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Chemical Technology • May 2016
waters — a temperature that would normally kill corals. In
parts of the ocean near Palau, the water is extremely acidic
which should dissolve the carbonate skeletons of the corals
living there. Except that it doesn’t. These particular corals
are made up of a wide variety of ‘extremophil’ coral polyps
and zooxanthellae.
Interviewed for the journal, ‘Nature’, Steve Palumbi, a
marine biologist as Stanford University in California, rec-
ognised that these corals are a genetic wonder. “The real
question is: how did they do that and can all corals do that?”
Palumbi and others at the University of Hawaii at Manoa,
are researching whether they can transfer these favourable
genetic traits to other species. Genetic modification is prov-
ing too controversial, and so the researchers are attempting
to speed up evolution through selective breeding.
One experiment run off the coast of Ofu Island in Ameri-
can Samoa, has two populations of
Acropora hyacinthus
living in very different waters: one at 35 °C and the other at
29 °C. Samples from each were placed in controlled tanks
and shocked with temperatures of over 3 °C above normal
for four days. Both corals bleached, but the high tempera-
ture corals survived longer and showed higher expression
in a range of genes associated with thermal tolerance.
Palumbi and his team believe that corals can ‘toughen
up’ if raised in nurseries under more extreme conditions.
Over the generations, they express these thermophile genes
to a higher degree. Even better, once transplanted, these
corals also do significantly better and grow faster than those
raised in cooler pools.
Other research by Hollie Putnam of the University of
Hawaii shows that the larvae produced by corals subjected
to stress have increased resilience to heat and ocean
acidification. These tolerances are then passed on to their
offspring as well. And that’s only part of the overall picture.
The zooxanthellae which infect corals can offer additional
protection to their hosts. Infecting coral larvae with different
species of symbiotic zooxanthellae conveys very different
survival patterns. In other words, some combination of con-
trolled stress during coral farming, and the introduction of
appropriate zooxanthellae, will convey an optimum survival
strategy for corals.
The objective of all these researchers is to create a
seed bank of gametes and fertilised embryos optimised for
extreme environments which can be used to re-seed corals
at risk of bleaching-related death.
Zooxanthellae are much shorter-lived and have a faster
reproductive lifecycle than do corals. Intentionally seeding
entire ecosystems with hardier species of the microalgae
could be a dramatic life-changer.
In agriculture, producing heat- and drought-tolerant
crops is crucial to climate change adaptation. Billions of
the world’s poorest are subsistence farmers and, without
new crops, they will suffer famine.
Even as governments as diverse as those in Australia,
China, Brazil and the US refuse to acknowledge the true
extent of the damage global warming is causing, they are
also funding research to support adaptive response, such
as new crop varieties produced to deal with reduced rainfall
and hotter weather.
The question is not whether such adaption techniques
will work on coral reefs. It is whether the scientists working
on the problemwill solve it fast enough to make a meaning-
ful difference.
Thirty percent of the world’s coral reef populations have
already died from repeated bleaching. With millions of
people depending for their livelihoods on the survival on
the complex ecosystems that live on and in coral reefs, we
can only hope that they solve the problem in time.
RENEWABLES