Evolutionary ecology of sea turtles

DNA can teach us many things about natural populations, for example, where they come from and how many there are, which is important for studying endangered species like sea turtles. Thanks to our DNA research on sea turtles, we learned that there is an increasing number of sea turtles in the sea near Bonaire that come from nesting colonies where nesting numbers are increasing thanks to succesful conservation. We also saw that sea currents near Madagascar had an important influence on the migration of young sea turtles: they move with the currents. We could also look in the past using DNA, at the evolution of sea turtles. Apparently, the ice ages had a major influence on sea turtles. When the earth started to cool down around 115 thousand years ago, sea turtles in the Atlantic Ocean became separated from their neighbors in the Southwest Indian Ocean. Because of this, their DNA slowly became more different over time during the previous ice age. The ice ages also influenced sea levels. The formation of land ice caused sea levels to drop. Sea levels were almost 120 meters lower than the present level during the peak of the previous ice age. Many shallow seas became exposed, wich resulted in less areas where sea turtles could feed. Less food apparently resulted in fewer sea turtles, because in their DNA we see, using mathematical models, a reduction in diversity during the last ice age!