Phytoplankton color the sea in this image acquired on August 27, 2005. Phytoplankton are tiny, microscopic plants that form the base of the food web in marine ecosystems. The vibrant blue color is caused by coccolithophores, a type of phytoplankton that have chalky, white shells; light reflects off of the shells and the surrounding water to produce these rich, vibrant colors. Phytoplankton are consumed by zooplankton, or microscopic animals, which in turn are eaten by variety of fish, whales, and birds. Some of these fish species, such as cod, capelin, and herring, are harvested commercially for food for humans, although some fisheries have shown signs of pressure. The Barents Sea is a part of the Arctic Ocean and lies North of Norway and the Russian Federation. It is kept relatively warm and ice-free all year long by ocean currents that carry warm water from the North Atlantic. Oil and gas extraction, as well as the dumping of waste, pose a serious threat to the long-term health of this fragile ecosystem.