Plankton Found in 100-Million-Year-Old Amber

Nov. 17, 2008 -- Scientists have discovered for the first time a menagerie of perfectly intact marine microorganisms trapped in tree resin at least 100 million years ago, according to a new study.

The unexpected find in the Charente region of southwestern France pushes back by at least 20 million years the period when a type of single-cell algae called diatoms are known to have appeared on Earth, said the study.

It also creates a mystery: how did sea creatures wind up trapped in a glob of resinated amber that oozes out of trees?

The most likely scenario, the scientists concluded, is that the forest producing the amber was very near the coast, and that the tiny organisms -- which also included primitive plankton -- were either carried inland by strong winds or flood waters during a storm.

"This 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 Period," which spanned from 145 to 65 million years ago, the researchers said in a statement.

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It also challenges certain theories about the evolution of these organisms, and vindicates the research of molecular geneticists, said Jean-Paul Saint Martin, a scientist at the National History Museum in Paris and a co-author of the study.

Using "molecular clocks," biochemists move backward in time to figure out at what point in the evolutionary process certain plant and animal species split off into different branches.

"We had no record of these microorganisms over a period of 20 million years. These fossils have filled that void in the most extraordinary manner," Saint Martin told AFP.

The study, carried out in collaboration with the National Center for Scientific Research in Strasbourg, was published in the Proceedings of the National Academy of Sciences.

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