Audalio Rebelo Torres Junior

Estudo da influência das anomalias da TSM do Atlântico Sul extratropical na região da Confluência Brasil-Malvinas no regime hidrometeorológico de verão do Sul e Sudeste do Brasil

This study analyses the influence of the extratropical South Atlantic sea surface temperature (SST) anomalies in the Southern and Southeastern Brazilian hydrometeorological pattern. The Brazil-Malvinas Confluence (BMC) is one of the most important South Atlantic Ocean features. This region is characterized by a strong thermal front formed by the confluence between the warm waters transported by the Brazil Current (BC) and the cold waters carried by the Malvinas Current (MC). The knowledgement of its dynamics could represent an important advance to understand its connection with locally and remotely generated ocean and atmospheric processes. This investigation is made with computational modeling using a Community Atmosphere Model (CAM 2.01). The spatial and time SST anomalies were numerically generated inside the model code in such a way to reproduce the summer 2005 event. Significant changes were observed in this experiment in the vertical atmospheric circulation pattern. The precipitation over South Brazil region decreased and more favorable conditions to the South Atlantic Convergence Zone (SACZ) formation appeared over the northern part of the Southeastern Brazil region. These model generated patterns were similar to those observed during the summer 2005, especially the precipitation anomalies results.

Volume and heat transports in the world oceans from an ocean general circulation model

Monitoring the volume and heat transports around the world oceans is of fundamental importance in the study of the climate system, its variability, and possible changes. The application of an Oceanic General Circulation Model for climatic studies needs that its dynamic and thermodynamic fields are in equilibrium. The time spent by the model to reach this equilibrium is called spin-up time. This work presents some results obtained from the application of the Modular Ocean Model version 4.0 initialized with temperature, salinity, velocity and sea surface height data already in equilibrium from an ocean data assimilation experiment conducted by Geophysical Fluid Dynamics Laboratory (GFDL). The use of this dataset as initial condition aimed to diminish the spin-up time of the oceanic model. The model was integrated for seven years. Volume and heat transports in different sections around the world oceans showed to be in good agreement with the literature. The results showed a well defined seasonal cycle starting at the second integration year, also some important dynamic and thermodynamic aspects of the Global Ocean Circulation, as the great conveyor belt, are well reproduced. The obtained results could constitute an important data source to be used as initial and boundary conditions in regional ocean model experiments as well as for long integration runs in order to study oceanic climate variability.

A screening test based on hematological and histological biomarkers to evaluate the environmental impacts in tambaqui (Colossoma macropomum) from a protected area in Maranhão, Brazilian Amazon

Nowadays biomonitoring programs can benefit with mathematical models able to correlate biomarkers to monitor water pollution. The aim of this study was to develop a screening test based on hematological parameters and histological lesions in tambaqui (Colossoma macropomum), to allow the assessment of environmental impacts on fish inhabiting a protected area in Maranhão inside of Brazilian Amazon. Samples collected during three years (2012, 2013 and 2014) were grouped by season (dry and rainy) Water samples were also collected for physical chemistry analysis. Blood samples were stained with Acridine Orange to detect micronuclei and erythrocyte abnormalities. Gill tissues were stained with hematoxylin and counterstained with alcoholic eosin, and histopathological lesions were scored on a scale of 1-3, being 1 = minimal pathological importance, 2 = moderate pathological importance and 3 = marked pathological importance. A screening test for evaluating environmental impact was developed by fitting the measured data (necrosis, erythrocyte abnormalities, number of micronuclei) from tambaqui. A three-dimensional surface was fit to the empirical data. Our proposed model predicted the probability of necrosis (observed in euthanized animals) based on the numbers of micronuclei and abnormal erythrocytes (observed in blood samples from live animals) (correlation coefficient R = 0.89). The methodology could be applied for predicting contamination histories (chronic pollution that induces branchial lesions) in rivers using the micronucleus and erythrocyte abnormalities of the fishes (with a simple blood sample).

