Oceanography

Question 1

divergent plate boundry

Answer 1

2 plates drifting away from eachother

Question 2

transform plate boundry

Answer 2

2 plates sliding past eachother (lateral sliding)

Question 3

convergent plate boundry

Answer 3

1 plate goes underneath another

Question 4

isostacy

Answer 4

gravity and bouyancy act on earths outer layers to bring them closer together

Question 5

bathymetry

Answer 5

the measurement of ocean depths and the charting of the shape of the ocean floor

Question 6

ring of fire

Answer 6

a string of volcanoes around edge of pacific ocean, substantial seismic activity and earthquakes caused by plate tectonics

Question 7

ocean ridges

Answer 7

occupy 33% of total ocean floor area (continuosly spreading), sites of geological and biological importance due to deep sea thermal vents

Question 8

abyssal plains

Answer 8

gradients less than 0.05 deg, flattest ocean feature (only interrupted by seamounts) and are covered in deep layers of sediments

Question 9

sea mounts

Answer 9

most are ocean floor volcanoes (dont rise above sea level), slope angle as great as 25 deg

Question 10

guyots

Answer 10

flat topped seamounts planed off by wave erosion

Question 11

the hydrological cycle

Answer 11

the cycle of water through air/atmosphere, water and earth (water spends 7 days in clouds, 6.6 years in lakes and 3,060 years in the ocean)

Question 12

key properties that determine the chemical structure of the oceans

Answer 12

temperature, salinity, depth/pressure determine the density of seawater

Question 13

3 distinct zones of ocean temperature

Answer 13

1 - Surface zone (25-500m variable depth depends on mixing)
2 - Thermocline (200-1000m variable) rapid decrease in temp as surface heat diffuses down and advection of cool water
3 - Deep zone (below 1000m) stable temp around 1 deg C

Question 14

Stratification

Answer 14

Temp and salinity determines the density of water, ocean therefore made of density layers. This stratification is key in determining nutrient supply to surface, and hence phytoplankton distributions and blooms.

Question 15

warm tropical waters stratification

Answer 15

very stratified so nutrient depleted due to surface layers de-coupling from deep

Question 16

Polar waters stratification

Answer 16

Cool at surface so easier to pull water down from surface (denser), so less stratified

Question 17

important seawater nutrients for phytoplankton

Answer 17

• nitrogen as nitrate NO3- and ammonium NH4+
• phosphorus as phosphate (PO43-)
• silicon as silica SiO2).

Question 18

Effects of salinity

Answer 18

As salinity increases
Density increases
Boiling point is higher
Freezing point is lower

Question 19

what are ocean currents driven by

Answer 19

wind driven: generally surface currents.
Or can be part density driven: the global overturning circulation. Cold salty dense water produced at poles and sinks. There is a surface warm water flow. Most of the upwelling occurs in southern ocean. Thousand year timescale.

Question 20

wind driven currents

Answer 20

major wind belts
The major surface loops: link closely to wind patternts with continential barriers

Question 21

The gulf stream

Answer 21

The northerly loop of the north atlantic subtropical grye. About 4mph Carries warm water to the uk

Question 22

Atlantic circumpolar current

Answer 22

It is the only current that circumscribes the whole earth. Connects all the other ocean basics. Driven by poweful westerly wind belt: ultimitaly drives upwelling of global deep waters back to surface. Stormiest ocean.

Question 23

Pacific circulation

Answer 23

Two huge subtropical gryes dominate the pacific with a dominant equatorial countercurrent due to its size.

Question 24

The plastic vortex

Answer 24

The convergent flow in the north pacific grye is also known as plastic vortex bc of collection over time of masses of debri non bio degradable

Question 25

Equatorial flow

Answer 25

divergence and upwelling
Currents and winds drive vertical upwelling (as well as horiz flow) that replenishes surface nutrients to euphotic zone