Bathymetry is the study of the underwater depth of
sea and ocean floors, lake floors, and river floors. It has been carried out for more than 3,000 years, with the first recorded evidence of measurements of water depth occurring in ancient Egypt. Bathymetric measurements are conducted with various methods, including
depth sounding,
sonar and
lidar techniques,
buoys, and
satellite altimetry. However, despite modern computer-based research, the depth of the seabed of Earth remains less well measured in many locations than the topography of Mars. Bathymetry has various uses, including the production of
bathymetric charts to guide vessels and identify underwater hazards, the study of
marine life near the bottom of bodies of water, coastline analysis, and
ocean dynamics, including predicting currents and tides. This video, created by the Scientific Visualization Studio at
NASA's
Goddard Space Flight Center, simulates the effect on a satellite world map of a gradual decrease in worldwide
sea levels. As the sea level drops, more seabed is exposed in shades of brown, producing a bathymetric map of the world.
Continental shelves appear mostly by a depth of 140 meters (460 ft),
mid-ocean ridges by 3,000 meters (9,800 ft), and
oceanic trenches at depths beyond 6,000 meters (20,000 ft). The video ends at a depth of 10,190 meters (33,430 ft) below sea level – the approximate depth of the
Challenger Deep, the deepest known point of the seabed.
Video credit: NASA / Goddard Space Flight Center / Horace Mitchell, and James O'Donoghue
