Coral reefs are made up of tiny creatures called coral polyps. When coral dies it skeleton still stays and new coral grows on top creating huge coral reef.
Irresponsible fishing practices and pollution kills the coral reefs.Because the pollution creates global warming.Then the coral gets stressed and releases the algae which gives it its food,color,and growth.
Local goverments created protected areas to fix these problems but rising water temperatures are harder to fix.They found that mixing warm surface water with cold water will prevent it from bleaching.