Lake Superior other Great Lakes fish, populations have also been affected by the accidental or intentional introduction of foreign species such as the sea lamprey and Eurasian ruffe. Accidental introductions have occurred in part by the removal of natural barriers to navigation between the Great Lakes. Overfishing has also been a factor in the decline of fish populations. Lake Superior Lake Superior (; ), the largest of the Great Lakes of North America, is also the world's largest freshwater lake by surface area, and the third largest freshwater lake by volume. The lake is shared by the Canadian province of Ontario to
Lake Untersee Institute's Carl Sagan Center for the Study of Life in the Universe, and Ian Hawes of Aquatic Research Solutions dived in Lake Untersee to study its unique microbial communities. Lake Untersee Lake Untersee ( "Lower Lake") is the largest surface freshwater lake in the interior of the Gruber Mountains of central Queen Maud Land in East Antarctica. It is situated to the southwest of the Schirmacher Oasis. The lake is approximately long and wide, with a surface area of , and a maximum depth of . The lake is permanently covered with ice and is partly bounded by glacier ice.