969 resultados para Regencia coral


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116-year record of coral skeletal delta18O is presented from a colony of Porites lutea from Ningaloo Reef, western Australia. Interannual variability of sea-surface temperatures (SST) inferred from skeletal delta18O is dominated by a 9.5-year period, and may constitute a characteristic signal of the Leeuwin Current. On long-terms coral skeletal delta18O indicates a near-continuous increase of SST at Ningaloo Reef over one century. The skeletal delta18O time series was checked for the presence of seasonal cooling events resulting from major volcanic eruptions. An ~1 °C cooling is evident following the eruption of Pinatubo in 1991, which reproduces the results of previous investigations. However, only weak or no signals can be related to the eruptions of Krakatau (1883) and Agung (1963).

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Records of skeletal delta18O in monthly and Sr/Ca ratios in half-yearly resolution were obtained from a Bermuda coral (Diploria labyrinthiformis) for the time period 1520-1603 (+/-15 yr) AD within the Little Ice Age. Annual and decadal averages of both sea-surface temperature proxies indicate temperature variabilities of 0.5°C (standard deviation) and 0.3°C, respectively. Both numbers are close to recent instrumental observations. Approximately 30% of the interannual time series variance of delta18O is concentrated in broad bands centered at periods of ~30, 16, and 7.8 yr, the last two reflecting the influence of the North Atlantic Oscillation. Although this large-scale climate signal is present in the record, there is no correlation with other contemporaneous northern hemisphere proxy data, resulting from spatial differences in climate variability.

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We present a 55-year-long record (1928-1982) of Sr/Ca in a Bermuda coral (Diploria strigosa), which we use to reconstruct local twentieth century climate features. The clearest climate signal emerges for the late-year Sr/Ca. Although the coral was collected in shallow water (12 m), the correlation with station data is highest for temperatures at 50 m depth (r = -0.70), suggesting that local temperatures at the collection site are not representative for the sea surface temperatures in the adjacent open ocean. The most striking feature of the coral record is the persistent and significant correlation (r = -0.50) with the North Atlantic Oscillation (NAO) index. Field correlations of fall Sr/Ca with the winter sea level pressure (SLP) show the typical spatial NAO pattern. The stable relationship with the NAO shows that Sr/Ca in Bermuda corals is a suitable tool for the reconstruction of North Atlantic climate variability.

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Several proxy-based and modeling studies have investigated long-term changes in Caribbean climate during the Holocene, however, very little is known on its variability on short timescales. Here we reconstruct seasonality and interannual to multidecadal variability of sea surface hydrology of the southern Caribbean Sea by applying paired coral Sr/Ca and d18O measurements on fossil annually banded Diploria strigosa corals from Bonaire. This allows for better understanding of seasonal to multidecadal variability of the Caribbean hydrological cycle during the mid- to late Holocene. The monthly resolved coral Delta d18O records are used as a proxy for the oxygen isotopic composition of seawater (d18Osw) of the southern Caribbean Sea. Consistent with modern day conditions, annual d18Osw cycles reconstructed from three modern corals reveal that freshwater budget at the study site is influenced by both net precipitation and advection of tropical freshwater brought by wind-driven surface currents. In contrast, the annual d18Osw cycle reconstructed from a mid-Holocene coral indicates a sharp peak towards more negative values in summer, suggesting intense summer precipitation at 6 ka BP (before present). In line with this, our model simulations indicate that increased seasonality of the hydrological cycle at 6 ka BP results from enhanced precipitation in summertime. On interannual to multidecadal timescales, the systematic positive correlation observed between reconstructed sea surface temperature and salinity suggests that freshwater discharged from the Orinoco and Amazon rivers and transported into the Caribbean by wind-driven surface currents is a critical component influencing sea surface hydrology on these timescales.

