Motion in the Ocean - Marine Bio

Coriolis effect

Northern hemisphere = clockwise (R)

Southern hemisphere = counterclockwise (L)

Deflection of winds/ water due to earth’s rotation

Gyres

Large currents produced by global wind patterns and the Coriolis effect

Marine Benefits of Currents

• Migration

• Food distribution

• Oxygenation of ocean water

• Distribution of heat

Marine Benefits of Tides

• planktonic distribution

• Reproductive cycles

• Food distribution

• Oxygenation

Crest

Top of wave

Wave

The undulation of oceanic fluid from a disturbance that moves along the surface of the water.

Trough

The bottom part of a wave.

Wave height

The vertical distance measured between the crest and the trough.

Wavelength

The horizontal distance between two consecutive crests or troughs.

White cap

Foam formed by strong winds blowing off the top of a wave.

Breaker

A wave that collapses and loses its shape when it approaches shallow water.

Fetch

The span of open water over which wind blows to generate waves.

Swells

Rolling waves with rounder crests and troughs formed of longer waves.

Tsunami

A long ocean wave produced by earthquakes or other seismic disturbances on the seafloor, also known as a harbor wave.

Tides

The rhythmic rising and lowering of ocean water caused by the gravitational attraction of the Sun and Moon.

High tide

deep

Low tide

Shallow

Diurnal tide

1 high, 1 low per day

Ex: Gulf of Mexico

Semi-diurnal tide

2 high, 2 low per day

Easy to predict, equal in height

Ex: East Coast

Mixed tide

2 high, 2 low per day

Tides not equal in height

Hard to predict

Tidal currents

Horizontal water movements where water periodically flows in one direction and then reverses in the opposite direction.

Flood current

Tide on way “in”, toward the coast

Ebb current

The movement of water traveling out away from the coast as the water level recedes. “Out”

Slack water

The period of calm with no current movement between flood and ebb

Tidal Range

Vertical distance between high and low tides

Spring tide

Greatest tidal range

Neap tide

least tidal range

Rip tide

Caused by two converging currents over an a regular surface