Atualizado: 27 de ago. de 2020
Já encontra-se disponível “on line” o mais recente trabalho publicado no âmbito do inctAmbTropic. O trabalho intitulado “The narrow, shallow, low-accommodation shelf of central Brazil: sedimentology, evolution, and human uses” tem como autores Dominguez, JML, Silva, RP, Nunes, AS, Freire, AFM. O trabalho está publicado na revista Geomorphology (Impact Factor: 2,552, 5-Year Impact Factor: 3,066).
Atividade Pesqueira na Borda da Plataforma Continental Central do Brasil
O trabalho apresenta uma síntese e modelo conceitual da sedimentação na plataforma continental central do Brasil e é a primeira publicação a apresentar informações detalhadas para esta região. O trabalho é uma contribuição do GT2.1 Geodiversidade e Biodiversidade dos Substratos do inctAmbTropic.
ABSTRACT
The continental shelf off the coast of central Brazil, extending from 10 to 16°S, is unusually narrow (~ 20 km) and rests on the São Francisco craton. The shelf break is located between the 45 and 50 m isobaths and coincides with major hinge-lines of the marginal basins. The shelf was exposed for most of the Quaternary period, particularly during the last 1 my, when the average sea level was −62 m. Submarine geomorphology is strongly influenced by this extended sub-aerial exposure and reduced subsidence, resulting in widespread incisions on the shelf. During the limited episodes of shelf inundation, as is the case today, a few meters of non-framework grain assemblages dominated by coralline algae accumulated on the outer shelf, while quartz sands were restricted to water depths of less than 10–15 m. Mud accumulation on this unusually shallow shelf is aided by additional accommodation space provided by incisions and canyon heads indenting the shelf. Artisanal fisheries, targeting high-value commercial species associated with hard bottoms located on the outer shelf and shelf break, are the most important human use of this shelf. Data used in this study have been compiled from theses and previously conducted surveys and consist of four piston cores, 509 km of chirp subbottom profiles and side scan recordings, and 711 bottom grab samples that have been analyzed for various textural and compositional aspects.
Conceptual model for sedimentation in the narrow, shallow shelf off central Brazil. Highstand sedimentation — during the few, brief highstand episodes, the shelf and coastal zone were flooded. Highstand coastal bays formed at the upstream end of incised valleys and were later infilled. On the shelf these incised valleys were partially infilled with fine-grained sediments. On the rest of the shelf, the reduced siliciclastic influx favored an essentially carbonate sedimentation, of non-framework rhodoalgal, oligophotic grain assemblages. Framework builders (hermatipic corals) developed on the very shallow areas bordering the coastline. Fonte: Dominguez, J.M.L., et al., The narrow, shallow, low-accommodation shelf of central Brazil: Sedimentology, evolution, and human uses, Geomorphology (2013), http://dx.doi.org/10.1016/j.geomorph.2013.07.004
Chama-se a atenção que a base de dados gerada para este trabalho está disponibilizada na forma de Dados Suplementares no portal do periódico Geomorphology, publicado pela Editora Elsevier, incluindo arquivos no formato kml para visualização da distribuição espacial do dados no Google Earth.
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
Foi publicado no último mês de dezembro, no periódico Coral Reefs um trabalho da Dra. Beatrice Padovani (integrante do GT1.3 – Recifes e Ecossistemas Coralinos, do inctAmbTropic) relatando os efeitos de anomalias de temperatura nos recifes de corais do Atlântico Tropical. O trabalho foi realizado em Fernando de Noronha e Atol das Rocas. O estudo constatou que anomalias de temperatura determinadas a partir da plataforma AVHRR (Advanced Very High Resolution Radiometer – NOAA/NASA) e medidas em bóias do projeto PIRATA, apresentam uma forte correlação com eventos de branqueamento dos corais, sugerindo que os dados do projeto PIRATA podem ser utilizados como indicadores de primeira ordem de estresse afetando os recifes.
Atol das Rocas
Este trabalho, do qual participou também o Dr. Moacyr Araújo (coordenador do GT3.2 – Ciclos Biogeoquímicos, Fluxo de CO2 e Acidificação no Oceano Atlântico Tropical, do inctAmbTropic) constitui um exemplo de sinergia entre dois GTs do inctAmbTropic, que deve ser ativamente buscada pelos demais GTs do AmbTropic.
O trabalho da Dra. Beatrice, pode ser acessado utilizando este link.
O abstract está reproduzido abaixo:
“In 2010, high sea surface temperatures that were recorded in several parts of the world and caused coral bleaching and coral mortality were also recorded in the southwest Atlantic Ocean, between latitudes 0°S and 8°S. This paper reports on coral bleaching and diseases in Rocas Atoll and Fernando de Noronha archipelago and examines their relationship with sea surface temperature (SST) anomalies recorded by PIRATA buoys located at 8°S30°W, 0°S35°W, and 0°S23°W. Adjusted satellite data were used to derive SST climatological means at buoy sites and to derive anomalies at reef sites. The whole region was affected by the elevated temperature anomaly that persisted through 2010, reaching 1.67 °C above average at reef sites and 1.83 °C above average at buoys sites. A significant positive relationship was found between the percentage of coral bleaching that was observed on reef formations and the corresponding HotSpot SST anomaly recorded by both satellite and buoys. These results indicate that the warming observed in the ocean waters was followed by a warming at the reefs. The percentage of bleached corals persisting after the subsidence of the thermal stress, and disease prevalence increased through 2010, after two periods of thermal stress. The in situ temperature anomaly observed during the 2009–2010 El Niño event was equivalent to the anomaly observed during the 1997–1998 El Niño event, explaining similar bleaching intensity. Continued monitoring efforts are necessary to further assess the relationship between bleaching severity and PIRATA SST anomalies and improve the use of this new dataset in future regional bleaching predictions”
Referência completa: Ferreira, B.P., Costa, M.B.S.F., Coxey, M.S., Gaspar, A.L.B., Veleda, D., Araujo, M. 2012. The effects of sea surface temperature anomalies on oceanic coral reef systems in the southwestern tropical Atlantic. Coral Reefs. DOI 10.1007/s00338-012-0992-y.
Para mais informações contactar a Dra.Beatrice Padovani: beatrice@ufpe.br