5. 2
million
Total barrels of
oil released in
gulf spill
Barrels of oil
not recovered
at source of spill
gulf floor tainted
by oily deposits
Patches are the remnants of
an oil-eating bacterial bloom
and cells were evident.
“This is the
mechanism that we
propose deposited
oil to the [Gulf’s] bot-
tom,” Joye said.
Photos taken in
September in areas
that had encountered
BP oil show streamers
of microbial spit “all
over the place,” she
said. “The stuff we’re
seeing in the lab form-
ing from the addition
of oil is very similar
looking to what we see on the bottom.”
When Joye and her colleagues
extracted cores of sediment from the
Gulf’s spill-impacted zones, the top
sediment layers often showed signs
of what appeared to be the microbial
spit. That layer also was devoid of living
by Janet raloff
Huge quantities of oil that gushed from
BP’s well blowout last spring and summer now taint the Gulf of Mexico’s
seafloor, newly released video and chemical sampling data show. Within 40 miles
of the damaged wellhead, the oil deposits
appear extensive but patchy, and range
from little spots of oil on the seafloor
to localized blankets of goopy hydrocarbons several inches thick.
New data suggest that much of this
oil may have rained down from the
sea surface, fostered by what scientist
Samantha Joye calls “microbial spit.”
Joye, an oceanographer and biogeo-chemist at the University of Georgia in
Athens, described her team’s findings
on February 19.
Joye shared underwater images
depicting eerie strings of bacterial
slime — mucus streamers ranging from
1 millimeter to almost 2 meters long. The
key ingredient of the slime is a material
that, like laundry detergent, helps break
apart large oil globules. Such surfactants
are secreted by many oil-eating bacteria and render the oil easier to digest. As
the sticky slime picks up cells and other
debris from the water, the goop becomes
heavy and sinks.
Or that’s what appeared to be happening, Joye said. To investigate, her
team went back to the lab and added
a milliliter of oil from the BP well to a
liter of surface seawater collected from
an oil-free part of the Gulf.
After a day, naturally occurring
microbes in the water began growing
on the oil. After a week the cells formed
blobs that were so heavy they began
sinking to the bottom of a jar. Two weeks
later, large streamers of microbial slime
strands of oil-laden “bacterial spit” floating in the gulf of
mexico will eventually sink, carrying oil to the seafloor.
animals, forming what Joye called an
“invertebrate graveyard.”
She often saw dead corals, crabs and
sea stars in the affected seafloor areas.
Absent were sea cucumbers that are
normally abundant in parts of the Gulf
where natural petroleum seeps occur.
callous-unemotional traits an omen
Lack of guilt and empathy in bad kids signals trouble to come
by bruce bower
When an unrelenting penchant for
misbehaving joins forces with lack of
emotion, guilt and empathy, 7-year-olds
are headed for years of severe conduct
problems, a long-term study of British
youngsters suggests.
Kids who regularly misbehave and
get into trouble at age 7 and also display
traits termed “callous-unemotional” frequently stay on a troubled course until at
least age 12, according to a new investigation described February 20.
These findings indicate that callous-
unemotional traits should factor into the
definition of a particularly virulent form
of childhood conduct disorder in the next
manual of psychiatric disorders, said
study leader Nathalie Fontaine of Indiana
University in Bloomington. Chronic mis-
behavior alone defines conduct disorder
in the current edition of the book that
doctors use to define mental ailments.
www.sciencenews.org
March 12, 2011 | science news | 17
