WOR 9 summarizes the current state of knowledge about marine biodiversity. Available free of charge, it is the ideal starting point for anyone keen to understand marine life.  Life on Earth is linked inseparably with the ocean. It covers around 71 per cent of the surface and is the largest habitat on our planet. Much of its species diversity is still unknown – and yet it is vital for human well-being. The greater the health and diversity of marine life, the greater the benefits for people and