Are the reefs dying?
Ray Lopez Braindead Killfile the Pest
Are the reefs dying?
RAMYA KANNAN
As latest research confirms the effect of climate change on the coral
reefs of the Great Barrier Reef, Australia is gearing to deal with the
threat to its greatest natural resource.
The Great Barrier Reef, which stretches over 2300 km along the Queensland
coast, is not only home to corals but also to a host of other marine
organisms including over 1500 species of fish, 4000 species of molluscs,
24 species of sea birds that live a nd breed on islands, mammals such as
whales, dolphins, and the endangered dugong.
Photo: AP
The rare batfish: It can successfully remove the forest of algae that
kill the reefs.
A TOURIST surfaces spluttering as water enters his snorkel tube… Pausing
to grab some air, he strokes out to the yellow dinghy bobbing on the
clear waters of Radical Bay, off Townsville in Queensland.
Pointing to the abundant coral reefs below him, concern etched on the
lines of his face, he asks the skipper of his tourist yacht, now in the
dinghy, “Those corals out there, are they brown naturally or are they
dying?” Skipper Grant Lewis says, “Some of these corals are naturally
brown, but sure enough there are those that are dying across the reef.
They have been for some years now.”
Grappling with the issue
South of the country, a few days ago, the Fifth World Science Journalists
Conference was grappling with the issue of climate change. In one
session, John ‘Charlie’ Veron, eminent Coral Reef Researcher with the
Australian Institute of Marine Sciences, described as having spent more
time under water than above it, is using hyperboles to articulate his
agitation: “We are committing the earth to unrivalled destruction… The
Great Barrier Reef is dying. We need to pay immediate attention to it.
All these things cannot wait.”
If you are on the right wavelength, you can pick up the churning
undercurrents of climate change nearly everywhere in Australia: On the
radio, television, on a calm seashore, in pubs, among tourists, tour
guides, not just with marine researchers and climatologists. Clearly, the
continent is concerned about climate change and the far-reaching impact
on what it believes is its greatest natural resource — the Great Barrier
Reef.
Not without reason though. The coral bleaching survey for 2005-2006,
published in May 2006, ( www.gbrmpa.gov.au) conducted by the Great
Barrier Reef Marine Park Authority noted: “At the height of summer, sea
temperatures were either at or above levels known to cause thermal stress
to corals in all regions of the Great Barrier Reef Marine Park,
particularly in the far southern area.” There is now worldwide consensus,
in the face of evidence, that high sea temperatures — a fallout of
climate change — are responsible for the vast coral bleaching.
The report pointed out “At the start of summer, a hot water anomaly
developed early and persisted over much of the southern area of the Great
Barrier Reef Marine Park. In January… cloud cover over the central and
northern Great Barrier Reef Marine Park (led to), cooling water
temperatures in this region. However, waters in the southern region
continued to warm.”
While low level bleaching (less than 10 per cent) was recorded in Lizard
Island, Cairns, Townsville and Whitsunday survey regions, severe
bleaching of over 75 per cent was observed in the far southern region.
The inshore reefs, around Keppel Islands, were the worst affected, with
an average of 84 per cent of corals affected, according to the report.
Scientists studied 34 reefs within the area of the Great Barrier Reef
Marine Park, in order to “assess the spatial extent and severity of coral
bleaching throughout the Great Barrier Reef Marine Park”. Participants of
the BleachWatch programme of the GBRMPA also called in with complaints of
bleaching. According to the final report, the surveys were timed to
coincide with the peak of the bleaching event, and to document the
patterns of bleaching, so as to be able to “interpret the causes and
significance of changes in reef condition”.
Substantial bleaching
Paul Marshall, Manager, Climate Change Response Program, Research and
Monitoring Co-ordination Unit, says, “Even an increase of 1.5 degrees
above the normal maximum temperature is sufficient to bleach corals —
when water temperature increases, it kills off the zooxanthellae, the
algae that lives in symbiosis with the animal coral and gives it the
flamboyant colours.” The hottest years in Australia so far, he says, have
been 1998, 2005, 2002, 2003, 2004, in that order.
Marshall has been studying coral bleaching and regeneration since 1998
when a sudden surge in temperatures as a result of El Nino led
tosubstantial bleaching. In 1998, he says, 50 per cent of the reefs were
bleached as a result of increasing water temperature and, in another
episode in 2002, 60 per cent was bleached. Globally, 16 per cent of all
reefs were destroyed.
Marshall has reason to be anxious. The 2006 bleaching around Keppel
Islands is an indication of how things are going to be in the future.
Bleaching does not kill the coral. It will still live and can recover
when other zooxanthellae come to live in its midst, but “recovery can
take years,” he says. “It could be decades before they are restored to
their original glory.” However, if the temperature stress remains, corals
die and new formations must settle and grow on the reef for recovery.
Janice Lough, climatologist and principal research Scientist at the
Australian Institute of Marine Studies, Townsville, says x-rays of coral
slices that show annual density bands, indicate that the corals stopped
growing for about a year in 1998 after the warming episode, before they
started growing again. Dr. Lough also served on the United Nations Sigma
XI Scientific Expert Group on Climate Change, which identified
“substantial loss of coral along the Great Barrier Reef” as a result of
climate change in its February 2007 report.
