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WORLD ATLAS OF CORAL REEFS
Part II
The Atlantic and Eastern
Pacific
The
Atlantic Ocean covers one fifth of the
surface area of the planet, second only in
size to the Pacific. It is the world's youngest
ocean, only beginning to form around the
time of the break-up of the supercontinent
of Pangea about 180 million years ago. It also has the
biggest drainage basin of any ocean, and the large
amounts of sediment entering it from the great rivers
such as the Amazon, Orinoco, Mississippi, Niger and
Congo certainly have a role to play in inhibiting coral
reef development along much of its perimeter
In the eastern tropical areas of the Atlantic the
coastline is relatively simple, following the continental
coast of West Africa, and with only a few significant
island groups, notably the Cape Verde Islands and
Sao Tome and Principe. The Central Atlantic has few
shallow water features and, although there is some
volcanic activity associated with the mid-ocean ridge,
there are only a few oceanic islands in the tropics. The
western coastline of the Atlantic is quite different:
between the eastern coast of Venezuela and the
southern tip of Florida there is a chain of islands
separating the Atlantic proper from the Caribbean Sea
in the south and from the Gulf of Mexico in the north.
These semi-enclosed seas actually have an older
geological history than the Atlantic itself. As the
Central American Sea they would have been directly
connected to the Mediterranean until the break-up of
Pangea and the appearance of the Atlantic. There is
volcanic activity in a few areas on the eastern and
western edges of the Caribbean Basin.
The only major coral reef development in this
entire region is centered around the Caribbean Sea
and to the north of Cuba in an area bounded by the
Bahamas and Florida. There are smaller reef developments in a few locations in the Gulf of Mexico and
around Bermuda in the Northern Atlantic. Brazil too
has some reef structures, although in general these
are small and intermittent. There are no true reefs on
the other oceanic islands or in the Eastern Atlantic.
Even in the Caribbean Sea, reef development rarely
reaches the extent of reefs in the Indo-Pacific. and
there appear to be real physical differences in reef
structures between these regions. Many Caribbean
reefs are deeper submerged features, while many of
those with a clear reef crest often only have a narrow
reef flat. Although there are a small number of barrier
reefs and atolls these are clearly not as prolific as
in many parts of the Indo-Pacific. In all, less than
8 percent of the world's coral reefs are found in
this region.
In terms of biodiversity the coral reefs of this
region are depauperate, but they are also unique. The
Atlantic corals now share only seven genera with
the Indo-Pacific. There are three clear regions in the
Atlantic reef province, with the highest diversity
focussed in the Caribbean [from Bermuda to Trinidad),
but with other small centers of coral diversity in Brazil
and the Eastern Atlantic. Current coral faunas are
uniform across the Caribbean sub-region, with few
geographically restricted species. The Brazilian subregion is isolated from the Caribbean by a substantial
barrier posed by the long, sediment-rich coastal areas
of the Guyanas and the Brazilian Amazon. Although
these reefs have a very low diversity of species, many
are endemic. Some appear to be relict species with
evidence of a wider distribution shown in the fossil
record, while others are probably the result of
allopatric speciation, and appear to have sister species
in the Caribbean. The Eastern Atlantic has even
lower levels of species diversity and there only one
is endemic. The remainder show affinities to both
WORLD ATLAS OF CORAL REEFS
Part II
The Atlantic and Eastern
Pacific
The
Atlantic Ocean covers one fifth of the
surface area of the planet, second only in
size to the Pacific. It is the world's youngest
ocean, only beginning to form around the
time of the break-up of the supercontinent
of Pangea about 180 million years ago. It also has the
biggest drainage basin of any ocean, and the large
amounts of sediment entering it from the great rivers
such as the Amazon, Orinoco, Mississippi, Niger and
Congo certainly have a role to play in inhibiting coral
reef development along much of its perimeter
In the eastern tropical areas of the Atlantic the
coastline is relatively simple, following the continental
coast of West Africa, and with only a few significant
island groups, notably the Cape Verde Islands and
Sao Tome and Principe. The Central Atlantic has few
shallow water features and, although there is some
volcanic activity associated with the mid-ocean ridge,
there are only a few oceanic islands in the tropics. The
western coastline of the Atlantic is quite different:
between the eastern coast of Venezuela and the
southern tip of Florida there is a chain of islands
separating the Atlantic proper from the Caribbean Sea
in the south and from the Gulf of Mexico in the north.
These semi-enclosed seas actually have an older
geological history than the Atlantic itself. As the
Central American Sea they would have been directly
connected to the Mediterranean until the break-up of
Pangea and the appearance of the Atlantic. There is
volcanic activity in a few areas on the eastern and
western edges of the Caribbean Basin.
The only major coral reef development in this
entire region is centered around the Caribbean Sea
and to the north of Cuba in an area bounded by the
Bahamas and Florida. There are smaller reef developments in a few locations in the Gulf of Mexico and
around Bermuda in the Northern Atlantic. Brazil too
has some reef structures, although in general these
are small and intermittent. There are no true reefs on
the other oceanic islands or in the Eastern Atlantic.
Even in the Caribbean Sea, reef development rarely
reaches the extent of reefs in the Indo-Pacific. and
there appear to be real physical differences in reef
structures between these regions. Many Caribbean
reefs are deeper submerged features, while many of
those with a clear reef crest often only have a narrow
reef flat. Although there are a small number of barrier
reefs and atolls these are clearly not as prolific as
in many parts of the Indo-Pacific. In all, less than
8 percent of the world's coral reefs are found in
this region.
In terms of biodiversity the coral reefs of this
region are depauperate, but they are also unique. The
Atlantic corals now share only seven genera with
the Indo-Pacific. There are three clear regions in the
Atlantic reef province, with the highest diversity
focussed in the Caribbean [from Bermuda to Trinidad),
but with other small centers of coral diversity in Brazil
and the Eastern Atlantic. Current coral faunas are
uniform across the Caribbean sub-region, with few
geographically restricted species. The Brazilian subregion is isolated from the Caribbean by a substantial
barrier posed by the long, sediment-rich coastal areas
of the Guyanas and the Brazilian Amazon. Although
these reefs have a very low diversity of species, many
are endemic. Some appear to be relict species with
evidence of a wider distribution shown in the fossil
record, while others are probably the result of
allopatric speciation, and appear to have sister species
in the Caribbean. The Eastern Atlantic has even
lower levels of species diversity and there only one
is endemic. The remainder show affinities to both