Atualizado: 27 de ago. de 2020
Os GTs 2.1 Geodiversidade e Biodiversidade dos Substratos Plataformais e 3.2 Ciclos Biogeoquímicos, Fluxo de CO2 e Acidificação do Oceano Atlântico Tropical, publicaram recentemente dois trabalhos em periódicos conceituados, listado abaixo:
Mapa batimétrico mostrando as principais falhas perfis batimétricos e sísmicos: (a) —Coroa das Lavadeiras b—arenitos de praia, c—Campo de dunes subaquosas de Guamaré, d— Coroa Branca, e—Vale Inciso do Açu, f— Vale Inciso do Apodi; (B) Compartimentos batimétricos da platform continental. Principais falhas: 1—Afonso Bezerra; 2—Carnaubais; 3—Macau; 4—Ubarana; 5—Pescada; 6—Shelf Edge Faults; 7—Areia Branca.
Resumo:
The primary objective of this study is to assess the control of faults of the rift and post-rift stages on the shelf morphology of the Potiguar Basin in northeastern Brazil. This aborted rift basin was generated during the opening of the Equatorial Atlantic in the Aptian. The offshore portion of the continental margin consists of a narrow (~ 40 km) and shallow (~ 70 m below present sea-level) continental shelf with a very steep continental slope (1:11). Our dataset encompasses gravity, bathymetric, shallow seismic and structural data. The results indicate that low sedimentation rates during the Quaternary period contributed to the identification of structural controls in pre-Holocene rocks. The key evidence for fault reactivation on the seafloor is the link between coastal and shelf features associated with pre-Cenozoic structures of the Potiguar Basin. During periods of low sea level, the incision of shelf valleys was readjusted longitudinally and transversally due to the structural controls. Shelf gradient breaks are associated with the occurrences of coplanar ESE– WNW-oriented faults, and uplifted and subsided areas occur in between these fault systems. The results indicate a strong correlation between the margin geometry, modern shelf surface, near-surface expression, and the rift-phase faults, which appear to be reactivated in concordance with the present-day margin stress field. We conclude that neotectonics has influenced both the sediment deposition and morphology of the NE Brazilian Equatorial margin during Quaternary times.
Mudança na SST (°C) e PWS (m2/s2) durante 1964–1975 (a) and 1976–2012 (b). Os contornos em magenta indicam 95% do teste de confidência de Mann– Kendall para a SST; apenas os vetores PWS significativos de acordo com 95% do teste de confidência de Mann–Kendall estão plotados.
Resumo:
A homogeneous monthly data set of sea surface temperature (SST) and pseudo wind stress based on in situ observations is used to investigate the climatic trends over the tropical Atlantic during the last five decades (1964–2012). After a decrease of SST by about 1 °C during 1964–1975, most apparent in the northern tropical region, the entire tropical basin warmed up. That warming was the most substantial ([1 °C) in the eastern tropical ocean and in the longitudinal band of the intertropical convergence zone. Surprisingly, the trade wind system also strengthened over the period 1964–2012. Complementary information extracted from other observational data sources confirms the simultaneity of SST warming and the strengthening of the surface winds. Examining data sets of surface heat flux during the last few decades for the same region, we find that the SST warming was not a consequence of atmospheric heat flux forcing. Conversely, we suggest that long- term SST warming drives changes in atmosphere parameters at the sea surface, most notably an increase in latent heat flux, and that an acceleration of the hydrological cycle induces a strengthening of the trade winds and an acceleration of the Hadley circulation. These trends are also accompanied by rising sea levels and upper ocean heat content over similar multi-decadal time scales in the tropical Atlantic. Though more work is needed to fully understand these long term trends, especially what happens from the mid-1970’s, it is likely that changes in ocean circulation involving some combination of the Atlantic meridional overtuning circulation and the subtropical cells are required to explain the observations.
Atualizado: 27 de ago. de 2020
Três novos trabalhos foram publicados em periódicos internacionais apresentando resultados do inctAmbTropic. Lembramos que apenas os trabalhos que declaram nos agradecimentos a chancela do inctAmbTropic são computados como produção acadêmica do Instituto.
