14 November, 2003
In a place where winter lasts so long, the rest of the seasons seem to move along at a rather rapid pace. Other than the daily variation in temperature and wind, each day has some reminder that we are not much more than a month away from the summer solstice. For those of you in the middle latitudes of the northern hemisphere, think about late May; the sun rises higher in the sky each morning and stays longer in the evening, birds are returning from their winter migration, leaves are appearing on the trees, spring wildflowers are exhibiting their colors, and rivers are rising with meltwater from high alpine snows. Change happens rapidly and suddenly, it's summer.
The spring/summer transition seems much more subtle here in Antarctica. The sun, which last set in late October, just marches across the sky a little higher each day and night and won't dip below the horizon at McMurdo until February 20th. Besides burning our faces a little darker brown each day, the sun plays an important role in the subtle shift from spring to summer. It's certainly warmer now than it was when we first moved out here to our camp at Big Razorback. It hasn't been below -18C (about 0F) for a couple of weeks. High temperatures have been around -7 to -5C at camp and are probably much higher in some of the places we visit that are protected from the wind.
How does this affect the ice? There are new melt pools on top of the ice near some of the cracks. In addition, some of the more prominent tidal cracks are getting wider, while new smaller cracks are appearing near some of the seal colonies that we visit regularly. The water we see in some of the cracks or in the seal swimming holes no longer looks like a giant slushy. I even noticed icicles hanging from some of the crack edges today-to get icicles you need to have melting, so it must have been over 0C along those cracks. It's a good time to pay attention when cruising across the ice since the crack you saw today might be quite different the next time out.
What are the seals doing? Well, the pups are getting fat. Their days are spent lounging next to their mothers drinking milk with a fat content of 60%. Think about sitting in front of the TV with an endless supply of pizza and Twinkies and very little exercise. The pounds add up. Today we weighed a seal pup that was 92kg. Since most weigh around 30 to 35 kg at birth, this one has definitely put on some weight. Some of the pups are swimming with their mothers, or at least lolling about in the holes and taking short dips. The mothers are losing weight, regaining just a bit of their former svelte seal selves. They will not eat until their pups are weaned, so the pup's weight gain is their weight loss. Many of the mothers are now swimming while their pups continue to lounge on the ice. In addition, the pups are losing their original furry coats and replacing them with a coat of short seal fur now that they have developed a substantial layer of blubber for insulation. Many of the pups look like mini-seals now, instead of awkward furry babies.
Our Skua population has increased from the first few stragglers. They are a constant part of the seal colonies, feasting on dead seals or on the bloody afterbirth that remains when the seal pups are born. The warm temperatures thaw these Skua snacks, so they can eat them. Until now much of their food was too frozen to access. We also see the occasional flightless bird, when stray Adelie Penguins cruise in from Cape Royds. We're not sure where they're heading, but they definitely keep moving along!
This is not to say that we are all running around here in our t-shirts basking in the warm almost-summer sunshine. The transition from spring to summer in Antarctica seems as fickle as that same transition at home. While you can have a long streak of beautiful warm days, there are always a few cold and blustery ones thrown in to remind you that it is not quite summer yet. I've been reminded of this on a few mornings when I step outside anticipating the Antarctic equivalent of balmy, only to be greeted by a chilling wind coming straight from the South Pole. Oh well, just keep pulling on all those nice layers of long underwear!
Twenty-four hour sun
Its rays penetrate the ice
Thawing and changing
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