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Blobrana


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RE: Amazon Sea
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Tree rings reveal Amazon's rainfall history

Samples from eight cedar trees in Bolivia have helped shed light on the seasonal rainfall in the Amazon basin over the past century, say researchers.
A study led by UK-based scientists said the data from the trees provided a key tool to assess the natural variation in the region's climate system.
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Blobrana


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Amazon water level
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 Scientists correct Amazon water level gauges from space

NASA's laser satellite, ICESat, has been used to make corrections to water level gauges that are critical in monitoring water flow in the Amazon, the worlds largest river. The new study, conducted by scientists at the University of Bristol, will improve our understanding of water flows and floodplain processes.
Previously, gauges used to measure changes in water level in the Amazon were not on the same reference level. This meant water levels could not be directly compared, limiting the use of the gauges in research, especially understanding and modelling water flows and flooding.
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Blobrana


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Amazon Underground 'River'
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Underground 'river' is fed all along its course

Valiya M. Hamza has discovered a 6,000 km-long underground 'river' in Brazil at a depth of 4 km. He started his career in 1966 as a Senior Scientific Assistant at the National Geophysical Research Institute (NGRI) in Hyderabad, and is currently Head of the Geothermal Laboratory of the National Observatory, Rio de Janeiro, Brazil.
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Blobrana


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Subterranean Amazon 'River'
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Subterranean Amazon river 'is not a river'

A subterranean river said to be flowing beneath the Amazon region of Brazil is not a river in the conventional sense, even if its existence is confirmed.
The "river" has been widely reported, after a study on it was presented to a Brazilian science meeting last week.
But the researchers involved told BBC News that water was moving through porous rock at speeds measured in cm, or inches, per year - not flowing.
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Blobrana


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Posts: 131433
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Subterranean Amazon River
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The subterranean Amazon: Mighty river found flowing 13,000ft below ground

The Amazon river is known to be the second longest in the world, shorter only than the Nile but, remarkably, scientists have discovered another river flowing thousands of feet beneath it.
Researchers from Brazil's National Observatory believe the subterranean river is 3,700 miles long, about the same length as the Amazon on the surface.
Dr Valiya Hamza, from the BNO, said the discovery of the underground river came from studying temperature variations at 241 inactive oil wells drilled in the 1970s and 1980s by Brazil's state-run oil company, Petrobras.
He said the 'thermal information' provided by Petrobras allowed his team of researchers to identify the movement of water 13,100ft under the Amazon River.
Their findings were presented last week in Rio de Janeiro at a meeting of the Brazilian Geophysical Society.
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Brazilian scientists find signs of huge river under Amazon river.
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Blobrana


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Amazon droughts
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Two severe Amazon droughts in five years alarms scientists

New research shows that the 2010 Amazon drought may have been even more devastating to the region's rainforests than the unusual 2005 drought, which was previously billed as a one-in-100 year event.
Analyses of rainfall across 5.3 million square kilometres of Amazonia during the 2010 dry season, published in Science, shows that the drought was more widespread and severe than in 2005.



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Blobrana


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Amazon river
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Researchers at the University of Liverpool have discovered that the Amazon river, and its transcontinental drainage, is around 11 million years old and took its present shape about 2.4 million years ago.
University of Liverpool researchers, in collaboration with the University of Amsterdam and Petrobras, the national oil company of Brazil, analysed sedimentary material taken from two boreholes near the mouth of the river to calculate the age of the Amazon river and the Amazon deep sea fan.

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Blobrana


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Amazonerivier elf miljoen jaar oud
De Amazonerivier is elf miljoen jaar geleden als een transcontinentale rivier ontstaan. Ongeveer 2,4 miljoen jaar geleden kreeg de rivier zijn huidige vorm. Dit zijn de belangrijkste resultaten uit onderzoek aan een boorkern uit de monding van de Amazonerivier door een samenwerkingsproject tussen het Instituut voor Biodiversiteit en Ecosysteem Dynamica (IBED) van de Universiteit van Amsterdam, de Universiteit van Liverpool en de de Braziliaanse oliemaatschappij Petrobras. Het onderzoek is deze maand gepubliceerd in het wetenschappelijke tijdschrift Geology.

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Blobrana


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Andes mountains
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The geologic faults responsible for the rise of the eastern Andes mountains in Colombia became active 25 million years ago - 18 million years before the previously accepted start date for the Andes' rise, according to researchers at the Smithsonian Tropical Research Institute in Panama, the University of Potsdam in Germany and Ecopetrol in Colombia.

"No one had ever dated mountain-building events in the eastern range of the Colombian Andes. This eastern sector of America's backbone turned out to be far more ancient here than in the central Andes, where the eastern ranges probably began to form only about 10 million years ago" - Mauricio Parra, a former doctoral candidate at the University of Potsdam (now a postdoctoral fellow with the University of Texas) and lead author.

The team integrated new geologic maps that illustrate tectonic thrusting and faulting, information about the origins and movements of sediments and the location and age of plant pollen in the sediments, as well as zircon-fission track analysis to provide an unusually thorough description of basin and range formation.

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Blobrana


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RE: Amazon Sea
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Title:     Spatiotemporal Evolution of Neotropical Organisms: New Insights into an Old Riddle
Authors:     Antonelli, Alexandre

Nowhere else on Earth are there so many species of plants and animals as in the Neotropical region. Yet, many questions remain concerning the causes underlying such outstanding diversification. In this thesis, I use a combination of molecular-based methods (phylogenetic inference, molecular dating, biogeographic reconstruction, analyses of diversification and extinction) together with geological, palaeontological, hydrological and climatological evidence to reconstruct the evolution of some Neotropical organisms in space and time. Diversification patterns obtained from case studies in the plant families Rubiaceae, Chloranthaceae and Campanulaceae are compared to published studies of other plants and animals, especially tetrapods (birds, non-avian reptiles, amphibians and mammals). The uplift of the Northern Andes in the Neogene (~23 Ma to today) is concluded to have played a major role in promoting Neotropical diversification, by fostering allopatric speciation of lowland organisms and inducing adaptive radiations in newly formed montane habitats. In addition, its formation caused the end of a lowland corridor episodically invaded by marine incursions that separated the Northern and Central Andes, enabling the southward dispersal of boreotropical groups already present in northwestern South America. The fact that most Neotropical plant groups are either Andean-centred or Amazonian-centred is explained by the long-lasting effect of the Palaeo-Orinoco and Lake Pebas as dispersal barriers between these two diversity centres. Finally, a new diversification model is proposed to explain the origin and evolution of organisms in two areas characterized today by unusually high levels of species richness and endemism: the Huancabamba region and western Amazonia. Under this model, speciation is proposed to have occurred over several million years in connection with the recolonisation of previously submerged areas, by means of adaptive radiation of founder colonies and secondary contact of previously isolated populations.

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