The Gerlache Strait
Water is the only naturally occurring substance that exists in all three phases - gaseous or vapor, liquid, and solid - over the normal range of temperatures encountered on our planet. Today we experienced all of these. In the early morning, the National Geographic Explorer entered Charlotte Bay, passing large chunks of glacial ice - freshwater ice floating in a saline sea. At the head of Charlotte Bay, we encountered shore-fast sea ice - frozen ocean left over from the past winter, protected from ocean swells and firmly attached to the land of the Antarctic Continent. It is another peculiar feature of ice that it is less dense as a solid than as a liquid, hence it floats, and the combination - floating sea ice firmly attached to land - gave us the opportunity to walk over the ice, walking on water, literally. The solid ice also provided a platform for (fanfare!) emperor penguins. In fact, our wake-up call brought the news that these, the largest of all penguins, could be seen from the bow. Our ship entered the ice - really, it was driven right into it, and we could step off the ship and directly onto the ice. Under our feet was about 4 feet of ice and, below that, 500 meters of water between the bottom of the ice and the seafloor below. Quite the place for a morning stroll.
And here is why one should never try to finish the Daily Expedition Report before the day is truly over. I had written about our afternoon Zodiac cruises in the Enterprise Islands: icebergs, seals, gentoo penguins, and the history of Antarctic whaling. It was a lovely way to spend an Antarctic afternoon. But hit the delete button. Tear the paper out of the typewriter and start over. We have just finished a most remarkable experience with feeding humpback whales in the Gerlache Strait. At dinner, a guest looked out the window and called "Whales!" Little did we know what awaited us! The ship slowed as we finished our chocolate mousse and rushed to our cabins for warm clothing, then to our favorite observation perches.
Humpback whales were all around us, perhaps a dozen of the giant beasts. Clearly, they had found a swarm of their favorite prey, Antarctic krill, and were diving repeatedly through the swarm in a tight group, with each dive and lunge to the surface engulfing who-knows-how-much of the abundant prey. Hordes of Southern fulmars, ghostly gray and white, joined in the feeding frenzy, dashing to the vicinity each time the whales rose to the surface. The dives were shallow, short, and frequent. Bubbles rose to the surface just ahead of the whales. They were using bubbles as a tool to concentrate the prey, not quite the highly organized, cooperative bubble-net feeding that we see in Alaskan water but clearly a related behavior. Tool using in whales! As the birds dispersed and the whales became less frantic in their feeding, it appeared that the krill swarm was either exhausted or had escaped from the whales. But our evening was far from over. Two of the whales took a great interest in our ship, or perhaps in the joyous screams of people hanging over the side in amazement as the whales passed along the port side, then the starboard side, then again the port. We looked down their massive heads with paired blowholes. We could see commensal barnacles and the protuberances that the whalers called stovebolts, each of them holding a single hair follicle. Sometimes their inordinately long pectoral flippers (each 1/3 the total length of the whales) were extended on each side, glowing white through the productive water. Simple put, it was a spectacular evening in Antarctica, and we were there to take it in. How fortunate we are!
