Ocean

Ocean: Reflections on a Century of Exploration

Wolf H. Berger
With contributions by E. N. Shor
Copyright Date: 2009
Edition: 1
Pages: 536
https://www.jstor.org/stable/10.1525/j.ctt1ppnnt
  • Cite this Item
  • Book Info
    Ocean
    Book Description:

    The past one hundred years of ocean science have been distinguished by dramatic milestones, remarkable discoveries, and major revelations. This book is a clear and lively survey of many of these amazing findings. Beginning with a brief review of the elements that define what the ocean is and how it works—from plate tectonics to the thermocline and the life within it—Wolf H. Berger places current understanding in the context of history. Essays treat such topics as beach processes and coral reefs, the great ocean currents off the East and West Coasts, the productivity of the sea, and the geologic revolution that changed all knowledge of the earth in the twentieth century.

    eISBN: 978-0-520-94254-7
    Subjects: Aquatic Sciences

Table of Contents

  1. Front Matter
    (pp. i-vi)
  2. Table of Contents
    (pp. vii-viii)
  3. FOREWORD
    (pp. ix-x)
    CHARLES F. KENNEL

    One of the major events celebrating the centennial year of the Scripps Institution of Oceanography (2003) was a reunion and symposium commemorating the fiftieth anniversary of Scripps’s great MidPac Expedition and its predecessor, Capricorn. I am afraid that my opening remarks may have dismayed the veteran scientists gathered there, for I ventured that their great research cruise brought the age of European geographic exploration, which started with Prince Henry the Navigator 500 years ago, to a definitive end. I borrowed a thought that John Maynard Keynes had applied to Isaac Newton: they were the last generation to look upon the...

  4. Introduction: COPING WITH A SEA OF CHANGE
    (pp. 1-6)

    What ocean scientists do has changed drastically in recent years. Not only are we using tools undreamed of a few decades ago, tools that produce immense data floods of entirely new types of observations, but also now the very objects of study have become moving targets. The various ecosystems of the ocean environment are changing rapidly in unforeseen and practically unpredictable ways. Today’s graduate students and their mentors deal with a sea that is quite different from the one we studied even three decades ago.

    It is a good time to take stock of what we have learned about the...

  5. ONE Discovering the Ocean: OF FISH AND SHIPS AND PEOPLE
    (pp. 7-30)

    Lobster, scallop, and tuna are among the more expensive items on the seafood menu, and for good reasons. We like to eat these things, and there are many of us, and not so many of them any more. In fact, with regard to fish suitable for fine dining, there are now roughly 10 times fewer in the sea than only a few decades ago.¹ Many other animals of the sea once or recently heavily exploited are similarly diminished, including, for example, sea turtles and large whales. Jellyfish, however, remain in sufficient abundance (fig. 1.1). Their nutritional value, in relation to...

  6. TWO A Portrait of the Ocean Planet: ELEMENTS OF OCEAN LITERACY
    (pp. 31-62)

    Earth literacy has at least one big benefit: a sense of delight at living on this very special planet. Also, clearly, Earth literacy is useful when trying to follow discussions about human impacts on the planet and what to do about it.¹ Knowledge of the ocean is crucial to Earth literacy. Ocean literacy starts with the knowledge that the ocean covers 70 percent of the planet’s surface and is typically 2.5 miles (4 kilometers) deep, with the bulk of the water being very cold, and in the dark. It includes knowing why fishing is good in some parts of the...

  7. THREE Life at the Edge of a Fertile Sea: THE BIRTHPLACE OF MARINE SCIENCE
    (pp. 63-94)

    Exploration of the sea starts at the shore, whether for food or for science.

    Seabirds are in evidence along practically all coasts and invite much observation and marveling about different life histories of these feathered vertebrates. Some breed locally and raise their young in full view (fig. 3.1). Others stop over on long migrations, using marine wetlands to rest and to feed. Yet other, permanent residents, add drama to the scene (fig. 3.2). But beyond the many types of birds that enliven the scenery, an incredible diversity of creatures can be found along almost any rocky, sandy, or muddy shore....

  8. FOUR Of Coral Reefs and Atolls: STONE GARDENS OF TROPICAL SEAS
    (pp. 95-124)

    Reef-forming stony corals potentially can grow everywhere in the tropical and subtropical realm of the planet—about one-third of its surface—where the water is warm throughout the year (greater than 20 °C).

