Icebergs that calve off giant ice shelves can create "deserts"
in the ocean by blocking sunlight from reaching marine life. An
iceberg 20 miles wide and 124 miles long named C-19, that
broke off from the Ross Ice Shelf in Antarctica last year, is
wiping out marine wildlife. It's killing phytoplankton, which is a
key element in the Antarctic food chain. Entire colonies of
penguins have disappeared.
Geophysicist Kevin Arrigo says, "It's absolutely horrendous."
An earlier iceberg, called B-15, that broke loose from the Ross
Ice Shelf in 2000, also had a giant impact. Arrigo thought
that one was "really big?But it was just dwarfed by what we
saw this past year.
"Not only is [phytoplankton] down 90%, but whatever
production there was happened really late in the season and
a lot of these animals, like penguins, time it so that their
chicks hatch right at the time that the Ross Sea is most
productive, which is December. And now, suddenly, we don't
have a peak in production until March, and the peak is 90%
below the normal peak. So in terms of the food supply,
there's almost nothing there this past year," Arrigo says.
Lee Dye writes in abcnews.com that entire colonies of
penguins have disappeared, since the iceberg has ended up in
the area where one of their biggest rookeries used to
be. "The birds can't get around this thing," Arrigo says. "It
would be like swimming around the state of Rhode Island.
They just can't do it."
If we
listen closely, we can feel their pain.
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