Environmental Impact on the Great Barrier Reef

1
ENVIRONMENTAL IMPACT ON
THE GREAT BARRIER REEF
September 1, 2018
ECU103 Geography for Schools newsletter is
developed through collaboration, respectful
discussions and critical and creating thinking.
Each student should contribute one short article
for review by other students. There is
opportunity to vote for your favorite article and a
prize for the people’s choice award – since there
is limited time for students to read all articles and
the assignment requirement is to read only 3 you
are advised to make yours stand out through use
of an imaginative title.
The Great Barrier Reef
Image Source - The Great Barrier Reef Foundation
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 zone1, 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 decay2. 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 expelled3.
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 corals4. 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.
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.
1 De’ath, Fabricus, Sweatman, & Puotinen (2012)
2 Wooldridge (2009)
3 Hughes, Graham, Jackson, Mumby, & Steneck, (2010)
4 Hughes, Hughes, & Smith (2014)