The continental shelves, ridges and sea mounts are the most productive areas in terms of biodiversity, and is of highest importance for economic activities. It is also here that natural resources extraction - such as oil and gas - takes place. The largest expanses of ocean are vast plains of depths between 1500-5000 meters. The deepest areas are the trenches where the continental plates meet, such as the Marian Trench of the Pacific.
From collection: Topographic maps
Hugo Ahlenius, UNEP/GRID-Arendal