Wave Action PDF

### Wave Action 1. **What is a wave?** A wave is a disturbance that transfers energy through matter or space, characterized by oscillations or vibrations about a rest position. 2. **How are waves formed?** Waves are formed primarily by the wind. When the wind blows over the surface of...

### Wave Action 1. **What is a wave?** A wave is a disturbance that transfers energy through matter or space, characterized by oscillations or vibrations about a rest position. 2. **How are waves formed?** Waves are formed primarily by the wind. When the wind blows over the surface of the water, it interacts with the water's surface, creating friction, which transfers energy to the water forming ripples. As these ripples gain energy and momentum, they develop into larger waves. 3. **What causes a wave to break?** A wave breaks when it moves into shallow water and the bottom of the wave interacts with the seafloor. As the wave's energy is compressed, it becomes steeper until the crest falls over, producing a breaking wave. 4. (a) **Constructive Wave**: A constructive wave is a type of wave that has a gentle slope, low frequency, and carries more sediment onshore, contributing to beach formation and positive sediment deposition. (b) *Diagram of a Constructive Wave*: - [Diagram Description]: A gentle wave with a long wavelength, featuring gradual rises to the crest and a slow descent to the trough. The wave's energy typically results in it being wider, with labeled sections indicating the crest and trough. (c) **Destructive Wave**: A destructive wave is a type of wave characterized by steeper slopes and higher energy, which erodes the coastline by pulling sediment back into the sea and causing the beach to narrow. (d) *Diagram of a Destructive Wave*: - [Diagram Description]: A steep wave with a shorter wavelength, featuring abrupt rises to the crest and a steep drop to the trough. The diagram would include labeled sections for the crest and trough. 5. - (a) **Crest of a wave**: The highest point of a wave. - (b) **Trough of a wave**: The lowest point between two waves. - (c) **Wave length**: The distance between two successive crests or troughs. - (d) **Wave height**: The vertical distance between the crest and the trough. 6. (a) When a wave breaks and the water runs up the beach this motion is called the **swash**. (b) The water that flows back down the beach to the sea is called the **backwash**. 7. Destructive waves with lots of energy, high energy waves/coastlines can be seen along the **east** and **south** coasts of Barbados. 8. (a) **Four ways by which a wave erodes the land**: - Hydraulic action - Abrasion - Attrition - Solution (b) **Descriptions**: - **Hydraulic action**: The force of water compressing air in cracks of rocks, causing them to break apart. - **Abrasion**: The scraping and wearing away of rock surfaces by sediment carried by waves. - **Attrition**: The breakdown of rocks into smaller particles as they collide with each other and the shore. - **Solution**: The chemical action of seawater dissolving soluble materials in rocks, leading to erosion. 9. *Diagram of cliffs and wave-cut platforms*: - [Annotated Diagram Description]: Draw a profile of a cliff with waves crashing against it. Label sections showing erosion (like the formation of caves, arches, and eventually, a wave-cut platform). 10. Describe **four ways by which waves transport eroded material**: - **Suspension**: Small particles are carried within the water column. - **Saltation**: Larger particles are bounced along the seabed. - **Traction**: Heavy materials are rolled along the seabed. - **Dissolution**: Soluble materials are dissolved and carried away in the water. 11. (a) **What is longshore drift?**: Longshore drift is the process by which sediment is transported along the coastline due to the angle of waves hitting the shore. (b) **Explain the process of longshore drift**: Longshore drift occurs when waves approach the shore at an angle, moving sediment up the beach at an angle. As the water recedes (backwash), it pulls sediment directly back down the beach, creating a zig-zag pattern of sediment movement along the shore. 12. (a) **What is a headland?**: A headland is a rocky protrusion into the sea, formed by the erosion of softer rock, leaving more resistant rock exposed. (b) **What is a bay?**: A bay is a coastal body of water partially surrounded by land, typically formed between two headlands where softer rock has been eroded. (c) **How are headlands and bays formed?**: They are formed through the erosion of coastal rocks, where softer rock is weathered away more quickly than harder rock, leading to the formation of extended points (headlands) and recessed areas (bays). ### Coral Reefs 1. (a) **Define the term ‘coral reef’**: A coral reef is a diverse underwater ecosystem made up of colonies of tiny animals called coral polyps, which build calcium carbonate structures. (b) **How are coral reefs formed?**: Coral reefs are formed by the accumulation of coral polyps that secrete calcium carbonate, building upwards over time, creating structures that provide habitat for numerous marine species. 2. (a) **Conditions necessary for coral reefs to thrive**: - Water temperature: Usually between 23-29°C. - Sunlight: Requires shallow, clear water for photosynthesis by symbiotic algae (zooxanthellae). - Salinity: Coral reefs thrive in warm, saline waters. - Clear and well-aerated water: Essential for the health of corals and their symbiotic partners. - Presence of beneficial algae and fish: Helps maintain the balance of the ecosystem. (b) **Negative impacts of conditions**: - **Muddy or turbid water**: Reduces light penetration, hindering photosynthesis, and can smother corals. - **Polluted water**: Nutrients from pollutants can lead to algal blooms that outcompete corals for resources and oxygen. 3. (a) **Fringing reef**: A coral reef that is directly attached to the shore or lies very close to it. (b) **Barrier reef**: A reef that is separated from the shore by a lagoon, typically wider than a fringing reef. (c) **Atoll**: A ring-shaped coral reef that encircles a lagoon, formed from the subsidence of volcanic islands. 4. **Four reasons why coral reefs are important to Caribbean countries**: - They provide habitat for a diverse range of marine life. - They protect coastlines from erosion and storm surges. - They support tourism and recreational activities, contributing to the economy. - They are sources of food and income for local communities. 5. **Five ways by which man’s actions can negatively impact coral reefs**: - Coastal development: Destruction of habitats when building resorts or infrastructure. - Overfishing: Reducing fish populations that maintain the reef ecosystem. - Pollution: Runoff from agriculture and urban areas can harm coral health. - Climate change: Elevated water temperatures and acidification threaten coral health. - Tourism impacts: Poorly managed tourism can lead to physical damage and pollution. 6. **Explain how climate change poses a major threat to coral reefs**: Climate change results in increased sea temperatures, which can cause coral bleaching—a stress response that expels the symbiotic algae, leading to a loss of color and nutrients. Additionally, ocean acidification, caused by higher CO2 levels, reduces corals’ ability to produce their calcium carbonate skeletons, diminishing reef structures over time.