13 - Oceans and Earth System Interrelationships

Question 1

Define:

oceanography

Answer 1

The scientific study of oceans and their properties.

Oceanography explores physical, chemical, biological, and geological aspects of oceans, explaining their role in climate, ecosystems, and Earth’s processes.

Question 2

Explain:

What are the main physical properties of ocean water?

Answer 2

• Temperature
• Salinity
• Density
• Pressure

Temperature: Affects the heat distribution in the ocean and influences marine life and weather patterns.

Salinity: Determines the concentration of dissolved salts, impacting water buoyancy and marine ecosystems.

Density: Dictates water movement and layering, essential for ocean currents and nutrient cycling.

Pressure: Increases with depth, affecting marine organisms and underwater exploration.

Question 3

Explain:

What are the layers of the ocean water column?

Answer 3

• Epipelagic Zone
• Mesopelagic Zone
• Bathypelagic Zone
• Abyssopelagic Zone
• Hadalpelagic Zone

Epipelagic Zone: The sunlit surface layer, home to most marine life.

Mesopelagic Zone: The twilight zone with limited light, home to diverse deep-sea species.

Bathypelagic Zone: The dark zone, where no sunlight reaches, inhabited by adapted organisms.

Abyssopelagic Zone: The near-freezing layer with high pressure, supporting specialized life.

Hadalpelagic Zone: The deepest trenches with extreme conditions and unique ecosystems.

Question 4

Explain:

Why does ocean water have salinity?

Answer 4

It comes from dissolved salts, mainly from rocks and volcanic activity.

Salinity in ocean water is primarily due to dissolved salts from rock weathering and volcanic eruptions. Evaporation increases salinity by concentrating salts, while freshwater from rivers, rain, and melting ice reduces it.

Question 5

True or False:

Denser ocean water is colder and saltier.

Answer 5

True

Dense water, created by cold temperatures and high salinity, sinks and drives deep ocean currents, redistributing heat across the planet.

Question 6

Explain:

Why is water denser at lower temperatures?

Answer 6

Cold water molecules are more tightly packed, increasing density.

This is why cold, dense water sinks, driving deep ocean currents.

Question 7

Define:

ocean circulation

Answer 7

The large-scale movement of water within the oceans.

Ocean circulation plays a vital role in redistributing heat, transporting nutrients, and exchanging gases. This process helps regulate Earth’s climate, sustain marine ecosystems, and connect surface and deep ocean layers.

Question 8

Explain:

How does the Coriolis effect influence ocean currents?

Answer 8

It deflects currents based on hemisphere direction.

The Coriolis effect, caused by Earth’s rotation, deflects currents to the right in the Northern Hemisphere and to the left in the Southern Hemisphere. Its strength increases with proximity to the poles and impacts global ocean circulation.

Question 9

Explain:

What are the main types of ocean currents?

Answer 9

• Surface Currents
• Deep Currents
• Upwelling Currents

Surface Currents: These are driven by wind and move water across the ocean’s surface.

Deep Currents: These are driven by temperature and salinity, circulating water at great depths.

Upwelling Currents: These are responsible for bringing nutrient-rich water from the deep to the surface.

Question 10

Explain:

What are the characteristics of ocean waves?

Answer 10

• Crest
• Trough
• Wavelength
• Wave Height
• Wave Period

Crest: The highest point of a wave.

Trough: The lowest point of a wave.

Wavelength: The distance between two consecutive crests or troughs.

Wave Height: The vertical distance between the crest and the trough.

Wave Period: The time it takes for two consecutive crests to pass a fixed point.

Question 11

Define:

tidal range

Answer 11

The difference in height between high and low tides.

Tidal ranges vary due to the Moon’s position, geography, and ocean depth.

Question 12

Explain:

Why do tides occur?

Answer 12

The Moon and Sun’s gravitational pull causes water movement on Earth.

The gravitational forces of the Moon and Sun, combined with Earth’s rotation, create the regular rise and fall of tides.

Question 13

True or False:

Spring tides happen when the Sun, Moon, and Earth align.

Answer 13

True

Spring tides occur during full and new moons, resulting in the highest high tides and the lowest low tides due to the combined gravitational pull of the Sun and Moon.

Question 14

Fill in the blank:

Waves are primarily generated by ______.

Answer 14

wind

Wave size depends on wind speed, duration, and the distance it travels.

Question 15

Define:

coastal erosion

Answer 15

The wearing away of land by waves, currents, and tides.

Coastal erosion shapes coastlines and can endanger habitats and infrastructure.

Question 16

Explain:

What are the main causes of island formation?

Answer 16

• Volcanic Activity
• Coral Reef Growth
• Tectonic Movements

Volcanic Activity: Creates islands when magma erupts and solidifies above the ocean surface.

Coral Reef Growth: Forms islands as coral builds up over time, often around submerged land.

Tectonic Movements: Uplifts land masses to create islands or exposes underwater terrain.

