Discover and explore worlds containing unexpected life.
As some scientists search for life on the frozen planet of Mars, others are discovering life in unexpected places here on Earth.
Frozen Oceans follows the expeditions of polar scientists in the Arctic and Antarctic as they investigate the life found in and around the ice caps, which cover up to 13 percent of the Earth's surface.
Every year during the harsh polar winter, the surface of the ocean freezes, forming a temporary ice layer called pack ice, or sea ice. The Antarctic is the site of the greatest seasonal event on Earth. In March, the air temperatures drop to as low as -40°F, the ocean, which turns to ice at 28.7°F, starts freezing at the incredible average rate of 2.22 square miles per minute!
This is the first book to explain in non-technical terms and show with color photography the abundance of life on, in and under the ice.
Scientists are continually being surprised by the abundance of life where no life was expected. For many years, ice was seen as an obstacle to exploration and a threat to life. The ice is now perceived as central to global ocean circulation as well as global climate patterns. Frozen Oceans is a must for anyone with an interest in the polar regions, marine biology and the Earth's environment.
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David N. Thomas is a marine biologist who has conducted four expeditions to the Antarctic and two to Arctic pack ice. He has written science features for Science, BBC Wildlife Magazine and New Scientist.Excerpt. © Reprinted by permission. All rights reserved.:
Pack ice is a layer of frozen seawater typically seen floating on the polar oceans, although it is also a feature of seas such as the Baltic, Caspian and White. It varies in thickness from a few centimetres to tens of metres and at its maximum extent covers up to 13% of the Earth's surface. This makes pack ice one of the major habitat types on the planet, similar, in terms of surface area, to deserts and tundra. Ever since the sealers and whalers began to navigate through regions of pack ice at the end of the 19th century, the physical and mechanical properties of sea ice have been a focus of intense research.
Pack ice, or as it is commonly called sea ice, not only dominates polar regions but it is also central to global ocean circulation as well as global climate patterns. On a smaller scale, the formation, consolidation and subsequent melt of millions of square kilometres of ice have a fundamental impact on every ecosystem in which sea ice forms. A plethora of micro-organisms live within the ice itself, and sea ice is an important ephemeral feature affecting the seasonal dynamics of many plankton species, as well as the mammals and birds that depend on plankton as food. Some of the larger animals affected by pack ice include whales, seals, polar bears, walruses and even Arctic foxes.
Although the microscopic ice dwellers were discovered over 150 years ago, it is only in the past 25 years that the biology and chemistry of sea ice have become the focus of systematic investigations. In recent years the study of this extreme environment has intensified, fuelled by the biotechnological potential of micro-organisms from cold habitats. Astrobiologists have even explored their potential as proxies for life on an early Earth or extraterrestrial systems such as Mars and the moons of Jupiter. This book is an introduction to the large-scale distribution of pack ice around the world. The physics of ice formation, ocean dynamics and the consequences for the biology that depends on sea ice is discussed. Historical aspects of pack ice exploration are introduced together with a synopsis of many of the modern-day techniques used to study sea ice.
Places referred to in the text can be found on the maps on pp. 210 and 211.
David Thomas is a reader in marine biogeochemistry and heads the biogeochemistry group in the School of Ocean Sciences at the University of Wales, Bangor. He has worked with sea-ice related issues since 1991 when he made his first research expedition to the pack ice of the Weddell Sea, Antarctica. He has participated in further sea-ice expeditions in the Southern Ocean, Arctic, Baltic Sea and the White Sea, Russia. He was awarded his PhD from the Botany Department, University of Liverpool in 1988. Before taking up his position in Bangor in 1996, he held four research positions in Germany at the Universities of Bremen and Oldenburg, the Alfred Wegener Institute for Marine and Polar Research, Bremerhaven and the Centre for Marine Tropical Ecology, Bremen.
EXCERPTED FROM CHAPTER 1:
What is pack ice?
