Tide pool | Nature Adventure

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Biology

A tide pool is a very special, strange environment created by pockets of seawater that get left behind on rocky shores during low-tide! These pools are usually very shallow, but can be several feet long. Despite how isolated they are from the rest of the ocean, they hold an entire world of strange creatures like snails, barnacles, mussels, urchins, sea stars, and other marine life!

Whether swept into the pools during high-tide or specially adapted for life in these pools, the animals in them must figure out how to survive in an environment with a lot of direct sunlight, hotter water, lower oxygen, and easy access for predators like birds. To survive here, animals that make these pools their permanent homes have had to change their bodies in strange, wonderful ways in order to adapt!

A common strategy to withstand the rise and fall of water is to anchor yourself to a rock as a solid base. This is how barnacles choose to survive! They secret a cement=like substance that glues them to the walls of the pool, ensuring that they're not washed away as the tides change.

Sea anemones do the same anchoring technique, but catch food floating through the water with their numerous tentacles. Depending on the species, these may contain stinging cells call nematocysts that paralyze their prey!

Other animals, like crabs, have evolved to be comfortable both in and out of the water. This allows them to even walk on land for short periods, hopping between pools to find more resources.

Each time the tide rises, it brings more nutrients and new organisms into the pools, and washes debris back out to see. Due to this cyclical recycling, tide pools are abundant with food and fresh water, making them ideal habitats for the creatures that can withstand them!

Ecological Importance

Tide pools provide homes, either temporary or permanent, for creatures in the "intertidal zone". This is a really fragile but intense ecosystem, where the boundary between ocean and land is very thin! Animals adapted to live in this specific environment cannot survive in deeper ocean waters, or without any water at all. They rely entirely on the unique ecological structure of their tide pools, and that makes them extremely unique!

These tide pools are also valuable sources of food for land animals, namely seabirds. Some fish species also use tide pools as nurseries for their young, letting them grow there before being washed out to sea.

If you have the chance to explore tide pools yourself, make sure that you're not disturbing any of the creatures who live there! Be gentle when moving rocks and don't attempt to detach any of the animals from their homes. If you move something, you should always try to put it back exactly where you found it.

Or better yet, you should look, but not touch! Since some of the creatures in tide pools have adapted defenses like sharp spines or stingers. The high-tides may also sometimes wash in more dangerous animals, like deadly species of jellyfish, that could seriously harm you if handled. it's much safer to simply keep your hands to yourself when exploring.

Did you know?

Sea urchins - the black, spiny looking balls that sometimes inhabit tide pools - have been known to wear "hats" made from shells and other debris!

The reason they do this isn't fully known! While once hypothesized to be a method of keeping themselves safe from the waves coming in at high-tide, using their "hats" more like a shield, ocean-dwelling urchins deep on the seafloor have also been seen preforming this strangely adorable behavior. It may be a courtship ritual, it may be for protection, but in any case, aquarium keepers with sea urchins in their tanks have discovered that they will wear anything - including 3D printed cowboy hats!

Photo (and hat) by Wilson Souza

The most likely explanation is simply camouflage. To avoid predation from bigger fish and seabirds, urchins will cover themselves in all kinds of light accessories, from shells to rocks and bits of plant matter!

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