The Tidepool
Chapter 48
Book, to be published
March 24, 2018
Featured image Copyright © 2018 Jill Buchanan
“As the season changes. Spring seems to come in while the tide is out and winter creeps back with the cold waters of high tide.”
John and Mildred Teal, “Life and Death of the Salt Marsh”.
It is March 24th. Patches of snow still dot the shore of Pavilion Beach, but the sun is struggling to break through the pewter sky. It holds the promise of spring after our long winter of stormy discontent.
I have come out here with Sandy Tilton and Marc La Croix of UAV Look to see how sand makes its way to Crane’s Beach. Marc’s drone takes off and disappears over Plum Island Sound on its way to Sandy Point.
We lean into the monitor and see acres of shallow sand flats, a long thin sandbar and where 500 feet of new sand has accreted to the end of the point. It is now only a short swim from the shallow water flats of Plum Island to Crane’s Beach; but it is an impossible swim, because of the tidal currents that rush through the narrow opening.
Someday, the sand flowing off of Plum Island will seal off the mouth of the Parker River and it will have to find a new way to get to the ocean. We can see where that will be. The March storms had smashed through the dunes and undermined one of the Parker River Wildlife Refuge’s most beloved boardwalks.
The waves had also come close to forming a new inlet from the ocean into Stage Island Pond. When this does happen, it will make Sandy Point into an island connected to Crane’s Beach by walkable sand flats. And Ipswich will gain several hundred new acres of dunes, beaches, uplands and clam flats.
Changes like these have happened out here since the last Ice Age. Then, the ocean level was 200 feet lower and the coast was almost three miles further east. Wooly Mammoth strode across the landscape, which we were standing on, which was itself under half a mile of ice.
The glaciers had ground their way through New Hampshire’s White Mountains pulverizing their granite cores into millions of tons of quartz, magnetite and garnet sand that the proto Merrimack River had washed onto the Continental Shelf.
As the seas rose they shaped this reserve of Paleolithic sand into barrier beaches and then gently nudged them toward their present locations making what we now call Crane’s Beach, Plum Island and Plum Island Sound.
By the time we finished filming it was close to low tide so Sandy and I wandered down Little Neck to see how much the storms had also filled in the Ipswich River.
Walking with Sandy was like walking with myself where I had grown up on Cape Cod. She knew every nook and cranny and could tell stories about each rock, pebble, and dune.
Today she was searching for a heart-shaped rock she had discovered several years before. She knew the location of dozens of heart-shaped rocks and believed Nature had put them there for her enjoyment.
She pointed to a large rock. She and her brother had almost been stranded on it when the tide had caught them unawares only a few years before. She explained that when she was a girl the thing to do was to swim across the mouth of the Ipswich River at slack water, then swim back as quickly as you could before the outgoing tide swept you out to sea.
We lingered at a tidepool that she used to visit with her daughter. It was almost perfectly round, fifteen feet across, and protected by a 4-inch tall wall of peat. The perimeter of the peat was covered with a profusion of periwinkles, preparing to hunt on the incoming tide.
The tide pool was only a few inches deep but it cradled blue mussels, oysters, boat shells and clean white barnacles in an isolated world of red and green algae. It was like looking back into Paleolithic times, because all these plants and animals had evolved millions of years before humans had appeared on our planet, and millions of years before this shore had been created by the rising seas.
Suddenly we noticed an eight-inch long sandworm swimming sinuously on the surface. Its body had a bluish green iridescence flecked with spots of red and gold. It poked its head out of the water making it look like a tiny Loch Ness monster with two sets of intelligent eyes.
It looked up at Sandy and swam in her direction before burying its head in the sand and thrashing its tail. Soon we saw another worm on the other side of the pool doing the same thing.
But this time I noticed that after the worm thrashed its tail the water turned milky and we could see the feathered feet of nearby barnacles kicking something into their mouths. And a gastropod army of predatory mud snails advanced waving their proboscises in the water to pick up the scent of this new source of food. They looked like Hannibal’s elephants galloping in for a charge.
Then it hit me these were Nereid worms, Nereis Virens, the sea nymphs of the ocean and we had chanced upon their spawning dance. Like Sandy’s childhood friends they were taking advantage of the low tide’s slack waters. It was the day before the quarter moon when the tidal currents were at their weakest so the sperm would stay in the tidepool and fertilize eggs that the female worms were extruding out of their underwater burrows. In forty-eight hours this pool would be full of tiny drifting trochophore larvae.
If we had wandered by half an hour later we would have missed this ritual, an annual spring ritual that is triggered by the phase of the moon and the rapidly changing day-length.
But we had allowed Nature to guide our walk and seen this sensual ritual in a sun-warmed pool so similar to where life may have first evolved.
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