Ocean Quiz 2

Salinity

The total amount of solid material dissolved in water, including dissolved gases but excluding dissolved organic substances

Origin and concentration of salinity

Typically about 3.5% (35 parts per thousand), 220 times saltier than freshwater

• come from runoff, eruptions, atmospheric gases, and the biological interactions of living organisms

Four major ions in seawater

• sodium

• chloride

• magnesium

• sulfate

Density variations with temp and salinity

direct effect on sanity: high → high

• more dissolved material so water tends to sink beneath lower-salinity water

inverse effect on temp: high → low

• has a greater influence than salinity bc temp varies more

Principle of constant proportions

the major dissolved constituents responsible for the salinity of seawater occur nearly everywhere in the ocean in exactly the same proportions, independent of salinity

• evidence of the ocean being well-mixed

Factors that affect salinity of coastal and surface waters

• freshwater input

• evaporation

• vertical and tidal mixing

• latitude and climate (lower in high-latitude, rainy regions)

Processes that decrease seawater salinity

Adding freshwater to the sea

• precipitation

• runoff

• icebergs melting

• sea ice melting

Processes that increase seawater salinity

Removing water from the ocean

• sea ice forming

• evaporation

Salinity variations with depth

Low-latitude regions:

• increased salinity at the surface

• increased depth, lower salinity

High-latitude regions:

• decreased salinity at the surface

• increased depth, higher salinity

Density variations with depth

Remains constant until about 300 meters bc of surface mixing

• increased density as you travel further down until 1000 meters

• constant density below 1000 meters

Halocline

layer of rapidly changing salinity with depth

• separate layers of different salinity in the ocean

Pycnocline

layer of rapidly changing density

Thermocline

layer of rapidly changing temperature

Energy from gas to solid

loss of energy and formation of intermolecular bonds

Energy from solid to gas

energy added to loosen (melting) and then overcome molecular attractions (vaporization)

Average salinity of the ocean

34.5 parts per thousand

Range of salinity in an estuary

freshwater from rivers meets salty ocean water, creating strong gradients

• brackish water

• 1-3% PPT

Plane of ecliptic

the surface connecting all points in Earth’s orbit

• earth’s rotation tilts at an angle of 23.5 degrees to it

Effect of Earth’s ecliptic on the climate

different hemispheres are tilted more directly toward or away from the Sun causing seasons

• seasonal changes in angle of the Sun create differences in the length of days and climate

Coriolis Effect

deflection of air and water as it flows north to south

• changes the intended path of a moving body

• causes moving objects on Earth to follow curved paths

Effect of Earth’s rotation on wind and water movement

Causes a curved appearance rather than traveling in a straight line

• Northern hemisphere: veers right

• Southern hemisphere: veers left

Difference between weather and climate

the conditions of the atmosphere at a specific time and place in opposed to the long-term average of weather in a region based on observations over many years

Relationship between air pressure and wind direction in cyclonic flow

air in high pressure zone sinks and rotates clockwise

Relationship between air pressure and wind direction in anticyclonic flow

air in a low pressure zone rises and rotates counterclockwise

Factors in the development of land breezes

• air over land cools at night

• cool, high-density air sinks

• high-pressure region around the land causes wind to blow toward the ocean

Factors in the development of sea breezes

• land heats the air

• warm, low-density air over the land rises

• a low-pressure region over the the land pulls cool air over the ocean toward the land

Hurricane

topical cyclones in North and South America

Typhoon

tropical cyclones in western North Pacific Ocean

Cyclone

tropical cyclones in the Indian Ocean

Tropical cyclones

huge rotating masses of low pressure characterized by strong winds and torrential rain

Wind-driven ocean currents

move water horizontally and occur primarily in the ocean’s surface waters

Density-driven ocean currents

low temperature and high salinity surface waters sink beneath the surface, spreading slowly

Gyre

large circular-moving loops of water driven by the major wind belts of the world

Formation of gyre

wind belts push surface water, creating broad currents

• when winds oppose each other, water is driven in a circular pattern within the ocean basin

Five subtropical gyres

• North Pacific Gyre

• South Pacific Gyre

• North Atlantic Gyre

• South Atlantic Gyre

• Indian Ocean Gyre (southern hemisphere)

Coriolis effect and western boundary currents in gyres

equatorial currents reach the western portion of ocean basins and must turn

• deflected by Coriolis away from the equator

Physical characteristics of western boundary currents

• carry warm water to higher latitudes

• narrow

• deep

• fast

Physical characteristics of eastern boundary currents

• very wide

• shallow

• slow

• small volume

• carry cold water

Ekman transport

transport of surface water set in motion by surface winds and the spiral

• 90 degrees right or left (depending on the hemisphere)

Ekman spiral

balance between the Coriolis effect where objects curve from their intended path and frictional events reduce the water’s speed with depth

Geostrophic current

when subtropical convergence flowing downhill in response to gravity and the Coriolis effect opposing gravity deflecting water in a curved path add to the hill

• factors balancing move in a circular path around the hill (path of ideal geostrophic flow)

Western intensification of subtropical gyres

Upwelling

Downwelling

Causes of upwelling

Where upwelling would occur

El Niño-Southern Oscillation (ENSO)

Effects of El Niño on global weather patterns

Thermohaline circulation

Process of bottom/deep water formation