Warmer waters
aid some corals
Western Australian reefs
faring better than eastern
By Devin Powell
Corals on Australia’s Great Barrier Reef
have fallen on hard times recently. But
on the opposite side of the continent,
their west coast brethren have been living the good life for at least a century.
Global warming may be helping these
creatures out, a new study finds. “To
date, it is the changes in temperature
that are having the dominant impact on
coral growth,” says Timothy Cooper, a
marine biologist at the Australian Institute of Marine Science in Crawley.
Cooper and his colleagues collected
samples of Porites coral at six spots off
Australia in the southeastern Indian
Ocean. Porites build skeletons with layers
that, like tree rings, can measure growth.
None of the creatures had slowed their
growth in the last 110 years, the team
reports in the Feb. 3 Science. Those at
the southernmost sites have even been
building reefs faster as surface waters
there have warmed markedly.
Samples collected at reefs in Western
Australia (one shown) suggest that corals in these locations have been thriving.
+ 6. 2
percent
Porites growth rate change
at Coral Bay, Western
Australia, 1900–2010
− 14
percent
Porites growth rate
change on Great Barrier
Reef, 1990–2005
On the Great Barrier Reef, the same
type of coral is stressed, previous work
has shown. Porites grew 14 percent slower
in 2005 than in 1990, a slowdown blamed
on both warming waters and ocean acidification linked to rising carbon dioxide.
About a third of all atmospheric carbon
dioxide emissions are soaked up by the
oceans, where the gas reacts to make
carbonic acid. That lowers the water’s
pH and levels of dissolved carbonate, the
raw material corals use to build skeletons.
Ocean acidification is expected to have
a greater effect at some of the higher lati-
tudes surveyed in the new study, where
dissolved carbonate is less plentiful to
begin with. But Cooper and colleagues
found no sign that changing pH both-
ered the corals they sampled. Acidifica-
tion may still be a problem in the long run,
but for now temperature seems to be the
bigger factor. Warmth seems to make the
reef builders more productive.
‘Nonstick’ chemicals pose risk
Pollutants dampen immune response after childhood
By Janet Raloff
Tiny amounts of two common pollutants— chemicals known as PFOA and
PFOS— in the blood may be linked to
impaired immunity in children. In kids
with the highest exposure, vaccinations
can fail to trigger sufficient levels of protective antibodies, a new study finds.
“We were shocked, to be frank, in the
magnitude of the effect,” says Philippe
Grandjean of the Harvard School of Public Health in Boston. He and colleagues
report the result in the Jan. 25 Journal of
the American Medical Association.
The long-lived pollutants— part of a
class of chemicals called perfluorinated
compounds, or PFCs — have been generated over the years by the production of
synthetic substances that impart nonstick properties and water- and stain-repellency to fabrics, cookware and more.
These substances include older formulations of treatments marketed under such
trade names as Teflon and Scotchgard.
Grandjean’s group followed 587
children in Denmark’s Faroe Islands
from before birth through age 7. The
researchers measured PFCs in the blood
of the kids’ moms during pregnancy and
in the kids at ages 5 and 7. Blood levels of
the chemicals were in the same ballpark,
if a bit lower, than typical in Americans.
