At Sea in the South Atlantic
Crossing the Antarctic Convergence last night we left the great Southern Ocean in our wake. The convergence is an invisible boundary, flexible and ever-shifting but nonetheless tangible and real. Global travelers cross many lines of this kind, most of them subtle borders; in many cases we might not be aware of them without some foreknowledge of the situation. Often they are indistinct, difficult to define precisely, but they hold a fascination for us. They can exert a power over us, and sometimes crossing one can be like stepping through a doorway into a completely new world.
Some are absolutely definite. The Equator, the Tropics and the Polar Circles can be placed to within millimeters, but would any of us be a keen and patient enough observer to see these boundaries, defined as they are on the tremendous scale of astronomy had they not been discerned long ago and laid down for us? Some seem as solid as rock but are truly ephemeral in the deep time of geology. Stepping onto the shore of a new continent, we can say “This is Antarctica.” But in the recent past, when sea levels stood lower, some of the nearby islands on which we landed were also part of the continent, and if the ice were to melt, all of West Antarctica would be an off-shore archipelago, a part of the continent only in the sense that Japan is a part of the Asian continent. Drift back into time a bit further and the separate identities of the continents vanish completely into the ages-long dance of plate tectonics.
Some of these boundaries are restless, ever-moving. The terminator sweeps around the planet each day, bringing the change of day and night wherever it finds us. Weather fronts pass over our vessel, the winds shift and clouds come and go as a new mass of air arrives.
We crossed the Antarctic Convergence silently. Without our ship’s thermometers, we wouldn't have known that over a period of hours the water temperature rose from just a few degrees above freezing to the mid-40’s Fahrenheit. Although it is sometimes sharp and distinct, this season the boundary has been broad, smeared north and south from its average position. Nonetheless, we have crossed the line; we are in the South Atlantic and the biology of the waters around us is completely different than that of the seas we sailed only a few hours ago. After 15 days and many adventures, we have stepped back through the door and left the Antarctic behind.
Crossing the Antarctic Convergence last night we left the great Southern Ocean in our wake. The convergence is an invisible boundary, flexible and ever-shifting but nonetheless tangible and real. Global travelers cross many lines of this kind, most of them subtle borders; in many cases we might not be aware of them without some foreknowledge of the situation. Often they are indistinct, difficult to define precisely, but they hold a fascination for us. They can exert a power over us, and sometimes crossing one can be like stepping through a doorway into a completely new world.
Some are absolutely definite. The Equator, the Tropics and the Polar Circles can be placed to within millimeters, but would any of us be a keen and patient enough observer to see these boundaries, defined as they are on the tremendous scale of astronomy had they not been discerned long ago and laid down for us? Some seem as solid as rock but are truly ephemeral in the deep time of geology. Stepping onto the shore of a new continent, we can say “This is Antarctica.” But in the recent past, when sea levels stood lower, some of the nearby islands on which we landed were also part of the continent, and if the ice were to melt, all of West Antarctica would be an off-shore archipelago, a part of the continent only in the sense that Japan is a part of the Asian continent. Drift back into time a bit further and the separate identities of the continents vanish completely into the ages-long dance of plate tectonics.
Some of these boundaries are restless, ever-moving. The terminator sweeps around the planet each day, bringing the change of day and night wherever it finds us. Weather fronts pass over our vessel, the winds shift and clouds come and go as a new mass of air arrives.
We crossed the Antarctic Convergence silently. Without our ship’s thermometers, we wouldn't have known that over a period of hours the water temperature rose from just a few degrees above freezing to the mid-40’s Fahrenheit. Although it is sometimes sharp and distinct, this season the boundary has been broad, smeared north and south from its average position. Nonetheless, we have crossed the line; we are in the South Atlantic and the biology of the waters around us is completely different than that of the seas we sailed only a few hours ago. After 15 days and many adventures, we have stepped back through the door and left the Antarctic behind.
