Environments and People - Dragons and Tigers: A Geography of South, East and Southeast Asia - page 32

Papua New Guinein the east and West Papua in the
west. West Papua is part of Indonesia. This island is the
focus of one of Indonesia' s many political and environ-
mental controversies (Chapter 15).
There are more island groups in the Indian Ocean.
Strung between Myanmar and Sumatra is a 600 mile
(966 km) chain of more than 200 islands. These are
known as the Andaman and Nicobar Islands and belong
to India. The majority are merely exposed tops of moun-
tains protruding from the ocean floor. Southwest of India
lie the Maldives, 115 square miles (298 km 2 ) of low-lying
islands, banks, and reefs. Only about 10 percent of the
roughly 2,000 of these are inhabited.

Are you aware that the world' s best dive sites are in the
Asia-Pacific region?

Coral Reefs

Thriving in warm, tropical waters, coralline
formations cover an estimated 109,769 square
miles (284,300 km 2 ) of oceans, occur in more
than 100 countries, and comprise roughly a third
of tropical coastlines. It is estimated that more
than half of the world' s coral reefsare in the
Indian Ocean, occurring along continental
shelves and around islands.
Biological process is responsible for the forma-
tion of coral reefs. A coral is a small marine animal
related to other marine invertebrates such as
anemones and jellyfish. Corals excrete calcium car-
bonate from the lower half of their polyp bodies,
forming a hard, calcified skeleton. Reefs are formed
by colonies of corals that live in a symbiotic rela-
tionship with algae. Over centuries, skeletons
accumulate on raised submarine features. This
biological formation makes up a coral reef.
Coral reefs, the most biologically diverse
oceanic ecosystem, are the marine equivalent of
rain forests, the richest ecosystem on Earth. As
many of 100,000 reef species have been named thus

LIMESTONE AND CORAL ENVIRONMENTS
Chemically weathered limestone is the essence of karst
topography Fractured limestone formations, with at
least 80 percent calcium carbonate, are subject to solu-
tion processes. Subsurface drainage channels are formed
as water seeps through joints in the otherwise imperme-
able limestone. Chemical weathering takes place, result-
ing in pitted and lumpy surface forms and labyrinths of
caves below (Figure 2-7). Karst regions in Asia are found
in northwestern India, southern China, and in various
parts of Southeast Asia. An especially beautiful area of
karst features is Halong Bay in North Vietnam. Karst for-
mations are popular tourist attractions, drawing sight-
seers, photographers, rock climbers, and spelunkers
from around the world.

Figure 2-7
This is an example of tower “karst” topography
in Guilin, China. Photograph courtesy of
B. A. Weightman.