"Now we are in the very midst of what the prophets would have had us dread so much. The ice is pressing and packing round us with a noise like thunder. It is piling itself up into long walls. And heaps high enough to reach a good way up the Fram's rigging; in fact, it is trying its utmost to grind the Fram into powder."
This frightening description of the awesome power of the ice was written by the Norwegian Fridtjof Nansen on Friday, October 13, 1893, as his robust ship, the Fram, became stuck in the Arctic pack ice. Together with 12 other adventurers, he was at the beginning of an epic three-year voyage to traverse the Arctic Ocean. During the journey they would be exposed to conditions that would test their seamanship and survival skills to the absolute limits. Nansen, arguably the greatest polar explorer, knew that there was nothing he or his crew could do to combat the extreme physical forces that dominate moving fields of pack ice. He recognised that their survival was down to the strength of their ship and having enough provisions to last the long frozen winter months.
This can be taken as the point at which scientific investigation of pack ice opened up and understanding of its complexity, and its role in the functioning of the global environment, began to develop and useful practical information in navigation, fishing and climate forecasting was made available. Before this the 'civilized' world had mostly looked on pack ice as a nuisance, unpredictable, obstructive, unproductive and a potential destroyer and wrecker. But at the same time in the Arctic but not in the Antarctic, there was a race of people, Eskimos or, more properly, Inuit, who had knowledge and deep understanding of pack ice. They had lived with it, travelled on it and hunted their food from it for thousands of years. Mostly these people with their natural wisdom were ignored until comparatively recently More will be said about them later.
Even with all the developments in shipbuilding that have produced immensely strong metal-hulled ice-breaking ships crammed full of the latest satellite-based navigation aids, pack ice just a few centimetres thick can hinder modern day seafarers just as much as the early polar explorers in their wooden vessels. The pack-ice regions of the world are hostile, and only inhabited by man at the very fringes of their extent. They are places of extreme low temperatures, darkness for long periods of the year and severe winds.
My first impression of the Antarctic pack ice was actually one of extreme beauty. The tranquillity I felt was a complete contrast to the buffeting ocean that had been my lot as the research ship travelled 15 days from Cape Town in South Africa towards the Southern Ocean. But a closer inspection of the huge ice floes, up to several metres thick, effortlessly moving on the ocean surface, rafting on top of each other and forming massive ridges of ice blocks twice my height, was a humbling experience that inspired a healthy caution. The pack ice is not a silent place, and when a ship slowly negotiates a passage between ice floes there is a constant creaking and grinding of ice, almost a haunting groaning that emphasises the alien nature of the frozen landscape.
Icebergs are not pack ice
Pack ice is mostly frozen seawater. In simple terms, the surface of the ocean is cooled down and ice crystals form. These crystals rise to the surface and coalesce to form a frozen layer on the surface of the water. This layer can become thicker, break open and refreeze. Slabs of ice can raft on top of each other and deform, as in Nansen's description above. Ice formed from seawater, or sea ice, therefore varies from loose aggregations of ice crystals through to structures that are tens of metres thick.
However, when most people think of the polar oceans and seas they picture huge floating icebergs that have broken off from coastal glaciers or ice shelves. There is no doubt that icebergs are a distinctive feature of many pack-ice regions, but they are produced from outside of the pack ice, and are only a small part of a much larger frozen seawater system. Icebergs are not made in the sea, but are large chunks of freshwater ice that have been built up over thousands of years by the gradual freezing of snow and ice on glaciers covering land.
Nevertheless, one of the most striking sights for anyone who ventures into polar waters is the wonderful array of iceberg shapes. Wind and wave action combine to create bizarre forms, from cathedral-like spires and pinnacles, to caverns and other improbable structures. Icebergs also come in a spectacular range of colours, from the familiar blues and whites through to dark green and even black.
Ice shelves and glaciers
Many of the 'ice stories' that hit the news headlines are in fact talking about icebergs and the breaking up of ice shelves (the thick plates of ice, fed by glaciers, th
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Book Description Natural History Museum. Hardcover. Book Condition: Used: Good. illustrated edition. Bookseller Inventory # SONG0643090878
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