Things which catch my eye or make me think - looking for aquamarinegreen, the evidence and the truth of it all.....

Friday, 21 September 2007

Green Sea Turtles and sea floor spreading

I've always been fascinated by the migration of green sea turtles. They are found all over ther world, but the ones which nest on Ascension Island in the mid-atlantic, where there is a major nesting colony, then migrate to their feeding grounds off the coast of Brazil. It's a distance of over 2,000 km and the mother turtles make the return journey every few years to the beaches where they were born.

Ascension Island is located on the mid-atlantic ridge, and the foraging grounds for this colony of turtles is at the Eastern extremity of South America at Recife in Brazil. One rather romantic theory for this extraordinary migration is that when the Atlantic was starting to open up, several hundred million years ago the ancestors of the green turtles were to be found in the place where Recife and Ascension Island were very close together. As the sea floor spreading continued, the turtles evolved a mechanism to find their way back and forth as the two places moved apart (and continue to do so) at a rate of about 2cm per year.

No comments: