Flowers of the intertidal zone

Published 9:00 am Wednesday, April 20, 2022

Stare into the shallow seawater pools that collect between boulders at low tide and a bright, colorful flower may seem to sprout from a rock, reaching toward the surface.

This delicate creature may be a sea anemone, a soft-bodied animal known as a cnidarian. This classification of freshwater and marine dwellers also includes jellyfish, corals and sea fans.

The sea anemone may take its name from a terrestrial flower, but is in fact a carnivorous sea creature. Living on the border between sessile and mobile, the sea anemone possesses an adhesive foot on its column, resembling the stem of a plant, that helps it to attach to the sea floor.

A circle of flowing, leaflike tentacles extend from the stem to provide a food source, the tentacles containing stinging structures called nematocysts that paralyze small fish and crustaceans.

To the curious human hand, however, these tentacles have only a slight grip and won’t cause any harm. The sea anemone can handle a light touch, even though it doesn’t like to be stepped on.

These ocean dwellers are highly adapted to the tidal zone, retracting their tentacles and folding themselves inward as the tide recedes. To survive the dry conditions, their flower-like appearance transforms to reveal a soft, green outer shell.

Despite their tolerance of low tides and brackish waters, sea anemones thrive at nearly all ocean depths, ranging from the tidal zone to some trenches more than 30,000 feet below sea level.

These creatures can be found in virtually all of the world’s oceans, with few predators and an adaptable structure.

If necessary, the sea anemone can pick up its foot and move, finding the best spot to bask its “petals” in the sea.

Friday is Earth Day, making this week a great time to experience and steward the wondrous natural beauty around us on the North Coast, including these curious marine creatures.

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