Oceans on the Edge

• Study of one marine ecosystem that is under threat – coral reefs

• Disruption to marine food webs – overfishing

• Impact of climate change on the marine environment

• A local scale case study – CEBU, Philippines i.e. the issues, causes and management strategies

Coral Reefs

Coral reefs are often referred to as the rainforests of the oceans because they are so biodiverse.

Coral reefs are warm, clear, shallow ocean habitats that are rich in life.

The reef's massive structure is formed from coral polyps, tiny animals that live in colonies; when coral polyps die, they leave behind a hard, stony, branching structure made of limestone.

The coral provides shelter for many animals in this complex habitat, including sponges, fish (e.g. blacktip reef sharks, groupers, clown fish, eels, parrotfish, snapper, and scorpion fish), jellyfish, anemones, sea stars, crustaceans (like crabs, shrimp, and lobsters), turtles, sea snakes, snails, and mollusks (like octopuses and clams). Birds also feast on coral reef animals.

Coral reefs develop in shallow, warm water, usually near land, and mostly in the tropics; coral prefer temperatures between 24-26 °C and depths not exceeding 25 metres so that light can penetrate. The water must also be clear and free from sediment.

There are coral reefs off the eastern coast of Africa, off the southern coast of India, in the Red Sea, and off the coasts of northeast and northwest Australia and on to Polynesia.

There are also coral reefs off the coast of Florida, the Caribbean and Brazil.

Coral Reefs are amazingly bio-diverse - They have an enormous range of species of flora and fauna

Coral polyps live on and in the limestone structures that make up the reef

Fish off all kinds live from the nutrient rich seas in and around the corals

It a scuba divers paradise – but the corals are extremely delicate and may be easily damaged

What amazing colours!

If the corals are damaged they die, nutrients decay and fish disappear

The coral reefs are second to the tropical rainforests for the richness and variety of life

But as said the corals are very delicate – one scuba divers foot on the coral and several square metres of coral die!

CEBU (Philippines)- part of the Coral TriangleThreats arising from human action

• Trampling by tourists - unintentional but still destroys large areas of coral

• Cyanide & dynamite fishing that destroy the reef

• Overfishing that reduce biodiversity

• Sun lotions that contaminate the corals

• Fertilizer leakage from farmland that contaminates the corals

• Clearing reefs for port installations

• Sale of corals for the aquarium trade

• Use of the limestone (the superstructure of the reef) for building etc

• Global warming due to excessive discharge of greenhouse gasses (carbon dioxide, nitrous oxides, etc) that will ‘bleach’ the coral reef as the polyps die

Managing coral reefs• Policing protected areas

• Education

• Action on global warming

• Quotas fixed for fishing

• Coral farming

THESE ACTIONS DECIDED WITHIN A PARTNERSHIP OF THE DIFFERENT COUNTRIES MAKING UP THE CORAL TRIANGLE

HOMEWORK

Research the recent oil spill disaster in the Gulf of Mexico

What caused the spill?

What is likely to be the long term impact of this disaster?

What is the response?

What are the difficulties dealing with the problem?