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Ebb and Flow Tides and Life on Our Once and Future Planet This article has This been published in or collective redistirbution of any portion of this article by photocopy machine, reposting, or other means is permitted only with the approval of The approval portionthe ofwith any permitted articleonly photocopy by is machine, of this reposting, means or collective or other redistirbution BOOK REVIEWS Ebb and Flow Oceanography Tides and Life on Our Once and Future Planet , V By Tom Koppel, The Dundurn Group, which is the loss of much of the fleet of olume 21, Number 2, a quarterly journal of journal The olume 21, Number 2, a quarterly 2007, 296 pages, ISBN 9781550027266, Alexander the Great due to a tidal bore), Paperback, $26.99 US coastal ecosystems, modern analysis, and extracting energy from tides. Chapter 1 REVIEWED BY JOHN L. LuiCK contains an account of the ancient tidal dockyards at Lothal, India—surely a can- Ebb and Flow: Tides and Life on Our didate for “Engineering Wonders of the Once and Future Planet is well titled. It Ancient World.” The most ambitious and O tells the story of tides, why they matter, original chapter is the final one, whose ceanography Society. Society. ceanography what causes them, and how they have three subheadings are Sea Level Change changed over time. The author, Tom Causes Intertidal Zones to Migrate; Giant all sorts of ammonia and phosphoric Koppel, is not an analyst or theoretician Ancient Tides and Earth’s Rotation; and salts.” Again, tides are shown to play a C of tides but a man of inquisitive mind The Origin, Evolution, and Future of Life crucial role in both the origin and the opyright 2008 by The 2008 by opyright and substantial beachcombing and on Earth. The subject of the first section evolution of life on earth, with polymer- sailing experience. He tells his stories in may seem self-evident, but Koppel does a ization made possible by repeated cycles an engaging style, be they of gathering great job of developing it, beginning with of tidal-pool drying. O clams on tidal flats or harrowing escapes an anecdote concerning dieback among I have seen many nonmathematical ceanography Society. All rights reserved. Permission is granted to copy this article for use in teaching and research. Republication, systemmatic reproduction, reproduction, systemmatic Republication, article use for research. and this copy in teaching to granted rights All reserved. Society. is ceanography Permission O ceanography Society. Send all correspondence to: [email protected] or Th e [email protected] Send Society. ceanography to: all correspondence from tidal races. They are woven into trees he found on the shores of British attempts to explain how the moon and a well-paced and thoughtful narrative, Columbia. Clearly, the trees had grown sun combine to cause tides on earth, and never straying far from the tidal theme. to maturity at a time when the local rela- have yet to find a satisfactory one. (Most Most of the chapters combine two tive sea level was at least a meter lower. of the mathematical ones are equally elements—typically, a story of how tides This story provides a nice lead-in to a unenlightening.) Without the simplify- have played a defining role in the lives discussion of local tectonics, and from ing power of potential theory and of a coastal people, and a discussion of there to how macrotidal embayments Legendre polynomials, one inevitably the related natural history. For example, like the Bay of Fundy became tuned must resort to counterintuitive devices Chapter 9 begins with the story of how to resonate with external tidal forcing such as “revolution without rotation,” certain coastal Native Americans harvest as global mean sea level changed since confusing diagrams with lots of circles a small fish (eulachon), describes the the last ice age. The second subheading and arrows, and a balance between involvement of tides, and then broadens considers how tides have evolved over gravitational and centrifugal forces in O ceanography Society, P Society, ceanography the discussion to include tides in coastal millennia from a time when the moon a rotating reference frame. No wonder, ecosystems generally. This format suits was much closer and days much shorter. then, that the subject has a well-deserved the topic well, successfully drawing in As Koppel poetically put it, “the record reputation for being arcane—especially the reader and maintaining interest. of these changes is written in limestones, if the derivation (quite unnecessarily) O Box 1931, Rockville, MD 20849-1931, USA. Koppel ranges over many historical, corals, and seashells” (rhythmites, rugose employs “fictitious stars” (two each for scientific, and practical aspects of tides: corals, and nautaloid cephalopods, as he the moon and sun, to account for their what the “ancients” thought of them, goes on to explain). The third subhead- diurnal and semidiurnal effects) and the the advances in understanding from the ing takes us back to the origin of life. individual frequencies, like