Ocean Floor

Ocean Floor

1. UNDERWATER LANDFORMS

   • Continental shelf
     • The continental shelf is an area of relatively shallow water, usually less than a few hundred feet deep, that surrounds land.
     • It is narrow or nearly nonexistent in some places; in others, it extends for hundreds of miles.
   • Abyssal plains
     • Depths of over 10,000 feet and covering 70% of the ocean floor, abyssal plains are the largest habitat on earth.
     • Not uniformly flat
   • Mid-ocean ridge
     • Underwater mountain range, over 40,000 miles long, rising to an average depth of 8,000 feet.
   • Ocean Trench
     • The deepest part of the ocean
     • Mariana Trench, for example, is the deepest place in the ocean at 36,201 feet.

2. OCEAN FLOOR

   • Bathymetry
     • The shape of the ocean floor, is largely a result of a process called plate tectonics
   • Convection currents in the molten mantle cause the plates to slowly move about the Earth a few centimeters each year

3. HYDROTHERMAL VENTS

   • Discovered in 1977
   • Organisms in these deep, dark, ecosystems have no access to sunlight, and instead metabolize hydrogen sulfide or other chemicals in a process called chemosynthesis.