Travel Reference
In-Depth Information
Beyond the Corals…
Coral reefs are more than just corals, and our worries about a warming climate extend to
the multitude of critters that call these ecosystems home. Green and loggerhead turtles bury
their eggs at the back of coral-island beaches, the warm sand incubating the developing
embryos. The sex of the hatchlings is determined by the temperature the eggs experience:
cooler temperatures cause eggs to develop into male hatchlings; warmer eggs become fe-
males. Turtle researchers are worried that a warmer world could create an imbalance in the
sex ratio, putting extra strain on already depleted turtle populations. For turtles the risks
don't stop there. Rising sea levels (predictions are as much as 1.1m higher by the end of
this century) put many nesting areas at greater risk of deadly flooding. Turtles will need to
find higher ground for nesting, but in many coastal areas natural barriers or urban develop-
ment limit their options.
For coral-reef fish, sea-level change might not be a big issue, but changes in ocean tem-
perature have the potential to affect the timing and success of important processes such as
reproduction. There is also growing evidence that fish might be prone to the effects of
ocean acidification, which is the direct result of increased absorption of CO
2
by the world's
seas. The upside to this process is that it has kept the atmosphere from warming even faster.
But the pH of seawater is important to a wide range of chemical and biological processes,
including the ability of fish to find their home reef and to avoid predators.
Climate change is also altering ocean currents, making life difficult for animals that rely
on the timing and location of water movements for their survival. Scientists have already
observed mass deaths of seabird chicks on remote islands as a result of their parents having
to travel too far to find the schools of fish they need to feed their flightless young. Plank-
ton, too, are vulnerable to changing chemistry and currents, with potential flow-on effects
through entire food chains. Corals don't escape the effects of ocean acidification, either.
More-acidic water makes it more difficult for corals to build their skeletons, leading to
slower growth or more fragile structures.
