Stratospheric Ozone Depletion - The Changing Arctic Environment: The Arctic Messenger - page 117

primary production in the world's oceans. However, remember that most UV radiation is
absorbed within the first metre from the ocean surface.
Some shallow water fish species have shown increased incidences of skin conditions,
including cancers, that are normally associated with high UV exposure. However, adult
fish appear to be generally quite resilient - perhaps because they show behavioural adapt-
ations, such as simply swimming to deeper water. Last year, in Cyprus, we visited some
large aquaculture fish tanks constructed in Ptolemaic times (about 300 BCE). The walls of
the tanks had deep but blind tunnels that provided the fish with a midday refuge. Nothing
new under the sun?
Once again, climate change complicates assessing future aquatic exposure to UV radi-
ation. For example, the turbidity of ocean coastal waters is much influenced by the amount
of coloured dissolved organic matter being added by terrestrial runoff. This depends on the
amount and nature of precipitation. Regional changes in patterns of rainfall predicted in
climate models will therefore affect the intensity profile of UV in adjacent marine waters.
In the Arctic, species that have evolved to live in an environment in which very little UV
penetrated the sea ice are now experiencing ice-free summers.
This is the end of our short review of ozone depletion. Despite the apparent effective-
ness of the Montreal Protocol and the emerging scenario of ozone layer recovery, we may
have some unpleasant interludes on our way to (or beyond) pre-1980 ozone levels, espe-
cially in the Arctic. However, these will be much easier to consider when we have taken a
look at polar atmospheric circulation and climate change.
Finally, from the perspective of the Arctic Messenger, I think the situation is not en-
tirely satisfactory. Yes, ozone levels have been stabilized and the massive depletions seen
in the Antarctic may have been avoided in the Arctic. However, 25 years ago, leaders of
Arctic indigenous peoples' organisations knew that ozone depletion was more pronounced
at both poles and were asking about the implications to their health and their natural envir-
onments. I expect the reader will have noticed that most of the answers to their questions
today come not from Arctic data but from extrapolations and inferences from studies at
mid-latitudes. Sometimes, this approach works. Sometimes, it does not.