Revisiting Tropical Instability Wave Variability in the Atlantic Ocean using SODA reanalysis

Abstract. The spatial and temporal variability of energy exchange in Tropical Instability Waves (TIWs) in the Atlantic Ocean were investigated. A spectral analysis was used to filter the 5-day mean results from Simple Ocean Data Assimilation reanalysis spanning from 1958 to 2008. TIWs were filtered over periods of 15 to 60 days and between wavelengths of 4 and 20 longitude degrees. The main approach of this study was the use of bidirectionally filtered TIW time series as the perturbation fields, and the difference in these time series from the SODA total results was considered to be the basic state for energetics analysis. The main result was that the annual cycle (period of ~ 360 days) was the main source of variability of the waves, and the semi-annual cycle (period of ~ 180 days) was a secondary variation, which indicated that TIWs occurred throughout the year but with intensity that varies seasonally. Barotropic instability acts as the mechanism that feeds and extracts energy to/from TIWs as alternate zonal bands at equatorial Atlantic. Baroclinic instability is the main mechanism that extracts energy from TIWs to the equatorial circulation north of Equator. All TIW patterns of variability were observed at west of ~ 10o W. The present study reveals new evidences regarding TIW variability and suggests that future investigations should include a detailed description of TIW dynamics as part of Atlantic Ocean equatorial circulation

In situ assessment of two catfish species (pisces, Ariidae) to evaluate pollution in a harbor

A histopathological and biometric database for the catfish Sciades herzbergii and Bagre bagre from Sao Luis Island (Harbor area) and Caranguejos Island (reference area) in Brazil is presented. Branchial and hepatic lesions were classified into three reaction patterns: 1) circulatory or inflammatory disturbances; 2) regressive changes; 3) progressive changes. The total length (Lt), standard length (Ls), furcal length (Lf), total weight (Wt), and gonad weight (Wg) of each fish were recorded. As expected, most populations of catfish considered in this study are highly heterogeneous, with lengths and weights deviating from the reference sample. No histopathological lesions were observed in Sciades herzbergii examined at the reference site (Caranguejos Island). In contrast, 90% of the catfish S. herzbergii from sites located in the Harbor Area (Sao Luis Island) had one or more types of branchial and hepatic lesions. As opposed to what was observed in S. herzbergii, more than 86.33% of Bagre bagre individuals s...

Morphological biomarkers in Prochilodus lineatus (pisces, prochilodontidae) for environmental impact assessment in the region of the Baixada Maranhense, Brazil

This study aimed to identify the types of histopathological lesions found in gills of Prochilodus lineatus of the Environmental Protection Area of the Baixada Maranhense region (Brazil). Fish were collected in Mearim river. Sampling took place in October, November and December 2014. We have purchased 30 samples of fish from local fishermen. In the laboratory fish gills were removed, and then fixed in 10% formalin solution and kept into alcohol 70% to the usual histological processing. The tissue was performed by light microscopy and findings were photomicrographed in light microscope - ZEIS. The following lesions were identified: epithelial displacement, the marginal channel shift a start vascular congestion, hyperplasia and merging multiple slides; epithelial disruption, edema, vascular congestion, total fusion of lamellae and disorganization of secondary lamellae. These changes express a response of the body to some xenobiontes. Morphological changes in the gills may represent adaptive strategies for conservation of some biological functions when animals are facing changes in the water quality.

Fish biomarkers for environmental monitoring: An integrated model supporting enzyme activity and histopathological lesions

We present a mathematical model describing the association between glutathione-S-transferase activity and brachial lesions in the catfish, Sciades herzbergii (Ariidae) from a polluted port. The catfish were sampled from a port known to be contaminated with heavy metals and organic compounds and from a natural reserve in Sao Marcos Bay, Brazil. Two biomarkers, hepatic glutathione S-transferase (GST) activity and histopathological lesions, in gills tissue were measured. The values for GST activity were modeled with the occurrence of branchial lesions by fitting a third order polynomial. Results from the mathematical model indicate that GST activity has a strong polynomial relationship with the occurrence of branchial lesions in both the wet and the dry seasons, but only at the polluted port site. The model developed in this study indicates that branchial and hepatic lesions are initiated when GST activity reaches 2.15 μmol min−1 mg protein−1. Beyond this limit, GST activity decreased to very low levels and ...