Title : Deepest Ozone Hole Matched by Record Ultraviolet Radiation
Type : Press Release
NSF Org: OD / LPA
Date : November 18, 1993
File : pr9387
Lynn Simarski November 18, 1993
(202) 357-9498 NSF PR 93-87
Deepest Ozone Hole Matched by Record Ultraviolet Radiation
This year's ozone hole over Antarctica, notable for the lowest values of
ozone ever recorded on Earth, is also apparently allowing record levels
of ultraviolet (UV) light to strike Antarctica. Scientists supported by
the National Science Foundation (NSF) are now investigating what impact
the increased UV might have on Antarctic life, and whether animals and
plants may employ natural mechanisms to avoid harm from UV. Studies
have already estimated that UV damage has reduced the productivity of
ocean phytoplankton--the tiny plants that comprise the base of the food
chain in the Southern Ocean--by six to 12 percent.
At the United States' South Pole research station, up to November 3, the
average level of UV-B--the part of the spectrum most harmful to
life--has been 19 percent higher than in the past two years. The
average "erythema" level of UV--a measure relating sunlight to skin
cancer--is 23 percent higher than in the past. According to another
criteria, an assessment of UV's damage to exposed DNA, this year's
values were 56 percent higher. The station is part of a UV-monitoring
network sponsored by NSF and run by Biospherical Instruments, Inc. At
the U.S. McMurdo Station on the Ross Sea coast, where UV has been
monitored since 1988, UV-B is 44 percent higher this year, the erythema
level is 55 percent higher, and the DNA damage is 96 percent higher than
in past years. Values are significantly greater at McMurdo because the
sun is higher in the sky and delivers a stronger dose of UV radiation
than at the Pole.
On the other side of the continent, at Palmer Station on the Antarctic
peninsula, record UV levels have also been registered that significantly
exceed any measurements from the entire monitoring network over the past
six years. The average UV-B is 55 percent higher, erythema 73 percent
higher, and the DNA dose is 113 percent greater than in the past.
Various NSF-supported researchers are also studying how the rising UV
levels may affect Antarctic life. Currently, researchers aboard the
Nathaniel B. Palmer, the U.S. Antarctic Program's icebreaking research
vessel, are investigating how ozone depletion affects phytoplankton in
Antarctica's Weddell Sea.
As summer comes to Antarctica and winter's constricted atmospheric
circulation over the continent breaks down, this year's ozone hole may
follow one of two patterns, based on past behavior. The hole may "die"
in place--with the tight winter vortex slowly stopping, followed by
gentle mixing of low-latitude, ozone-rich air into the antarctic
stratosphere. The hole would then appear to have closed.
The other possibility is that the vortex may wobble like a slowing top,
eventually breaking up into large masses of ozone-poor air, which would
sail off, more or less intact, to lower latitudes. In any case, another
NSF UV-monitoring station at Ushuaia, Argentina, has not yet registered
any sign of this year's ozone hole.
The National Science Foundation is an independent agency of the federal
government established in 1950 to promote and advance scientific
progress in the United States. NSF accomplishes its mission primarily
by competitively awarding grants to educational institutions for
research and education in the sciences, mathematics, and engineering.
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