* Astronomy

Cyanobacteria dating back 100 million years

Quoi de plus difficile, en paléontologie, que d'identifier sans équivoque des bactéries fossiles ? Des paléontologues de Géosciences Rennes (CNRS-INSU, Rennes I), en collaboration avec un microbiologiste du laboratoire Ecosystèmes, biodiversité, évolution (CNRS-INEE, Rennes I) viennent pourtant de révéler la présence de cyanobactéries (algues bleues) datant de 100 millions d'années dans de l'ambre fossile provenant des gisements de Charente Maritime. Une étude qui vient de paraître dans Journal of Paleolimnology.

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-- Edited by Blobrana at 19:35, 2009-01-27

Marine microorganisms have been found in amber dating from the middle of the Cretaceous period. The fossils were collected in Charente, in France. This completely unexpected discovery will deepen our understanding of these lost marine species as well as providing precious data about the coastal environment of Western France during the Cretaceous.
The presence of these marine organisms in the amber is an ecological paradox. How did these marine species become stuck and then trapped in the conifers resin? The most likely scenario is that the forest producing the amber was very close to the coast, potentially shrouded by plankton-bearing mist or flooded by sea water during storms.

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Title: Evidence for marine microfossils from amber.
Authors: Girard V, Schmidt AR, Saint Martin S, Struwe S, Perrichot V, Saint Martin JP, Grosheny D, Breton G, Néraudeau D.

Amber usually contains inclusions of terrestrial and rarely limnetic organisms that were embedded in the places were they lived in the amber forests. Therefore, it has been supposed that amber could not have preserved marine organisms. Here, we report the discovery amber-preserved marine microfossils. Diverse marine diatoms as well as radiolarians, sponge spicules, a foraminifer, and a spine of a larval echinoderm were found in Late Albian and Early Cenomanian amber samples of southwestern France. The highly fossiliferous resin samples solidified approximately 100 million years ago on the floor of coastal mixed forests dominated by conifers. The amber forests of southwestern France grew directly along the coast of the Atlantic Ocean and were influenced by the nearby sea: shells and remnants of marine organisms were probably introduced by wind, spray, or high tide from the beach or the sea onto the resin flows.

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Research on a treasure trove of amber has yielded evidence that France once was covered by a dense tropical rainforest with trees similar to those found in the modern-day Amazon. The report is on 55-million-year-old pieces of amber from the Oise River area in northern France.
In the new study, Akino Jossang and colleagues used laboratory instruments to analyse the fossilized tree sap in an effort to link specific samples of amber to specific kinds of trees. The amber remained intact over the ages, while the trees from which it oozed disappeared. Efforts to make such connections have been difficult because amber from different sites tended to have very similar chemical compositions. The report describes discovery of a new organic compound in amber called quesnoin, whose precursor exists only in sap produced by a tree currently growing only in Brazils Amazon rainforest.

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 Scientist Scanned 50 million year old spider
A 50-million-year-old fossilised spider has been scanned in stunning 3D by a scientist at The University of Manchester.
 
In a paper published in the latest issue of the Zootaxa journal, Dr David Penney and co-authors from Ghent University in Belgium report on the use of a technique called Very High Resolution X-Ray Computed Tomography (VHR-CT) to digitally dissect tiny fossils and reveal the preservation of internal organs.
Dr Penney, from The School of Earth, Atmospheric and Environmental Sciences (SEAES), specialises in studying spiders trapped and preserved in amber tens of millions of years ago.
The male spider studied in his latest paper is a new species named Cenotextricella simoni. It is around 53-million years old and was found preserved in amber in an area of France known as the Paris Basin.
This is the first time the VHR-CT technique has been used to digitally dissect a fossil in amber and Dr Penney says it has the potential to revolutionise their study.
The VHR-CT technique was originally developed for medical diagnostic purposes.

This technique essentially generates full 3D reconstructions of minute fossils and permits digital dissection of the specimen to reveal the preservation of internal organs. Up until recently the only place to do such scans was at The University of Texas, although they never achieved results like these.  My colleagues in the department of Subatomic and Radiation Physics at Ghent University in Belgium have significantly increased the resolution of the technology, bringing some quite amazing results. This is definitely the way forward for the study of amber fossils. Amber provides a unique window into past forest ecosystems. It retains an incredible amount of information, not just about the spiders themselves, but also about the environment in which they lived - Dr David Penney.

Dr Penney is currently spending an indefinite period in the African jungle in a living laboratory' studying spiders.
Earlier this year, a species of spider which dates back more than 20 million years was named after Dr Penney. The amber-encased spider which was discovered deep in a Mexican mine is thought to have lived long before the first humans.
It was found by a Mexican researcher who earned the right to name the species and he chose the name Episinus penneyi in honour of his former colleague.

Source: University of Manchester