Ch 6b: Hydrosphere (Oceans) Flashcards
Oceans cover:
71% of Earth’s surface, uneven distribution.
Max depth of the ocean, average depth, volume of water
11km, 4.5km, 1.35x10^18
Ocean structure
Changing layers: fresh water influx, ocean size, more land exposure. Temperature, salinity, density
Ocean layer changes are more
noticeable at the surface and near coastlines.
Ocean water properties: Density
Variable and Temperature dependent, pycnocline.
Ocean water properties: Salinity
varies from 32-37%. Increases with depth, salinity is high where evaporation is high. Low where river water enters ocean
Temperature and Salinity with Depth
saline water is denser sinks
Halocline:
is region of rapid salinity change
Thermocline:
is zone of rapid temperature change
Ocean Temperature:
surface varies from 0 to 28degrees, still remains above 0 at depth. Lowest is 0.4 as salt doesn’t allow the water to freeze.
Ocean composition
relatively constant, proportions do not change but the amounts can change. Species maintain
Ocean movement: surface currents
Wind driven surface currents, 10% by volume. Caused by atmospheric circulation and Earth’s rotation. Affects upper 100m
Large scale movement: subsurface
Density driven subsurface currents, 90% by volume. Drives the thermohaline circulation
ENSO
El Nino -southern oscillation, occurs in the pacific ocean. Extreme ends are termed El Nino and La Nina
La Nina
lower pacific ocean temperature than normal
El Nino
higher pacific ocean temperature than normal