The tundra of North Slopes has a rich biodiversity with some of the highest densities of Arctic birds breeding here. The increase of red fox versus decrease of polar fox population may be one of many environmental impacts of the Prudhoe Bay Oil Field, which is the largest oil field in North America, covering 86,418 ha and originally containing approximately 25 billion barrels (4.0_109 m3) of oil. The amount of recoverable oil in the field is more than double that of the next largest field in the United States, the East Texas oil field. The oil itself lies in porous rock formations anywhere from 1,700 to 7,000 m below the surface. It rises to the wellhead under its own geologic pressure, so no pumping is required. The mixture of oil, gas and water coming to the surface gets separated in special gathering centers. All of the water and some of the gas is reinjected back into the ground to enhance the formation pressure. A fraction of the natural gas is used to heat all the buildings in Prudhoe Bay. The rest, an enormous amount, must simply be burned off. - On March 2, 2006, a a large oil spill was discovered in western Prudhoe Bay. Up to 1,010,000 liter were spilled, making it the largest oil spill on Alaska's north slope to date. The spill was attributed to a pipeline rupture. Other environmental impacts of this huge oil field include fragmentation and disruption of America's formerly largest tundra wilderness area.
From album: Alaska Prudhoe Bay Oil Field and Arctic Tundra Wilderness