Page 161 - (DK) Ocean - The Definitive Visual Guide

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INDIAN OCEAN CENTRAL INDIAN OCEAN CENTRAL
ATOLLS WITHIN ATOLLS
Diego Garcia Atoll Maldives The numerous ringlike structures in this
aerial view are faros—mini-atolls within
TYPE Atoll TYPE Atolls, fringing a larger Maldivian atoll.
reefs
AREA 17 square miles
(44 square km) AREA 3,500 square miles
(9,000 square km)
CONDITION Generally
good; recovered from CONDITION Recovering
coral bleaching in 1998 from coral bleaching
LOCATION Chagos Archipelago, central Indian Ocean, LOCATION Off southern India, southwest of Sri
southwest of Sri Lanka Lanka, in the Indian Ocean

This atoll, best known as a US military The Maldives are a group of 26 atolls,
base, is also home to one of the many of them very large, in the Indian
world’s largest populations of breeding Ocean. The majority are composed of
sea birds. The reefs around the atoll’s numerous separate reefs and coralline
edges and within its central lagoon islets (some 1,200 in all), arranged in
are home to 220 species of stony coral. ringlike structures. Within most of the
In 2010, the Chagos Archipelago, of atoll lagoons, which are 60–180 ft
which Diego Garcia forms a part, (18–55 m) in depth, there are usually
was declared a “no-take” marine many patch reefs and numerous
reserve, making it the largest marine structures called faros, which are rare
protected area in the world. outside the Maldives. These look like
mini-atolls and consist of roughly
elliptical reefs with a central lagoon.
Most of the Maldivian atolls are HUMAN IMPACT
themselves arranged in a large, elliptical ATOLL CITY
ring, some 500 miles (800 km) long
and 60 miles (100 km) wide. The reefs
that fringe all the Maldivian atolls, Male, the Maldives’ capital city, The partly dismantled reef leaves
islets, and faros contain more than 200 covers the entire surface area of a the island poorly protected from
species of colorful stony coral, more coral island that forms part of an storms, so a sea wall has been built
than 1,000 different fish species, and atoll rim. Its reef has been mined around much of its perimeter,
are abundant in other marine life. to provide building materials for preventing major damage during
Groupers, snappers, and sharks, for artificially extending the island. the 2004 Indian Ocean tsunami.
example, are frequently encountered.
In 1998, a severe coral bleaching
event killed up to 90 percent of the
corals in some areas, and had a strong
negative impact on diving tourism.
Since 1998, a recovery has occurred,
although another severe bleaching
WESTERN SIDE OF DIEGO GARCIA event took place in 2010.

INDIAN OCEAN NORTHEAST and breeding grounds for endangered
sea turtles. A coral bleaching event in
Andaman Sea Reefs 1998 badly damaged reefs around the
Andaman and Nicobar islands, and
TYPE Fringing reefs in 2010 another severe widespread
AREA 2,000 square miles bleaching event affected the reefs
(5,000 square km) along the coast of Thailand. The
CONDITION Some areas 2004 Indian Ocean tsunami caused
poor due to coral relatively little damage. Other threats
bleaching, diver damage to these reefs include collection
LOCATION Andaman Sea coasts: Thailand, Myanmar, of marine life for aquariums,
Andaman and Nicobar Islands, Malaysia, Sumatra
destructive fishing
techniques, siltation
Most Andaman Sea reefs are fringing caused by poorly
reefs around islands off the coasts of managed deforestation
Thailand and Myanmar or, in the on some of the
northwest, off the eastern coasts of the islands, and anchor
Andaman and Nicobar islands—the damage from
site of the largest continuous area of dive boats.
reefs in south Asia. About 200 coral
species and more than 500 fish species
have been recorded here. The reefs
and islands are also important feeding OCEAN ENVIRONMENTS

SOFT CORAL COLONIES
These soft corals and glass fish,
which are almost transparent, were
photographed off southwest Thailand.