Question 17

Explain:

How do tectonic forces shape ocean basins?

Answer 17

They create mid-ocean ridges, trenches, and rift valleys.

These features drive seafloor spreading and subduction processes.

Question 18

Define:

ocean acidification

Answer 18

The decrease in ocean pH due to carbon dioxide absorption.

Acidification threatens marine life, especially organisms with calcium carbonate shells.

Question 19

Identify:

What are the major dissolved gases in the ocean?

Answer 19

• Oxygen
• Carbon Dioxide
• Nitrogen

Oxygen: Supports respiration in marine life.

Carbon Dioxide: Regulates the carbon cycle.

Nitrogen: Aids nutrient cycling in the ocean.

Question 20

Explain:

Why is salinity higher in some parts of the ocean?

Answer 20

Higher evaporation and lower freshwater input increase salinity.

Salinity increases in regions with high evaporation rates and limited freshwater input, such as the tropics. Evaporation removes water but leaves salts behind, while freshwater from rivers or rain dilutes salinity in other areas.

Question 21

Identify:

What are the primary ions in seawater?

Answer 21

• Sodium
• Chloride

These ions make up the majority of dissolved salts in seawater.

Question 22

True or False:

Nutrient levels are most concentrated in deep ocean waters.

Answer 22

True

Nutrient levels are most concentrated in deep ocean waters due to the decomposition of organic matter and limited uptake by organisms at these depths.

Question 23

Explain:

What are the three main Earth systems that interact in the water cycle?

Answer 23

1. Hydrosphere
2. Atmosphere
3. Biosphere

Hydrosphere: Includes all water on Earth, such as oceans, rivers, and groundwater.

Atmosphere: Involves the air and weather systems that transport water as vapor.

Biosphere: Consists of living organisms that influence and depend on water.

Question 24

Explain:

Why is gas exchange between the hydrosphere and atmosphere important?

Answer 24

It regulates oxygen and carbon dioxide for life and climate balance.

Oceans act as a carbon sink by absorbing CO₂ and releasing O₂, playing a key role in Earth’s carbon cycle and stabilizing the global climate.

Question 25

# Explain: How do volcanoes **affect** the **hydrosphere** and **atmosphere**?

Answer 25

They release gases like **water vapor** and **CO₂**. ## Footnote These gases contribute to *rain*, *climate changes*, and *enrich* oceans with nutrients from ash deposits.

Question 26

# Explain: Why are **coral reefs** called **rainforests of the sea**?

Answer 26

They **host diverse species**, offering **food** and **shelter**. ## Footnote *Coral reefs* support 25% of marine species while covering less than 1% of the ocean floor.

Question 27

# True or False: Coral reefs **contribute** to **gas exchange** in the oceans.

Answer 27

True ## Footnote Coral reefs play a significant role in ocean gas exchange by **absorbing** CO₂ during photosynthesis and **releasing** oxygen.

Question 28

# Define: extreme environment

Answer 28

An area with **conditions** that **challenge survival**. ## Footnote Such conditions include *high pressure*, *extreme temperatures*, or *scarce resources*, found in places like deep oceans, deserts, and polar regions.

Question 29

# Identify: What are **two examples** of **extreme environments** in the hydrosphere?

Answer 29

1. Deep Ocean Trenches 2. Polar Ice Caps ## Footnote **Deep Ocean Trenches**: Deep areas with high pressure and no sunlight, home to adapted organisms. **Polar Ice Caps**: Frozen regions with extreme cold and unique ecosystems.

Question 30

# Explain: How does the **atmosphere** **affect** **life** in polar regions?

Answer 30

It regulates **temperatures** and **wind patterns**. ## Footnote These factors shape *ice distribution* and *trap heat*, supporting limited biodiversity in polar regions.

Question 31

# Define: chemosynthesis

Answer 31

Biological process where certain **organisms produce organic compounds using energy derived from inorganic chemical reactions**, rather than from sunlight. ## Footnote Chemosynthesis is commonly found in environments where sunlight is absent, such as **deep-sea hydrothermal vents**, cold seeps. and underground caves.

Question 32

# Define: hydrothermal vent

Answer 32

A **fissure** in the seafloor where **heated water** and **minerals** erupt. ## Footnote These vents support unique ecosystems relying on **chemosynthesis** instead of sunlight.

Question 33

# Explain: How do changes in the **atmosphere** affect **coral reefs**?

Answer 33

Increased CO₂ **harms** coral reefs. ## Footnote Atmospheric CO₂ causes *ocean acidification*, weakening coral skeletons and harming ecosystems.

Question 34

# Explain: What are **three ways** human activities impact the hydrosphere?

Answer 34

1. Pollution 2. Overfishing 3. Dams ## Footnote **Pollution**: Harms water quality and marine life with plastics and chemicals. **Overfishing**: Reduces fish populations and disrupts ecosystems. **Dams**: Changes water flow, impacting sediments and habitats.