Bahia Paraiso

wreckage of the Bahia Paraiso On January 28, 1989 the Argentine Polar Transporter Bahia Paraiso ran aground near Janus and DeLaca islands less than two miles from Palmer Station. The Bahia was en route to resupply the Argentine stations in the vicinity and had called on Palmer Station to allow the tourists on board an opportunity to visit. Although no passengers or crew members were injured as a result of the accident, diesel fuel and other petroleum products (Estimated at 600,000 liters spilled) began leaking from the hull. This presented a great threat to the environment and ongoing research in the area. I believe that this is probably the worst environmental disaster in Antarctica.

Why haven't I heard about it then? Well, it happened about the same time as another historic oil spill in a polar region. The Exxon Valdez also ran aground during 1989 in Alaska's Prince William Sound. Estimates of that spill put it at 38,156,952 Liters (240,000 barrels).

Why did the Bahia run aground? I have heard several different versions of the story. I'll let you draw your own conclusion. First was simply that the charts the captain had were inaccurate. But I've also heard that Palmer station radioed to the Bahia that they were entering a shallow area and the captain ignored them. Either way, it looks like the ship was running at moderate speed when she ran aground. And there were an extra 202 people for dinner. "The US Antarctic Program contacted two tourist ships in the vicinity, the Society Explorer and the Illyria, which immediately altered course to Palmer Station and took the passengers to South America. No loss of life occurred, but considerable logistical and scientific research resources from a number of nations and tour operators were diverted as a response to the accident." (Penhale 1997)

Researchers from Palmer station quickly started sampling water, soils, and biological specimens. This of course severely impacted research, but more importantly the local environment. "The early observations showed that by four days after the Bahia ran aground, a 30km2 area surrounding Palmer Station was covered in an oil slick (Kennicutt 1990). Because of differences in tides, winds, and currents, the quality of the petroleum products and the duration of exposure varied from island to island. Rocky intertidal sites, particularly those that had been exposed to the spill for 3 to 4 days, showed the first signs of ecological damage. By February, a 50% mortality of intertidal limpets was estimated and algal mats in the littoral zone also appeared dead (Penhale 1989).

The initial impact on seabirds in the area varied. Although few dead birds were observed, most adult birds appeared to have been exposed to the fuel oil (Fraser and Patterson 1997). Initial surveys of all local Adélie penguin (Pygoscelis adeliae) colonies indicated that more than 80% of the birds had been exposed to the spill. The exposure of the various species of seabirds in the area depended on their behavior. Adults were exposed primarily through feeding on krill and fish present in the area. As the spill occurred during the peak period of chick growth for many species, chicks were exposed to oiled parents and oiled food. Adélie penguin chicks fledged several weeks after the spill, and were thus exposed again at that time.

Initial observations on other ecosystem components suggested negligible effects (Kennicutt 1990). Marine mammals (Which were primarily absent from the area during February and March) and benthic fish appeared not to be affected by the spill. Initial results of microbial degradation of hydrocarbons indicated low levels of activity. Preliminary examination of the sub-tidal community suggested little impact. Most of the results and interpretations required further laboratory and data analyses or long-term observations before conclusions could be drawn on the environmental impact of the spill.

The effect of the oil spill on the seabird community varied with time and with species; effects appeared both direct and indirect. Both during the time of the spill and in subsequent years, results showed that among the breeding populations of giant petrels (Macronectes gigantes), brown Skuas (Catharacta skua), and South Polar skuas (Catharacta maccormicki) were not adversely affected (Fraser and Patterson 1997). At the time of the oil spill, however, a population wide mortality of the South Polar skua chicks occurred.

Alternative hypothesis exist as to whether this mortality was due to the oil spill, weather conditions, or a regional food limitation, or a combination of these factors (Eppley 1992, Eppley & Rubega 1990, Trivelpiece et al. 1990).

Comparison of changes in the Adélie penguin populations in the vicinity of Palmer Station with those receiving no exposure to oil suggests that colonies exposed to oil lost an additional 16% of their numbers, when the loss due to natural variability was less than 3% (Fraser & Patterson 1997). Populations exposed to oil showed no significant differences compared to control sites in subsequent years. Cormorants (Phalacrocorax atriceps) showed near 100% mortality of chicks following the spill; in subsequent years, the active number of active nests has decreased by approximately 85% (Fraser & Patterson 1997). This is most likely due to exposure to the fuel spill in areas of bathing and foraging used by cormorants.

An example of indirect effects has been suggested for the kelp gull (Larus dominicanus) (Fraser & Patterson 1997). While the adult populations did not appear affected at the time of the spill, the number of active nest sites in the area exposed to the oil spill has shown a steady decline since 1989. During the breeding season, males defend intertidal limpet populations for themselves and their mates. Fraser & Patterson proposed that the damage done to the intertidal limpet populations accelerated the depletion of this resource in an area where resource limitation was severe, thus driving limpet densities below the threshold levels needed to maintain gull reproduction. (Penhale 1997)"

In late 1992, an operation was undertaken to recover the remaining fuel from the wreckage. This action was spurred by concern by the United States and Argentine governments about the situation. After agreement on a new international Antarctic Treaty (Madrid, October 4, 1991) contacts between the governments of the Argentine Republic and the Kingdom of the Netherlands resulted in a Memorandum of Understanding, signed on February 18, 1992) The two parties undertook a joint effort to study and remove any remaining fuel and other products remaining on the Bahia wreckage. I won't address specifics of the recovery, just state that it was very successful. It did, however, show the difficulty of responding to an oil spill in these waters. I have watched video tape footage of oil spill exercises. Ice tends to get caught in the containment booms, and often the booms are easily moved by even fairly slight winds. But even today (1997) there is a small slick around the Bahia and the smell of hydrocarbons, from minute amounts of lubricants still coming out of fittings, or small areas of the ship where they were trapped in the initial sinking.

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