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: email@example.com
Esta disponível online a partir de hoje o primeiro trabalho publicado pelo inctAmbTropic: “Intraseasonal variability of the North Brazil Undercurrent forced by remote winds. Autores: D. Veleda, M. Araujo, R. Zantopp,e R. Montagne“. O trabalho foi publicado no volume 117 do Journal of Geophysical Research. O professor Moacyr Araújo coordena o GT3.2 (Ciclos Biogeoquímicos, Fluxo de CO2 e Acidificação do Oceano Atlântico Tropical) e é membro do Comitê Gestor do inctAmbTropic, representando a área de Oceanos.
Schematic representation of the Atlantic Subtropical Cell (STC) circulation, including subduction (blue) and upwelling (green) zones. Current branches involved in the STC flows are NEC, SEC, sSEC, NECC and EUC; NEUC, SEUC = North and South Equatorial Undercurrent; NBC, NBUC = North Brazil Current and Undercurrent; GD, AD = Guinea and Angola domes. Interior equatorward thermocline pathways dotted. Adapted from Schott et al. . The mooring array at 11S is shown by the red line.
ABSTRACT: “Intraseasonal signals with periods of 2 to 3 weeks in near-surface alongshore current measurements are detected from four moorings (K1–K4) deployed from 2000 to 2004 at the 11S section close to the Brazilian coast as part of the German CLIVAR Tropical Atlantic Variability Project. This section crosses the path of the North Brazil Undercurrent, the most powerful western boundary current in the South Atlantic Ocean. We investigate the origin of this intraseasonal variability of the North Brazil Undercurrent by relating the oceanic oscillation of the alongshore currents to its atmospheric counterpart, the meridional wind stress. On average, the results indicate a well-defined lagged (10 days) correlation (˜0.6) structure between meridional wind stress and alongshore currents. The oceanic region with the highest cross-correlations is identified as a relatively narrow band along the Brazilian coast, from 22–36S and 40–50W, bounded in the north by an eastward change in coastline orientation. The cross-wavelet transform establishes the common power between the time series of meridional wind stress and alongshore currents, predominantly during austral winter and spring. These signals propagate equatorward with an alongshore speed of 285+/-63 km day1, consistent with Coastal Trapped Wave theory“.
Veleda, D., M. Araujo, R. Zantopp, and R. Montagne (2012), Intraseasonal variability of the North Brazil Undercurrent forced by remote winds, J. Geophys. Res., 117, C11024, doi:10.1029/2012JC008392. (para baixar o pdf, clique neste link)
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