Sunday, July 16, 2017

'Tides' Turn

St. Mary's lighthouse, Whitley Bay, Northumberland.
Review by Bill Doughty

"Tides: The Science and Spirit of the Ocean" by Jonathan White (Trinity University Press, 2017):

"Although we think of ourselves as sailing across the ocean's surface, we are also sailing down the low tide's valleys and up the high tide's mountains."

"Large or small, the tide is always on the move, swelling against one coast while shrinking from another. It never begins and never ends."

Can we fully understand the mysteries of time and tides?

Aristotle was mesmerized and "perplexed" by tides and currents. Maori of New Zealand believed a woman-god who lived on the moon caused the rise and fall of the tides. Ancient Chinese saw the Milky Way as a great waterwheel that filled the oceans, and the tides as "caused by a sea serpent slithering in and out of its cave."

For the Mayans, a giant crab stirring caused the tides. Plato believed the earth was a large animal and "the tides were the sloshing of its inner fluids."

Superstitions ruled the world before the age of enlightenment, when science began to explain some of the mysteries of the universe, including the nature of the planets and the powerful relationship between our planet and its moon.

Newton discovered the "ghostly force called gravity" as the unseen cause of the tides.

Leonardo da Vinci (and recently Adm. James Stavridis) compared the oceans to lungs, vital to life on earth.

In "Tides" Jonathan White explores the history, science and study of tides, with short detours to examine Newton's death mask, contemplate gifted Polynesian navigators, listen to acoustic resonance in the ocean, observe a coming-of-age ceremony in the Caribbean, and jump in for discussion of big-wave surfing at Mavericks, California. 

He examines treacherous tides, rapids and passages, including Vancouver's Ripple Rock, which claimed the U.S. Navy steamer Saranac in 1875. "A crewmember wrote, 'Here the contending currents take a vessel by the nose and swing her from port to starboard and from starboard to port as a terrier shakes a rat.'" Over the decades Ripple Rock killed at least 144 people, until the rock was blown up and obliterated in 1958.

Rene Descartes
The quality of White's prose and his exploration of science are a joy for readers. Books/authors in epigraphs and text include:

  • John Steinbeck's "The Log from the Sea of Cortez"
  • Sir Walter Scott's "Redgauntlet"
  • The Bible -- story of Moses [in Bruce Parker's "The Power of the Sea"]
  • James Frazer's "The Golden Bough"
  • Pliny's "Natural History"
  • Benjamin Franklin's observation about wind and waves
  • Newton, Copernicus, Giordano Bruno, Kepler, Galileo, Descartes, Hugo, Bacon, Milton, Laplace, Whewel, Harris, "and scores of others" who championed science in the face of religious persecution

Some of the interesting science revealed in "Tides":

  • Four zones of tidal exposure
  • Grunion runs in southern California and northern Baja
  • The fact that the Atlantic is tied to the moon, and the Pacific is tied to the sun (Tied tides?)
  • The Bay of Mont Saint-Michel, off France's Normandy coast, with its 45-foot tidal range
  • Qiantang River bore-watching in China, where the tide comes in not in six hours but in six seconds.
  • One can be killed fighting a tide
  • The tide always turns.
  • Friction and energy run deep:

"Through friction, (the tide) loses energy – lots of it. Some is absorbed in the ocean floor as heat, but most of it exerts a torque on the earth's rotation, slowing ever so slightly the length of our days and, in turn, causing the moon to speed up and spiral away. Thus, the moon, which causes the tide, is in turn pushed away by the tide. What we witness when we sail through narrows is friction at work. Every whirlpool, every eddy, every dimple of tension is evidence of energy moving from the moon to the water and back to the moon."
White explores the potential of renewable energy and the future possibilities of tide, wind and wave energy.

The Kennedy administration examined tide energy possibilities in the early 1960s in coordination with Canada to address the energy needs of New England. 

"Harnessing the energy of the tides," Kennedy said, "is an exciting technological undertaking ... Each day, over a million kilowatts of power surge in and out of he Passamaquoddy Bay. Man needs only to exercise his engineering ingenuity to convert the ocean's surge into a great national asset."

According to White, "Kennedy's bold advocacy of tide energy ended abruptly with his assassination in November 1963, just four months after his groundbreaking speech at the White House." That speech included this insight from former naval officer President Kennedy: "The problems of the world cannot possibly be solved by skeptics or cynics whose horizons are limited by the obvious realities. We need people who can dream of things that never were."

Does a nautilus shell transcribe the nature of tides?
White explores not only the evolution of nature as discovered by Charles Darwin, but also the nature of evolution in dynamic environments, including the early formation of life. "What if we were born in a tidepool and our attraction to the sea is a coming home."

He asks: Can evidence of the earth's rotational history be found in coral and nautilus sea creatures? Can accelerating climate change be stopped in time to prevent increasing rises in sea level?
"Sea level itself is a slippery concept – not at all easy to distill into definitive measurements or predictions. The sea, in fact, is not level. It doesn't lie flat like undisturbed water in a bathtub or pool but piles up in one place and retreats from another. The western Pacific is about three feet higher than the eastern Pacific (due to the northeast trade winds), and the eastern Pacific is ten inches higher than the Atlantic. On the U.S. Atlantic coast, sea levels slope downward from south to north by four or five inches. Different landmasses, due to variations in density and gravitational pull, force seawater this way or that. The oceans are lifted by the Himalayas and Andes and sucked downward by undersea mountain ranges. In the Pacific during El NiƱo years, when the trade winds relax, seawater that had been pushed westward sloshes back eastward, bringing higher ocean levels to the U.S. west coast."
Kircher's 1646 "shadowdial" shows the yin and yang of moon phases.
White takes us from Alaska and the Arctic, to India and China; from France and UK, to Suriname and Venice; and to oceans, rivers and bays, including the Bay of Fundy in Canada. 

Science and spirit: He examines how tides were described by ancient monks and scholars, including in "The Selenic Shadowdial or the Process of Lunation" from Athanasius Kircher's "Ars Magna Lucis et Umbrae" (1646). And he contemplates how the tides influence biology.

The book begins and ends with what can be revealed in the life, bodies and "internal clocks" of mudshrimp, Corophium, that are the size of rice grains. These translucent organisms' lifecycles are tied to tides, as is are the lives of the sandpipers who feed on the tiny shrimp. 

Marine animals and birds aren't the only ones influenced by the tides; "More than half the world's population lives on or near the coast, and there is no coast or ocean without a tide," White writes.

"The economic and scientific, social and biological dynamics at play here are also at play for billions of people across our watery planet."

White concludes: The tide teaches. The tide vibrates. The tide lives. And the tide can kill.


The Kuna Yala people in Panama are particularly vulnerable to sea level rise. (Courtesy Jonathan White)

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