A marine research expedition has led to the discovery of perhaps the world's largest methane cold seep. The seep lies deep in the western North Atlantic Ocean, far from the life-sustaining energy of the sun. Mussels blanketing the the seep rely on bacteria that use the methane to make energy. The process, known as chemosynthesis, forms the basis for life in the harsh environment and could help scientists better understand how organisms can survive under these types of extreme conditions....