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Dampak dari
tumpahan minyak Deepwater Horizon di karang lebih dalam dan lebih luas daripada
yang diperkirakan
Penemuan baru
dua komunitas karang tambahan menunjukkan tanda-tanda kerusakan dari tumpahnya
minyak Deepwater Horizon memperluas jejak dampak dari tumpahan 2010 di Teluk
Meksiko.
Impact of Deepwater Horizon oil spill on coral is deeper and broader than
predicted
Date:
July 28,
2014
Source:
Penn State
Summary:
A new discovery of two additional coral communities
showing signs of damage from the Deepwater Horizon oil spill expands the impact
footprint of the 2010 spill in the Gulf of Mexico.
....................
A new discovery of two additional coral communities showing
signs of damage from the Deepwater Horizon oil spill expands the impact
footprint of the 2010 spill in the Gulf of Mexico. The discovery was made by a
team led by Charles Fisher, professor of biology at Penn State University.
A paper
describing this work and additional impacts of human activity on corals in the
Gulf of Mexico will be published during the last week of July 2014 in the
online Early Edition of the Proceedings of the National Academy of Sciences.
"The
footprint of the impact of the spill on coral communities is both deeper and
wider than previous data indicated," said Fisher. "This study very
clearly shows that multiple coral communities, up to 22 kilometers from the
spill site and at depths over 1800 meters, were impacted by the spill."
The oil from
the spill in the Gulf of Mexico has largely dissipated, so other clues now are
needed to identify marine species impacted by the spill. Fisher's team used the
current conditions at a coral community known to have been impacted by the
spill in 2010 as a model "fingerprint" for gauging the spill's impact
in newly discovered coral communities.
Unlike other
species impacted by the spill whose remains quickly disappeared from the ocean
floor, corals form a mineralized skeleton that can last for years after the
organism has died. "One of the keys to coral's usefulness as an indicator
species is that the coral skeleton retains evidence of the damage long after
the oil that caused the damage is gone," said Fisher. The scientists
compared the newly discovered coral communities with one they had discovered
and studied around the time of the oil spill, using it as a model for the
progression of damage caused by the spill over time. "We were able to
identify evidence of damage from the spill in the two coral communities
discovered in 2011 because we know exactly what our model coral colonies,
impacted by the oil spill in 2010, looked like at the time we found the new
communities."
Corals are
sparse in the deep waters of the Gulf of Mexico, but because they act as an
indicator species for tracking the impact of environmental disasters like the
Deepwater Horizon blowout, the effort to find them pays off in useful
scientific data. "We were looking for coral communities at depths of over
1000 meters that are often smaller than the size of a tennis court," said
Fisher. "We needed high-resolution images of the coral colonies that are
scattered across these communities and that range in size from a small
houseplant to a small shrub."
To begin the
search, the team used 3D seismic data from the Bureau of Ocean Energy
Management to identify 488 potential coral habitats in a 40 km radius around
the spill site. From that list they chose the 29 sites they judged most likely
to contain corals impacted by the spill. The team then used towed camera
systems and Sentry, an autonomous underwater vehicle (AUV), which they
programmed to autonomously travel back-and-forth across specific areas
collecting images of the sites from just meters above the ocean floor. Finally,
the team used a Shilling ultra-heavy-duty remote-operated vehicle (ROV), to
collect high-resolution images of corals at the sites where they were
discovered.
"With
the cameras on board the ROV we were able to collect beautiful, high-resolution
images of the corals," said Fisher. "When we compared these images
with our example of known oil damage, all the signs were present providing clear
evidence in two of the newly discovered coral communities of the impact of the
Deepwater Horizon oil spill."
In searching
for coral communities impacted by the Deepwater Horizon oil spill, the team
also found two coral sites entangled with commercial fishing line. These
additional discoveries serve as a reminder that the Gulf is being impacted by a
diversity of human activities.
In addition
to Fisher, the research team included Pen-Yuan Hsing, Samantha P. Berlet, Miles
G. Saunders and Elizabeth A. Larcom from Penn State; Carl L. Kaiser, Dana R.
Yoerger, and Timothy M. Shank from the Woods Hole Oceanographic Institution;
Harry H. Roberts from Louisiana State University; William W. Shedd from the
Bureau of Ocean Energy Management; Erik E. Cordes from Temple University; and
James M. Brooks from TDI-Brooks International Inc.
The research
was supported by the Assessment and Restoration Division of the National
Oceanic and Atmospheric Administration (NOAA), the Gulf of Mexico Research
Initiative funding to support the Ecosystem Impacts of Oil and Gas Inputs to
the Gulf (ECOGIG) consortium administered by the University of Mississippi, and
B P as part of the Deepwater Horizon Oil Spill Natural Resource Damage
Assessment.
Story
Source:
The above
story is based on materials provided by Penn State. The original article was written by Samuel J.
Sholtis. Note: Materials may be edited for content and length.
Journal
Reference:
- Charles R. Fisher, Pen-Yuan Hsing, Carl L. Kaiser, Dana R. Yoerger, Harry H. Roberts, William W. Shedd, Erik E. Cordes, Timothy M. Shank, Samantha P. Berlet, Miles G. Saunders, Elizabeth A. Larcom, and James M. Brooks. Footprint of Deepwater Horizon blowout impact to deep-water coral communities. Proceedings of the National Academy of Sciences, 2014; DOI: 10.1073/pnas.1403492111