Saltwater Test Review: Key Concepts and Definitions

Ocean salinity

typically about 3.5%, which is equivalent to 35 parts per thousand (ppt).

Salinity of ice

Ice formed from salt water has much lower salinity than the surrounding water because most of the salt is excluded during freezing.

Areas of varying salinity

Regions with high evaporation rates like the Red Sea and the Persian Gulf, while lower salinity areas are found near river mouths and polar regions where freshwater input is higher.

Dissolved minerals in water

Collectively known as salts

CO2 and the ocean

CO2 dissolves in this place and forms carbonic acid, leading to ocean acidification which affects marine life and ecosystems.

Thermohaline circulation

Refers to the global ocean circulation driven by differences in temperature and salinity, causing significant temperature variations between surface and deep waters.

Density

A measure of mass per unit volume, typically measured using a hydrometer or densitometer.

Density variation causes

Caused by changes in temperature and salinity, with salinity being the most important factor.

Pycnocline

The layer in the ocean where the density gradient is greatest.

Spring tides

Occurs during full and new moons, when the sun, moon, and Earth align.

Neap tides

Occurs during quarter moons, when the sun and moon are at right angles to each other.

Flood tides

Rising water levels

Ebb tides

Falling water levels

Tidal flats

Coastal areas that are exposed during low tide and submerged during high tide.

Tidal range

The vertical difference between high and low tide.

Moon phases

Refers to the appearance of the moon as it orbits Earth, affecting the timing and amplitude of tides.

Rip currents

Strong, narrow currents moving away from shore

Fetch

The distance over water that wind blows in a constant direction

Prevailing winds

Winds that blow predominantly from a single direction.

Wave crests

The highest points of waves

Wave troughs

The lowest points of waves

Wave length

The horizontal distance between two crests or troughs

Wave period

The time it takes for a wave to pass a point

Motion of water molecules

Takes place in waves & is circular.

Plankton

Small and microscopic organisms drifting in the sea.

Epipelagic zone

Most animals live in this upper layer of the ocean because it receives sunlight, supporting photosynthesis and a high concentration of marine life.

Seaweed growth

Tends to grow in shallow, coastal waters where there is sufficient sunlight for photosynthesis.