Oceanography: An Observer’s Guide For: sailors, fishermen, yachtsmen, merchant seamen, Navy and Coast Guard personnel, midshipmen and cadets, Sea Semester students... ...and everyone else going to sea. Nelson Marshall Oceanography: An Observer’s Guide Marshall, Nelson. Oceanography: An Observer’s Guide. IAN Press, Cambridge, Maryland. 299 pages. © 2009 IAN Press P.O. Box 775 Cambridge, MD 21613 U.S.A. www.ian.umces.edu [email protected] Original images may not be reproduced without permission of the copyright holder. Disclaimer: The information in this book was current at the time of publication. While the book was prepared with care by the authors, IAN Press accepts no liability for any matters arising from its contents. ISBN: 978-0-9822305-1-0 First published 2009. 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Oceanography: An Observer’s Guide by Nelson Marshall Professor Emeritus of Oceanography and Marine Affairs, University of Rhode Island Coordination, design, and layout by Emily Nauman Preface During my career as an oceanographer I have sailed on ships equipped with very sophisticated instruments and yet, while cruising on my own thirty-foot sailboat, it occurred to me that many meaningful observations can be made with the equipment on board even the most modest vessels that go to sea. For example, a thermometer, a wind gauge, a depth finder, a wrist watch, ordinary buckets, some note paper, and much more that is readily available, can be useful to an observer interested in learning more about the surroundings. Actually, one’s eyes can serve as the best equipment of all, once one knows what to look for. Accordingly, I have written this guide for sailors, yachtsmen, sport and commercial fishermen, merchant seamen, Navy and Coast Guard personnel, midshipmen and cadets, sea semester students, in fact for anyone traveling on the high seas. The scope of this book is largely limited to conditions on the high seas because covering offshore-inshore interactions would require an additional and very lengthy book. However, I do bridge gaps to some degree, particularly in a brief chapter at the end titled, What about Estuaries? Being largely restricted to features that can be discussed on the basis of observations on the surface, it is obvious that this guide does not cover some important aspects of oceanography. Even so, I am confident that anyone traveling on the high seas can learn a great deal by observing and with the simplest of equipment. Nelson Marshall Professor Emeritus of Oceanography and Marine Affairs, University of Rhode Island v Acknowledgements While writing this guide I have been regularly visiting the College of Oceanographic and Atmospheric Sciences at Oregon State University where Bill Pearcy, Charlie Miller, Doug Reese, Jane Huyer, Bob Smith, Kelly Faulkner, Gary Egbert, Charlie Goldfinger, Murray Levine, Jonathon Nash, Mike Kozro, Ernie Pertersen, George Taylor, Bruce Mate, Doug Caldwell, Clayton Paulson and many others have been especially helpful in responding to my many inquiries. In addition, I wish to extend a special thanks to Linda Lafleur, receptionist at the college, who constantly looked after my various needs in relation to offerings at Oregon State University. Several of my former students, especially Thierry Jacques, Hank Parker, Ray Gerber, Barbara Welsh and her husband, Bob, helped in supplying information and reviewing drafts of my writing. In addition, my former Dean, John Knauss, reviewed the discussion of Law of the Sea provisions. Karen Wishner, another colleague at the University of Rhode Island, provided updated information on the subsurface volcano in the Caribbean. Many members of the University of Maryland Center for Environmental Science (UMCES) played a range of contributing roles including providing basic information and helping to organize and review the text. Leading this group was Bill Dennison. Others included Bill Boicourt, Larry Sanford, Judy O’Neil, Roger Newell, Tom Fisher, Ben Longstaff, Emily Nauman, Emily Benson, and Joanna Woerner. Bob Shoop and Paul Hargraves of the University of Rhode Island, Paul Joyce of the Sea Education Association, Bill Dillon of the U.S. Geological Survey, Hugh Ducklow of the Ecosystems Center of the Marine Biological Laboratory, Nat Mantua and Knut Aaguard of the University of Washington, Amy Schoener formerly with the University of Washington, and Jack Bash, formerly with the University Oceanographic Laboratory Ships organization are among the many others who have provided important information. vi You may note that many of the fine illustrations that are original with this publication or are taken from one of my earlier writings were drawn by my colleague, Debbie Kennedy. Assistance in editing was provided by several of the above, also by my son-in-law, David Griffiths, who is on the Faculty of Reed College. vii Foreword Oceanography: An Observer’s Guide uniquely captures the perspectives of both an oceanographer and a mariner—Nelson Marshall has excelled at both over a long and varied career and life. In this book, the physics, chemistry, biology, and geology of the oceans are presented in a way that virtually everyone can understand. The title, Oceanography: An Observer’s Guide, better captures the spirit of what Nelson Marshall does with this book—he conveys the importance of using the power of observation with little or no accompanying instrumentation to understand nature. This is a powerful lesson, and one of the iconic figures in marine science, Louis Agassiz, who ran a summer program on an island off Cape Cod, Massachusetts in the 1870s, captured this lesson in his famous sign that read “Study nature, not books.” Ironically, this sign resides in one of the world’s greatest marine science libraries at the Marine Biological Laboratory in Woods Hole, Mass. Nelson Marshall’s book is teaching us how to study nature by providing us with enough of the background and conceptual framework to make observations ourselves. So while this lesson of how to “Study nature, not books” is provided in a book, it is a book intended to be taken to sea so that observations can be enhanced and the mariner can study nature firsthand. In our modern age, increasing numbers of sensors measure the Earth in various ways. With the increasing information instantly available via the internet, simply using our eyes to observe the Earth, particularly the 70% of the Earth covered by water, has become a novel approach. We should not ignore the wonders that technology can bring to our fingertips; however the act of looking, that is keenly observing, is often indeed ‘overlooked’. Nelson Marshall has kindly provided us with some guidelines on observing. Scientific specialization has made the task of crossing the various disciplines that Prof. Marshall has done so seamlessly, an increasing rarity. Perhaps a result of the broad-based training that Nelson Marshall received in the early days of oceanography, chronicled in his book, viii In the Wake of a Yankee Oceanographer, or a result of his varied and diverse career, Prof. Marshall has the unique breadth and depth of understanding to undertake such an ambitious scope presented in this book. Another remarkable facet of the book is the combination of his historical perspective with modern concepts and understanding. Prof. Marshall has indeed defined what it is to have had a lifelong learning experience. After his first retirement from an active and varied career culminating at the University of Rhode Island’s School of Oceanography, he came to the Chesapeake Bay, where he and his wife, Grace, could sail regularly. Nelson struck up an active participation at the Horn Point Laboratory, University of Maryland Center for Environmental Science, where he challenged graduate students and professors with insightful questions and began writing books. He then retired (again) to Oregon, where he continued to make weekly sojourns to Oregon State University, even sitting in on seminars—the only octogenarian graduate student. This book benefits from Nelson’s wealth of firsthand experience in the corridors of research institutions and sailing on tall and small ships on the world’s oceans. This book was Nelson’s final project, as he passed away on the day that the manuscript went to the printer. One way to read this book is to imagine yourself standing along the rail of a ship alongside your favorite uncle as he patiently explains what is unfolding in front of your eyes.