the explorers journal the global adventure issue - The Explorers Club

Secret Lifeoficebergstext by Kenneth L. Smith, Jr.photographs by Rob SherlockDrifting islands of ice, sculpted by fragmentation,erosion, and melting, icebergs have become harbingersof climate change. And nowhere on Earth are theymore prevalent than in the Southern Ocean along theAntarctic Peninsula, a curved finger that juts out tothe northeast from the main ice-shrouded continent,separating the Amundsen Sea to the west from theWeddell Sea to the east. It is along the eastern boundaryof the Antarctic Peninsula that a major northerlyflow from the southerly reaches of the Weddell Seahas been dubbed “iceberg alley. “The recent breakup of the huge ice shelves alongthe western boundary of the Weddell Sea has calveda large number of icebergs. These sculptures of blueand white ice, tens of thousands of years old, occurin an endless variety of tabular and pinnacle forms asthey proceed along iceberg alley on a northerly “deathmarch” into the warmer waters of the Scotia Sea andSouth Atlantic.46I have been fascinated by icebergs since my firstoceanographic cruise to the Antarctic more than30 years ago. I reasoned that as guardians ofthe ice-shrounded continent, these magnificentfrozen sculptures, with their large underwatermass, would be havens for enhanced marine life.Indeed, on many subsequent cruises I have observeda preponderance of seabirds associatedwith most icebergs.In 1992, one of my post-doctoral students,Ron Kaufmann, and I decided to place a seriesof upward-looking acoustic arrays moored tothe sea floor of the Weddell Sea to observe anddocument the pelagic communities associatedwith the advancing and receding of the seasonalpack ice. It became clear from the data we collectedthat icebergs drifting north through clearwater, free of pack ice, did not travel alone butwith an entourage of zooplankton and nekton.The author prepares to deploy an ROV from the deck of the RV L.M. Gould