[an error occurred while processing this directive]
5 of 5
Ominous Thaw Photograph by Joel Sartore
Graduate students Kyle Whittinghill, at left, and Marselle Alexander-Ozinskas inspect a soil sample in one of the North Slope's many thermokarsts, or tundra fractures, caused by melting permafrost. Thermokarsts on the slope have become more frequent in recent years, due in part to rising temperatures and a loss of insulating ground vegetation. When tundra soils—which are rich in sphagnum mosses—thaw, they decompose and release carbon into the atmosphere, a process that some scientists fear will increase global warming.
Camera: Nikon F5 Film Type: Fujichrome Velvia Lens: Nikon 17-35mm f/2.8 Speed and F-Stop: 1/60 @ f/8
Weather Conditions: Partly cloudy Time of Day: 2 p.m. Lighting Techniques: Natural light