Much of his current research centers on the use of acoustic telemetry and satellite-based tagging technology to study the ecology and behavior of sharks. His shark research has spanned the globe from the frigid waters of the Arctic Circle to coral reefs in the tropical Central Pacific. For more than 30 years, Greg has been actively involved in the study of life history, ecology, and physiology of sharks. He holds a master’s degree from the University of Rhode Island and a Ph.D. He is also adjunct faculty at the University of Massachusetts School for Marine Science and Technology and an adjunct scientist at the Woods Hole Oceanographic Institution (WHOI). He has been a fisheries scientist with the Massachusetts Division of Marine Fisheries since 1987 and currently heads up the Massachusetts Shark Research Program. Gregory Skomal is an accomplished marine biologist, underwater explorer, photographer, and author.
Here the old ice is exposed on the surface, revealing bright patches of blue amid the white snow.ĭr. These areas can be a few football fields in size or cover thousands of square kilometers (hundreds of square miles). But in some parts of Antarctica, wind scours the surface, removing those upper layers.
Ice sheets are typically covered with layers of new ice and snow that appear white. The deep layers of ice in ice sheets are also blue. This happens along the leading edge of the glacier, where the ice is calving, or breaking apart. We can only see that blue color when we see the deeper layers of ice. At the same time, they scatter short-waved blue light, which makes the ice appear blue. When light hits these crystals, they absorb long wavelengths of light. This not only removes much of the air, it also causes the ice to form large, dense crystals. These heavy layers press the air out of the deeper layers of ice. The same is true of newly formed ice, which also traps air bubbles.īut over long periods of time, glacier ice is buried under new layers of ice and snow. Air bubbles scatter all wavelengths of light, making the snow appear bright white. One reason snow is so reflective is because there is so much air trapped between the snowflakes. Green leaves absorb everything except the green that reaches our eyes. A black t-shirt, on the other hand, absorbs all wavelengths of light. Any that bounce off eventually reach our eyes, and we see the object as the color or colors that reflect back at us. Some of the wavelengths of light may be absorbed by the object.
We see color when light reflects off the surface of an object. Red has the longest wavelength, and the wavelengths get shorter as you move through the rainbow, with violet the shortest of all visible colors of light. Each wavelength creates its own band of color. When white light travels through water droplets, they bend the light, creating a rainbow. This is the distance from the top of one wave to the top of the next. Light travels in a wave, and each of those colors has its own wavelength. Sunlight includes all colors of the rainbow, from red to violet and everything in between. Ice deep inside a glacier or an ice sheet is always this deep hue.
BLUE ICEBERG CRACKED
The surface may look white, but places where the ice has cracked open look almost turquoise. But if you get a good look at the leading edge of a glacier, you’ll find that the ice inside is a brilliant blue. When sunlight shines on a field of snow, it reflects a bright-even blinding-white.