Cyclone Yasi and the Great Barrier Reef
Contributed by Tim Hochgrebe
After the massive impact of Cyclone Yasi, Australia stops to
consider the consequences of this natural disaster on the economy,
nature and life in Australia as such.
We all know that natural disasters
such as cyclones can have devastating effects on our reefs. Even though
tropical cyclones are part of nature we do have to realise
that with the global climate change the border between 'natural' and
impact' becomes blurred and the incidences of extreme weather patterns
such as Category 5 Tropical Cylcone Yasi and the recent floods we have
seen in Queensland and Victoria will become more frequent.
What does this mean for the Great Barrier Reef and consequently the
livelihood of people who are dependent on the world's largest reef
system? The northern end of the 2600km Great Barrier Reef was directly
in the path of Cyclone Yasi. The Great Barrier Reef is composed of 2900
individual reefs and stretches over an area of 344,000 square
The immediate effect would be the physical damage to the reef. It is
the fast growing coral such as the Staghorns that get destroyed by
storms and slow growing more solid coral such as Brain Coral generally
get spared by the physical effects of storms.
In addition to the physical damage to the reef by this massive storm
there are the huge problems of excessive runoff of sediment after
months of Queensland's floods, followed by another bashing by flooding
from the storm surges created by Cyclone Yasi. Since the actual coral
reef is formed by filterfeeding organisms this will result in the
demise of many more corals, other filterfeeders and loss of habitat for
many more organisms and their predators.
Adding to that are consequences of a decrease in salinity following
heavy rains, which add more stress to the reef.
We are all aware of the fragile state of the world's coral reefs
triggered by global warming, ocean acidification, excess nutrients,
overfishing, the list goes on - and any additional stress will add to
the danger of this huge ecosystem by shifting the fragile balance
What Yasi really did to the Barrier Reef will take a while to find
out. Major damage caused by Tropical Cyclone Larry was to underlying
reef structures, breakage and displacement of corals, which is overall
consistent with previous tropical cyclone events.
One hope could be my personal theory that if the cyclone passed over
the barrier reef at high tide, much of the storm damage could have been
minimized, but it is not until we get out there in weeks and months to
come that we will be able to survey the impact of this natural disaster
on the Great Barrier Reef.
Another positive thought is of course that the destructive path of
Yasi was limited to the part of the reef it crossed over and a large
part of the Great Barrier Reef will have been left untouched by the
Queensland's tourism industry has been devastated by the events of
late 2010 and early 2011 and we hope everyone will remember quickly
Queensland's motto: beautiful one day, perfect the next! The Great
Barrier Reef is a 'must see' on everybody's Australia travel itinerary
and this should not change after Yasi.
Our thoughts go out to all of those personally affected by Cyclone
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*Image from Wikipedia