South Georgia is the place where colossal icebergs go to die.
The huge tabular blocks of ice that frequently break off Antarctica get swept towards the Atlantic and then ground on the shallow continental shelf that surrounds the 170km-long island.
As they crumble and melt, they dump billions of tonnes of freshwater into the local marine environment.
UK scientists say the giants have quite dramatic impacts, even altering the food webs for South Georgia's animals.
Those familiar with the epic journey of Ernest Shackleton in 1916 will recall that it was at South Georgia that the explorer sought help to rescue his men stranded on Elephant Island.
The same currents that assisted Shackleton's navigation across the Scotia Sea in the James Caird lifeboat are the same ones that drive icebergs to South Georgia today.
"The scale of some these icebergs is something else," said oceanographer Dr Mark Brandon from the Open University.
"The iceberg known as A-38 had a mass of 300 gigatonnes. It broke up into two fragments, but it also shattered into lots of smaller bergs. Each smaller berg was still fairly big and each dumped lots of freshwater into the system".
Dr Brandon has been presenting his research here at the 2010 American Geophysical Union (AGU) Fall Meeting, the largest annual gathering in the world for Earth scientists.
Slow deathWith a group of colleagues he planted scientific moorings off South Georgia in several hundred metres of water. The moorings held sensors to monitor the physical properties of the water, including temperature, salinity and water velocity. The presence of plankton was also measured.
The moorings were in prime position to capture what happened when the mega-berg A-38 turned up in 2004.
It is one of many tabular blocks, such as B-10A and A-22B, which have been caught at South Georgia, which lies downstream of the Antarctic Peninsula in currents known as the Weddell-Scotia Confluence.
The island's continental shelf extends typically more than 50km from the coast and has an average depth of about 200m, and when the mega-bergs reach the island, they ground and slowly decay.
"All that freshwater has a measurable effect on the structure of the water column," said Dr Brandon. "It changes the currents on the shelf because it changes the seawater's density. It makes the seawater quite a lot cooler as well". A-38 probably put about 100 billion tonnes of freshwater into the local area. BBC News
