA production.

La glándula de Harder: un transductor neuroinmunoendrocrino / The Harderian gland: neuroinmunoendrocrine transductor

La glándula de Harder es una glándula túbulo-alveolar localizada en la parte posterior de la órbita ocular de animales que poseen membrana nictitante. En estos mamiferos la glándula contiene una gran cantidad de lípidos. La glándula de Harder de roedores contiene un pigmento café rojizo, el cual ha sido identificado como porfirina. Las funciones de la glándula de Harder son; síntesis y liberación de ferhormonas, fotoprotección y termorregulación, osmoprotección y se le ha propuesto además un papel inmunoendocrino