Valuable background information about oil slicks: excerpts from Science

Links to interesting articles about the Gulf oil spill.

The definitive report about oil spills is Oil in the Sea III — Inputs, Fates, and Effects“, National Academy of Sciences, 2003.

Excerpts from Science

Here are 3 excerpts with information about oil spills, partial antidotes to the hysterical guessing that the news media passes off as journalism.  All are subscription-only.

  1. Why hasn’t there been more research on mitigating the effects of oil spills?
  2. What are the long-term effects of oil spills?
  3. What were the long-term effects of the Exxon Valdex spill?

(1)   Why hasn’t there been more research on mitigating the effects of oil spills?

Science Lags on Saving the Arctic From Oil Spills“, Michael Torrice, Science, 11 September 2009 — Excerpt:

In 1986, the federal government set up the Oil Spill Liability Trust Fund to pay for cleaning up spills, putting a nickel tax on every barrel of crude oil produced domestically or imported into the country. In 1990 — 1 year after the Exxon Valdez spilled 250,000 barrels of crude into the sub-Arctic Prince William Sound in the Gulf of Alaska — Congress created a national research program funded by the trust fund to improve cleanup technologies and study spill effects on ecosystems in all regions, including the Arctic. A 13-agency coordinating committee led by the U.S. Coast Guard oversees the program.

But the national oil-spill research plan hasn’t been updated since 1997, and the federal agencies have spent only a fraction of the $28 million a year that was authorized —

  • last year’s total for all oil-spill research was $7 million.
  • The Oil Spill Recovery Institute in Cordova, Alaska, which, under the 1990 Oil Pollution Act, was created to study spills in the Arctic, typically spends $800,000 a year.
  • In contrast, Norway, for example, has invested $10 million since 2006 to study new oil-spill technologies in the Arctic.

A 1993 U.S. National Research Council (NRC) report on the coordinating committee’s original plan concluded that the “effectiveness of the plan is in doubt” because of the low level of funding, adding that public interest in oil spills wanes quickly after an accident occurs.

Another problem, says Mead Treadwell, chair of the U.S. Arctic Research Commission, which is charged with recommending national policy on Arctic research, is that the Coast Guard has been preoccupied with homeland security since the 2001 terrorist attacks. “It just isn’t working,” Treadwell says about the 1990 law’s research program. “We need to have the confidence that we can prevent and respond to spills in this frontier region.”

(2)  What are the long-term effects of oil spills?

Long-Term Ecosystem Response to the Exxon Valdez Oil Spill“, Charles H. Peterson et al, Science, 19 December 2003 — Abstract:

The ecosystem response to the 1989 spill of oil from the Exxon Valdez into Prince William Sound, Alaska, shows that current practices for assessing ecological risks of oil in the oceans and, by extension, other toxic sources should be changed. Previously, it was assumed that impacts to populations derive almost exclusively from acute mortality. However, in the Alaskan coastal ecosystem, unexpected persistence of toxic subsurface oil and chronic exposures, even at sublethal levels, have continued to affect wildlife. Delayed population reductions and cascades of indirect effects postponed recovery. Development of ecosystem-based toxicology is required to understand and ultimately predict chronic, delayed, and indirect long-term risks and impacts.

(3)  What were the long-term effects of the Exxon Valdex spill?

Exxon Valdez Turns 20“, Lila Guterman, Science, 20 March 2009 — Except:

Scientists on both sides agree that many species have recovered in Prince William Sound, including bald eagles, cormorants, salmon, and river otters. But the oil, government scientists think, has had severe impacts on at least two photogenic animals: killer whales and sea otters.

The two pods of whales photographed and identified in the oil slick in 1989 each lost about 40% of their members around the time of the spill, says Rice. “That is just totally unprecedented,” he says. One pod is recovering slowly, but the other, originally comprised of 22 whales, has lost all of its females of reproductive age and is down to seven or eight members. Eventually, Rice says, “they’re going to become extinct.” Because the two unrelated pods declined so suddenly and at the same time, researchers argued last year in Marine Ecology Progress Series, the deaths were almost certainly caused by the spill when the whales breathed oil fumes or ate contaminated prey. But Exxon scientists say the deaths can’t be conclusively linked to oil.

Meanwhile, sea otters have rebounded in most of the sound, but populations remain low in some heavily oiled areas where oil lingers in the intertidal zones. U.S. Geological Survey biologist James Bodkin fitted 16 otters with time-depth recorders and reported in February at a meeting of the Alaska Forum on the Environment that shallow intertidal digging represented about 18% of female sea otters’ dives. “They’re going to get exposure to oil,” says Rice.

Most scientists do agree about the fate of at least one injured species: Pacific herring, whose populations are only 15% of their prespill numbers. In the late 1980s before the spill, the herring f ishery in Prince William Sound was worth $12 million and the population was at a record high. The year after the spill, the population seemed high again—estimated at 120,000 tons—and the fishery opened. But then in 1993, the population crashed: Only 20,000 tons of herring appeared.

Was this due to the spill? Many scientists think not. A poor bloom of plankton in 1992 left the fish hungry and vulnerable to disease, says fish pathologist Gary Marty of the British Columbia Ministry of Agriculture and Lands in Canada, who has been studying the herring since the spill. He and Terrance Quinn of the University of Alaska, Fairbanks, developed a model that he says can “describe every blip in the population for the past 15 years.”

But Richard Thorne, an acoustics researcher at the Prince William Sound Science Center, says hydroacoustic monitoring results suggest that the spill—and the subsequent 3 years of fishing—caused the population to crumble. In 1993, he started conducting annual hydroacoustic surveys, which use sonar to count fish. He and Gary Thomas, a fisheries scientist at the University of Miami, noted that the acoustic results correlate well with aerial surveys of herring spawn, which have been done every year for more than 30 years, and suggest the decline began in 1989.

Unfortunately, most herring studies stopped after 1990, so neither side in this debate has data about the critical precollapse years. As a result, researchers may never know for sure, says George Rose, a fisheries conservation expert at Memorial University in St. John’s, Canada. “In a way, it doesn’t matter,” says NOAA’s Rice. “We need to know why they don’t come back.”

Another perspective:  “Lasting legacy of the Exxon Valdez“, Naomi Lubick, Nature, 20 March 2009 — “Twenty years on, the iconic oil spill remains an expensive ecological disaster.”  Excerpt:

Ten years after the spill, ecologists estimated that between 100,000 and 700,000 birds had died because of oil exposure, based on an extrapolation of the number of oiled carcasses collected on beaches and from the water1. While many species are now back up to pre-spill levels, or are recovering well, two have not recovered at all: pigeon guillemots and Pacific herring.

On 31 December 2008, the Exxon Valdez Oil Spill Trustee Council submitted a recovery plan for the herring, an economically important fish in the region. But some argue that the oil spill may not have been responsible for the demise of the herring fishery. Overfishing or other ecosystem shifts, such as an increase in disease or decline in available food sources for the fish, may have contributed.


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