1b Horizontal and vertical variations in temperature and salinity

Question 1

1. Salinity

Answer 1

• Definition: The concentration of dissolved salts in seawater, usually measured in parts per thousand (ppt).
• Importance: Affects water density and ocean circulation.

Question 2

2. Halocline

Answer 2

• Definition: A layer in the ocean where salinity changes rapidly with depth.
• Importance: Acts as a barrier to mixing between different water layers.

Question 3

3. Water Density

Answer 3

Definition: Mass per unit volume of seawater, affected by temperature and salinity.
• Importance: Drives ocean currents and layering (stratification).

Question 4

4. Specific Heat Capacity

Answer 4

• Definition: The amount of heat energy required to raise the temperature of 1 kg of a substance by 1°C.
• Importance: Water has a high specific heat capacity, meaning it heats and cools slowly, regulating climate.

Question 5

5. Thermocline

Answer 5

• Definition: A layer in the ocean where temperature decreases rapidly with depth.
• Importance: Separates warm surface water from cold deep water.

Question 6

6. Argo Project

Answer 6

• Definition: A global program using autonomous floats to measure temperature and salinity in the ocean.
• Importance: Provides data to understand climate change and ocean circulation.

Question 7

7. Thermohaline Circulation (Ocean Conveyor Belt)

Answer 7

• Definition: A global ocean circulation system driven by temperature and salinity differences.
• Importance: Distributes heat and regulates climate.

Question 8

8. Gyres

Answer 8

• Definition: Large-scale circular ocean currents driven by wind and the Coriolis effect.
• Importance: Transport heat, nutrients, and marine debris.

Question 9

9. Coriolis Effect

Answer 9

• Definition: The deflection of moving objects (e.g., winds and currents) due to Earth’s rotation.
• Importance: Causes ocean currents to curve right in the Northern Hemisphere and left in the Southern Hemisphere.

Question 10

1. Horizontal Temperature Variation (Across the Surface)

Answer 10

• Equator vs Poles: Warmer at the equator due to direct sunlight, cooler at the poles due to lower solar intensity.
• Coastal vs Open Ocean: Coastal waters can be cooler/warmer due to land influence and currents.
• Ocean Currents: Warm currents (e.g., Gulf Stream) heat regions, cold currents (e.g., Labrador Current) cool regions.

Question 11

2. Vertical Temperature Variation (With Depth)

Answer 11

Surface Layer: Warmest due to solar heating and mixing by wind.
• Thermocline: A layer where temperature drops rapidly with depth.
• Deep Ocean: Cold and stable, with little variation below ~1,000m.

Question 12

1. Horizontal Salinity Variation (Across the Surface)

Answer 12

• Equator vs Poles: Higher at mid-latitudes due to evaporation, lower at the equator and poles due to rainfall and ice melt.
• Rivers and Ice Melt: Coastal areas near large rivers (e.g., Amazon) have lower salinity. Melting ice lowers salinity in polar regions.
• Ocean Currents: Some currents bring more saline water, others dilute it.

Question 13

2. Vertical Salinity Variation (With Depth)

Answer 13

• Surface Layer: Variable due to evaporation and freshwater input (rain, rivers).
• Halocline: A layer where salinity changes rapidly with depth.
• Deep Ocean: More uniform, but varies based on water mass origins.