Geography - Case study: the Andros Barrier reef

Ecosystem of the planet and Andros Barrier Reef Case Study

[Ecosystems] Ecosystem

A natural area formed by the interaction of living (biotic) organisms and the non‑living (abiotic) elements of the environment.

[Ecosystems] Biotic factor

A living component of an ecosystem (plants, animals, micro‑organisms).

[Ecosystems] Abiotic factor

A non‑living component of an ecosystem (soil, water, light, temperature).

[Ecosystems] Fauna

The animals of an ecosystem.

[Ecosystems] Flora

The plants of an ecosystem.

[Ecosystems] Interdependence

The mutual reliance of living organisms and non‑living elements within an ecosystem.

[Ecosystems] Biomass

The total mass of living organisms in an ecosystem.

[Ecosystems] Litter

The layer of dead organic material on the ground (such as fallen leaves, humus).

[Ecosystems] Nutrient cycling

The process through which minerals and nutrients are recycled between organisms, soil and water within an ecosystem.

[Ecosystems] Symbiotic relationship

A relationship in which two different organisms live in close association, often mutually beneficial.

[Ecosystems] Zooxanthellae

Plant‑like algae that live inside coral tissue and supply nutrients to the coral.

[Ecosystems] Deforestation

The removal or clearing of forest vegetation, typically for timber or to make way for agriculture, mining or other land uses.

[Ecosystems] Indigenous tribe

Traditional groups who have lived in a region for generations, often with minimal historical external influence.

[Ecosystems] Over‑fishing

The removal of fish from an ecosystem at a rate faster than the species can reproduce, causing disruption.

[Biomes] Biome

A large‑scale ecosystem that covers vast regions, characterised by a particular climate, soils, plants and animals.

[Biomes] Tropical rainforest

A hot, humid biome with high rainfall (>2000 mm), tall evergreen trees and great biodiversity.

[Biomes] Coral reef

A marine biome in shallow, warm (≥18 °C) and clear water, where coral animals, algae and diverse fish species live.

[Biomes] Tropical grassland (savanna)

A hot biome with low to moderate rainfall and a long dry season, dominated by grasses and adapted trees like baobabs.

[Biomes] Hot desert

A biome found typically between 5° and 30° N/S of the Equator, with very low rainfall (≈40 mm) and plants adapted to scarce water.

[Biomes] Temperate grassland

A biome found between 40° and 60° N/S, with cold winters, hot summers and dominant grasses rather than trees.

[Biomes] Temperate forest

A biome found in mid‑latitudes (40°-60° N/S) with four distinct seasons, high rainfall (750-1500 mm) and deciduous trees.

[Biomes] Polar region

A biome around the poles with very cold temperatures, low rainfall (

[Processes: Rainforest] Nutrient cycle

In tropical rainforests the warm, wet climate means dead material is rapidly decomposed, making nutrients quickly available for new plant growth.

[Processes: Rainforest] Water cycle

In tropical rainforests evapotranspiration leads to convectional rainfall, supporting vegetation growth.

[Processes: Rainforest] Vegetation layers

In tropical rainforests there are several layers: emergents → canopy → under‑canopy → shrub layer.

[Processes: Rainforest] Carbon cycle

Trees absorb carbon dioxide for photosynthesis and store carbon; when trees are burned the carbon is released back into the atmosphere.

[Case Study: Peruvian Amazon] Overview

The rainforest covers ~60% of Peru; ideal hot and wet climate; high biodiversity.

[Case Study: Peruvian Amazon] Biodiversity

Home to 44% of all bird species and 63% of all mammals (worldwide range).

[Case Study: Peruvian Amazon] Threats

Including illegal logging, mining, oil extraction, agriculture and highways.

[Case Study: Peruvian Amazon] Management

Strategies include national parks, indigenous land rights and conservation corridors.

[Processes: Coral Reef] Conditions for coral reef formation

Warm (23-25 °C), shallow, clear water necessary for coral growth and photosynthetic algae.

[Processes: Coral Reef] Symbiosis

The coral and zooxanthellae exchange nutrients and waste: algae photosynthesise and feed the coral, coral supplies waste nutrients.

[Processes: Coral Reef] Nutrient sources

In coral reefs nutrients come from zooplankton, dissolved nitrogen and fish waste.

[Processes: Coral Reef] Threats

Threats include over‑fishing, pollution, tourism damage (divers), climate change (bleaching).

[Processes: Coral Reef] Management

Marine reserves, national parks, coral nurseries and controlled fishing help protect reefs.

[Case Study: Andros Barrier Reef] Overview

The third‑largest reef system (~200 km long) off the Bahamas.

[Case Study: Andros Barrier Reef] Biodiversity

Over 164 species of fish and coral including snapper, rock lobster and green turtle.

[Case Study: Andros Barrier Reef] Value

Provides coastal protection, fish breeding grounds, tourism income (≈$150 m/year) and scientific research.

[Case Study: Andros Barrier Reef] Threats

Over‑fishing, pollution and damage from boats and anchors.

[Case Study: Andros Barrier Reef] Management

Use of national parks, reserves and coral restoration projects to protect the reef.