EPOW - Ecology Picture of the Week

White Cliffs of Dover, England

Explanation:  Through the clouds, far below, over the English Channel appears a visage of a dim and distant past ... the famous White Cliffs of Dover, England.  But from this height, one can imagine their origin -- the white sediments of an ancient sea that covered this part of Great Britain some seventy million years ago in the Cretaceous Period when dinosaurs still roamed.  Subsequent faulting and uplift created the cliff structure.  

Why are the cliffs white?  They are comprised of the settled remains of ancient coccoliths, tiny algae such as Emiliania huxleyi, which later compressed into chalk.  

Today, several species of seabirds nest along the cliffs, including kittiwakes and fulmars.  The chalk cliffs are unique enough, ecologically, to warrant conservation concern.