Between the Tides
A minus 3.2 tide on July 13th turned the beach at Burfoot Park into this shimmering summer tableau (with the help of some cumulus clouds and beachcombers in "photographer's red" shirts). This is the second super-low tide beach visit I've made here in South Sound and I must admit that I have mixed feelings about it. Here, exposed and vulnerable, are a myriad intertidal creatures adapted to survive occasional exposure to the air...and hundreds of trampling feet. Moonsnails, sand dollars, ghost shrimp, sea stars, and hermit crabs were all there for the looking, photographing, poking, prodding, digging, and handling. I loved the sight, last year, of busses of elementary school kids scampering around at low tide, full of glee and curiosity, but is it okay to crush them on our way to learning about them?
Here (above), the first surge of the incoming tide reaches the beach. The next minus 3.2 tide occurs in 2011.
As if jealous of my attention to what lay at my feet, the sky put on quite a show Of course I aimed my camera upward. But the drama in the sky didn't last for long. The weekend's gray mornings (and early afternoons) made conditions just right for bellyflopping on the dock at Zittel's Marina at high tide (plus 11.1) where bouquets of frilled anemones grow on the pilings and tires (below).
I spent well over two hours gazing at the display of anemones of various sizes and colors (white to bright orange), tube worms, ochre sea stars, nudibranchs, sea cucumbers, comb jellies, and an unfortunate egg yolk jelly. If you look very carefully at the photo below you can see the jelly's tentacles being pulled into the centers (mouths) of the surrounding anemones.
Both the jelly and anemone are members of the phylum Cnidaria (pronounced
nye-dare-ee-uh). The anemones are sessile polyps, the jelly's free-swimming medusa. Both are passive predators equipped with tentacles, some containing cells called nematocysts. These cells may contain venom or be barbed or sticky. When they are stimulated--by passing bit of flotsam, zooplankton, or small fish--the nematocysts rapidly uncoil and subdue the prey. The tentacles then maneuver the prey into the anemone's or jelly's mouth.
So, who is preying on whom here? Or is this a case similar to the clown fish and the anemone? Or is the hapless jelly simply stuck in the throat of an overstimulated anemone? Is there some kind of mutualism happening here--both cnidarians feeding off each other's trapped prey? This scene brings to mind the cartoon image of a person unable to let go of an electrical cord that is shocking them. I am sure there is an explanation. I will try to find it.