AICE Marine Science AS Level Chapter 2.3 Key Terms

Terms with definition

tide

the periodic rise and fall of the surface of the ocean resulting from the gravitational pull of the moon and the sun

semi-diurnal

occurring twice daily

diurnal

occurring daily

tidal range

the difference in height between the high-tide mark and the low-tide mark over the course of the day; also called the tidal amplitude

tidal surge

the coastal flooding of an abnormally high seawater level associated with low pressure weather systems; also called a storm surge

spring tide

a tide that occurs when the Sun and Moon are aligned, causing the largest tidal range

neap tide

a tide that occurs when the Moon and Sun are at right angles from each other, causing the smallest tidal range

current

a continuous physical movement of water caused by wind or density

Coriolis effect

a force that results from the Earth’s rotation that causes objects or particles in motion to deflect to the right in the Northern Hemisphere and to the left in the Southern Hemisphere

thermohaline circulation

large-scale ocean circulation caused by density differences due to temperature and salinity changes in the world’s oceans

global ocean conveyor belt

constantly moving systems of deep-ocean water driven by thermohaline circulation

downwelling

the downward movement of water in the sea due to density differences

upwelling

the movement of cold, nutrient-rich water from deep in the ocean to the surface

El Nino

a warm current that develops off the coast of Ecuador around December, which can cause widespread death within local food chains

La Nina

a cold current that develops off the coast of Ecuador and spreads across the Pacific, reducing sea surface temperatures for extended periods of time

Humboldt Current

a coldwater current with low salinity levels that flows north along the western coast of South America; also called the Peru current