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What Lessons Have We Learned?
The raison d'etre for the NOAA Prince William Sound Monitoring Program has always been to improve the way we respond to oil spills in a complex environment like the Sound. Our goal is to use science to better understand physical and biological recovery, and then apply the lessons to spill response. The insights we gain relate to both the process of environmental monitoring itself, and impacts caused by the spill and cleanup. With that in mind, what have we learned?
First, it is difficult to assess the impacts from a disturbance--even a major one like the Exxon Valdez spill--in a dynamic system like Prince William Sound. The inherently high degree of variability found in such systems limits or precludes the use of standard or traditional statistical methods.
So-called "setaside sites," areas that were oiled but intentionally left uncleaned, have been critical in the NOAA Emergency Response Division monitoring program's ability to discern impacts attributable to oiling alone and those due to cleanup. During an oil spill, there are compelling reasons to clean up all oil; however, to monitor the recovery of shorelines, setaside sites are key considerations. We recommend that the concept be discussed during oil spill contingency planning, and again during the inevitable spill events.
High-pressure, hot-water washing of shorelines, while effective at removing stranded oil, can damage plants and animals in the treated zone directly and indirectly, short-term and long-term. This might seem obvious, but before the Exxon Valdez spill there was almost no real documentation of these impacts.
Much has been made of the cleanup doing "more harm than good." While to some extent true, this statement is a bit of an oversimplification that does not fully convey the complexities and competing interests associated with evaluating environmental tradeoffs. We now know the detrimental effects of intrusive shoreline cleanup methods like high-pressure, hot-water washing. However, this does not mean we would eliminate its use in the future. Hopefully, with the guidance of monitoring efforts like this one, we can employ the method in a wiser fashion.
Physical characteristics of the environment determine the makeup of biological communities. Therefore, altering the physical features of a beach or shoreline can significantly affect the recovery of impacted plants or animals. Physical recovery and stabilization of a site are necessary for biological recovery. The adjacent photo shows one of our study sites on Eleanor Island being cleaned, with silty sediments being noticeably washed out into the water. We believe that many, if not most, of the animals that normally live in this kind of beach require a certain mix of fine-grained sediments, and so may not return until the beach sediments have stabilized.
If there is a proverbial silver lining to the Exxon Valdez oil spill, it must include the fact that the incident and its aftermath have represented a remarkable opportunity to learn from misfortune. Our research is but one example of the many scientific investigations in Prince William Sound that should help us to understand the environment, how it responds to oil spills and cleanup, and how we can facilitate the process of recovery--however you may choose to define that term.
Other pages in this series
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