Cambridge IELTS 20 Academic Reading Test 3 (Questions 24-26)

B. Corals are composed of tiny animals, known as polyps, with tentacles for capturing small marine creatures in the sea water. These polyps are transparent but get their brilliant tones of pink, orange, blue, green, etc. from algae that live within them, which in turn get protection, while their photosynthesising of the sun’s rays provides nutrients for the polyps. This comfortable symbiotic relationship has led to the growth of coral reefs that cover 0.1% of the planet’s ocean bed while providing homes for more than 25% of marine species, including fish, molluscs, sponges and shellfish.
C. As a result, coral reefs are often described as the ‘rainforests of the sea’, though the comparison is dismissed by some naturalists, including David Attenborough. ‘People say you cannot beat the rainforest,’ Attenborough has stated. ‘But that is simply not true. You go there and the first thing you think is: where are the birds? Where are the animals? They are hiding in the trees, of course. No, if you want beauty and wildlife, you want a coral reef. Put on a mask and stick your head under the water. The sight is mindblowing.’
D. Unfortunately, these majestic sights are now under very serious threat, with the most immediate problem coming in the form of thermal stress. Rising ocean temperatures are triggering bleaching events that strip reefs of their colour and eventually kill them. And that is just the start. Other menaces include ocean acidification, sea level increase, pollution by humans, deoxygenation and ocean current changes, while the climate crisis is also increasing habitat destruction. As a result, vast areas – including massive chunks of Australia’s Great Barrier Reef – have already been destroyed, and scientists advise that more than 90% of reefs could be lost by 2050 unless urgent action is taken to tackle global heating and greenhouse gas emissions.
Pearce-Kelly says that coral reefs have to survive really harsh conditions – wave erosion and other factors. And ‘when things start to go wrong in the oceans, then corals will be the first to react. And that is exactly what we are seeing now. Coral reefs are dying and they are telling us that all is not well with our planet.’