Coral reefs are aragonite structures produced by living
organisms. In most reefs the predominant organisms are
colonial cnidarians that secrete an exoskeleton of calci-
um carbonate. The accumulation of this skeletal materi-
al, broken and piled up by wave action and bioeroders,
produces massive calcareous formations that make ideal
habitats for living corals and a great variety of other an-
imal and plant life.
Coral reefs can take a variety of forms, defined in
• – a reef that is directly attached to a shore or borders
it with an intervening shallow channel or lagoon.
• – a reef separated from a mainland or island shore by
a deep lagoon (see Great Barrier Reef).
• – an isolated, often circular reef, usually within a
lagoon or embayment.
Diagram of a fringing coral reef.
Fringing reef off the coast of Eilat, Israel.
• – a short reef resembling a fringing reef, but more
sloped; extending out and downward from a point or
• – a linear or semi-circular shaped-outline, larger
than a patch reef.
• – a long, narrow, somewhat winding reef, usually
associated with an atoll lagoon.
• – a more or less circular or continuous barrier reef
extending all the way around a lagoon without a
• – an isolated reef, approaching an atoll type, but
without a lagoon.
BVI salts ponds were all shallow and mostly hypersaline
and their waters were generally well mixed. They exhib-
ited large variations in salinity, both temporally and
From Wikipedia, the free encyclopedia
Locations of coral reefs.
Coral reefs are estimated to cover 284,300 square kilo-
metres, with the Indo-Pacific region (includin