The growing problem of green algae on several beaches in northern France has reached crisis point after a horse died and its rider lost consciousness within seconds of falling into the decomposing seaweed.Locals in the Brittany village of Saint-Michel-en-Greve say enough is enough and are calling for something to be done. One woman warned: “If the algae is left to rot and a child falls in it, I don’t know what we will do.” Up to 70 beaches are said to be affected by the spread of the seaweed which is known locally as “green lettuce”. When the plant decomposes, it forms an impermeable white crust under which toxic hydrogen sulphide accumulates. Some scientists believe it is what wiped out the dinosaurs. The modern-day problem is being blamed on intensive farming practices and the widespread use of phosphates. The build-up of the algae is affecting the local tourist trade with beaches periodically having to be closed. The warning is: if you smell something like rotten eggs – don’t go there!