Life On The Rock at Low Tide

the first anemone to open to the incoming waves

On the beach at Fort Flagler State park there is a huge rock. Uncovered at low tide, it is teeming with life, a world that may stay submerged days at a time. Only when the moon and earth sync for a super low tide does this world come up for air as we know it.  Giant barnacles, colorful little snails, other critters I’m not familiar with, and zillions of sea anemones.  Slimy looking, gelatinous, olive green little ‘donuts’, the anemones close up during this air ‘exposure’ and wait for the sea to return.  Fascinated, I waited with them, ankle deep in the cold water, shifting and moving as the sand washed out from under my feet, I watched as the first ones, the front line, began to swell.  I wanted to see them open, exposing their seemingly delicate pink ‘mouths’ and tentacles. Open to the touch of water and the nutrients it provides them, the life it gives them. It is all quite magical and lovely, but as with all of nature, there is a survival dance going on. Those little tentacles, called Cnidocytes, both defend and kill…….

From Wikipedia:
Cnidocytes contain nematocyst…..Each nematocyst contains a small vesicle filled with toxins (actinoporins), an inner filament, and an external sensory hair. When the hair is touched it mechanically triggers the cell explosion, a harpoon-like structure which attaches to organisms that trigger it, and injects a dose of poison in the flesh of the aggressor or prey. This gives the anemone its characteristic sticky feeling. The sea anemone eats small fish and shrimp……”

I wondered as I waited – do the creatures of this rock world like, even look forward to, these involuntary forays into the world of breezes and blue skies (or gray, as was the case on this particular day)?  Is it necessary to their survival?  Or do they feel stressed, waiting for the waves to return and cover their world once again?  Of course biologist know the answers to my wonderings, but I enjoy standing there watching, (though there is little to watch except the occasional shift of a tiny snail) curious to what is going on in the primitive ‘minds’ (nervous systems) of this thriving pile of life.  

Tiny sea snails are the only action on the ‘The Rock’,
moving at snail’s pace of course!
gelatinous anemones wait, squished in between giant barnacles

opening……looking for something to eat!

  (click photos for a larger view of this crowded micro world)

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