Horizon: Investigation into the mysterious mutated seaweed caulerpa taxifolia : known as 'killer algae' : which forms choking blankets over the seabed, posing a potential threat to marine life across the world. It was first discovered to have spread into the waters off the coast of Monaco toward the end of the 1980s after having been cultivated in nearby public aquaria and has recently been found in Californian waters, with no-one knowing how to stop its progress.

Starring:

Bernard Hill, Jack Fortune

Genre:

Documentary