    For stony corals to grow, the seafloor has to be shallow and the ground firm. Also, the water has to be clear, so that plenty of sunlight reaches the seafloor. The reason is that the coral animals bear inside their bodies, within the outermost cells, photosynthesizing microscopic algae (symbiotic dinoflagellates called zooxanthellae), which need light. This association between animals and green microbes (which gives most corals olive...

  9. FIVE The Zen of the Beach: MUSINGS ON A RIVER OF SAND
    (pp. 125-150)

    Few things are more pleasant than walking along the beach barefoot, feeling the sand between the toes.

    Millions enjoy these simple delights every year. They come and spread their blankets on the sand and watch the children build sand castles, fated to be washed away by the waves of the rising tide. They watch the shorebirds hunting for worms and crabs hidden within the sand.

    But what is sand? What is the nature of the grains that feel gritty between toes and fingers? What stories do they have to tell?

    The answer depends on the location, of course. The beaches...

  10. SIX Unraveling the Gulf Stream Puzzle: ON A WARM CURRENT RUNNING NORTH
    (pp. 151-184)

    A mighty ocean current runs north and east offshore from the East Coast, between the Florida Keys and Cape Hatteras (fig. 6.1).

    It moves warm water northward, from the Gulf of Mexico into the northern North Atlantic, on the way entraining warm water from the Sargasso Sea. It is one of the two most powerful warm currents on the planet.¹ The heat it transports feeds the storms of the northern Atlantic and helps maintain low air pressure in the vicinity of Iceland, stabilizing the Iceland Low. In turn, the anticlockwise winds running about the Iceland Low direct the heat-bearing marine...

  11. SEVEN Sardines and the California Current: ON A COLD CURRENT RUNNING SOUTH
    (pp. 185-214)

    The California Current brings cold water south along the sunny parts of the West Coast, and it does so while moving surface waters offshore (fig. 7.1). As a consequence, additional cold water rises from the thermocline and below, producing a narrow cold strip of highly productive waters in sight of the land. The processes involved (referred to as “upwelling in an eastern boundary current”) are responsible for the rich sea life supported by the current, including seabirds such as cormorants and pelicans, and mammals such as the California sea lion and the elephant seal.

    Productivity varies through the decades. There...

  12. EIGHT Meadows and Deserts of the Sea: ON THE ELUSIVE CONCEPT OF OCEAN PRODUCTIVITY
    (pp. 215-244)

    Production varies widely in the sea; it is largely controlled by nutrient supply and the availability of sunlight. The crucially important nutrients are phosphate (fig. 8.1) and nitrate (which has a distribution similar to that of phosphate), as well as silicate (which tends to follow the same distribution patterns but with important exceptions). Silicate is the nutrient that allows diatoms to make shells of glass. Diatoms are an important group of primary producers sometimes referred to as “grass of the sea.” Primary production in the sea is carried out by both photosynthetic bacteria and microscopic algae, including diatoms and dinoflagellates....

  13. NINE Of Whales and Sharks and Giant Squid: REFLECTIONS ON THE BIG, THE STRANGE, AND THE POWERFUL
    (pp. 245-278)
    W. H. Berger and E. N. Shor

    The largest animals on the planet are the great whales. The biggest among these weigh more than 20 big elephants.

    Modern whales arose within the last 30 million years or so, as a result of the cooling of the planet, which changed the productivity patterns of the sea in ways favorable for the development of large size. This is true both for whales that hunt (toothed whales) and for whales that filter the water containing small fish and krill and other plankton (baleen whales). Other vertebrate groups also have large animals; pinnipeds have elephant seals and walrus, sharks and their...

  14. TEN The Deep, the Cold, the Dark: LIFE AT THE END OF THE LINE
    (pp. 279-310)

    Living in the dark is the normal state of affairs on our planet: the dark and cold waters below the sunlit surface layer of the sea constitute the largest life habitat on Earth. This habitat is largely a desert, except at the margins, including the outer shelf and upper continental slope. The animals seen in the dark and cold habitat are on the whole quite closely related to those near the surface, but many of them have special adaptations for seeing at low light, for making light, and for stalking and attracting prey in the dark.

