Corals and Coral Bleaching

Healthy coral can be very colourful.

Healthy.coral.reef.No.Title.jpg

Some coral reefs recently have started to look rather different.

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This is called 'coral bleaching'.

To understand this, we need to start by looking at corals.

Corals are animals that make a framework around them that looks like rock.



Coral animals (polyps) have tiny plants - algae - living in their tissues.

The algae provide food to the corals, which they produce by photosynthesis.

Corals only live in a limited temperature range.

Like porridge, they need to be not too hot and not too cold.



Coral reefs are concentrated in a band around the equator, between 30°N and 30°S latitude.

Corals grow in warm shallow waters that receive plenty of light.

Most corals grow in the warmest water they can stand (about 85° F or 29° C). 

This means that slight increases in ocean temperature can harm corals.

High sea temperature is the main reason for coral bleaching.

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