THE OCEANS

ENDURING UNDERSTANDINGS Earth is an ocean planet.Earth is an ocean planet. 71% of Earth’s surface is covered by water. 71% of Earth’s surface is covered by water. The global ocean is the major contributor to the water cycle.The global ocean is the major contributor to the water cycle. The oceans store most of the thermal energy received from the sun.The oceans store most of the thermal energy received from the sun.

THE GLOBAL OCEAN The global ocean is divided into 5 major regions: the Pacific, Atlantic, Indian, Southern (or Antarctic) and Arctic oceans.The global ocean is divided into 5 major regions: the Pacific, Atlantic, Indian, Southern (or Antarctic) and Arctic oceans. Antarctic Ocean

HOW DID THE OCEANS FORM? Between 4.5 and 4 billion years ago, as the Earth cooled, water vapor began to condense and fall as rain.Between 4.5 and 4 billion years ago, as the Earth cooled, water vapor began to condense and fall as rain. The water vapor had accumulated from volcanic gases and ice from comets.The water vapor had accumulated from volcanic gases and ice from comets.

SALINITY Salinity is a measure of dissolved salts and solids in a given amount of liquid.Salinity is a measure of dissolved salts and solids in a given amount of liquid. Ocean salinity comes from minerals & rocks on land eroded and carried by streams to oceans.Ocean salinity comes from minerals & rocks on land eroded and carried by streams to oceans. Higher salinity occurs where evaporation is higher than input, freezing removes fresh water, areas of low river runoff, or mixing by currents is low.Higher salinity occurs where evaporation is higher than input, freezing removes fresh water, areas of low river runoff, or mixing by currents is low. The composition of the ocean salinity is 55% Cl, 30.6% Na, 7.7% Mg, 3.7% S, 1.2% Ca, 1.1% K and other solids. Most ocean salt is NaCl.The composition of the ocean salinity is 55% Cl, 30.6% Na, 7.7% Mg, 3.7% S, 1.2% Ca, 1.1% K and other solids. Most ocean salt is NaCl.

THE THERMOCLINE The thermocline is a layer of water extending from the surface zone to the deep zone where water temperature drops rapidly.The thermocline is a layer of water extending from the surface zone to the deep zone where water temperature drops rapidly. The temperature of the surface zone depends on the amount of thermal heating. The temperature of the deep zone is a relatively constant 2 o C throughout the global ocean.The temperature of the surface zone depends on the amount of thermal heating. The temperature of the deep zone is a relatively constant 2 o C throughout the global ocean.

THE WATER CYCLE The water cycle is the movement of water between the ocean and atmosphere by evaporation, condensation and precipitation.The water cycle is the movement of water between the ocean and atmosphere by evaporation, condensation and precipitation. The global ocean is the major contributor to the water cycle.The global ocean is the major contributor to the water cycle.

A GLOBAL THERMOSTAT Oceans store most of the thermal energy received from the sun.Oceans store most of the thermal energy received from the sun. The angle of the sun’s rays determines the amount of solar radiation absorbed. Rays strike high latitudes at low angles but strike the tropics at nearly 90 o.The angle of the sun’s rays determines the amount of solar radiation absorbed. Rays strike high latitudes at low angles but strike the tropics at nearly 90 o. Oceans store thermal energy because water has a high heat capacity.Oceans store thermal energy because water has a high heat capacity.

THE OCEAN FLOOR The continental margin is divided by depth and slope into the continental shelf, continental slope, continental rise, abyssal plain, mid-ocean ridges and rift valleys, with features such as seamounts and ocean trenches.The continental margin is divided by depth and slope into the continental shelf, continental slope, continental rise, abyssal plain, mid-ocean ridges and rift valleys, with features such as seamounts and ocean trenches. Scientists study the ocean surface and floor using sonar and satellites.Scientists study the ocean surface and floor using sonar and satellites.

LIFE IN THE OCEAN Plankton float in the water column, nekton swim under their own power and benthos live in or on the ocean floor.Plankton float in the water column, nekton swim under their own power and benthos live in or on the ocean floor.

OCEAN ZONES The benthic environment is the ecological zone where benthos live, divided by depth into the supralittoral, littoral, sublittoral, bathyal, abyssal and hadal zones. The pelagic environment is the water column divided into the neritic zone, the water above the continental margin, & the oceanic zone, the water of the open ocean. Most ocean life lives in the neritic zone. SHELF BREAK

SURFACE CURRENTS Surface currents are streams of water near the surface of the ocean controlled by global winds, the Coriolis Effect and continental deflections.Surface currents are streams of water near the surface of the ocean controlled by global winds, the Coriolis Effect and continental deflections. Currents distribute thermal energy stored by the ocean, keeping Earth’s climate mild.Currents distribute thermal energy stored by the ocean, keeping Earth’s climate mild. Surface currents affect climate by distributing thermal energy.Surface currents affect climate by distributing thermal energy.

EARTH’S SURFACE CURRENTS Currents flowing from poles toward the equator carry cold water. Currents flowing from the equator toward poles carry warm water.Currents flowing from poles toward the equator carry cold water. Currents flowing from the equator toward poles carry warm water.

THE CORIOLIS EFFECT Earth’s rotation causes wind and surface currents to curve to the right in the northern hemisphere and to the left in the southern hemisphere.Earth’s rotation causes wind and surface currents to curve to the right in the northern hemisphere and to the left in the southern hemisphere.

DEEP WATER CURRENTS Deep currents are driven by density differences determined by temperature and salinity, & flow from the poles toward the equator.Deep currents are driven by density differences determined by temperature and salinity, & flow from the poles toward the equator.

CIRCULATION OF DEEP & SURFACE CURRENTS

EFFECTS OF CURRENTS Upwelling is the rising of deep bottom water to the surface, carrying nutrients to the surface and replacing warm surface waters.Upwelling is the rising of deep bottom water to the surface, carrying nutrients to the surface and replacing warm surface waters. El Nino is the interruption of upwelling along the western coast of SA, and the spread of warm water into the Pacific. Temperature change and lack of nutrients greatly affect wildlife.El Nino is the interruption of upwelling along the western coast of SA, and the spread of warm water into the Pacific. Temperature change and lack of nutrients greatly affect wildlife.

SURFACE WAVES The size of waves is determined by: The strength of the windThe strength of the wind The length of time the wind blowsThe length of time the wind blows FetchFetch

PARTS OF A WAVE

WAVE PERIOD

WAVE FREQUENCY & WAVE SPEED Wave frequency is the number of waves that pass a stationary point in a given amount of time.Wave frequency is the number of waves that pass a stationary point in a given amount of time.

DEEP vs SHALLOW-WATER WAVES Deep-water waves become shallow-water waves when wave base touches the bottomDeep-water waves become shallow-water waves when wave base touches the bottom

MOON PHASES NEW MOON CRESCENT 1 ST QUARTER GIBBOUS FULL MOON GIBBOUS 3 RD QUARTER CRESCENT