Environmental Impacts on the Great Barrier Reef

The Australian continent, strategically positioned in the middle of the Indian Ocean and the
Pacific Ocean, is a mega-diverse landmass, with deserts, mountain ranges, rainforests, and
various other biodiversity hotspots. The Great Barrier Reef, located to its north-east is a
highly diverse ecosystem in itself, with nearly 3000 reefs and 300 islands. This is one of
Australia’s hotspots, and is a major economical boost to the nation.
The Great Barrier Reef is the world’s largest coral reef, situated in the Coral Sea. The reef
provides a large marine ecosystem, and serves as a habitat to a variety of marine species.
Coral reefs are greatly beneficial to the landmass, by protecting the shoreline. The Great
Barrier Reef has been inhabited by indigenous Australians since long. Today, it serves as a
major point in Australia for tourism and fishing. However, the stability of the reef is
threatened by human factors such as pollution due to pesticides and fertilizers, overfishing,
shipping, etc, and environmental factors such as climate change.
The reef was formed as a result of global warming in the last glacial period, and is ironically
threatened by the global warming of today. Out of the 3000 reefs, over 700 reefs are in the
risk zone, due to various factors, including coastal encroachment and development, and river
runoffs into the sea. Three major environmental factors that affect the reef are discussed
below.
1. Ocean acidification – It is the decrease in the pH levels of the ocean, doe to the
increase in carbon dioxide in the atmosphere. As coral reefs tend to calcify, the
decrease in the substance aragonite in the sea waters impacts calcification, and causes
decay. This impacts the ecosystem, leading to loss of marine biodiversity. The
increase in acidity causes an increase in the oceanic temperatures. This leads to coral
bleaching, wherein the algae living inside the coral polyps are expelled. This leads to
coral starvation, and also reduced coral reproduction.
2. Predator Attack – The corals of the reef are threatened by the “Crown of Thorns”
starfish, which is its major predator. The starfish attacks the corals by climbing on
them, and secreting digestive enzymes to digest the liquefied tissue of the coral. Even
though it is a normal predator-prey relationship, an increase in the starfish count
would pose a great risk to the reef. An increase in their population, known as an
“outbreak” could be disastrous for corals. However, human factors play a major role
in this, as reduction in the oceanic water quality, fertilizer wastes; etc can cause the
predator larvae to thrive, thus increasing their population.
3. Natural disasters – Coral reefs are extremely resilient to any kinds of tropical sea
storms and cyclones, thus any natural calamity would have a minimal impact on them.
However, as the coral bleaching is occurring at a fast rate due to increase in the
atmospheric carbon dioxide, ocean acidification, etc, there are great chances of the
collapse of the reef, which would lead to mass damage and destruction of the marine
ecosystem supported by the reef.
The environmental impacts on the reef are huge, and however inevitable, they are hastened
by the unscrupulous human activity. Increase in the atmospheric carbon levels are mainly due
to increased carbon footprint by humans. The increase in acidity of the sea waters is mainly