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The largest
structure and natural wonders seen on this earth is the jewel of
Queensland's coast located in the Coral Sea. The Great Barrier Reef, one
of earth's spectacular wonders, runs some two
thousand kilometers along the edge of the
continental shelf of northeast Australia making
it the largest living entity on this world and
the first European to set eyes on it was Captain
James Cook.
 As the world's
largest coral reef, The Great Barrier
Reef is the tropical rain forest of the ocean
and this natural wonder is a must-visit when you
are vacationing in Australia.
Instead of trees and plants, coral takes their
place while animals and birds are replaced by
fishes and marine creatures and both possesses
the same rich diversity of life. It is actually
a large system of about nine hundred islands and
over three thousand coral reefs. Competing for
survival is not surprising among the sea
creatures since there are roughly one hundred
and fifty species of fish alone.
Photo: The Great Barrier Reef in Queensland
Color is very
important to these marine creatures because they
use it to entice, to warn, to camouflage and
also to deceive. For example, the blue-spotted,
red coral trout blend with their rocky
background, the silver harlequin tusk fish are
striped to mask their outlines while the peacock
sole can change color to match their
surroundings.
Partly, it is
grouped about real islands, actually the summits
of a long-drowned mountain range but its
uniqueness comes from its three thousand coral
reefs, islands, cays and lagoons, which are all
at different stages of development. The reefs
are the product of ten thousands years of labor,
during which the oceans rose to their present
level after the last Ice Age. Its engineers are
the tiny cousins of the jellyfish known as the
polyps. There are more than three hundred
species of them with each having a mouth
surrounded by a ring of tentacles on top whereby
each polyp can draw calcium carbonate from the
sea and turn it into a casing of limestone that,
when multiplied by billions, forms the
extraordinary reef. Minute plants such as the
zooxanthellae, share the polyp's limestone
shelter because these plants use light to change
carbon dioxide and water into carbohydrates and
oxygen which is absorb by the polyps and in
return, presenting nitrates and other waste
products to the plants. This is why coral reef
can grow only in areas where there are sunlight.
The reef has become
a place in which its inhabitants compete for
both food and space. Seen in the reefs are soft
and hard (reef-building) corals of different
shapes and sizes, some strong enough to endure
the pounding of the surf while others are so
delicate that they can live only in the stillest
waters. Some types can outgrow their neighbors
just to steal their light while others get rid
of their rivals by using their poisonous
tentacles or by releasing poisonous chemicals
into the water. Other factors that may destroy
the reefs include predators such as the parrot
fish and the crown-of-thorns starfish besides
the usual ocean storms and cyclones.
The busiest time in
the reef is during night when the coral polyps
feed, pushing out their multi-colored tentacles
to entrap tiny sea creatures and plants called
plankton. The reef looks as if it has burst into
flowers when the billion of tentacles come out.
However, the most remarkable sight can be seen
during spring when the entire polyp population
releases orange and red, blue and green parcels
of eggs and sperms which float to the surface,
covering it with a wash of color. The reef is
growing continuously because no sooner has a new
speck of coral broken the surface of the sea
than it acquires a cap of white sand with
something growing in it. Some of these pioneer
colonizers appear with miraculous speed and they
have salt-tolerant fruits that may bob about for
months in the water before finding an
appropriate place and germinating whereby the
paves the way for more plants. Birds too help by
distributing plant seeds and providing
fertilizer to improve the soil condition.
Night-shade berries seeds are spread across the
islands by gulls while black noddies help to
distribute pisonia seeds.
The coral islands
are home to all sorts of sea birds such as
frigate birds, gannets, gulls, noddies, sea
eagles, shearwaters and terns. Female
turtles can be seen laying their eggs here
during the summer. The Great Barrier Reef is one
of the world's most vigorous and best integrated
ecosystems, and it is also one of the most
delicately balanced since pressures on a single
aspect can have disastrous effects upon the
whole. Storm and sea's rages are no longer its
main enemies, humans are what it feared most.
Overfishing, whaling, trade in beche-de-mer
(dried, smoked sea slugs), hunting for
mother-of-pearl and pollution are among the new
dangers threatening the coral reefs. However,
many such problems are controlled when this area
was declared as a national park and in 1981, it
was inscribed as a UNESCO World Heritage Site.
The Great Barrier Reef Marine Park became the
largest marine protected area in the world when
the Australian Government increased the areas
protected in 2004.
Recently, global
warming has become a significant threat to the
future of the Great Barrier Reef. Many of the
corals here are living at the upper edge of
their temperature and if the water remain too
warm for too long, the corals will turn
colorless when the zooxanthellae are being
driven out. If the water continues to stay warm,
the corals will die. Visited by over two million
tourists every year, the Great Barrier Reef is
one of the most famous tourist attractions found
in this country. This spectacular area has also
become one of the top scuba diving sites in the
world while day tours by boat trips are very
popular among visitors.
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