WEEK 8 - Beaches + Coastal Flashcards
1
Q
Why do people go to the beach for comfort?
A
- It’s an easy and cheap way to cool down on hot days.
- Keeps kids busy during summer.
2
Q
Why do people go to the beach for fun?-
A
- It’s a natural place to relax and play.
- People go to swim, build sandcastles, play games, etc.
3
Q
What is the “Zen factor” of going to the beach?
A
- Makes people feel like part of something bigger.
- You experience the power of nature (waves, wind, sand).
- Safe way to feel vulnerable to natural forces.
4
Q
How does the beach connect us to nature?
A
- People explore nature’s beauty and power.
- The environment shows how land and water interact.
5
Q
What are the sociological reasons people go to the beach?
A
- People act more freely (e.g. relaxed dress code).
- They show off or try to impress others (attract mates, show confidence).
6
Q
What is the deeper cultural meaning of going to the beach?
A
- Sociologist Dr. William Kornblum calls it a “great mammalian migration.”
- People are naturally drawn to the coast in large numbers every year.
7
Q
What allows beaches to exist in the first place?
A
- Geological processes like erosion, sediment transport, and wave action.
- Without these, there would be no beaches to gather at.
8
Q
What is a coastal system?
A
- A coastal system includes all the zones near a shore.
- Each zone is defined by how close it is to land and what processes affect it.
9
Q
What are the main zones (parts) of a beach/coastal system?
A
- Offshore zone
- Shoreface zone
- Lower shoreface
- Upper shoreface (includes surf zone)
- Foreshore zone (includes swash zone)
- Backshore zone (includes dunes and storm beach face)
10
Q
What are the offshore and shoreface zones?
A
- Both are always underwater (below low tide mark).
- Offshore = deeper, farther from shore.
- Shoreface = closer to shore, shallower.
11
Q
What is the fairweather wave base?
A
- It’s the depth where normal waves can no longer move water.
- Separates the offshore zone from the shoreface zone.
12
Q
What happens in the offshore zone?
A
- Lies below wave base → not affected by normal waves.
- Only fine sediment settles here (unless storms bring coarse sediment).
13
Q
What happens in the lower shoreface zone?
A
- Constantly stirred by normal wave motion.
- Has a gentle slope due to back-and-forth wave movement.
14
Q
What happens in the upper shoreface zone?
A
- Waves begin to break due to friction with the seabed.
- The breaking wave forms the surf zone.
- Energy loss here allows sand bars to form.
15
Q
What is the foreshore zone?
A
- Also called the swash zone (between high and low tide).
- Where swash (water going up beach) and backwash (water going back to sea) occur.
16
Q
What happens in the foreshore zone?
A
- Swash slows and can deposit sediment.
- Backwash pulls some sediment back into the upper shoreface.
17
Q
What is the backshore zone?
A
- Found beyond the foreshore.
- Features sand dunes built by wind and waves.
- Can also receive sediment from storm waves (a storm beach face can be seen well away from the normal beach face).
18
Q
Where does beach sediment come from?
A
Erosional areas, where material is worn away from the land and transported by water
- Most on beaches along continental coastlines is delivered by rivers
19
Q
Do all shorelines have the same type of activity?
A
- No
- Some shorelines are erosional (where material is removed), and others are depositional (where material is deposited, like on sandy beaches).
20
Q
Shoreline Activity (Two Types)
A
- Erosional
- Depositional
21
Q
What is Erosional and Depositional Shoreline Activity?
A
- Erosional shoreline: Material is taken away (e.g., cliffs wearing down).
- Depositional shoreline: Material is added (e.g., sandy beaches forming from sediment buildup).
22
Q
What kind of shorelines supply beach sediment?
A
Shorelines with exposed bedrock and strong wave activity are major sources of beach sediment
23
Q
What are source rocks?
A
Source rocks are the original rocks that get broken down by erosion to form sediment.
24
Q
Where do the minerals in beach sediment come from?
A
- They usually come from eroded coastal rocks
- The minerals in the beach sediment match the source rocks
25
What does it mean when beach sediment "matches" the source rock?
The sediment has the same minerals as the nearby rocks it came from.
26
What’s an example of sediment matching source rock?
Black sand on beaches (like in Hawaii) comes from basalt, a type of volcanic rock nearby
27
What happens when a river enters a large body of water (like an ocean)?
The river's flow slows down, causing sediment to be deposited at the river mouth, forming a delta.
28
What is a delta?
- Forms when a river carries sediment to the ocean or lake
- The water slows down and drops off the sediment
- The shape is often like a fan or triangle, where the river splits into smaller channels
Example: Mississippi Delta
29
What is Beach Drift?
Beach drift is the movement of sediment along a beach in a zig-zag pattern.
