Coastal habitats

Question 1

6 conditions for coral reefs

Answer 1

shallow water 25m deep
low turbidity(clear water)
salinity
sunlight(for photosynthesis)
strong wave action(supplies O2)
warm water(23°C - 25°C)

Question 2

5 threats for coral reefs

Answer 2

high temperature
- corals get rid of algae(bleaching)
siltation
- sediment blocks sunlight
acidic pH
parrot fish, crown of thorns and sea star
oil/fuels

Question 3

Polyps

Answer 3

millions of them create a coral reef
they are tiny animals that deposit calcium carbonate
have symbiotic relationship with algae
provide shelter, carbon dioxide, nitrogen and phosphorous(compounds needed for photosynthesis)

Question 4

Algae in coral reefs

Answer 4

Zooxanthellae
they photosynthesise, providing oxygen, glucose and energy(corals use to make proteins, fats, CaCO3 and carbs)
have symbiotic relationship with polyps

Question 5

Coral reef value

Answer 5

large biodiversity
protect coastline
rich fish stocks
tourism

Question 6

7 Mangrove values

Answer 6

protect coastline from erosion and flooding
large biodiversity- nurseries for fish
restores economy
traps silt and helps create new land
reduces water pollution
carbon sink
provide timber for fuel

Question 7

4 conditions for Mangroves

Answer 7

high temperature
- grow only 30° latitude of the equator
exposure to too much oxygen is harmful
high salinity
intertidal zone

Question 8

4 Mangrove threats

Answer 8

overharvesting
fresh water
pollution from river system
coral reef destruction

Question 9

Mangrove adaptations

Answer 9

halophytic trees
- salt filtering and excretion
snorkel roots to intake oxygen
tangled roots

Question 10

5 Salt marsh value

Answer 10

collectors of silt and organic matter
carbon sink
protection against erosion and flooding
nursery areas for fish and crustaceans
deliver nutrients to coastal waters

Question 11

Threats to salt marsh

Answer 11

sea level rise
human disturbance
industrial and agricultural pollution
land reclamation for ports
coastal squeeze due to anthropological structures
sea defences

Question 12

Formation of salt marsh

Answer 12

mud and silt are deposited along a sheltered part of the coastline
deposition builds up so mud breaks surface to form mudflats
they are colonised by halophytic plants

Question 13

Pioneer plants of salt marsh

Answer 13

glasswort and cordgrass
halophytic
- have salt-excreting glands instead of photosynthesising stems

Question 14

Upper lower marsh vegetation

Answer 14

Pioneer species accumulate sediment
Flocculation of meandering creeks help build up the marsh
Sea purslane grows

Question 15

Upper marsh vegetation

Answer 15

More sediment and decaying vegetation improves the humus content of the muddy soil
vegetation succession occurs
- sea lavender, sea aster and sea couch grass
can tolerate submergence from extreme high tides

Question 16

Climax salt marsh vegetation

Answer 16

Elderberry

Oak and ash trees

Question 17

Sand dune formation

-embryo dunes

Answer 17

beach dries out at low tide and sand is blown to the back of the beach
Sand accumulates and embryo dunes are formed
Pioneer species like saltwort, Lyme grass and sea couch grass
- halophytic and xerophytic (arid tolerant because of the lack of moisture)

Question 18

Yellow dune formation

Answer 18

Pioneer species trap sediment, forming yellow dunes
they are succeeded by less resilient species
- dominantly marram grass

Question 19

Marram grass adaptations

Answer 19

have large deep-tap roots which spread(rhizomes)
curling leaves
- cope with fast draining sand soil(reduce evaporation)

Question 20

Grey dune formation

Answer 20

More sediment is trapped and decaying vegetation improves humus content
pH becomes lower due to humic acid and more moisture
colonised by heather, cord grass, marram grass, red fescue and sea spurge

Question 21

Dune heath

Answer 21

Surface of soil is leached by rainwater and washes out the basic minerals which reduces the pH even more
colonised by gorse, bracken, heather and brambles

Question 22

Vegetation climax of sand dune

Answer 22

oak, birch, ash and pine trees

Question 23

9 users of coastal areas

Answer 23

1. local residents
2. employers
3. farmers
4. port authorities
5. fishermen
6. transport companies
7. tourists
8. developers

Question 24

conditions for formation of sand dunes

Answer 24

1. wide beach and large quantity of sand
2. prevailing wind is onshore(from sea to shore)
3. suitable location for land to accumulate

Question 25

conditions of sand dune

Answer 25

1. high salinity
2. lack of moisture as sand drains quickly
3. high wind
4. submergence by wind-blown sand