More than 30 meters below the surface of the ocean lies the “twilight zone.” The coral reefs that grow here are complex ecosystems, but they may be under threat from extreme weather events. Rather than providing a refuge from the storm, these deep reefs may be as vulnerable as their shallow-water counterparts.







  • twilight zone – scuba diving term for the point where sunlight no longer penetrates the water
  • to flourish – to grow or develop successfully
  • vulnerable – exposed to the possibility of being attacked or harmed, either physically or emotionally
  • refuge – a place where you go for safety and protection, for example from violence or from bad weather
  • to shelter – to provide protection or cover
  • current – a movement of water in a particular direction
  • upwelling – a process in which deep, cold water rises toward the surface
  • to weather the storm – to reach the end of a very difficult situation without too much harm or damage
  • (colour) bleaching – removing the colour from something or making it lighter, with the use of chemicals or by the effect of light from the sun



Discuss in pairs, small groups, or with your teacher.

  • Are there endangered species in your country?
  • Why are so many species becoming endangered?
  • Do you think endangered species can be bred in zoos or captive breeding programmes and then released into the wild?
  • What do you think of the sale of products made from endangered species and how can we stop it?
  • Do you do anything to protect endangered species?

Practice Makes Perfect

Use the glossary words and expressions to fill in the sentences. Make sure to use the correct form. Go to deep-reefs-under-threat to find out more.

twilight              weather the storm            flourish

vulnerable                  bleaching           refuge

  1. Scientists have long known that shallow reefs are ……….. to hurricanes.
  2. Deeper reefs have also been thought to provide a temporary ………. for shallow reef species.
  3. The reefs of the ………. zone have been assumed to be protected from the worst effects of hurricanes.
  4. Extreme weather events, ocean warming and human activities can lead to coral reef diseases and colour ……… .
  5. The next few days will show if the prime minister can ……….. the political …….. caused by his remarks.
  6. Our tomatoes are …………. this summer – it must be the warm weather.

ANSWERS: vulnerable; refuge; twilight; bleaching; weather storm; flourishing





Explore it more to create your own teaching-learning experience!

Here`s some jaw-dropping footage of amazing sea creatures, including a color-shifting cuttlefish, a perfectly camouflaged octopus, and a Times Square’s worth of neon light displays from fish who live in the blackest depths of the ocean. This short talk celebrates the pioneering work of ocean explorers like Edith Widder and Roger Hanlon.