We have some beautiful low tides coming up, but they're going to arrive here after dark. (Sunset these days falls around 7::30 PM.) I followed the tide as it started out in the late afternoon, and found anemones, feeding happily, then closing down as the water disappeared.
|Window into a tide pool.|
The surface of the water in the tide pool reflected the sky, but the shadow of my head revealed a pink-tipped green anemone, Anthopleura elegantissima, fully open. With it in this little tide pool are several rockweeds, and three red algae; a feathery, delicate one, a narrow-bladed species, and a broad blade; the white algae is a red that has been sun-bleached. On the right are strands of the brown Sargassum. And there are several fragments of the green sea lettuce, Ulva spp. Also present: periwinkle snails, limpets, and something orange, probably a sponge. And unseen, but always there in great numbers: the worms. And a clam on the sand nearby was spitting at me.
|Still underwater, still waving those tentacles.|
The colours of this anemone vary; the tips go from barely pink to red. The columns and the oral disc are sometimes bright green, in others they may be more of a yellowish cream. The green colour is usually due to the presence of single-celled green algae, but the anemone may also produce its own colour. The green algae are photosynthetic and provide a large part of the anemone's energy needs.
"Although the green colour present in some specimens is produced by the animals themselves, this process can only occur when the unicellular symbiotic alga Chorella is residing in their tissues." (Marine Life of the Pacific Northwest)
|Very pink. The column is always covered by rows of tubercules, seen here as pale green bumps.|
As the water recedes, the anemones start to shut down.
|Edge zone; open tentacles on the right, closing, closed out of water.|
|And when the water is gone, they turn into yellowish donuts with cherry filling.|
These anemones grow on rock. The sand has collected around them. As the sand dries, they will all shrink back to their base, and disappear from the surface, leaving only slight depressions. Until the tide comes in.
"Aunque el color verde presente en algunos de estos animales es producidos por los mismos, este proceso solo puede operar cuando la alga simbiótica unicelular reside en sus tejidos." (Marine Life of the Pacific Northwest)