What are coral reefs and why are they important?
Coral are a type of marine animal that stay in the same place for their whole lives. They have a hard skeleton surrounding them and can sometimes resemble rocks. Coral reefs are made of massive groups of many types of coral. Reefs are an important habitat for marine species, as they provide food and shelter for a wide variety of animals. This means that damage to a coral reef can have an impact on many species of animal, not just corals.
Coral reefs are usually found in tropical oceans near the Earth’s equator. They are usually found in shallow water near the coast. Some examples include the Great Barrier Reef next to Australia, and the Amazon reef next to Brazil.
Why have coral reefs been damaged?
Coral reefs have been damaged by a variety of problems. Rising sea temperatures and ocean acidification have led to coral bleaching. This is where corals lose the layer of algae that gives them their colour. The algae provide the coral with energy to live through photosynthesis. Photosynthesis is where plants use energy from sunlight to turn water and carbon dioxide into food. Corals become stressed when their living conditions change too much, such as when the water becomes too hot or acidic. This does not require huge changes, as coral are sensitive to small alterations in these conditions. When this happens, they expel the algae, leading to a white or grey colour. It is very difficult for coral to survive without algae.
How can coral gardening help restore coral reefs?
Coral gardening is where fragments of a coral are used to grow more coral in a nursery. These fragments are often bits of coral broken off from reefs by storms, anchoring of boats, or grounding of boats on the reef. Coral is raised in nurseries for 3-4 weeks, before being ‘planted’ on the reef.
Nurseries need to be in areas with free-flowing water that is free of sediment, currents, and boat traffic. To do this, artificial reefs can be made. These can be built with concrete blocks, or rock boulders held together with cement. Corals brought to the reef from nurseries have a 75% survival rate, which means that of every 4 corals brought to the reef, 3 will survive.
Wasini Island Case Study
In 2016, large amounts of the coral reefs around Kenya’s shores had been damaged or destroyed. In some areas, between 60-70% of coral had been killed. On Wasini Island, locals formed the Wasini Beach Management Unit. This now has 250 members, 150 of whom are women. They have helped restore the local reefs by setting up a coral nursery.
The success of the project led to funding from the Kenyan Coastal Development Project. This project also boosted ecotourism to the island, helping locals earn money from the restoration work. Previously, only 30% of the community’s income came from ecotourism. This figure has since risen to 80%.