Case study: Andros Barrier Reef

Where is the Andros Barrier Reef?

Bahamas, off the southeast coast of Florida, USA

How long is the Andros Barrier Reef?

200km

Why is the Andros Barrier Reef important?

Biodiversity → One of the most biodiverse ecosystems, with over 164 species of fish & coral

Scientific research → An ideal place for scientific research as it is one of the healthiest & 3rd most extensive coral reefs

Coastal protection → Barrier reefs help protect coastlines from powerful storm surges

Fishing → Corals provide an ideal breeding ground for fish, fish are then sold at local & export markets

Tourism → Accounts for over $150 million of tourism revenue a year as many people visit to do snorkeling, diving & deep sea fishing

How is the Andros Barrier Reef under threat from human activity?

Over-fishing

Pollution

Climate change

Over-fishing

Intensive fishing can deplete fish stocks & cause an imbalance in the ecosystem

Trawling nets, anchors & outboard motors can cause physical damage to corals

The commercial harvesting of sponges can also affect the ecosystem balance

Pollution

Agricultural chemicals & silt that is discharged from rivers can reduce sunlight penetration & therefore reduce the rate of photosynthesis in zooxanthellae

Oil & chemicals released from boats can trigger a stress reaction in coral which results in coral ‘bleaching’

This is because the coral evicts it zooxanthellae, causing it to lose its colour & become translucent

Climate change

Climate change can cause higher water temperatures which then triggers a stress reaction in coral

This leads to the ‘bleaching’ of coral as its zooxanthellae has been evicted, leaving the coral translucent

Eventually the coral dies because it gets 80% of its energy from zooxanthellae

In 2040, coral bleaching is expected to be a major issue in the Andros Barrier Reef

How is the Andros Barrier Reef sustainably managed?

→ The Andros West Side National Park protects over 50% of the Andros Island from further development, aiming to balance economic activity with conservation & tourism

→ The North & South Marine Park have regulated fishing, anchoring & scuba diving

→ The Crab Replenishment Reserve aims to provide a sustainable crab population

→ A coral nursery has been established in the Exuma Cays Land & Sea Park, protecting threatened species & re-introducing them to the reef

Explain the interdependence between the climate, plants and animals in your chosen coral reef.

• The Andros Barrier Reef is a coral reef in the Bahamas off the coast of Florida. The warm sea temperatures of 23 to 29 *C encourage organisms to grow.

• Located near the equator means there is sufficient sunlight that penetrates the clear water so that the phytoplankton can photosynthesise.

• Phytoplankton are plants and act as primary producers for the rest of the coral reef food chain. Zooplankton and fish feed on the plankton. Other species are carnivores, such as the reef shark, they feed on fish.

• The fish also use the shelter of the reef for safety and breeding. The fish in turn excrete nitrogen from their gills. This provides nutrients to help the reef plant life to grow and thrive.