Coral reefs

Question 1

Formation of coral reefs:

Answer 1

polyps attach themselves to a hard surface in shallow seas where there is sufficient light for growth
these polyps exude calcium carbonate creating a ‘stony’ exterior/skeleton
these exoskeletons join together and allow for more polyps to attach themselves
polyps have an algae growing inside called Zooxanthellae which gives the polyp o2 and sugars from photosynthesis whist the algae gets co2 and shelter

Question 2

how diverse are coral reefs?

Answer 2

richest and most biodiverse ecosystems on earth, home to over 25% of all marine species despite occupying less than 1% of the ocean

Question 3

how old are coral reefs?

Answer 3

several millions of years old

Question 4

how fast do coral reefs grow?

Answer 4

2.5-60cm a year making them the largest & oldest structures on earth

Question 5

why are coral reefs important?

Answer 5

they are carbon sinks
more than 240million people use them for food food and an income
they have an est global value of $30bn annually
they are a natural protection from storm surges, tsunami waves and coastal erosion
they have medicinal qualities

Question 6

describe the distribution of coral reefs?

Answer 6

centered on the pacific ocean
found almost exclusively between the tropics
the coral triangle consists of the Philippians, Malaysia, Singapore, Indonesia

Question 7

conditions required for coral growth:

Answer 7

temperatures between 18-25degrees
salinity - between 32-34psu
ALKALINE - ph of 8
air - exposure kills, grows up to low tide
water opacity - clear, sediment clogs feeding structures
light - cannot grow below 25m, photosynthesis

Question 8

types of coral reefs:

Answer 8

fringing
barrier
atolls

Question 9

what are fringing reefs?

Answer 9

surrounding an island

Question 10

what are barrier reefs?

Answer 10

following a rise in sea level or drop in the level of land, separated from land by lagoons

Question 11

what are atoll reefs?

Answer 11

rings of coral protected with a lagoon, following further sea level rise or land drop

Question 12

evidence that coral reefs are fragile ecosystems:

Answer 12

since 1930, more than 30% of the world’s coral reefs have died with an estimate that 90% could disappear

Question 13

how can climate change be a threat to coral reefs?

Answer 13

ocean acidification
rising sea levels
increase in strength and re-occurrence of storm patterns
altered ocean currents, temp regimes
changes in precipitation - reduce salinity

Question 14

how is pollution a threat to coral reefs?

Answer 14

eutrophication and algal blooms from agricultural sewage discharge
sedimentation from deforestation of development clogs feeding structures

Question 15

how is physical damage a threat to coral reefs?

Answer 15

fishing and tourism
coral mining for bricks or road fill
land reclamation

Question 16

how is human activity a threat to coral reefs?

Answer 16

an increase in coral disease
overfishing reducing the biodiversity

Question 17

Coral reef management example:

Answer 17

St Lucia

Question 18

What management plan is in place in St Lucia?

Answer 18

Soufriere Marine Management Area scheme (SMMA)

Question 19

Why were management strategies put in place in St Lucia?

Answer 19

A 1998 survey showed that 65% of coral reefs in the Caribbean are in danger

Question 20

How was it ensured that all people stuck to the management plans in St Lucia?

Answer 20

All decisions and planning involved all stakeholders, a holistic approach ensured that all grievances were aired and a suitable compromise was created to guarantee everyone would stick to the plan

Question 21

What did the SMMA plans in St Lucia involve for the coral reef?

Answer 21

+ all of the coral reefs in the area were designated Marine Reserves – only diving, snorkelling and glass-bottomed boats allowed.
+ provided loans for fishermen to buy boats and equipment so they could fish further out at sea, where they would not damage the coral.
+ used clear coastal zoning to make recreational, fishing and protected areas.
+ there were bans on damaging fishing methods and the fishermen were taught less damaging fishing techniques.

Question 22

Where is the Andros Barrier Reef?

Answer 22

The Bahamas

Question 23

key facts about the Andros Barrier Reef?

Answer 23

200km long
home to 164 species of fish and coral, including the red snapper, reef shark and green turtle

Question 24

What are threats are there to the biodiversity of the Andros Barrier Reef? (6)

Answer 24

+ Overfishing: commercial fishing is reducing the number of fish, off balance in the food chain
+ Harvesting goods: sponges are being removed to sell
+ Tourism: tourists damage by touching and standing on the coral
+ Land-based pollution: chemicals from
agriculture or sewage enters rivers, Which clouds the water and reduces the sunlight,
restricting photosynthesis.
+ Marine-based pollution: oil and chemicals released by boats.
+ Climate change: higher temperatures cause corals stress, causing them to expel zooxanthellae.

Question 25

What value is the Andros Barrier Reef to humans and the planet? (6)

Answer 25

+ Tourism: recreational activities and the
the sun makes it particularly attractive. This bringing in over $150 million a year.
+ Fish: attract the tourists, when caught and sold the Lobster and snapper earn locals millions of dollars
+ Breeding grounds: shelter for fish to breed, especially in mangrove forests
+ Coastal protection: reduces coastal erosion and flooding
+ Medicine: chemicals released by coral species may help cure various
+Research: this is one of the healthiest in the world and so scientists use it for research