Many park plants and animals live on or near the seabed. These organisms inhabit three distinct zones, each with its own particular conditions

• The intertidal zone is located between the high- and low-tide marks, and is twice a day exposed to the open air. It is inhabited by marsh plants, algae, (Ascophyllum, Fucus), blue mussels, periwinkles... each at a specific height.
  
• The subtidal zone lies between the low-tide mark and a depth of 200 metres. Where the seabed is rocky, brown algae (Alaria and Laminaria), red algae, small crustaceans, blue mussels and starfish flourish next to such colourful organisms as anemones and sponges. In contrast, quahogs, Polychaeta sp. (sea worms), whelks and Ophiwia sp. (brittle stars) dominate where the substrate is soft.
  
  
• The bathyal zone, a deeper underwater area, is inhabited primarily by Polychaeta sp.