Environmental campaigners have called for greater restrictions on shipping around Antarctica in order to prevent damage to its unique ecosystems.
According to a report in BBC News, a major cause of concern is the fact that more tourists than ever before are visiting Antarctica, some in ships not designed for the harsh conditions.
Antarctic tourism has grown about five-fold in the last 15 years, with figures from the International Association of Antarctica Tour Operators suggesting that 37,552 tourists visited Antarctica during 2006-07, the majority arriving by sea.
The ASOC (Antarctic and Southern Ocean Coalition) is concerned that many of the vessels carrying them are not ice-strengthened. This makes serious accidents more likely, and increases the risk of an oil spillage if a ship gets into trouble.
Campaigners have cited the example of the sinking of the M/S Explorer last year, which they say should be taken as a wake-up call.
They have also documented six incidents in little more than a year which carried a risk of major contamination.
According to John Shears, head of the Environment and Information Division at the British Antarctic Survey (BAS), "BAS's ice-strengthened research vessels use marine gas oil, which is like diesel fuel, and if it spills it will evaporate and disperse quickly in the sea."
"A spill of heavy fuel oil would have a more significant environmental impact because the fuel coalesces in the cold water and is very persistent, making it exceptionally difficult to clean up," he added.
As a positive step in curbing Antarctic ships, ASOC is asking the International Maritime Organisation (IMO) to strengthen its rules.
"The IMO is the only body that can agree stringent vessel standards, equipment and procedures in order to protect human life and the marine environment for all vessels using Antarctic waters," said James Barnes, ASOC's executive director.
ASOC and its allies are calling for the banning from Antarctic waters of ships that use heavy oil as fuel. They want to see tighter restrictions on the discharge of sewage and grey water, and a requirement that all vessels entering the region are strengthened to withstand icy conditions.