Coasts gateway 2

Question 1

why are coastal areas being used for fisheries and aquaculture and example

Answer 1

-demand for fish increases, large areas of the oceans are overfished so coastal areas are valuable

• Ca Mau, Vietnam is the nation shrimp production centre but they cut down 60,000 hectares of mangroves.
• This left Vietnam’s coastline more vulnerable to coastal erosion and storms.
• However, the areas cleared from mangrove forests are favourable for shrimp production as it is already waterlogged and the remaining mangroves protect the coastline from storms and coastal flooding.
• The land is also fertile as it contains minerals as the aerial roots of mangroves trap sediments.
• Shrimp culture business, Thailand.
• It protects the fertile mangrove forests which stretches along the coastline.
• Areas cleared are converted into shrimp ponds and mangrove reforestation areas
• Farmers benefit from the business by earning a income and they play a part in mangrove reforestation and conservation, thus benefitting the environment

Question 2

Coastal areas for housing and transportation

example
who uses it and why
description

Answer 2

• fishermen, located close to their source of income
• houses are stilts on water, use boats for transportation
• Kukup, Malaysia
• Air Masin is a village in Kukup with a stilt house community
• fresh fish and marine products are sold at these farms
• boats are used by locals and ferrys are available for visitors to visit Kukup

Question 3

Coastal areas for tourism and recreation

example
why
description

Answer 3

• economic benefits. there are more job opportunities, leading to an increase in income
• offers a range of relaxing and rejuvenating activities to promote tourism (eg spas, resorts, theme parks)
• Sentosa, Singapore maximised the use of the waterfront by building its hotel, museum and marine life park there.
• 19 million visitors in 2011 which was a 600% increase from 2003
• more tourists means more developments and more attractions

Question 4

coral reef ecosystems

Answer 4

• located at the sea bed of shallow waters
• made up of coral polyps
• when coral polyps die, new polyps grow in its place. Calcium carbonate skeletons accumulate as limestone

Question 5

distribution of coral reefs

Answer 5

• mostly found between the topic of cancer and tropic of capricorn
• southeast asia as the highest area and biodiversity of coral reefs

Question 6

Environmental conditions for coral reef growth

5

Answer 6

1. Level of salinity and oxygen content
   - require average sea salinity of 34-37 parts per thousand
   - moderate water movement to ensure coral receive sufficient oxygen
2. sediments (BAD)
   - sediments suffocate living corals
3. Sea surface temperature
   - require a minimum sea surface temp of not lower than 17-18 degrees celcius, hence corals are mostly found in the tropics
   - will not grow if temp is too high
4. heat is unfavourable
5. amount of sunlight and water turbidity
   - found in clear saline water of 10-60m deep to allow sufficient sunlight to penetrate, triggering algae photosynthesis
   - turbidity(level of murkiness) should be low enough to allow sufficient sunlight to penetrate

Question 7

Value of coral reefs

economic, habitat for marine life, coastal protection

Answer 7

1. economic value
   - coral reefs are a breeding ground for many species of fish
   - community depends on fish for food and jobs
   - tourism depends on them for activities like snorkelling or scuba diving
2. habitat for marine life
   - smaller fish that live in coral polyps are food for bigger fish
   - some fish evade predators by hiding in coral polyps
3. coastal protection
   - coral reefs absorb wave energy, thus protecting the adjacent land mass from erosion
   - in severe storms, coral reefs may be severely damaged. As recovery takes a long time, the coast are be more vulnerable during this time

Question 8

Pressures that threaten coral reefs

5

Answer 8

• development of coastal areas, 75% of world’s corals are threatened, 95% of corals in southeast asia are threatened
  1. overcollection of corals weakens and disrupts the coral ecosystem resulting in corals being more vulnerable to threats. Eg, Philippines
  2. Fishing methods. Blast fishing (Philippines) destroys coral reef habitats and coral reefs. Spear fishing (The Netherlands), the selective fishing disrupts the food chain
  3. Recreational use of coast. Used for tourism, expansion of coastal resorts, anchoring of boats. There is more waste deposited in the sea, oil spills pollute waters and stress corals, anchors from boats damage corals. Eg. Sri Lanka
  4. Coastal development. Reclamation and expansion of land (Japan) and the expansion of coastal resorts and urban housing results in more waste deposited in the sea. This suffocates corals and destroys them
  5. climate change. There is a rapid increase of temp and sea level and corals cannot adapt fast enough resulting in coral bleaching. Eg Philippines

Question 9

mangrove ecosystems (general)

Answer 9

grow in tidal mud on sheltered coasts and are home to many plants and animals

Question 10

Distribution of mangroves

Answer 10

• found at the coasts

- majority found at tropical coastlines, between the tropic of cancer and tropic of capricorn

Question 11

Environmental conditions affecting growth

Answer 11

• sheltered coasts where there is muddy and waterlogged land. They live in saline water and oxygen-deficient soil of tidal environment
• the low wave energy causes sediments like mud or plant litter to be trapped in the roots. This provides nutrients
• The mangroves are subjected to strong effects of the tidal environment or sediment changes
• Mangroves are salt-tolerant so they excrete excess salt, some species do it through the underside of their leaves

Question 12

Mangrove roots, fruits

Answer 12

• aerial roots help the trees to breathe and take in oxygen. They more mostly found in Southeast asia (eg sg) and have a pencil like shape
• prop roots anchor the tree firmly to the ground and prevent it from being uprooted or swept away in strong winds or waves
• kneed roots trap soil between roots and prevent the tree from being uprooted
• the fruits are javelin shaped to pierce the soft mud and germinate
• the fruits are buoyant so that they can be carried to other parts of the coast to germinate

Question 13

Value of mangroves

Answer 13

1. stabilise shorelines
   - dense network of roots absorbs wave energy and this slows down the flow of water. Sediments that were washed up on rivers and coasts now build up among mangrove roots
2. protects coastal environment from erosion from tides, storm waves, tsunamis
   - dense network of roots absorbs wave energy and the speed of waves is reduced due to friction. This reduced the impact of storms on coastal environments
   - 2004 Indian ocean tsunami, coastal areas with mangroves were less badly affected then those without mangroves
3. habitat for marine life
   - anchor on the hard surfaces of aerial roots
   - forage for food in muddy sediments
   - breed in nearby waters

2006, Study by United Nations Environment Programme report showed that the value of mangroves to an economy was between US$200,000 and US$900,000 per square kilometre This is from the protection of beaches and fish, provision of building materials, improved water quality, used for tourism and recreational activities

Question 14

Pressures on mangroves

4

Answer 14

• since the 1980s, 3.6 million hectares of mangroves have been cut down (approx 20% of all mangroves)
  1. Clearing of mangroves for fuel, food, and charcoal (eg Indonesia)
• especially in areas with low technology and low income
• fish breeding ground decreases and coastal environments are more vulnerable to storms
  2. Conversion of land for other uses (eg Vietnam)
• flat, well-watered land is cleared for paddy fields and shrimp farms
• Mangroves are cleared and the coast is more vulnerable to storms
  3. Development of coastal areas (Caribbean Islands)
• land is reclaimed for housing, industry and recreational uses
• as mangroves largely disappear from the environment, the water becomes more polluted due to human activities
  4. Climate change (eg thailand)
• rising temperatures and rising sea levels occur
• difficult for mangroves to grow further inland and they have to compete with human activities such as housing