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13 July, 2003

I have always thought of the Arctic as being the end of civilization. Indeed, this clean, icy world of fresh air and clear water contributes to an immense feeling of remoteness far from anything to do with humanity. And at first glance, the two Polar Bears that we observed this afternoon would seem to confirm this.

That's right, the great white Ursus maritimus! Although the two bears were a considerable distance away from the ship, they still provided quite a show for the large audience that gathered on the Palmer’s bridge to see them. Earlier in the day, we had noticed several Ringed Seals lounging by their holes in the ice, and speculated that where there were seals there must be bears; therefore, it was no surprise when Leopoldo Llinas, a graduate student interested in zooplankton as well as bears, knocked on my cabin door to tell me about the bears. (Several of us have an agreement to wake-up or inform each other of unusual wildlife sightings.)

They are not easy to see. Polar bear fur, like the ice, is translucent. Usually it is easier to spot the bears' tracks than the bear itself. Fortunately, this time of year at least, their fur has a slightly yellowish color (from algae?) that helps me to quickly find one of the bears in the surrounding white frozen seascape.

However, as I enjoy watching the bears with everyone else, I am reminded of some disturbing news that I recently learned about polar bears before our cruise. The trouble involves human-made pollutants that some scientists suspect may threaten the bears’ very survival. In one study for example, polar bears near Svalbard, Norway were found to have high doses of some industrial chemicals such as PCBs (polychlorinated biphenyl compounds). And research in Barrow, Alaska has detected high levels of mercury spread throughout the food chain reaching all the way up to the Arctic's top predator, the Polar Bear. The pollution seems to be transported by the wind or ocean where it is concentrated by plankton, and then consumed by fish and marine mammals such as seals, and ultimately, bears.

What this means for bears is not yet known, but there are some disturbing signs beginning to be linked to high concentrations of pollutants. Denning mother bears that lost their cubs were found to have levels of PCBs three times higher than mothers whose cubs survived. PCBs also seem to reduce the bears' immunity to disease by suppressing their ability to produce antibodies. Certain pollutants seem to be altering the levels of hormones in both male and female bears and scientists are trying to determine if this affects their fertility. In fact, in the Svalbard population of bears, 3 or 4 bears out of a hundred, exhibit genital abnormalities. And PCBs seem to deplete the bears' reserves of vitamin A, which is essential for regulating growth. Of course, much work remains to be done, but it seems that the top of the world isn't as clear as it seems.

I guess we're not that far from the rest of the world after all.

Eric's shot of the bear up on the ice.

Eric Hutt's photo of a swimming polar bear.

Bear watching from the Palmer's bridge.

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