A Beach Littoral Cell

Summary

This educational video explores coastal processes, focusing on longshore drift and nearshore circulation cells. It explains how sediment moves along beaches due to wave action, tides, and currents, emphasizing the interplay between sediment deposition and erosion. The video illustrates the influence of coastal topography and the distinction between passive and active margins on sediment dynamics. By examining these interactions, viewers gain insights into the formation and evolution of coastal environments, highlighting the importance of these processes in geomorphology and oceanography.

Takeaways

• 😀 Nearshore circulation cells are areas where the ocean interacts with the land, characterized by sediment movement and energy exchange.
• 🌊 Longshore drift refers to the movement of sediment along the coastline due to waves approaching at an angle.
• 🏖️ The beach profile is influenced by the balance between sediment deposition (constructive processes) and erosion (destructive processes).
• 🌅 Swash and backwash are essential processes; swash moves water up the beach while backwash returns it to the ocean, influencing sediment dynamics.
• 💧 Sediment is transported in two forms: suspended load (carried within the water) and bed load (pushed along the sea floor).
• 🏔️ Coastal geomorphology, including features like headlands, affects wave refraction and sediment transport patterns.
• 🌀 Rip currents are strong water flows moving away from the shore, which can transport sediment and impact coastal processes.
• 📏 The size and shape of the coastline and the continental shelf influence the dynamics of nearshore circulation and sediment movement.
• 📉 A sediment budget is crucial for maintaining beach health, as it balances the input and output of sediment in coastal systems.
• 🌍 Environmental factors such as climate, seasonality, and human activities significantly impact coastal erosion and deposition processes.

Q & A

What is the primary focus of the coastal processes video?

The video focuses on how oceans and large lakes interact with land, specifically examining longshore drift, nearshore circulation cells, and sediment movement along beaches.

What is a nearshore circulation cell?

A nearshore circulation cell is an area where sediment is circulated due to the interactions between tides, waves, and currents in the coastal zone.

What types of sediment are primarily discussed in the video?

The video discusses various types of sediment including sand, pebbles, gravel, clay, and silt, which are influenced by weathering and erosion processes.

How do rivers contribute to sediment transport to the ocean?

Rivers contribute approximately 90% of the sediment that is transported to the ocean, linking terrestrial erosion processes with marine sediment dynamics.

What are the differences between bed load and suspended load?

Bed load consists of sediments that are pushed along the ocean floor by currents, while suspended load refers to sediments held in the water column and moved with the flow of water.

What is longshore drift and how does it occur?

Longshore drift is the movement of sediment parallel to the coastline, caused by waves approaching at an angle, which results in the deposition and erosion of materials along the beach.

What is the significance of swash and backwash in coastal processes?

Swash and backwash are crucial for sediment dynamics as they dictate how much material is deposited on the beach and how much is eroded back into the ocean.

How do wave energy and coastal topography affect sediment movement?

Higher wave energy can increase erosion and deposition, while coastal topography features like headlands and coves can affect wave refraction, influencing sediment transport patterns.

What factors contribute to the balance between deposition and erosion on beaches?

The balance between deposition and erosion is influenced by wave energy, seasonal variations, and the characteristics of the beach, such as its slope and sediment supply.

What are some coastal features that can result from longshore drift?

Longshore drift can lead to the formation of coastal features such as spits, barrier islands, and changes in beach morphology.