One Seacoast Mile 

Spring

A sprinkling of yellow footprints brightens the grassy slope leading to the tip of Cape Sitka, the northernmost point of my chosen mile. Not actually footprints at all, these matted patches are native wildflowers. Called footsteps of spring, they have yellow maple-shaped leaves that lie flat beneath clusters of half-inch-high canary-colored flowers. Keeping a low profile helps this species to survive the strong winds that buffet the cape.

Stretching out to lie prone on the hillside, I become part of this plant’s ground-hugging world. Just downslope, I see another group of blossoms peeking above the grass: Menzies’ baby blue eyes. As the name suggests, these flowers are usually blue, but sometimes, like the ones growing below me, the plants produce bright white petals lined with purple dots.

Nearby, a tiny fish skeleton no more than two inches long lies in the lee of a small rock, the remains of some seabird’s sardine or anchovy catch. The hungry bird unknowingly gifted the cape’s shallow soil with a miniscule dose of growth-boosting nutrients from the sea. Dropped from the bird’s bill as it flew above the cape, the tiny fish’s flesh decomposed into the soil, where shallow roots absorbed the minerals transported from the saltwater below.

Plants with ocean-derived minerals in their cells can grow up to three times faster than those without. As this nourishment delivered on the wing accumulates bit by bit over time, organic material builds up, creating rich soil. Slowly, the rocky cape becomes meadowed and wildflowers spangle its slopes.

The water where the fish spent its brief life is part of a highly productive coastal ecosystem that owes its existence to one phenomenon: wind-driven ocean upwelling. In spring and summer, the prevailing winds come from the north and drive surface water offshore. Scientists have discovered that, in the northern hemisphere, surface waters always move to the right (west) of winds blowing in a southerly direction; this phenomenon is known as the Coriolis Effect.

Winds blow down the coast, forcing the top layers of water westward, away from the shore. Deep nutrient-rich water moves up to replace the dissipated surface water, bringing seafloor sediments enriched with nitrogen and phosphorus to the top. Here, the infusion of nutrients fuels an explosive growth of plankton and seaweed, the foundation of a marine food web that feeds tidepool creatures, schooling fish, salmon, seabirds, seals, whales and humans. Looking out to sea, I witness an upwelling in progress: a mass of brownish-green water meets the blue as the winds bestow their life-giving gifts on the nearshore waters.

Leaving the blustery cape behind, I hike down toward the rarely-visited beach at its foot. Descending along a faint trail, I find myself at the top of an extremely steep sand chute only twenty feet wide. Looking around for another route, I conclude that this precipitous slope is, indeed, the main access. Gazing downhill, I notice something else: a meandering course of animal tracks descending the narrow opening. A thicket of conifers edging the sand prevents the wind from erasing the footprints. Closer examination reveals each round track to be about two inches wide with four toes, no claw marks and three lobes on the back edge of the heel pad – a bobcat! This reclusive cat normally hunts at night but occasionally sneaks out in daylight, too. The tracks reveal nothing about the hour in which this creature prowled, but their condition indicates that they’re several days old.

Still curious about the secluded beach below, I plunge my heels in the soft sand and make a slow glissade down the unstable slope, obliterating the cat tracks as I go. Safely reaching the bottom, I scramble over driftwood pushed up by last winter’s storms and step onto firm sand several yards from the surf. No footprints blemish this wild strand; I have it all to myself, or so I think.

Walking south, I find evidence that I’m not alone: multiple pointy impressions in the sand border each side of a pencil-thin drag mark. The tracks lead me closer to the water and soon I find their maker: a northern kelp crab brought in by the waves. About three inches wide, the top of its slick brown shell forms the shape of a small shield with a large point in the front and a smaller point tipping each forward corner.

As the crab slowly ambles sideways, I watch its eight legs and two claws emboss the sand with tiny tracks while the posterior end of its shell inscribes a shallow furrow. Kelp crabs are seasonal carnivores, eating small clams and barnacles each winter and switching to an herbivorous diet of kelp and other seaweeds during the warmer months. I resist the urge to pick this one up, knowing from painful experience how hard they can pinch.

Gentle waves part around barnacled boulders as I continue south. Thousands of clam-like blue mussels wait for high tide, their shells snapped shut like calcified coin purses. Rocky towers and turrets rise above gardens of shiny seaweed. Picking my way through a stretch of basketball-sized rocks, I come upon one of the most bizarre creatures inhabiting the intertidal zone: a Pacific giant chiton. Resembling a partially deflated football, this mollusk has thick leathery skin and can grow up to a foot long. Lacking a head and eyes, it uses its muscular foot to clamp onto rocks. A flattened mouth on its underside contains tiny teeth for scraping algae from hard surfaces. To resist abrasion, the teeth are capped with magnetite, a mineral thought to be produced by some animals (sea turtles, birds, whales) to help them navigate using the Earth’s magnetic field. Although the chiton’s mineralized teeth are magnetic, it does not use this adaptation to find its way; it’s simply reinforcement for the tools needed to obtain its slimy meal.

Reaching down to touch its pebbly skin, I find that this chiton has been knocked loose from its rock, likely by a strong wave. Turning it over, I see the cantaloupe-colored foot flanked by a groove on either side, each filled with a row of rounded gills. Tucked safely in one of the grooves, a skinny white scale worm moves its head, but will not harm its slow-moving host. Instead, it forages for tube worms and organic debris as the chiton carries it around. 

Returning the chiton and its wriggling passenger to the spot where I found them, I look back to the sand chute I must scale to return to the car. It promises to be a slow breathless climb, but it’s a small price to pay for today’s exploration of the wildest part of my seacoast mile.