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Most people now recognize that coral reefs worldwide are in decline,
and fingers are commonly pointed at algae as the culprit. The
authors have had the good fortune to study pristine reefs at more
than 50 uninhabited islands in the Pacific Ocean. Although
unaffected by human activity, these reefs show considerable variety
in their percentage of coral versus algal cover, with some being
dominated by various species of algae. It has thus become clear
that, although algae may pose a problem in some situations, these
plants are an essential part of nearly every healthy reef system.