A small portion of iceberg B17, which broke off the Ross Iceshelf in 2000 is grounded on the shelf just off South Georgia. © Gary Krosin
After crossing the Antarctic Convergence, icebergs become a regular sight and no two icebergs are ever the same. © Gary Krosin
Antarctic Convergence: Experience it on an Antarctica, South Georgia and Falklands Small Ship Cruise
Posted by Kevin Clement
in Of Interest and Polar Regions
“And now there came both mist and snow
And it grew wondrous cold;
And ice mast-high came floating by,
As green as emerald.”
–Samuel Taylor Coleridge, The Rime of the Ancient Mariner
I think of Coleridge’s words every time I cross the Antarctic Convergence on a cruise to Antarctica, South Georgia and Falkland Islands. Although the poet never sailed the Southern Ocean himself, he read the accounts of mariners who had, and his words seem a very apt description of the experience.
The Convergence is the line where cold, dense waters emanating from the ice of the Antarctic continent meet the somewhat warmer sub Antarctic surface water, and eventually sink below it. The line is shifting and irregular, and is really more of a broad band than a distinct line, but it marks a discernible change. It represents the biological boundary of Antarctica. As a meeting point between two ecological zones, it is also a rich and productive area itself. The mist that Coleridge summons often marks the crossing, as air warmed by the northern water mass cools and condenses over the southern.
So Antarctica actually begins far out to sea from the edge of the continent. Significantly, South Georgia lies within the Convergence, while the Falkland Islands do not. Thus, the Falklands have a cool temperate (albeit windy) climate, while South Georgia is festooned with massive glaciers.
It is an exciting day at sea during a small ship cruise to Antarctica, South Georgia and Falkland Islands. The temperature, both air and sea, drops and you start to see creatures native to the high latitudes: White-chinned and White-headed Petrels, and Black-bellied Storm Petrels. Later comes the ice—not quite mast-high, but in chunks large enough to qualify as bergy bits in the old sailors’ classification. Next you’ll encounter banks of fog and, by the end of the day, the colder temperatures level off.
The chill I feel at this point has nothing to do with the temperature–it is simply the excitement I always feel. We have crossed the Convergence; we have entered Antarctica. South Georgia, with its stark and glorious mountains and massive abundance of wildlife, lies ahead. Although it’s called a Convergence, to me it’s a separation—a line that separates the more ordinary world from the magic of Antarctica.
Join Kevin in January on our Antarctica, South Georgia and Falklands Small Ship Cruise.