Sue Daly / Maerl (Phymatolithon calcareum) Jersey, British Channel Islands, June.

Alex Hyde / Claigan 'coral beach', the beaches are not actually coral, but formed from bleached skeletons of a red coraline seaweed (Lithothamnion corallioides) known as maerl. Claigan, Isle of Skye, Inner Hebrid...

Alex Hyde / Close up of Claigan 'coral beach'. The beaches are not actually coral, but formed from bleached skeletons of a red coraline seaweed (Lithothamnion corallioides) known as maerl. Claigan, Isle of Skye,...

Alex Mustard / Wrinkled swimming crab (Liocarcinus corrugatus) displaying its claws on a Maerl (Phymatolithon calcareum) bed, Fal River Estuary, Cornwall, UK.

Alex Mustard / Edible crab (Cancer pagurus) foraging on a Maerl (Phymatolithon calcareum) bed, Fal River estuary, Cornwall, UK.