Cavalcante-Silva et al. 2013. Spasmolytic Effect of Caulerpine Involves Blockade of Ca2+ Influx on Guinea Pig Ileum. Marine Drugs , 11, 1553-1564; doi:10.3390/md11051553. Impact Factor: 3,174
Abstract:
In this work, we investigated the spasmolytic effect of caulerpine, a bisindole alkaloid isolated from marine algae of the Caulerpa genus, on guinea pig ileum. Our findings indicated that caulerpine inhibited phasic contractions induced by carbachol (IC50 = 7.0 ± 1.9 × 10−5 M), histamine (IC50 = 1.3 ± 0.3 × 10−4 M) and serotonin (IC50 = 8.0 ± 1.4 × 10−5 M) in a non-selective manner. Furthermore, caulerpine concentration-dependently inhibited serotonin-induced cumulative contractions (pD′2 = 4.48 ± 0.08), shifting the curves to the right with Emax reduction and slope of 2.44 ± 0.21, suggesting a noncompetitive antagonism pseudo-irreversible. The alkaloid also relaxed the ileum pre-contracted by KCl (EC50 = 9.0 ±0.9 ×10−5 M) and carbachol (EC50 = 4.6 ±0.7 ×10−5 M) in a concentration-dependent manner. This effect was probably due to inhibition of Ca2+ influx through voltage-gated calcium channels (CaV), since caulerpine slightly inhibited the CaCl2-induced contractions in depolarizing medium without Ca2+, shifting the curves to the right and with Emax reduction. According to these results, the spasmolytic effect of caulerpine on guinea pig ileum seems to involve inhibition of Ca2+ influx through CaV. However, other mechanisms are not discarded. Impact Factor: 3,978 (2012); 5-Year Impact Factor: 3,911 (2012)Link: http://www.mdpi.com/1660-3397/11/5/1553
Araujo et al. 2013. Nutrient Input and CO2 Flux of a Tropical Coastal Fluvial System with High Population Density in the Northeast Region of Brazil. Journal of Water Resource and Protection, 2013, 5, 362-375. Impact factor: 0,41 com base no ISI Web of Knowledge.
Abstract:
The carbon dioxide flux through the air-water interface of coastal freshwater ecosystems must be quantified to under- stand the regional balances of carbon and its transport through coastal and estuarine regions. The variations in air-sea CO2 fluxes in nearshore ecosystems can be caused by the variable influence of rivers. In the present study, the amount of carbon emitted from a tropical coastal river was estimated using climatological and biogeochemical measurements (2002-2010) obtained from the basin of the Capibaribe River, which is located in the most populous and industrialized area of the northeast region of Brazil. The results showed a mean CO2 flux of +225 mmol·m−2·d−1, mainly from organic material from the untreated domestic and industrial wastewaters that are released into the river. This organic material increased the dissolved CO2 concentration in the river waters, leading to a partial pressure of CO2 in the aquatic environment that reached 31,000 μatm. The months of April, February and December (the dry period) showed the largest monthly means for the variables associated with the carbonate system ( HCO− , DIC, CO , CO2− , TA, temperature and pH). This status reflects the state of permanent pollution in the basin of the Capibaribe River, due, in particular, to the discharge of untreated domestic wastewater, which results in the continuous mineralization of organic material. This mineralization significantly increases the dissolved CO2 content in the estuarine and coastal waters, which is later re-leased to the atmosphere. Impact factor: 0,41 com base no ISI Web of Knowledge.Link: http://www.scirp.org/journal/jwarp/
Lins et al (2013). Prediction of sea surface temperature in the tropical Atlantic by support vector machinesComputational Statistics and Data Analysis 61 (2013) 187–198. Impact Factor: 1,304. 5-Year Impact Factor: 1, 449
Abstract:
The Sea Surface Temperature (SST) is one of the environmental indicators monitored by buoys of the Prediction and Research Moored Array in the Tropical Atlantic (PIRATA) Project. In this work, a year-ahead prediction procedure based on SST knowledge of previous periods is proposed and coupled with Support Vector Machines (SVMs). The proposed procedure is focused on seasonal and intraseasonal aspects of SST. Data from PIRATA buoys are used in various ways to feed the SVM models: with raw data, using information about the SST slopes and by means of SST curvatures. The influence of these data handling strategies over the predictive capacity of the proposed methodology is discussed. Additionally, the forecasts’ accuracy is evaluated as the number of years considered in the SVM training phase increases. The raw data and the curvatures presented quite similar performances, they are more efficient than the slopes; the respective Mean Absolute Percentage Error (MAPE) values do not exceed 2% and all Mean Absolute Errors (MAEs) are lower than 0.37 °C. Besides, as the number of years considered in the training set increases, the MAPE and MAE values tend to stabilize. Impact Factor: 1,304. 5-Year Impact Factor: 1, 449 Link: http://www.sciencedirect.com/science/article/pii/S0167947312004240