Coasts Flashcards

Question

What are 5 pressures that threaten coral reefs?

Answer 1

OVERCOLLECTION OF CORALS (Philippines) - For personal & commercial use - Weakens corals & disrupts coral ecosystem, making them vulnerable to threats in FISHING METHODS (Philippines, Indonesia) Dynamite/cyanide fishing: - Stuns fish, destroys reef habitat Spearfishing: (Belize, Bonaire, Netherlands) - Selective depletion of certain fish pop. disrupting food chains - Spearfishing of parrotfish feeds on algae, affects coral growth RECREATIONAL USES Expansion of coastal resorts (Sri Lanka) - Sewage discharge in seawater, oil spills, stressing corals Anchoring boats damaging corals COASTAL DEVELOPMENTS Land reclamation (Japan, SG) - Rocks & sediment dumped into reefs, suffocating coral reefs Expansion of resorts & urban housing (Florida) - Increased waste discharge into sea, suffocating corals ``` CLIMATE CHANGE Rapid changes to sea temp & levels - Changes too rapid, corals cannot adapt Coral bleaching, (turns white) - Corals expel the algae, loss of algae causes it to bleach due to warmer temp ```

Answer 2

- Sediments provide nutrients essential for growth - Thrive on sheltered coasts, river estuaries, muddy, waterlogged land - Allow mud & plant litter to accumulate due to low energy waves - Low-lying areas, subjected to strong effects of tides & sediment changes

Answer 3

AVICENNIA & SONNERATIA ● Pencil-like shaped aerial roots, which takes in oxygen directly from air when they are not submerged, to cope with waterlogged coast RHIZOPHORA ● Prop roots anchor plant firmly into ground to avoid being uprooted by strong waves BRUGUIERA ● Kneed roots trap soil in between them, providing themselves with more nutrients for growth ● Fruits are BUOYANT, float away to germinate, also JAVELIN-SHAPED, to pierce mud to grow ● Salt-tolerant, excrete excess salt on underside of leaves

Answer 4

HABITAT FOR MARINE ANIMALS - Habitat & breeding ground for marine animals, (Oysters, barnacles anchor on mangrove roots) - Food for marine animals (Shrimps, crustaceans forage for food in sediments trapped between kneed roots) STABILISE SHORELINES - Dense network of mangrove roots, (Allows build up of sediments, protecting coasts from erosion by tides, tsunamis, storms) PROTECTING COASTS FROM STORMS (same as previous) - Mangrove roots absorb wave energy, -> slows flow of water due to friction, protects coasts from erosion

Answer 5

COASTAL DEVELOPMENTS - Land reclamation for housing, industry, recreation (Caribbean) - Mangroves cleared from environment, water pollution RISING SEA LEVELS - Climate change accelerates rising sea lvls & severity of storms (Gulf of Thailand) - Mangroves cannot grow further inland despite sea level, due to rising competition with human activities CONVERSION TO OTHER LAND USES - Flat, well watered mangrove areas cleared for paddy fields & shrimp farms (Thailand, Vietnam) - Coasts now vulnerable to erosion CLEARING OF MANGROVES FOR RESOURCES (lower income/tech economy) - Cleared for fuel wood, charcoal (Indonesia) - Reduces fish breeding grounds, coasts vulnerable to storms & erosion

Answer 6

1. LIMIT DAMAGING ACTIVITIES (Port Philip, Australia) - Damaging activities, eg. blasting coral reefs/clearing mangroves for fish farms/dumping waste - x Banning is costly & ineffective, dine through aligning demands of people with nature of coastal environment - Sand dunes fenced off, access path to beach built [Port Philip] Sand dunes were trampled on, left exposed to wind erosion & destroyed Houses behind dunes vulnerable to partly buried by sand +ve Allows coastal environment to recover -ve Fences make beach unattractive, blocks access to parts of beach 2. PROTECTING COASTAL RESOURCES (Goat Island Marine Reserve, New Zealand) - Prevents resources being depleted or exploited - Fish are protected (vulnerable to overfishing + dynamite fishing) [Goat Island Marine Park] Zones marked off to prevent commercial fishing, enforced by local management +ve Tourist spot, Allows fish to breed & thrive -ve Establishments strongly opposed by fishermen denied their source of food & livelihood/resources 3. RESTRICT DEVELOPMENTS IN AREAS PRONE TO NATURAL DISASTERS - Relocate structures from vulnerable areas - Restrict developments in vulnerable areas - Coastal defences are closely monitored +ve People still live in coastal areas due to natural resources/food/materials Provides many services, docks/ports/housing/recreation -ve People spend more on construction & maintenance Have to be prepared for emergencies & evacuations

