SIO 30 Unit 5/5: Ocean Basins and Physical Properties of the Ocean

bathymetry

study of ocean floor contour (i.e. continental shelf, slope, abyssal plains)

echo sounders

method of studying ocean floor; beams sound waves to bottom and measures the time for sound to bounce back to the ship

continental shelf

the area from coastline to shelf point; characterized through shallow water, gentle sloping and a rich sediment/marine life

continental slope

area between the shelf break and deep ocean marking true edge of the continent; characterized by steeper slope

continental rise

the base of the continental slope (common on passive margins); characterized through gentle sloping and an accumulation of sediment, connects to abyssal plains

abyssal plain

the flat, deep ocean (beyond the continental rise), covered in fine sediment

trenches

extremely deep depressions in the ocean floor, narrow/steep-sided and tectonically active

submarine canyons

steep-sided valleys that cut into the continental shelf/slope (basically underwater canyons)

sea mounts

submarine volcanoes that have not reached the surface

hydrothermal vents

openings on the seafloor where geothermally heated water escape from Earth’s crust (usually at mid-ocean ridges, typically very close to the spreading center)

black smokers

chimney-like structure emitting superheated dark, mineral-rich water (sulfides, iron)

white smokers

chimney-like structure emitting superheated light-colored, mineral-rich water (barium, calcium, silicon)

temperature

an object’s response to input/removal of heat, measures kinetic energy of molecules

heat

energy produced by vibration of atoms/molecules

heat capacity

measure of the heat required to raise the temperature of a substance by 1 degree Celsius (measured in calories)

thermostatic properties

ability to moderate temperature changes

thermal inertia

tendency to resist change in temperature with the gain/loss of heat energy

salinity

total dissolved ionic content/salt in water; high content characterized through significant evaporation or little rainfall

thermocline

layer in the ocean measuring temperature (rapid change in temperature with depth)

halocline

layer in the ocean measuring salinity (rapid change in salt concentration with depth)

pycnocline

layer in the ocean measuring density (rapid change in water density with depth)