Transcript The BP Oil Spill - Bob Graham Center

The BP Oil Discharge Experiment
Ian MacDonald,
Florida State University
The BP Oil Discharge Experiment
• Materials and duration
– Hydrocarbon discharged—light, sweet Louisiana
crude with 3000 cf/bbl gas
– Discharge phase 22 April – 15 July 2010 (84 days)
• (+/- 10%)
• Total oil discharge 4.1M bbl: 550,000 tons
• Total gas discharge 2.1M boe: 185,000 tons
Unified Command Discharge Rate Estimates
(all rates x thousand barrels of oil per day)
•
•
•
•
•
•
•
•
23 April: (Landry) 0
25 April: (Landry) 1
28 April: (Landry & BP spokesmen) 5
3 May: (Allen) Undeterminable: rate
determination “impossible” & “possibly
harmful to response”)
27 May FRTG 1st median estimate 15.5
10 June FRTG 2st median estimate 30
15 June FRTG 3rd median estimate 47.5
2 August FRTG final (+/- 10%)
62 (initial rate)
53 (rate after 84 days of discharge)
1500 m
1505 m
Deepwater Plumes
• Plumes of highly diluted oil plus µMolar concentrations of dissolved gas
were found at 1100 m and 1300 m (Joye et al. & Camilli et al.)
• Although it was reported that these plumes had “disappeared” S. Joye et
al. have found them at similar depths within the past few weeks
Hazen et al. Science (24 Aug)
(bacteria ate the oil)
•
A recent paper found high
cell counts of bacteria in
the plume. The authors
inferred that they had
consumed large amounts
of oil
Oceanospirillales A cold-water
γ-proteobacteria
Surface Oil
• In my opinion, the majority of the discharged oil was distributed in surface
layers a few µm in thickness.
• These layers can be detected using synthetic aperture radar and
quantified with semi-automated algorithms.
Spill at its worst
Comparing Seeps to
the BP oil:
Fresh & Degraded Oil
• Crude oil is a mixture of
many different molecules.
• Straight-chain n-alkanes
are abundant in fresh oil.
•Microbes prefer alkanes
and will eat them first in
seep sediments.
•Eventually biodegradation
leaves a complex mixture
of “other stuff” like
asphaltenes.
•NOTE: Natural seeps
support NO infaunal
burrowers.
Emulsified oil
Weathered oil (> 1mm)
23 July, ~95 km from
26 May, ~75 km from
Wellhead (S Pass, LA) Wellhead (NE Pass, LA)
Freshly surfaced oil
12 July, ~3km from
wellhead
Thanks to Markus Huettel, FSU
Thanks to Markus Huettel, FSU
End of July, oil
was buried in
layers as deep
as 60 cm
Deep-sea Benthic Samples N-NE of
well-site (courtesy S. Joye)
Shipek Grab samples from stations 1 and 2 miles off of Santa
Rosa Island (South of Pensacola Pass). Two of three grabs
contained sunken tar balls, asphaltic material. (Courtesy R.
Synder)
R/V Bellows 15-18 June 2010,
tar on shelf sediments south of Pensacola
NOAA Oil Budget & Revision
•The NOAA budget
should be recalculated
to show oil that was
discharged into the
ocean and what is
measured versus
estimated from
algorithms.
Fraction
Recovered direct
Burned
Skimmed
Chemically dispersed
Naturally dispersed
Evaporated & Dissolved
Residual
total
%total
17%
5%
3%
8%
16%
25%
26%
100%
Barrels
%discharged EV units
833000
3.2
245000
6%
1.0
147000
4%
0.6
392000
10%
1.5
784000
19%
3.0
1225000
30%
4.8
1274000
31%
5.0
4900000
1
19.1
Experimental Outcome
• H0 : There will be no lasting harmful effect of
the oil discharge.
"Did we hit the sweet spot here? To some extent,
that's true.“ Steve Murawski, NOAA
• HA : Lasting, significant ecological impact
How will we know?
• My concern is for a fractional loss of
productivity and biodiversity across a broad
sector of ecosystem components (populations
and habitats).
Conclusion: I advocate two approaches
• Identify and monitor key habitats &
populations to verify ecosystem health: E.g.
pelagic—tuna, flying fish, whales; coastal—
coquina, periwinkles, menhaden, etc.
• Put repayment of the Gulf of Mexico
ecosystem in the front of the line. Use the BP
fine ($4B to $24B) to establish an endowment
to restore, understand, and sustain the coastal
and marine environment in perpetuity.
Thank you