Atoll perhaps cultivated for cereal (5,4)

I believe the answer is:

coral reef

'atoll perhaps' is the definition.
(atoll is a kind of coral reef)

'cultivated for cereal' is the wordplay.
'cultivated' indicates an anagram.
'for'+'cereal'='forcereal'
'forcereal' anagrammed gives 'CORAL-REEF'.

(Another definition for coral reef that I've seen is " Navigational hazard in warm seas - real force (anag)".)

I've seen this clue in The Independent.

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