30
How Does Beach Drift Work?
- The swash (water moving up the beach) comes at an angle, carrying sand and pebbles obliquely.
- The backwash (water moving back into the sea) flows straight back at a right angle.
31
How Far Can Beach Drift Transport Sediment?
Beach drift can move sand and pebbles hundreds to thousands of meters per day.
32
What is Longshore Drift?
Longshore drift is the movement of sediment along the shore by a current flowing parallel to the coast
33
What Causes Longshore Drift?
- Waves hit the shore at an angle.
- Water flows back straight out.
- This creates a current (longshore current) that moves sediment sideways along the shore.
34
Where Does Longshore Drift Happen?
It occurs in the shoreface zone, where waves are constantly moving water and sediment
35
What is a Rip Current?
- A strong, narrow current that flows from the beach back out to sea.
- It forms when water from breaking waves escapes through low areas (like gaps in sandbars).
36
How Do Rip Currents Form?
- Waves push water toward shore.
- That water needs to go back out.
- It flows back through the easiest path—like dips in sandbars—creating a fast-moving stream: a rip current.
37
What Should You Do if Caught in a Rip Current?
- Don’t swim against it!
- Swim parallel to the shore to escape the narrow current.
- Then swim back to land safely.
38
What is a Rip Channel?
A gap in sandbars where water flows back to sea—this is where rip currents form
39
How to Spot a Rip Channel (From the Air or Beach)
Look for areas where:
- Waves are smaller or breaking less
- Water looks darker or smoother
- Foam or debris is flowing out to sea
40
What is an Undertow?
- Undertow happens when water pushed onto the beach by waves can’t escape as a rip current.
- Instead, it flows back to the sea underneath the waves
- It's a gentle current
- It pulls sand and water, not people (usually not dangerous to swimmers).
41
Rip Current vs Undertow
Rip current:
- Fast surface flow of water heading away from shore.
- Can pull swimmers out to sea (dangerous).
Undertow:
- Weaker flow underneath the surface, pulling water back after a wave.
- Most “undertow drownings” are actually due to people getting pulled out by a rip current, not undertow
- Mostly moves water and sand, not people, but can cause a loss of balance in shallow waters
42
What is a reef?
- A reef is a natural structure found in shallow ocean areas.
- Made from the skeletons of marine animals.
43
What are reefs made of?
- Built from calcium carbonate skeletons.
- These skeletons can be in the form of aragonite or calcite.
44
Who builds reefs?
- Today’s reefs are mostly made by corals.
- In the past, sponges and bizarre clams were also reef-builders.
45
Why are coral reefs called “rainforests of the sea”?
- Because they have a high diversity of living creatures.
- Many species live in and form the reef.
46
What are coral polyps?
- Individual coral animals that build coral reefs.
- Each polyp lives in a small skeleton it creates.
47
Why are coral reefs so colourful?
- Their bright colours come from microscopic algae in coral tissues.
- Different colours absorb different wavelengths of light.
48
Where do large reefs form?
- In warm seawater areas of the tropics.
- Warm water helps reef growth because calcium carbonate (reef skeleton material) is easier to precipitate in warm water than in cold water.
49
How do algae help reef-building animals?
- Algae live in their tissues and remove CO₂,
- This lowers acidity, helping animals make calcium carbonate skeletons.
50
Conditions Necessary for Reef Development
1. Little clastic sediment (avoids smothering reef builders)
2. Low nutrient levels (prevents overgrowth of algae)
3. Shallow water (allows sunlight for algae in corals)
51
Reef Zones (3 of them)
1. Reef crest: Dominated by encrusting forms (strong wave action)
2. Deeper water zones: Dominated by delicate branching forms (gentler water movement)
3. Lagoon: Protected area behind the reef from strong waves
52
An Atoll
A ring-shaped reef with a central lagoon formed by coral growth around a sinking volcanic island
Example: Likely inspiration for the setting of Gilligan's Island
53
How an Atoll Forms
- Initial Stage: A reef forms around a volcanic island
- Island Sinks: The volcanic island sinks due to cooling and densification of the crust
- Reef Growth: The reef continues to grow upward as the island sinks
- Final Result: The reef becomes a ring-shaped structure around a central lagoon
54
About Bikini Atoll
- Location: Central Pacific
- Significance: Famous nuclear testing site
- First Post-War Test: Site of the first post-war nuclear bomb test
55
Dark History of Bikini Atoll
- Treatment of Aboriginal Population: Bikini Atoll has a dark history regarding the treatment of its original population
56
Bikini Swimsuit Origin
- Fashion Designer: Louis Réard
- Inspiration: The "new swimsuit for the atomic age" was named the bikini after the Bikini Atoll
