The color of the ice ranged from this beautiful aquamarine blue to dirty brown. photo © C. A. Linder, WHOI Images and Facts - Facts Gallery | Dispatch Images | Facts | References The following pages provide a brief introduction to the natural history of the Arctic. For the purposes of these pages, I have defined this region as the Arctic Ocean and the land area north of the treeline (region where trees cannot grow). For a map of this region and to read about the other definitions of the Arctic region, visit the National Snow and Ice Data center Arctic Info page. For more detailed information on Arctic topics, please consult the References section. Oceanography  The Arctic Ocean is unique among the world’s oceans for many reasons. It is largely ice-covered (much of it year-round, the rest seasonally), it receives the majority of the fresh-water input from the world’s rivers (mostly from the Siberian continent), and it has an abnormally high ratio of shelf to abyssal area. Comparison of the Arctic and Antarctic  The Polar regions cap the opposite ends of the earth. How do they differ and how are they similar? Temperature and Climate  The Earth's tilt causes huge fluctuations in daylight at the Poles. Find out more about how this affects temperature and climate in the Arctic. Wildlife  Polar bears, snowy owls, and beluga whales are only a few of the many fascinating inhabitants of the far north. Read this page to learn more. Plant Life  This page covers the base of the food chain, from the treeless tundra to the miniature plants of the sea. Sea Ice  What is sastrugi? How does pack ice differ from a growler? This page is all about ice. Optical Effects  The Arctic's fogbows, sundogs, and mirages make it a truly otherworldly place. Read this page for more details about how these optical effects are formed. LINK: History of Arctic Exploration  For centuries explorers and scientists have been drawn to the Arctic seeking fame and knowledge. This link will take you to the WHOI Beaufort Gyre Exploration project History pages. Use your browser's Back button to bring you back to the Arctic Edge facts section.