I’m not talking a foreign language!  Convoluta Roscoffensis can be found on the beaches of Herm.  At low tide look out for ‘green sand’.  At first glance the green colouration of the sea water puddles may seem to be caused by accumulations of algae.  If you put a small amount of the ‘green sand’ into your hand or an empty shell you will see that the colour is due to millions of tiny green flatworms (up to 15 mm in length) continuously moving around.  The Convoluta Roscoffensis gather at the surface of the pools of water to provide optimal photosynthetic conditions for the symbiont Tetraselmis convolutae, a green algae living inside the flatworm’s body.

Next time you walk around the beaches of Herm on the low tide don’t forget to look out for the ‘green sand’ and remember the science lesson you have just had!