What are some examples of morphological adaptations that tide pool organisms have developed?

Answer 1

Tide pool organisms exhibit some of the most extreme environmental changes in nature. One moment under water, the next subject to drying sun. Even if an organism is mobile enough to escape into a tide pool, depending on the volume of water or temperature, the water in that particular tide pool can evaporate and experience extreme changes in salinity, temperature and oxygen levels. Some areas may be subject to pounding waves. Not surprisingly, you find many morphological adaptations to avoid dessication, predation, and pulverization, and adaptations to tolerate large swings in temperature, salinity and oxygen levels or to compete for limited space.
Some types of algae secrete mucous to deter predation and/or to prevent desiccation during low tide. Other algae simply shrivels up in the sun, but is then capable of seemingly miraculously and quickly rehydrating like a kitchen sponge. Some algae such as the coralline red algaes, absorb calcium carbonate from seawater to build thick cell walls that deter grazing.

Intertidal snails use an operculum and glue-like secretion to seal themselves shut against their substrate during low tide. Some, sealed and undisturbed, can survive for months without any water.

Some of the most fascinating morphological adaptations can be found in the octopus. Using muscles and pigment cells it can quickly change shape, texture and colour to escape predation, or utilize an ink sac and siphon to shoot a cloud of dark ink towards its predator and mask its escape strategy which may be fast swimming, or camouflage.

Sculpin (a type of intertidal fish), has a squat shape and large pectoral fins so it can balance on the bottom even where there are strong currents. Its body colour is mottled to blend into its tidepool surroundings and you often can't spot them until they move. Its body shape allows it to quickly tuck into rocky crevices to escape predation. A crab's morphology also allows it to move quickly sideways into rocky crevices and of course its hard shell and claws are deterrents to predation.


There are many more fascinating adaptations. For more details and photographs I can recommend the following books: "The Intertidal Wilderness: A Photographic Journey Through Pacific Coast Tidepools" by Anne Wertheim Rosenfeld, or "A Living Bay: The Underwater World of Monterey Bay" by Lovell Langstroth and Libby Langstroth.