the world. This was due to increased sea surface temperature. Coral
reefs are extremely sensitive to water temperature. Any change beyond
1 degree C for extended periods of time affects the corals.
Coral bleaching
Ten years ago saw a layer of warm water spreading from the south into
the tropical water. The warm water conditions persisted for as long as
one month in certain places.The mean maximum summer sea surface
temperature increased by 2 degree C. "About 40-50 per cent of corals
were lost in most of the reefs," said Dr. M. Wafar, Senior Scientist
at the National Oceanography Institute (NIO), Goa. "80-90 per cent of
corals in Lakshadeep were destroyed." Dr. Wafar has been involved in
coral research for nearly 25 years.
Scientists from NIO have recovered coral reef in Kavaratti island,
Lakshadeep through coral transplantation. "The recovery has been quite
good. In some places the live coral cover has increased by nearly 50
per cent," said Dr. Wafar. "The government now wants us to undertake
similar initiative in all the islands at Lakshadeep." Scientists will
soon start growing corals for transplantation work at Agatti and
Kadmat islands.
Coral transplantation
Pieces of corals broken naturally or otherwise are tied to slabs and
put in shallow water and allowed to grow. The coral are put in reefs
once they have grown well."We started the pilot exercise in Nov-Dec
2005. We used 100 coral tips, most of them belonging to fast growing
coral genera. "In 2 years' time the growth was up to 25 cm in the best
of the cases," Dr. Wafar said.
In all 4 fast growing coral species and 4-5 slow growing species were
grown and transplanted in the coral reefs in Kavaratti in 2008.
"We grew fast and slow growing coral species to offset a bias in the
natural species composition," he said. "We will do the same now as
well." Since reefs support many fishes, increased coral coverage has a
direct positive impact on fish population.
The Hindu, 8th January 2009
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