Coral reefs face extinction event

It sounds like the script for a disaster movie to say that the earth is rapidly heading for an extinction event, but scientist are now saying that coral reefs are facing extinction of a similar magnitude to the geological event that wiped out nearly half of the corals 65 million years ago, along with the dinosaurs.

Coral reefs have been called the ‘rain forests’ of the ocean because like tropical rainforests, they are one of world’s most species-rich ecosystems, supporting more than a quarter of marine species.

They are also economically important as they support activities such as fishing and tourism, contributing £15bn to the global economy each year.

The findings of a study by the Global Marine Species Assessment (GMSA), a joint initiative of the International Union for Conservation of Nature (IUCN) and Conservation International (CI), should therefore not be taken lightly.

Coral reefs are facing a number of threats, from fishing, pollution and coastal development for example, and some conservationists believe that efforts to protect the reefs should focus on these areas.

However, the study highlights the contribution that global warming is playing in the destruction of the reefs, and the importance of reducing greenhouse gas emissions immediately if our coral reefs are to stand any chance of surviving.

Climate change is causing water temperatures to rise, and solar radiation is becoming more intense.

This is leading to coral bleaching – a stress response which occurs when the coral expels algae from its tissues.

Healthy coral lives in a symbiotic relationship with the algae, which provides it with nutrients and energy, and also gives the coral its beautiful colours.

Expelling the algae gives the coral a bleached appearance and also makes it weaker and less resistant to disease.

Global warming also causes the oceans to absorb more carbon dioxide, making the water more acid.

This reduces the coral’s ability to build its skeleton, which is the basis of a coral reef.

Of the 704 species of reef-building corals, 231 have now been placed on the ICUN’s red list as either vulnerable, endangered, or critically endangered.

Not enough information could be gathered to assess 141 species of reef-building coral, but these are also likely to be at risk.

In total, it is estimated that a third of the world’s reef-building coral species are facing extinction.

A report on the study has been published in the journal Science.