Iceberg Threatens Penguin Survival in Antarctic

The calving of three giant icebergs from the Ross Ice Shelf over a relatively brief span of 14 years seems to be a significant increase over such activity in past decades, and it comes at a time of dramatic changes in Antarctica. Scientists have documented warming trends in some areas of the continent, in some cases by as much as 6 degrees, but Arrigo doesn't believe the intense level of activity in the Ross Sea has anything to do with global warming.

"There's no evidence that anything is warming up there," he says, referring to the Ross Sea, which is at a higher latitude, 77 degrees south, than the Antarctic Peninsula, where the warming trend has been found. It's still very, very cold in the Ross Sea.

‘Iceberg Graveyard’

Unlike people who have studied this kind of thing in the past, Arrigo and his colleagues have a continuous flow of critical data throughout the year, thanks to NASA. The satellite's SeaWIFFS instrument (Sea-viewing Wide Field of View Sensor) and other sensors aboard other satellites measure everything from light coming from the sea to sea water temperatures.

Phytoplankton contains green chlorophyll, so by measuring the intensity of the "greenness" of the water, the scientists can estimate the rate of phytoplankton production.

That gave them the basis for their dire predictions about the impact of C-19, which incidentally has finally moved on after lodging for awhile on a sand bar. Driven by currents, the berg has drifted into an area Arrigo calls an "iceberg graveyard" about 600 miles from the productive area that is so important to marine organisms.

But its legacy will linger on. The damage has been done.

Lee Dye’s column appears weekly on A former science writer for the Los Angeles Times, he now lives in Juneau, Alaska.

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