The Moon Rules
Last week, we were in the new moon phase of the lunar cycle. To me, that means one thing: spring tides.
I once thought the name of these tides with their extremes in high and low water levels derived from a season. Now I know the name relates to the moon, how and when and to what degree it either tugs or shoves. Occurring around a full or new moon phase, a spring tide’s waters brim, as though with a newly acquired energy. They “spring” forward. A more colorful but not particularly accurate measurement of a spring tide’s swing is the promise a recent houseguest made when departing for a low-tide walk on the shore: “I’ll be back when my butt gets wet.”
Unlike a fisherman wrestling tidal currents or a clammer working the mudflats, I don’t live by the tides. But I rely on them as a gauge of my day, how they help create its rhythms, how their constancy connects me to the world. Or how, when I’m walking the shore before an incoming tide returns and reclaims, they demand awareness, a concentrated attention.
Give me a spring tide, a daylight hour of stillness and little wave activity, and there is no place I’m more likely to be than wading out past the rim of a spring’s tide ebb.
Of course, regardless the lunar phase, any ebbing tide is rich with potential discovery. Even the smallest tidal pools are like miniature seas. In them, small dramas are enacted daily. Mostly they’re old stories – something being eaten by something in danger of being eaten – and the rules that govern are neither kind nor just.
Just to survive the alternate land and water worlds tides create twice daily, tidal creatures have had to adapt. Somewhere in its ancestral history, at the merest hint of a hungry gull’s shadow, the green crab learned to scuttle into the rockweed’s messy closet and duck behind heavy, dripping folds to wait out the ebb. At some point in its evolution, the pale sand shrimp may well have shelved its more colorful shirt to don conservative garb in hues more native to its habitat. The less particular hermit crab, on the other hand, merely rummages in the shoreline’s junk drawer of flotsam for whatever empty armoring shell he can scramble into and claim as his own.
Of course not all tidal zone dwellers are so active. To all but the most discerning eye, barnacles seem to do little more than plunk down on the porch and snooze beneath their coolie-shaped sunhats, until, like a pizza delivery guy, the sea hands over the next meal. Likewise, periwinkles could hardly be less dramatic. But a large population of them scraping about for food (albeit imperceptibly) can, over time, erode rocks, deepen tidal pools. In a recent 16-year study of a tidal pool, periwinkles altered the rock bottom by three-eighths of an inch – the equivalent more or less of the earth’s major erosive forces of rain, frost and flood.
Affixed to a rock face as water washes over its sloped roof, a limpet may look as much the lounge lizard as a barnacle. However, and Aristotle was among the first to point this out, a limpet actually goes afield to feed, wandering nearby rocks as the tide rises. Prior to the ebb, though, the limpet returns, often by the same path, and always to the same precise place, its home made as recognizable by a particular depression or scar as does a welcome mat or the color of shutters to the owner of a clapboard Cape.
Even were I not mindful of the moon’s phase or of how much farther out I can wade before “my butt gets wet,” one sure tip-off to a spring tide are the “pink paint” splotches of rose-colored corraline algae. Revealed only to shore-waders at a spring tides’ extremes, corraline algae is actually a type of seaweed that encrusts rocks and shells and looks a lot like coral. Here, its native form is prostrate. And though this implies that here’s another layabout, it’s important to note that the important work of corraline algae is subtle. It encourages into its crusty folds the settlement and subsequent metamorphosis of marine invertebrate larvae, work done best in a prone position (as many of us would like to persuade our spouses from a hammock on a summer’s afternoon.)
It’s out among the infrequently exposed corraline-encrusted rocks just off our shore where I often discover troves of Northern sea stars, including, last summer, one whopper in the middle of its breakfast. At first glance, the slow-moving sea star without eyes or claws seems the least likely Ruthless Predator recipient. But it’s armed – actually five-armed – with countless, tiny suction-cupped tube feet that pull. And pull. Often for hours or days. Any bivalve the tireless sea star latches its arms around is no match. Sooner or later, exhausted, it gives up and begins to open. And that’s when the sea star’s arsenal makes it the likely victor in any contest.
What I’d come upon in a morning stroll may be called eversion. I call it amazing. Having somehow turned one of its two stomachs inside out, the sea star had already pushed the oozing stomach out through its mouth located on its underside where the arms meet and into the hapless mollusk. With little notable action or fan fare, but with a blender’s puree-cycle efficiency, the sea star’s digestive enzymes were making of it a slurpable slop.
But my favorite reward of an early morning spring tide exploration happened last week. Wading out past the spring tide’s corrraline-splotched low water mark, I discovered for the first time a brittle star, the cousin more or less to the ravenous Northern sea star and, I suppose, given to the same dining habits. But with long, spiny arms, the brittle star is definitely the leaner, more buff family member. It’s also, I’ve read since, more secretive and only nocturnally active in deeper water, perhaps due its more fragile, breakable legs. But those legs are also jointed, snake-like and able to move independently of one another. Alternatively named “serpent star,” the brittle star slithers rather than grips and pulls, making for some pretty cool moves. And especially given its nocturnal habits, you have to figure the brittle star must be the kind of groovy mover you’d want on the dance floor. If you were an echinoderm.
Which was definitely an image more appetizing as, with the tide’s shift into flood, I headed back to the house for a breakfast of bacon and blueberry pancakes, to be eaten, if less amazingly, with knife and fork.