In a paper she published with four other scientist researchers in the
Bulletin of the Australian Meteorological and Oceanographic Society in
June last, Dr. Lough explains, “Coral bleaching is not a new phenomenon
due to global warming. Corals are known to bleach in response to several
environmental stresses — low salinity, pollution, unusually high or low
water temperatures. In the past, however, coral bleaching only occurred
on small space scales. What is new and clearly related to global warming,
is an increased frequency since the mid-1970’s of mass coral bleaching
events whereby entire reefs are affected.”
The paper also quotes studies by Hoegh-Guldberg and Berkelmans, modelled
on future impacts, suggesting that a 1-3º C increase in water temperature
in the Great Barrier Reef would result in approximately 80-100 per cent
bleaching of reef.
Factors
While warm sea temperature is clearly the causative agent for mass
bleaching, marine researchers are also concerned about the increasing
acidification of the sea. Explaining, Dr. Lough says this would also be a
direct effect of increasing greenhouse gases in on ocean chemistry and
its consequences for reefs. This alters the concentrate of carbonate and
bicarbonate ions in sea water which corals use to calcify and build
skeletons. Weakened skeletons will make corals more susceptible to storm
damage and erosion.
Changes in ocean current and rainfall and associated freshwater discharge
to reef, pollutant run-offs into the sea, excessive fishing and tourism
and coral diseases are all listed among the other causes for coral
bleaching and damage. Russel Reichelt, Managing Director, Reef and
Rainforest Research Centre, says 10 per cent of the reefs in the Great
Barrier Reef area are under risk from sediments, chemicals and
fertilizers.
The Great Barrier Reef, which stretches over 2300 km along the Queensland
coast, is not only home to corals, but also to a host of other marine
organisms including over 1500 species of fish, 4000 species of molluscs,
24 species of sea birds that live and breed on islands, mammals such as
whales, dolphins and the endangered dugong. Climate changes will
therefore naturally have diverse implications.
It has helped that the Australian Government has been concerned about
climate change and its effects on the nation’s most precious natural
resource. It has also helped some that the GBR, a UNESCO World Heritage
Site since 1981, is the largest protected marine environment in the
world. Yet the challenges are many and the debate now is on averting the
crisis by controlling and minimising damage.
Recognising the threat to the GBR, the GBRMPA has established a $2
million Climate Change Response Program, along with the Australian
Greenhouse Office, to better understand and respond to climate change
threats, including coral bleaching. The CCRP will aim to sustain GBR
ecosystems and industries and communities that depend on the Great
Barrier Reef; and foster supportive policy and networks, as outlined in
the May 2006 report.
The CCRP team is currently working on assessing the vulnerability of the
GBR to climate changes and also recommend strategies to minimise the
impact. The report will be ready by May-June. It will provide a road map
for the future and indicate where ‘rezoning’ must be done. The GBRMPA
took up ‘zoning’ of the reef in 2004 to protect and conserve areas of the
reef from excessive commercial exploitation. Certain areas are off limits
for fishing and even collection.
Marshall says rezoning the reef will help protect biodiversity. In
addition people have to reduce water pollution and stop over-fishing and
overuse. Studies are also on to evaluate the process of natural
adaptation. Corals will push the bleaching threshold over a period of
time, but the worry is that it might not grow sufficiently to match the
galloping pace of climate change.
In addition, as part of the Coral Bleaching Response Plan, the CCRP team
monitors water temperature and coral bleaching every summer. Satellite
measurements of sea temperature, regional weather forecast and reports
from bleachwatch volunteers are logged in periodically. When bleaching is
detected, a team is immediately assigned to study the full extent of the
bleaching and its ecological impacts.
Also coming up is a Resilience, Risk and Response Atlas to act like a GIS
tool on the region, Reichelt says. The Reef and Rainforest Research
Centre is also working on Conservation and Sustainable Use, studying
status and trends, risks and threats from climate and pests and water
quality.
Compelling reason
While focusing on conserving marine systems along the GBR, the
Australians have not lost sight of the fact that the aesthetics of the
coral reefs is, possibly, the most compelling reason for their
preservation. In fact, Marshall concedes that it is the aesthetics that
concerns people more. When corals lose colour, it is noticed almost
immediately and is directly linked to attracting tourists. “The tourism
industry is very sensitive… since it directly affects their prospects.”
Daniel Gschwind, of the Queensland Tourism Industry Council, says tourism
has been at the frontline of the battle against climate change in
Australia. “The GBR is Australia’s most important tourist asset. It
yields up to $2 billion to regional economies,” he says.
According to him, one of the tour operators in the Great Barrier Reef has
been testing the feasibility of providing shade to key reef areas to
reduce the risk of bleaching, along with scientists. From the industry’s
perspective, all tasks — managing assests, operational practices,
utilisation of energy and water and development — should promote
sustainable use.
As Marshall says, “No matter what we do, reefs are going to be degraded
in the future. But if we do nothing, there will be a complete
degradation. We have to help coral reefs bounce back after bleaching
events.” There are no two ways about that one.