On November 23, 2007 the M/S Explorer, a well-tested, ice-strengthened Antarctic cruise ship sank in Bransfield Strait near the South Shetland Islands, off the Antarctic Peninsula. The 154 people onboard were all safely evacuated and rescued by cruise ships in the vicinity within 4-5 hours. The response time was fast for Antarctic standards and was possible because the accident took place in that part of Antarctica that is most frequented by cruise ships, in perfect weather conditions, and close to the greatest concentration of Antarctic stations and thus help, accommodation and evacuation.
The Explorer sank in waters 1100 - 1500 meters deep, taking down with it approximately 185,000 L of diesel, 24,000 L of lubricants, 1200 L of gasoline and all the machinery, equipment and furniture that was onboard. On November 25 and 26 Chilean officials reported a surface oil slick of 1.5 km long, which decreased in size but oil was obviously still flowing to the surface. Chilean authorities deployed an icebreaker to the region and began to mechanically disperse the oil spill. Few methods exist that can be used to treat oil spills in icy waters. Some of them, such as burning or using chemicals to accelerate the natural dispersion of the oil are especially problematic for the remote and near-pristine environment of the Southern Ocean. In the case of the M/S Explorer, oil is rising from a depth of over 1000 meters through strong currents to arrive under a cover of sea ice. The only thing that can be done for now is to encourage the natural dispersion of the oil by mechanical means (i.e., stirring).
Over time, oil spills naturally break up under wind and wave action and are dissipated or scattered. Under temperate conditions, light products such as gasoline and diesel oils evaporate and dissipate quickly and naturally. However, this process is significantly slowed down by the low temperatures in the Southern Ocean. In the meantime, the high toxicity of gasoline and diesels can have significant impacts on wildlife and the local environment. Chilean officials sighted approximately 2500 birds, most of them penguins, around the site of the sunken M/S Explorer. The situation is being monitored closely. In general, marine wildlife can be impacted by oil spills through a variety of pathways:
- Physical contact with the oil: The insulating capacity of feathers is reduced, possibly leading to hypothermia; Flight or buoyancy can be hindered.
- Toxic contamination by ingestion and inhalation: Could lead to stress, disorientation, fatalbrain lesions, or damage in the digestive system, liver, or lungs.
- Less food available
- Pollution of sea ice: Less visibly, the underside of sea ice is home to millions of microscopic organisms that forms the base of the food chain in the Southern Ocean.
It is the primary food source of many species, including the Antarctic krill and larval fish, which, in turn, are eaten by the fish, seal, seabird and whale predators. To date, there are virtually no toxicity data available on sea-ice organisms and very little is known on how oil spills under sea ice impact the food web. It is possible that oil toxicity can reduce the abundance of seaice organisms. In addition, bioaccumulation of petroleum compounds could transfer contaminants throughout the food web. Any adverse effects on penguins or other birds may also have very serious consequences for eggs or chicks being incubated or brooded ashore by another parent. If the affected bird is unable to return to the breeding site within an appropriate time, the other parent bird will likely desert and the offspring consequently will perish. “When different kinds of oil enter the sea, many physical, chemical and biological degradation processes start acting on them. These processes change the properties and behaviour of the oil. Some processes cause the oil to “disappear”, but the fact that it is no longer visible on the water surface does not necessarily mean that it is gone or has been rendered environmentally harmless.”1
Clean Up and Liability
Two large outstanding questions remain: Who will clean up the accident, and who will pay for it?
To draw on an example from the past: The largest marine oil spill in Antarctica took place in 1989 when the Bahia Paraiso, an Argentine Navy re-supply ship, ran aground about 2 km from the US Palmer Station on Anvers Island off the Antarctic Peninsula. More than 680,000 L of blended diesel and jet fuel was released. (This is about 3.5 times the volume of fuel that sank with the M/S Explorer.) About 300 seabirds died in the three weeks after the event. The US, Argentine and Chilean authorities conducted a joint clean-up effort, which cost an initial $2.5 million for the US authorities alone. Two years after the accident, the remaining fuel and oil were removed from the wreck in a joint Dutch - Argentine operation, which cost US $4 million. Unlike the Bahia Paraiso, the M/S Explorer, which is owned by the Canadian company and licensed in Liberia, is not part of a national Antarctic program.
In 2005, a new Annex on “Environmental Liability Arising from Environmental Emergencies” was added to the Environmental Protocol. It establishes responsibilities and liability in the case of an environmental emergency, such as an oil spill. Under this regime, all Antarctic operators - public and private alike - are responsible for taking “prompt and effective response action” in case of environmental damage arising from their activities. If the operator fails to do so, it is liable to pay the full cost of clean-up actions undertaken by the states involved. Unfortunately, this new addition to the Antarctic Treaty System is still awaiting ratification from the majority of the Antarctic Treaty Parties and therefore has not� yet entered into force. In the meantime, how to address such environmental emergencies in the Antarctic is left in a legal vacuum.
1 What happens to oil in the water. http://oils.gpa.unep.org/facts/fate.htm
Antarctic Treaty Secretariat Circular No. 29/2007
Classroom Antarctica-Australian Government: Chapter 8.5 Oil spills in the Antarctic
Coastal Response Research Center at the University of New Hampshire. www.crrc.unh.edu
E. DeCola, T. Robertson, S. Fletcher and S. Harvey (2006): Offshore Oil Spill Response in
Dynamic Ice Conditions: A Report to WWF on Considerations for the Sakhalin II Project. Alaska, Nuka Research.
Matt Malinowski, “Explorer” Accident Raises Enviro Concerns In Chile, Santiago Times, November 29, 2007
Fate of marine oil spills. International Tanker Owners Pollution Federation Limited (ITOPF), http://www.itopf.com/marine-spills/fate/
Grounding of the Bahia Paraiso at Arthur Harbor, Antarctica, Distribution and Fate of Oil Spill Related Hydrocarbons, Mahlon C. Kennicutt et al., Environ. Sci. Technol. 1991, 25, 509-518.
Global Marine Oil Pollution Information Gateway, http://oils.gpa.unep.org/facts/fate.htm
J.D. Hansom and J.E. Gordon (1998): Antarctic Environments and Resources: a geographical perspective.
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