Though there are many problems facing coral reefs today, the increasing temperatures of our oceans due to climate change is one of the leading causes that threaten them. When temperatures are too high, the relationship between corals and their algae breaks down. The algae are what give corals some of their bright colors, so when this happens, corals appear "bleached." Just one degree above regular temperatures is enough to bleach them. If the temperature is too high for too long, corals and their microalgae are unable to recover. This has caused many corals to die off throughout the world.