Answer 7

Beach nourishment (Cape May Point, USA, New Jersey) Planting vegetation & stabilising dunes (Triton Place, West Australia) Encouraging growth of coral reefs (Maldives) Large steel rods supplied w low voltage solar power, facilitates coral growth, sustains large variety of coral & marine animals

Answer 8

1. BEACH NOURISHMENT (Cape May Point, NJ) - Sand from external source to replenish eroded beaches +ve: Forms a wide sandy beach + slows erosion -ve: Costly, time consuming, suffocates corals 2. PLANTING VEGETATION/ STABILISING DUNES - Sand dunes stabilised by planting grass (Triton Place, West Australia) - Mangroves planted, stabilise coastline, absorb wave energy Dense mangrove roots trap sediments & holds soil tgt +ve Roots of plants anchor sand, less erosion Dense mangrove roots protect coasts from erosion -ve Takes years to grow, trampling & vandalism Costly to build fences & paths to prevent trampling 3. ENCOURAGE GROWTH OF CORAL REEFS (Maldives) - Artificial reefs created by placing LONG LASTING STEEL & CONCRETE allow coral & marine creatures to colonise these materials functioning as natural reefs +ve Corals weaken wave energy, less erosion, breeding ground for fish [Maldives] Large steel rods supplied w low voltage solar power, facilitates coral growth, sustains large variety of coral & marine animals -ve: Encouraging coral reefs not easy, sites have to be surveyed for proper growth Takes very long, 20-30 years, coast vulnerable to erosion

Answer 9

Seawalls +ve: Isle of Wight, UK -ve: Drake's Island, England Gabions +ve: (Andaman Coast, Thailand) Tetrapods (Hokkaido, Japan) Breakwaters +ve: (ECP, SG) -ve: (Portland Harbour, England) Groynes -ve: Sandy Hook, NJ

Answer 10

Concrete walls, parallel to coasts +ve: (Isle of Wight, UK) Absorb wave energy, reflect incoming waves, less coastal erosion -ve: (Drake's Island, England) Costly & requires constant repair Initial success, walls still erode at base & eventually collapse

Answer 11

Wire cages of rocks along coast +ve: (Andaman Coast Thailand) Weaken wave energy, less coastal erosion, allow water to filter thru, no strong backwash -ve: (ECP) Unsightly, easily corroded & costly to maintain, vulnerable to vandalism

Answer 12

- Four pronged concrete structures placed in interlocking pattern along coast +ve: (Hokkaido, Japan) Weaken wave energy, allow water to filter thru, no powerful backwash, less erosion They are precasted, hence quick building & implementation -ve: Costly, Unsightly, Dangerous, Alter ocean currents & disrupts natural cycles of erosion & deposition

Answer 13

- PARALLEL to coasts or one end attached to coast +ve: (Almeria, Spain) Break force of oncoming waves Creates zone of calm water for deposition of sediments behind to form beaches/sheltered coasts -ve: (Portland Harbour, England) Costly & unsightly Uneven protection, areas away from breakwater still eroded [Erosion & flooding problems, affecting properties, beaches, communication infrastructure, Portland Habour]

Answer 14

- Low walls perpendicular to shore +ve: Retain sediments on updrift side, transported by longshore drift Absorb energy of waves, less erosion Sustain & extend beaches -ve: (Sandy Hook, NJ) - Costly to maintain, unsightly - Coast of downdrift side not protected, no new deposition of sediments Longshore drift erodes unprotected side of beach

Answer 15

Limit damaging activities (Port Phillips, Aus) Protect coastal resources (Goat island marine reserve, NZ) Restrict development in prone to natural hazard areas (USA FEMA)

Coasts Flashcards

(39 cards)