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La maleta de los nervios, de Antonio Álamo, pone en escena algunos elementos del carnaval -las chirigotas gaditanas, de desenfadado humor popular-, sacadas de su contexto original. El autor realizó un taller de dramaturgia con las integrantes de la agrupación 'La Chirigota de Las Niñas', y creó una 'partitura escénica' en la que incorporó personajes y acción dramática a la estructura de improvisación original. Incluyó también algunas coplas de una de las actrices convocadas, en cuya 'altísima calidad autoral' 'según Álamo', se trasluce la mejor poesía satírica tradicional, desde el Arcipreste a Quevedo. Surgió así una pieza en la que tres amas de casa muestran en escena su equipaje vital, saturado de ansiedades e insatisfacción. Emplean para ello un lenguaje que no rehúye lo obsceno, lo escatológico o lo irreverente, y tratan temas de la calle y de todos los días: la ausencia de proyectos vitales, el consumo de drogas como refugio, las pequeñas mezquindades en las relaciones personales, la falta de criterios firmes en la educación de los hijos, la pobreza, el desempleo, la reacción ante la inmigración. En nuestro trabajo, a partir del texto proporcionado por el autor, ahondaremos en el análisis de la pluralidad de elementos puestos en juego en la creación dramática

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Coral reefs represent major accumulations of calcium carbonate (CaCO3). The particularly labyrinthine network of reefs in Torres Strait, north of the Great Barrier Reef (GBR), has been examined in order to estimate their gross CaCO3 productivity. The approach involved a two-step procedure, first characterising and classifying the morphology of reefs based on a classification scheme widely employed on the GBR and then estimating gross CaCO3 productivity rates across the region using a regional census-based approach. This was undertaken by independently verifying published rates of coral reef community gross production for use in Torres Strait, based on site-specific ecological and morphological data. A total of 606 reef platforms were mapped and classified using classification trees. Despite the complexity of the maze of reefs in Torres Strait, there are broad morphological similarities with reefs in the GBR. The spatial distribution and dimensions of reef types across both regions are underpinned by similar geological processes, sea-level history in the Holocene and exposure to the same wind/wave energetic regime, resulting in comparable geomorphic zonation. However, the presence of strong tidal currents flowing through Torres Strait and the relatively shallow and narrow dimensions of the shelf exert a control on local morphology and spatial distribution of the reef platforms. A total amount of 8.7 million tonnes of CaCO3 per year, at an average rate of 3.7 kg CaCO3 m-2 yr-1 (G), were estimated for the studied area. Extrapolated production rates based on detailed and regional census-based approaches for geomorphic zones across Torres Strait were comparable to those reported elsewhere, particularly values for the GBR based on alkalinity-reduction methods. However, differences in mapping methodologies and the impact of reduced calcification due to global trends in coral reef ecological decline and changing oceanic physical conditions warrant further research. The novel method proposed in this study to characterise the geomorphology of reef types based on classification trees provides an objective and repeatable data-driven approach that combined with regional census-based approaches has the potential to be adapted and transferred to different coral reef regions, depicting a more accurate picture of interactions between reef ecology and geomorphology.

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La maleta de los nervios, de Antonio Álamo, pone en escena algunos elementos del carnaval -las chirigotas gaditanas, de desenfadado humor popular-, sacadas de su contexto original. El autor realizó un taller de dramaturgia con las integrantes de la agrupación 'La Chirigota de Las Niñas', y creó una 'partitura escénica' en la que incorporó personajes y acción dramática a la estructura de improvisación original. Incluyó también algunas coplas de una de las actrices convocadas, en cuya 'altísima calidad autoral' 'según Álamo', se trasluce la mejor poesía satírica tradicional, desde el Arcipreste a Quevedo. Surgió así una pieza en la que tres amas de casa muestran en escena su equipaje vital, saturado de ansiedades e insatisfacción. Emplean para ello un lenguaje que no rehúye lo obsceno, lo escatológico o lo irreverente, y tratan temas de la calle y de todos los días: la ausencia de proyectos vitales, el consumo de drogas como refugio, las pequeñas mezquindades en las relaciones personales, la falta de criterios firmes en la educación de los hijos, la pobreza, el desempleo, la reacción ante la inmigración. En nuestro trabajo, a partir del texto proporcionado por el autor, ahondaremos en el análisis de la pluralidad de elementos puestos en juego en la creación dramática