M2, are given 1600s to the present, the effect on the A well-known speculation of Charles names like, well, “M2.” Koppel makes a morphology of shorelines, various disas- Darwin sets the stage: “[perhaps life brave attempt, but he probably would ters attributable to tides (not the least of started in] some warm little pond with have done better to have simply stated Oceanography June 2008 77 a few of the fundamental results, such emphasis is a bit misleading because the term itself is not used, which seemed as that the tide-generating forces on Laplace’s progressive wave theory and like a missed opportunity in terms of Earth’s surface are inversely proportional dynamics remain the foundation of organizing things. Fourth, the book to the cube of the distance from either modern tidal hydrodynamic modeling. would have benefited from an index. the moon or sun, and then referred the It was really only the highly simpli- Fifth, showing the sense of rotation interested reader to a Web site such as fied version (for which Laplace found around the amphidromes in Figure 12 NOAA’s “Our Restless Tides,” which at analytic solutions) that turned out would have helped elucidate the text. least has some nice graphics. Actually, to be unrealistic. Finally, I noticed a couple of typos. the only mention of an inverse cube My few remaining negatives are This book will be of interest to those relationship (page 276) is incorrectly minor. First, the reproductions of pho- with affinities for natural history, seafar- stated (it would be correct if the words tographs mostly look like poor scans of ing, and tides in general—and even tidal “tide-generating forces” were substituted color prints. Second, I am allergic to the scientists will learn a few things about for “gravity”). The inverse cube relation- “National Geographic School of Writing” their science. ship is always surprising when first (the tale begins with a dramatic state encountered by anyone with basic phys- of affairs, then reverts back to tell how John L. Luick ([email protected]) ics training, in which one is taught that it came to pass, and finally reveals the is an oceanographer working for the South the gravitational attraction between two finale). Luckily, Koppel did not overuse Australian Research and Development bodies varies as the inverse square. the formula and my allergic rash disap- Institute and President, AusTides, Ltd. In Chapters 8 and 12, much is made peared quickly. Third, although in sev- Previously, he worked at the Australian of the shortcomings and ultimate failure eral places the book discusses phenom- National Tidal Facility (now the National of the “progressive wave theory.” This ena that are in fact circadian rhythms, Tidal Centre). Lagrangian Analysis and Prediction of Coastal and Ocean Dynamics Edited by Annalisa Griffa, Atmosphere) had previously sponsored A.D. Kirwan Jr., Arthur J. Mariano, similar meetings, which mostly involved Tamay Özgökmen, and H. Thomas European researchers; the proposed Rossby, Cambridge University Press, LAPCOD (Lagrangian Analysis and 2007, 487 pages, ISBN 9780521870184, Prediction of Coastal and Ocean Hardcover, $160 US Dynamics) would offer greater participa- tion by American scientists. Several of REVIEWED BY JOSEPH H. LaCasCE the organizers were from Miami and Italy, and thus there have been meet- During a colloquium on Lagrangian ings in Ischia, Italy (2000); Key Largo, dynamics in Liège, Belgium, in 1999, Florida (2002); and Lerici, Italy (2005). several participants discussed convening (I recall thinking, while enjoying several eclectic flavor. Although current meters a meeting devoted to Lagrangian stud- outstanding fish dishes near the harbor produce fairly straightforward data ies in the ocean and atmosphere. The in Lerici, that having an Italian as one of (e.g., a time series of velocity at a fixed European Science Foundation program the organizers was a good choice.) location and depth), floats and drifters TAO (Transport in the Ocean and Lagrangian studies have always had an move about, providing the drifter posi- 78 Oceanography Vol.21, No.2 given in the introduction) than on the present-day drifter. There are currently UPCOming BOOK REVIEWS 1312 surface drifters in the main ocean Arc Marine: GIS for a Blue Planet basins as part of the Global Drifter by Dawn J. Wright, Michael J. Blongewicz, Patrick N. Halpin, and Joe Breman, Program (GDP), and the authors discuss ESRI Press, 216 pages how these drifters track currents with a subsurface drogue, how they are tracked Climate Change: A Multidisciplinary Approach by William James Burroughs, Cambridge University Press, 378 pages by satellite, and how the satellite posi- tions are interpolated. The authors even Oceans Past: Management Insights from the History of Marine Animal Populations suggest the best way to deploy drifters by David J. Starkey, Paul Holm, and Michaela Barnard, Earthscan, 223 pages from a boat (from the stern, not more Our Changing Planet: The View from Space than 10 m from the surface).
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