Dorrik Stow - Böcker

This is a book about an ocean that vanished six million years ago - the ocean of Tethys. Named after a Greek sea nymph, there is a sense of mystery about such a vast, ancient ocean, of which all that remains now are a few little pools, like the Caspian Sea. There were other great oceans in the history of the Earth - Iapetus, Panthalassa - but Tethys was the last of them, vanishing a mere moment (in geological terms) before Man came on the scene. Once Tethys stretched across the world. How do we know? And how could such a vast ocean vanish? The clues of its existence are scattered from Morocco to China. This book tells the story of the ocean, from its origins some 250 million years ago, to its disappearance. It also tells of its impact on life on Earth. The dinosaurs were just beginning to get going when Tethys formed, and they were long dead by the time it disappeared. Dorrik Stow describes the powerful forces that shaped the ocean; the marine life it once held and the rich deposits of oil that life left behind; the impact of its currents on environment and climate. It is rarely realized how very important oceans are to climate and environment, and therefore to life on Earth. The story of Tethys is also a story of extinctions, and floods, and extraordinary episodes such as the virtual drying up of the Mediterranean, before being filled again by a dramatic cascade of water over the straits of Gibralter. And in the telling of that story, we also learn how geologists put together the clues in rocks and fossils to discover Tethys and its history.

The importance of the oceans to life on Earth cannot be overstated. Liquid water covers more than 70% of our planet's surface and, in past geological time, has spread over 85%. Life on Earth began in the oceans over 3.5 billion years ago and remained there for the great majority of that time. Today the seas still provide 99% of habitable living space, the largest repository of biomass, and holds the greatest number of undiscovered species on the planet. Our oceans are vital for the regulation of climate, and with global warming and decreasing land area, they have become increasingly important as the source of food, energy in the form of oil and gas, and for their mineral wealth. Oceans also form a key part of the biogeochemical cycles of carbon, nitrogen, and other elements critical to life. Nutrients in upwelling areas are spread by ocean currents, and the plankton of the seas supports a wealth of wildlife. In this Very Short Introduction Dorrik Stow analyses these most important components of our blue planet and considers their relationship with, and exploitation by, humans. He shows how the oceans are an essential resource to our overpopulated world, and discusses why exploration and greater scientific understanding of the oceans, their chemistry, and their mineral wealth are now a high priority. Stow also explores what we know of how oceans originate, and evolve and change; the shape of the seafloor and nature of its cover; the physical processes that stir the waters and mix such a rich chemical broth; and the inseparable link between oceans and climate. As polar ice melts and sea-levels rise, countless millions who have made their homes on low-lying lands close to the sea are threatened. As scientific exploration of the seas gathers pace, the new knowledge gained of the ocean-Earth systems and their interaction with the human environment is vital to our understanding of how we can preserve these ultimately fragile environments.ABOUT THE SERIES: The Very Short Introductions series from Oxford University Press contains hundreds of titles in almost every subject area. These pocket-sized books are the perfect way to get ahead in a new subject quickly. Our expert authors combine facts, analysis, perspective, new ideas, and enthusiasm to make interesting and challenging topics highly readable.