    Different depth levels bear...

  15. ELEVEN Seeing in the Dark: A SOUND APPROACH TO EXPLORATION
    (pp. 311-340)
    W. H. Berger and E. N. Shor

    Sensing sound in the sea is a strategy for survival that is geologically ancient, going back to the time when fish evolved a lateral-line system for detecting pressure waves, several hundred million years ago. The most ancient of marine mammals, the toothed whales, have lived by their skills as echo-hunters for millions of years. Within the last 25 million years, they have perfected their echo system to an astonishing degree, including the growth of ever-larger brains, to process acoustic information.

    The science of sound in the sea started with echo sounding for icebergs early in the twentieth century. By the...

  16. TWELVE Mountains, Trenches, Sunken Islands: THE GREAT REVOLUTION IN EARTH SCIENCE
    (pp. 341-372)

    What do the mountains of the Sierra Nevada have in common with the San Andreas Fault System of California and with the island chain of Hawaii (fig. 12.1)? They are among the large linear features that characterize the surface of our planet, and that result from the motions of large pieces of real estate called plates. There are about a dozen plates. The largest comprises much of the Pacific basin, the next largest includes much of the Indian Ocean and both India and Australia, the next the Americas and the western half of the Atlantic basin, and so on down...

  17. THIRTEEN The Ocean’s Memory of the Ice Ages: THE ENDLESS CYCLES OF CLIMATE CHANGE
    (pp. 373-404)

    We live in an ice age, geologically speaking. Some considerable portion of the water on this planet is locked up in ice, at high latitudes (fig. 13.1).¹ More precisely, we live in a warm period within a long series of ice age fluctuations.

    Over the last million years, the sea level was about 200 feet (60 meters) lower than today, on average. It was higher than today only for a few percent of this time span. The reason the sea level was normally much lower was the presence of large ice sheets that covered much of Canada and Scandinavia, and...

  18. FOURTEEN Abyssal Memories: A THOUSAND HOLES IN THE BOTTOM OF THE SEA
    (pp. 405-438)

    The deep ocean has memories going back 100 million years, and more. Ramming a steel tube into the seafloor is fine for getting samples for the last 1 percent of that. But to get the whole story one needs to use a floating drilling platform, a ship with a huge derrick over a hole in the center of the vessel, to handle a string of pipes armed with a drill bit that eats its way deep into the bottom (fig. 14.1). Sending a steel tube through the central hole of the bit, we can then sample the sediment well below...

  19. FIFTEEN Global Warming and the Ocean: HUMAN IMPACT ON A GREENHOUSE PLANET
    (pp. 439-470)

    Our planet has life because of greenhouse gases in the air. They keep Earth warm, so that water can flow and clouds can form to bring rain. Without these gases, most of the planet would be covered with thick masses of ice, and the air would be dry. The two most important greenhouse gases are water vapor and carbon dioxide. Molecules of these gases intercept heat radiation that attempts to leave the planet. As a result, the planet’s radiation balance is achieved several kilometers up in the atmosphere, and the ground and lower atmosphere, where we live, are pleasantly warm...

  20. Epilogue: THE GREAT TRENDS IN EXPLORATION AND THE CHALLENGES AHEAD
    (pp. 471-478)

    The difficulty in attempting to present a coherent picture of ocean sciences is that there is no such coherent picture—oceanography is whatever scientists interested in the ocean happen to do. Depending on the changing interests of the scientists practicing the art, ocean science can readily change focus and has done so many times over the last century. An early task was to make an inventory of what lives near the shore, and how. It was followed by exploration of coastal waters, and by systematic investigation of the global ocean—its physics, its chemistry, its biology, and its history and...

  21. Appendix One: Units Used in the Ocean Sciences
    (pp. 479-480)
  22. Appendix Two: Aspects of Ocean Chemistry
    (pp. 481-482)
  23. Appendix Three: Overview of Major Groups of Important Marine Organisms
    (pp. 483-488)
  24. Appendix Four: Geologic Time Scale
    (pp. 489-490)
  25. Appendix Five: Topographic Statistics
    (pp. 491-494)
  26. FIGURE SOURCES AND REFERENCES
    (pp. 495-500)
  27. INDEX
    (pp. 501-520)