Easterly winds drive masses of detached flotsam seaweeds ashore at certain times of the year. They can form great green floating rafts. Some people may not like it when it piles up on the beach or tangles around their legs while paddling – but it is not all bad. The National Trust sign reminds people that the seaweed that washes ashore is an important and unique habitat for animals that use the deposit for food and shelter. The seaweed helps to build up the dunes and provide nutrition for the plants growing on them and stabilising them – and the dunes in turn perform the function of protecting the erosional beach. And as the beach is so long, only a small percentage of the seashore is covered at any one time.
Jessica's Nature Blog 