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Time and Tide

Posted on 27 June 2010

web Foster plaque Long beach 10-18-08.1

By Julie Penny

About a year and a half ago I started noticing that the tides lapping Long Beach, both on its bay side and on its cove side, seemed to be getting higher. Was it my imagination? Perhaps you had noticed this too, or the similar rise in some other tidal body of water near you. Not only did the tides seem higher but the low tides didn’t seem all that much lower to me. Or, as low as I remembered them being. That is, in my transits along Long Beach, there never seemed to be very much difference in the tides. This being my little part of the world, it was something I was bound to see. I wondered if others were seeing a rise in tides in other parts of town. Surprisingly, when I asked my naturalist husband if he’d noticed a similar phenomenon taking place along East Hampton’s bays, he hadn’t. At the time I asked him, he, himself, hadn’t really even noticed any difference in the tide along Long Beach on his trips back and forth to work. He chalked up my observation to being “neap” tides. I remembered the term from my Earth Science class in high school. It’s when high tides are lower than average, and low tides are higher than average.

Both the sun and moon exert their gravitational pull on the earth’s tides — the moon’s pull being stronger than the sun’s. Neap tides occur twice in every 28-day lunar cycle when the moon is at first quarter or third quarter. By contrast, spring tides—which, incidentally, have nothing to do with the season — occur around the new and full moon, when the sun, moon, and earth are aligned in a straight line. This creates a stronger gravitational pull so that the high tides are higher than average and the low tides lower than average. In this sense, “spring” connotes a jump, a bounce, when the forces of gravity are pulling at their greatest upon the ocean.

 Secretly, I suspected that maybe what I was witnessing was due to global warming —after all, the world’s glaciers have been melting at an unprecedented and unexpected rate, along with the Arctic icepack. After existing for millennia they’ve now been disappearing in a veritable geological blink of an eye. What seemed to be happening with the water level in the bay didn’t seem to be related to the waxing and waning of the moon as described by spring and neap tides. If anything, they seemed a hybrid of them both: very high, high tides, and very high, low tides.

In the fall of 2008, I took a walk and photographic foray along Long Beach with Jean Held who, always with camera in hand, chronicles our natural world as well as all things of historic interest. We started on the southern side by Noyac Road walking north towards the North Haven side. Though there had not been any recent storm, the sea-wrack brought in on the tide was far up the beach, the closest I had ever seen it to the parking lot. It was practically touching it in spots where the Clifford Foster monument is located at Long Beach’s midpoint — sitting on the cusp of beach and parking lot. Foster is the benefactor whose family bequeathed this beautiful natural resource to the town for our enjoyment. Here, by his memorial rock, the tide had driven clear up to the concrete slab it rests on. In fact, there were even long horizontal eddies of water close to it and to one of the many benches that necklace the rim of the beach in memory of loved ones. These elongated, half-foot deep, self-contained eddies of the type that little kids love to splash and play in, and that can form near shore in the wake of receding tides, were still in place; seemingly fed by fingers of water indenting far up onto the shoreline. In fact, while Jean was photographing the monument and documenting other evidence of the water’s influx, we got chased by tongues of incoming tide.

Ten months later, I spied a headline in one of the local papers that said high tides were affecting all of the East Coast, especially the mid-Atlantic region. Aha! I hadn’t lost my marbles. I felt vindicated. What I’d been noticing was real and unusual. By June 2009, waterfront homeowners, scientists, and concerned citizens from Maine to Florida had been calling government agencies and marine science centers about rising tides. Experts checked and found that high tides had been rising anywhere between six inches to two feet above usual norms.

This onslaught by Mother Nature baffled the experts; even the National Oceanic and Atmospheric Administration weren’t quite sure they’d ever recorded an event like this — a sudden rise. Scientists thought we were seeing the beginning of a decade-long trend brought on by an “El Nino-like effect in the Atlantic” or that it could be the result of shifts in atmospheric pressure and wind known as North Atlantic Oscillations which, in effect, can affect ocean circulation. These extreme tides have happened before, they claim, before reverting back to normal. (Does anyone else remember this happening before in our area? I don’t. And, I don’t see that they’ve reverted back to normal either. Noyac Bay still seems elevated to me, and the tides higher.) What scientists can’t explain is what causes these anomalous tides to occur. They say that in 30 or 40 years this could be the norm due to the warming in ocean temperatures. And, of course, there’s the elephant in the room. Scientists have seen that the Greenland glaciers are melting at an alarming rate, their melt water flowing off land and into the ocean faster than they’d anticipated. Recently, an ice shelf the size of Rhode Island broke off the continent of Antarctica and into the sea. Just another in a string of ice shelves that have been falling off and into the Antarctic ocean.

Whereas the icepack that melts in the Arctic doesn’t affect sea-rise because the water is already displaced (just as ice-cubes in a drink don’t overflow your glass when they melt), the glaciers on land—as on Greenland and the Antarctic—add volume to the ocean once they melt or collapse into it, causing the sea-level to rise.

Even now, the tides at Long Beach seem sustained at high levels. Some days wind-driven waters spray over the tumble of boulders at its far northern end and close to the roadbed as we whiz by—this seems to be the new normal.



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