Call
for a "whole new type" of marine ecology
On the second anniversary of the
Deepwater Horizon blowout, a panel of researchers is offering a new model for
understanding what happened in the disaster, how to think of such events in the
future, and why existing tools were inadequate to fully predict what lay ahead.
The May issue of the journal BioScience
published the findings by the members of the University of California, Santa
Barbara's National Center for Ecological Analysis and Synthesis Gulf Oil Spill
Ecotox Working Group.
Many of the co-authors received rapid-response
and other funding from the National Science Foundation (NSF) to conduct
research in the Gulf of Mexico after the spill.
"The paper offers important new
thoughts on how we might respond to future environmental disasters of this
magnitude," said David Garrison, program director in NSF's Division of
Ocean Sciences, which, along with NSF's Divisions of Environmental Biology,
Earth Sciences and others funds Gulf oil spill research.
"This synthesis sheds new light on
the nature of spills and the potential, generally unappreciated, of subsurface
ecological effects," adds Henry Gholz, program director in NSF's Division
of Environmental Biology.
The old model assumed that oil would
"simply float up to the surface and accumulate there and along the coastline,"
said article co-author Sean Anderson of California State University Channel
Islands.
"That model works well for pipeline
breaks and tanker ruptures, but it is inadequate for this novel type of deep
blowout."
The 2010 Deepwater Horizon spill in the Gulf
of Mexico was unlike any other spill science and society had encountered.
The well blowout occurred at
unprecedented depths and released enormous quantities of oil--an estimated 4.9
million barrels, or 206 million gallons.
Marine and wildlife habitats suffered
major damage which, the co-authors say, continues to happen today, out of
sight. Local economies and livelihoods
suffered as well.
According to the paper's
authors--ecotoxicologists, oceanographers and ecologists who convened under the
auspices of NCEAS while the spill was active--the response to clean up and
contain the oil followed a certain framework.
That framework assumed the oil's
behavior would mimic the more familiar shallow-water and surface spills,
despite the fact that the dynamics, fate and effect of deep-water oil on
ecosystems are not well understood.
"As the Deepwater Horizon spill
unfolded, you would hear folks saying things like 'we all know what happens
when oil and water mix; the oil floats,'" said Anderson.
"But that wasn't the whole story.
And that oversimplification initially sent us down an incorrect path with
assumptions and actions that were not the best possible use of our time and
effort."
As they synthesized existing knowledge
to anticipate the potential ecotoxicological effects of the spill and
highlighted major gaps in scientific understanding, the scientists created the
first complete conceptual model for understanding both the Deepwater Horizon
spill and analogous disasters in the future.
The new model accounts for how
deep-water oil spills unfold and where the resulting ecological effects accrue.
It also emphasizes that the vast
majority of the oil is retained at depth--rapidly emulsified and dispersed due
to the physics of the pressurized oil jetting from the tip of the
wellbore--and, among other response actions, calls into question the efficacy
of dispersants.
"We have generally hailed the use
of [chemical] dispersants as helpful, but are basing this on the fact that we
seemed to have kept oil from getting to the surface," said co-author Gary
Cherr of the University of California, Davis Bodega Marine Lab.
"The truth is that much of this oil
probably was staying at depth independent of the amount of surfactants we
dumped into the ocean.
"And we dumped a lot of dispersants
into the ocean, all told approximately one-third the global supply."
Co-author Ron Tjeerdema, an
environmental toxicologist at UC Davis, concurs.
"The problem is that we must
address the downside of such compounds, particularly in light of the fact that
the upside probably was not as great as it seemed at the time," he said.
Armed with a new foundation for research
and policy implications, the scientists are calling for further investigation
on the long-term effects of deep-water oil spills like that of the Deepwater
Horizon.
"We now have a sense that the bulk
of the effects were probably in the mid-water and deep ocean," said the
paper's lead author, Charles "Pete" Peterson of the University of
North Carolina - Chapel Hill.
"We need an integrated
collaboration among deep-water explorers, modelers, ecotoxicologists, microbial
ecologists and others. All working together in unprecedented ways.
"We need a whole new type of marine
ecology."
-- Cheryl Dybas, NSF (703) 292-7734
cdybas@nsf.gov
-- George Foulsham, UCSB (805) 893-3071
george.foulsham@ia.ucsb.edu
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