1,080
fi sh
Catch rate per kilometer
in northern Gulf of Mexico,
2006–2009
1,989
fi sh
Catch rate per kilometer
in northern Gulf of
Mexico, 2010
Deep sea rich in
valuable metals
Cost would be high to mine
Pacific rare earth elements
North America
South America
Australia
By Devin Powell
Mud at the bottom of the Pacific Ocean
contains surprising levels of rare earth
elements, 17 chemicals with exotic
names like neodymium and europium
that are crucial to technologies ranging
from cell phones and televisions to fluorescent lightbulbs and wind turbines.
Hot plumes from hydrothermal vents
pulled these materials out of seawater
and deposited them on the seafloor, bit
by bit, over tens of millions of years. One
square patch of metal-rich mud 2. 3 kilometers wide might contain enough rare
earths to meet most of the global demand
for a year, Japanese geologists report
online July 3 in Nature Geoscience.
“I believe that rare earth resources
Concentration
of rare earth
elements (parts
per million)
400 – 700
700 – 1,000
1,000 – 1,500
> 1,500
Sunken treasure Geologists measured concentrations of rare earth elements in ocean
sediments at 78 Paci;c sites. In some places (shown), concentrations were comparable to those
in clays in China, which produces most of the world’s supply. SOURCE: Y. KATO ET AL/NATURE GEOSCIENCE 2011
undersea are much more promising than
on-land resources,” says Yasuhiro Kato,
a University of Tokyo geologist who led
the study.
About 97 percent of the world’s rare
earth elements come from China, which
has restricted exports in recent years.
With prices skyrocketing, shortages are
feared — especially in Japan, which lacks
minable deposits of these elements.
Kato’s team analyzed seafloor cores
taken from 78 sites throughout the Pacific
Ocean. Near Hawaii and in the southeast
Pacific, concentrations of rare earths
were comparable to those found in clays
mined in China. Some deposits of heavy
rare earths such as dysprosium, a com-
ponent of magnets in hybrid car motors,
contained twice as much as in the clays.
Some fish thrived despite oil spill
BP blowout didn’t dent populations in Gulf’s seagrass beds
By Janet Raloff
Young fish remained abundant last summer and fall in some areas of the Gulf of
Mexico that were slammed by the catastrophic BP oil spill. The finding runs
counter to expectations of huge losses,
especially among fish born during or
shortly after the April 20 well blowout.
F. Joel Fodrie of the University of
North Carolina at Chapel Hill and
Kenneth Heck Jr. of the University of
South Alabama Dauphin Island Sea Lab
tallied juvenile fish retrieved by research
vessels between mid-July and late October over five years ending in 2010. The
abundance of youngsters offered one
gauge of whether eggs and larval fish had
taken a big hit from exposure to the spill.
Among 20 different fish types (some
species, some larger groups) commonly
found in seagrass meadows in the
Seagrass-dwelling pipefish of the genus
Syngnathus (left), were as abundant
during and after the 2010 Deepwater
Horizon spill as in previous years.
northern Gulf, juveniles of a dozen types
were present in numbers notably higher
than during the previous four years. For
the remaining eight kinds of fish, Fodrie
and Heck found that 2010 catch rates
were “statistically indistinguishable”
from previous years. The pair detailed
their findings online July 6 in PLo S ONE .
Large trawl yields following the spill
probably reflect a reduction in fishing
resulting from a broad postspill ban on
commercial harvests, Heck says. Initial
fishery closures began 12 days after the
blowout and continued in some places
through April 19, 2011, just over nine
months after the well was capped.
“Our initial results don’t show cause
for concern,” Heck says. “But we don’t
know what we’re going to see in a few
years in terms of their growth or survival.” Indeed, he notes, “there’s reason
to believe from some prior work that
there may be delayed effects.”
FROM TOP: GEOATLAS/GRAPHI-OGRE, ADAPTED BY E. FELICIANO; KIKE CALVO VWPICS/SUPERSTOCK
www.sciencenews.org
