A study says that the population of marine species around the world declined by 49% between 1970 and 2012. The study shows that marine life is disappearing faster than scientists thought.
This is bad news for the animals, as well as people. Many people need the ocean to make a living.
The reason for this is rising water temperatures, over-fishing and climate change. Experts say that we could lose the coral reefs from most areas by 2050.
Difficult words: marine (relating to the sea), species (a type of animal), decline (to become less).
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