This morning, National Geographic Explorer continued its crossing from the Falklands to South Georgia. Settled seas and the occasional sun made for pleasant conditions on deck and good photo opportunities of myriad seabirds in our wake. Between meals, we were entertained by informative talks on whales and penguins as well as the mandatory South Georgia briefing, which prepared us for our arrival.
The day marked an important position on our journey as we crossed the Polar Front / Antarctic Convergence. Between 4 and 8 a.m., the water temperature dropped from 4C to 1.5C, marking the convergence zone, where cold surface water from the south meets the warmer waters from the north. This zone of temperature change defines the boundary of the Southern Ocean and the northern confines of the Antarctic, making it a zone of high productivity and biological diversity.
The Southern Ocean was identified and named by James Cook in 1769. Cook’s first voyage on the HMS Endeavour was charged with sailing to Tahiti to observe the transit of Venus—but it had a hidden agenda. Cook carried with him sealed orders instructing him to seek out the “Great Southern Continent,” or Terra Australis, which he did not find. Cook would later resume his search for the Southern Continent during his second circumnavigation of the globe in the early 1770s. He came close to sighting Antarctica before pack ice forced him to turn back. Thus, the discovery of the Southern Ocean predated that of Antarctica.
