WORLD ATLAS OF CORAL REEFS
environment. Wave action creates deep grooves in the
shallow reef front, while the corals themselves, with their
complexity of forms, create a highly convoluted surface.
Even the limestone at the base of the living reef surface
is a complex mass of holes formed by the older patterns
of coral growth, together with processes of erosion. This
not only provides a large area for the settlement of other
reef organisms, but also a complex background for the
drama of life on the reef, providing passages and holes
at all scales for the movement of animals, and for their
concealment, shelter, ambush and escape.
One final comparison with rainforests is that the
diversity of life in both ecosystems remains remarkably
poorly known. It has been estimated that less than 10
percent of the organisms found on reefs have been
described by scientists. But not all experts agree on
species identification and definition and there is no
central record even of the species which have been
described. It is thus impossible, at present, to estimate
accurately the total numbers of species occurring on coral
reefs. Using a number of broad assumptions, one recent
attempt has suggested that there may be some 93 000
described coral reef species. The global total, including
the vast number of undescribed species, could thus be
closer to 1 million. Others have estimated that there
may be over 3 million reef species. Perhaps the greatest
problem hindering a more detailed assessment of coral
reef biodiversity is the lack of basic taxonomic research
and inventory, combined with the lack of sufficiently
qualified taxonomists to undertake the work. Defining
and describing species is a complex task, and detailed
observation and description of external morphological
characteristics of animals and plants have traditionally
been key tools. A number of recent studies, however, have
suggested that many of these morphologically similar
"species" may in fact be species complexes, groups of
sibling species, each highly distinct in genetic terms.
If such examples prove to be commonplace, the final
analysis of species diversity may lead to massive increases
in the total species numbers.
"'^^B
"^(^^i
^^^H
^
'^^^H
I
n^'-^MMi
2 ^i/fnfiW
fc^^''.'
Left: Expansive beds of branching Acropora witfi damsetfish above, at the Great Barrier Reef. Right: A barrel sponge,
encrusting red algae and corals in the Philippines.
environment. Wave action creates deep grooves in the
shallow reef front, while the corals themselves, with their
complexity of forms, create a highly convoluted surface.
Even the limestone at the base of the living reef surface
is a complex mass of holes formed by the older patterns
of coral growth, together with processes of erosion. This
not only provides a large area for the settlement of other
reef organisms, but also a complex background for the
drama of life on the reef, providing passages and holes
at all scales for the movement of animals, and for their
concealment, shelter, ambush and escape.
One final comparison with rainforests is that the
diversity of life in both ecosystems remains remarkably
poorly known. It has been estimated that less than 10
percent of the organisms found on reefs have been
described by scientists. But not all experts agree on
species identification and definition and there is no
central record even of the species which have been
described. It is thus impossible, at present, to estimate
accurately the total numbers of species occurring on coral
reefs. Using a number of broad assumptions, one recent
attempt has suggested that there may be some 93 000
described coral reef species. The global total, including
the vast number of undescribed species, could thus be
closer to 1 million. Others have estimated that there
may be over 3 million reef species. Perhaps the greatest
problem hindering a more detailed assessment of coral
reef biodiversity is the lack of basic taxonomic research
and inventory, combined with the lack of sufficiently
qualified taxonomists to undertake the work. Defining
and describing species is a complex task, and detailed
observation and description of external morphological
characteristics of animals and plants have traditionally
been key tools. A number of recent studies, however, have
suggested that many of these morphologically similar
"species" may in fact be species complexes, groups of
sibling species, each highly distinct in genetic terms.
If such examples prove to be commonplace, the final
analysis of species diversity may lead to massive increases
in the total species numbers.
"'^^B
"^(^^i
^^^H
^
'^^^H
I
n^'-^MMi
2 ^i/fnfiW
fc^^''.'
Left: Expansive beds of branching Acropora witfi damsetfish above, at the Great Barrier Reef. Right: A barrel sponge,
encrusting red algae and corals in the Philippines.