A view of the Southern Ocean from the first digital map of seafloor. Light blue represents "calcareous ooze" that mixes the microscopic shells of organisms with mud. Green is "diatom ooze," a mix of mud and the remains of phytoplankton called diatoms. Yellow is sand. Brown is clay. Red is volcanic ash and gravel.
A new digital map of the composition of the seafloor reveals "microfossil" graveyards off the coast of Australia, as well as other complex deep-ocean geology.