DYNAMIC PLANET

Epipelagic (sunlight zone)

0-200m, warmest, most light, photosynthesis, life

Mesopelagic (twilight zone)

200-1000m, temp drops fast, limited light, no photosynthesis

Bathypelagic (midnight zone)

1000-4000m, cold, pitch black, high pressure

Abyssopelagic (The Abyss)

4000-6000m, near freezing, deep sea weirdos

Hadal (The Trenches)

>6000m, only in trenches like Mariana

Thermocline

zone of rapid temperature drop (usually mesopelagic)

Pycnocline

sharp incline gradient

Halocline

salinity changes quickly with depth

Stratification

separation of layers based on temp, salinity, density; strongest in tropical oceans, weakest in polar parts (due to uniform cold)

Coriolis Effect

Caused by Earth’s rotation; deflects moving fluids right in the Northern Hemisphere, left in the Southern Hemisphere

Subtropical Gyres

Large circular current systems; rotate clockwise in Northern Hemisphere and counterclockwise in Southern Hemisphere. Formed by wind + Coriolis

Gulf Stream

Warm, fast western boundary current of the North Pacific Gyre; flows south along west coast of the US; causes upwelling

California Current

Cold, eastern boundary current of the North Pacific Gyre; flows south along west coast of the US; causes upwelling.

Kuroshio Current

Warm, fast western boundary current of North Pacific; flows north along east coast of Japan.

Canary Current

Cold, slow eastern boundary current of North Atlantic Gyre; flows south along coast of NW Africa.

Ekman Transport

Net water movement is 90° to the right of wind in NH (left in SH) due to the Ekman Spiral from Coriolis + friction between water layers.

Ekman Spiral

Wind-driven surface current moves 45° to wind, deeper layers deflect further → forms spiral → net motion = 90° deflection.

Upwelling

When wind pushes surface water away from coast, cold nutrient-rich water rises; occurs on west coasts with parallel winds.

Downwelling

When wind pushes surface water toward coast, water piles up and sinks; lower biological productivity.

Western Boundary Currents

Warm, fast, deep currents on west side of ocean basins (e.g., Gulf Stream, Kuroshio); bring warm water toward poles.

Eastern Boundary Currents

Cold, slow, shallow currents on east side of ocean basins (e.g., California, Canary); often cause upwelling.

Western Intensification

Strengthening of western boundary currents due to Earth’s rotation and wind patterns; results in faster, deeper, narrower currents on west sides of ocean basins (e.g., Gulf Stream, Kuroshio).

Thermohaline Circulation

Global conveyor belt driven by differences in temperature and salinity → cold, salty water sinks in polar regions and moves deep around the globe.

Tsunami

Long-wavelength wave caused by seismic activity (earthquakes, landslides); travels fast in deep ocean but grows in height near shore due to shoaling.

Spring Tide

When Sun, Earth, and Moon are aligned → highest high tides and lowest low tides (new and full moon).

Longshore Current

Water movement parallel to shore caused by angled waves; transports sand and shapes coastlines.