Seawater chemical and physical structure - 4

Question 1

What is insolation?

Answer 1

The amount of sunlight striking Earth’s surface

Question 2

Why does ocean surface temperature strongly correlate with latitude?

Answer 2

Because insolation decreases with distance from the equator

Question 3

What is an isotherm?

Answer 3

Contour lines of equal temperature

Question 4

What direction do isotherms trend?

Answer 4

Generally, east-west except where deflected by ocean currents

Question 5

What do ocean currents do?

Answer 5

Transport warm water poleward on the western side of ocean basins and transport cold water equatorword on the eastern side of ocean basins

Question 6

What is a thermocline?

Answer 6

A layer in which water temperature and density change rapidly with depth

Question 7

How does the thermocline in polar and temperate oceans?

Answer 7

Temperate oceans have a seasonal thermocline whereas polar oceans do not

Question 8

Where are highest ocean salinities found? Why?

Answer 8

Between 20º and 30º N and S … due to high evaporation rates compared to annual precipitation rates

Question 9

Where is lowest ocean salinity found? Why?

Answer 9

equator and poleward of 30º … much lower evaporation rates relative to precipitation rates

Question 10

What is a halocline?

Answer 10

A zone of rapid change in salinity with depth

Question 11

Where is water stratification most pronounced?

Answer 11

Between 40ºN and 40ºS

Question 12

The density of seawater is a function of …

Answer 12

Temperature, Salinity, Pressure

Question 13

What is the pycnocline?

Answer 13

A layer in the water column where water density changes rapidly with depth

Question 14

What 3 layers can we separate the water column into?

Answer 14

• Surface layer
• Pycnocline
• Deep layer

Question 15

How thick is the surface layer?

Answer 15

100m

Question 16

What % of the ocean volume is found in the surface layer?

Answer 16

2%

Question 17

Why does the surface layer vary seasonally?

Answer 17

Because it is in contact with the atmosphere

Question 18

What % of the ocean volume does the pycnocline represent?

Answer 18

18%

Question 19

In low latitudes, the pycnocline coincides with …

Answer 19

A thermocline

Question 20

In mid-latitudes, the pycnocline coincides with …

Answer 20

A halocline

Question 21

What % of the deep layer does the deep layer represent?

Answer 21

80%

Question 22

What is solubility?

Answer 22

The ability of something to be dissolved and go into solution

Question 23

What is saturation value?

Answer 23

The equilibrium amount of gas dissolved in water at a given temperature, salinity and pressure

Question 24

Solubility and saturation value for gases in seawater …

Answer 24

increases as temperate and salinity decreases and pressure increases

Question 25

Where is there abundant oxygen in the ocean?

Answer 25

In the surface and deep layer

Question 26

Why is oxygen abundant in the surface layer?

Answer 26

• Photosynthesis

- Contact with atmosphere

Question 27

Where does the oxygen minimum layer occur?

Answer 27

At about 150-1,500 metres

Question 28

What does the oxygen minimum layer coincide with?

Answer 28

The Pycnocline

Question 29

Why is the oxygen minimum layer located where it is?

Answer 29

• Ample food in the pycnocline, attracting organisms which respire and use oxygen
• Decay of uneaten material consuming oxygen
• Density differences prevent mixing therefore prevent oxygen input

Question 30

Why is deep water rich in oxygen?

Answer 30

• Originated at the surface
• Low consumption due to fewer organisms
• Lack of bacterial decomposition

Question 31

What controls the acidity of sea water?

Answer 31

Carbon dioxide (dissolved to produce carbonic acid which then release H+ ions)

Question 32

What are some sinks of CO2 in the oceans?

Answer 32

Photosynthesis and construction of carbonate shells

Question 33

What are some sources of CO2 in the oceans?

Answer 33

Respiration and bacterial decomposition

Question 34

What is a buffer?

Answer 34

A substance that prevents large shifts in pH

Question 35

What range of salinity is observed in the oceans?

Answer 35

32-37 ppm