Under Antarctic Ice: The Photographs of Norbert Wu. Text by Jim Mastro, photographic notes by Norbert Wu. University of California Press, Berkeley, 2004. 176 pp., illus. $39.95 (ISBN 0520235045 cloth).
This book presents the reader with a view that few ever experience: the underwater world beneath the annual sea ice in McMurdo Sound, Antarctica. This view is presented through the lens of internationally renowned photographer Norbert Wu, who, under the auspices of the National Science Foundation (NSF), spent three years photographing the icy waters in the region. The book includes more than 100 full-color images that take the reader on a tour of the higher life forms and their sub-ice habitats in this unique ecosystem.
Wu also focuses his lens on the conditions that scientists and support staff have to face to work in one of the harshest environments on our planet. His remarkable images show the novel habitats frequented by tiny notothenioid fishes, which produce glycopeptide antifreeze molecules that inhibit the growth of ice crystals in the body; the graceful movement of penguins swimming under the ice; and minke whales trapped in ice-locked pools, to list just a few examples. Each individual image is accompanied by photographic notes by Wu that reveal his fascination with this underwater world, where visibility can reach 180 meters, and detail the obstacles that a photographer must endure to work in this environment. Wu graciously provides detailed descriptions of the equipment and printing processes that have yielded the one-of-a-kind images included in this book.
A real bonus is the narrative provided by Jim Mastro, who worked in Antarctica from 1982 to 1996, during which he served for five years as manager of the US scientific diving program for the NSF Office of Polar Programs. Mastro is a consummate science writer who has published feature articles in International Wildlife and is the author and photographer of Antarctica: A Year at the Bottom of the World (Boston: Little, Brown, 2002). Mastro's eloquent introductory text combines the history of exploration in this region with an overview of the history of Antarctica, bringing us to the icy continent we see today. With this backdrop, the reader is introduced to the physical and chemical differences that are present within McMurdo Sound, an arrangement that dovetails perfectly with Wu's photographs.
Beginning with Carsten Borchgrevink's 1899 winter expedition, and continuing through Robert F. Scott's unsuccessful attempts to reach the South Pole during his 1901 and 1910 expeditions and, later, Ernest Shackleton's 1914 voyage in the Endurance, the southernmost continent has lured explorers and scientists to its virgin land. The early explorers'diaries often depict Antarctica as a harsh, barren landscape devoid of life. I can attest to having had this feeling as a young scientist in the mid-1980s studying the micro-algae living in sea ice in McMurdo Sound. While traveling by snowmobile to a dive site near Cape Evans, the site of Scott's 1910 base camp, I could not help but think how lifeless the place was. It was not until I squeezed into my dry suit and shimmied through a hole 1 meter in diameter, drilled through sea ice 2 meters thick, that I realized the environment under the ice offered a clement refuge from the dry, cold, and windy surface. My haunting memories of the stark surface environment were immediately left behind as I witnessed the biotic diversity and abundance offered by the colorful sub-ice world. The hazards of working in such an environment also became vividly clear as my air regulator froze shut during my ascent, forcing me to reach the surface on a final gasp of air.
The Antarctic continent itself covers more than 13 million square kilometers (roughly 1.5 times the size of the United States), and during winter, the sea ice surrounding the continent nearly doubles its extent. How did Antarctica become the icy continent we know today? A model of Earth some 250 million years ago would show the continent in the center of the vast supercontinent Pangaea. Major rifting events then occurred, fragmenting the supercontinent until Antarctica developed its present shape. The rifting opened seaways between major oceans and changed the ocean circulation around the Antarctic continent. Throughout this time, Antarctica remained in the low southern latitudes and has been in a near-polar position for about 100 million years.
Despite its near-polar position, Antarctica's climate was initially warm. Seas surrounding the continent at this time had bottom-water temperatures ranging from 12 to 16 degrees Celsius and supported a complex fauna typical of contemporary temperate oceans, while temperate vegetation flourished on land. These temperate climatic conditions ended dramatically when rifting opened crucial oceanic passages, including the Tasmanian Seaway and the Drake Passage.
This rifting combined with declining atmospheric carbon dioxide levels to trigger dramatic cooling and the onset of rapid glaciation. Continued cooling shifted eastern Antarctica into a state of permanent glaciation and allowed the growth of the more dynamic West Antarctic ice sheet. Despite several climate reversals since Antarctica became perennially glaciated, the present polar ocean surrounding the continent is Earth's most severely and consistently cold marine environment.
The marine species that are depicted so eloquently in Wu's book have been shaped by evolution driven by a long period of stable, low temperatures; they illustrate Jared Diamond's comment that “unplanned natural experiments create ecological communities that we would have never dreamed of creating” (Science 294: 1848). Indeed, Darwin, if he could have peered beneath the Antarctic sea ice, would have found another powerful example of evolutionary divergence to support his theory of evolution. The rapid onset of extreme conditions in this isolated polar marine environment has clearly driven the rapid evolution of the species present, yielding a hotbed of evolutionary change in a cold portion of Earth.
Wu's photographs reveal vividly the contemporary result of evolution in a cold, insular environment. His images depict fish that, unique among vertebrates, lack red blood cells; microalgae that persist in brine channels within sea ice; fishes whose blood remains in the liquid state at subzero temperatures because of the presence of novel biological antifreeze proteins; giant jellyfish with tentacles 9 meters long; sea spiders the size of a human hand; and sponges that tower above the surface of the sediments.
Implicit in the images and accompanying text is the highly sensitive nature of sub-ice life to environmental change. Although highly adapted to the icy world, polar organisms are acutely sensitive to anthropogenic perturbation, such as the production of greenhouse gases and ozone-destroying chemicals. Human activities are already affecting polar ecosystems dramatically, and these effects are likely to increase in the future. This book provides important background to our understanding of the delicate life forms and behavioral patterns associated with Antarctic sea ice. The organisms pictured in the volume may well serve as “canaries in the coal mine” and provide warnings about the effects of climate change worldwide.
The fascination that polar ecosystems hold for scientists and nonscientists alike is not difficult to understand, given the key role of these ecosystems in many aspects of the Earth system. Though Under Antarctic Ice: The Photographs of Norbert Wu serves appropriately as a coffee table book, it goes well beyond this use. The informed reader should have no problem linking Jim Mastro's informative text with Wu's images to gain a scientific understanding of the complexity and sensitivity of the icy ecosystem depicted. After my initial reading of the book, I could not help but think of it as a beautifully illustrated introductory textbook on Antarctic nearshore marine life.
One final aspect that cannot be overlooked is the collection of photographic notes near the end of the volume. Any serious outdoor photographer can glean an enormous amount of information from the technical details Wu provides. Although the images alone are worth the cost of the book, there is also a plethora of information that will be of interest to the general public, to polar and nonpolar scientists, and to wildlife photographers. This book will remain a staple on my coffee table and on my scientific bookshelf for many years to come.