Waves, Tides, and Marine Environments Overview

Crest

Highest point of a wave.

Trough

Lowest point of a wave.

Normal surface level

Average water level without waves.

Deep-water wave

Wave in water deeper than half its wavelength.

Shallow-water wave

Wave in water shallower than half its wavelength.

Lake wave

Waves generated in lakes, typically smaller.

Wave period

Time for one complete wave cycle.

Wavelength

Distance between consecutive wave crests.

Wave base

Depth where wave energy diminishes.

Wave height

Vertical distance from crest to trough.

Ocean wave

Waves formed in ocean, larger than lake waves.

Tsunami

Large ocean wave caused by underwater disturbances.

Tidal bore

Strong tidal wave entering river estuary.

Tides

Regular rise and fall of ocean levels.

Diurnal tide

One high tide and one low tide daily.

Semi-diurnal tide

Two high tides and two low tides daily.

Mixed tide

Two high tides and two low tides of different heights.

Tidal range

Difference in height between high and low tide.

Spring tide

Higher high tides during full or new moon.

Neap tide

Lower high tides during first or last quarter moon.

Perigee

Moon's closest point to Earth in orbit.

Apogee

Moon's furthest point from Earth in orbit.

Perihelion

Planet's closest point to the sun in orbit.

Aphelion

Planet's furthest point from the sun in orbit.

Brackish water

Mixture of fresh and saltwater in estuaries.

Pelagic zone

Open water column of the ocean.

Benthic zone

Ocean floor environment.

Euphotic zone

Upper layer of ocean with sufficient light for photosynthesis.

Disphotic zone

Dimly lit ocean layer, some light penetration.

Aphotic zone

Deep ocean layer with no light.

Phytoplankton

Microscopic plants that perform photosynthesis in oceans.

Zooplankton

Microscopic animals that feed on phytoplankton.

Great Pacific Garbage Patch

Large area of marine debris concentration.

Thermohaline circulation

Ocean circulation driven by temperature and salinity differences.

Upwelling

Process bringing nutrient-rich water to the surface.

Downwelling

Process where surface water sinks.

Gyres

Large circular ocean currents.