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Abstract ULTRAVIOLET RADIATION EFFECTS ON SOUTHERN OCEAN PLANKTON Patrick J. Neale1, Wade Jeffrey2,
Ann Gargett3, Ultraviolet radiation influences the dynamics of plankton processes
in the near-surface waters in the Southern Ocean in the austral
spring period both under normal atmospheric conditions and during
periods of ozone depletion. Ozone depletion enhances exposure to
the shorter, more damaging, UV-B radiation. Progress has been made
in estimating the quantitative impact of UV (and enhanced UVB) in
the S. Ocean for such processes as phytoplankton photosynthesis,
bacterial incorporation and DNA damage. More recently, research
has focused on systems dominated by the colonial alga Phaeocystis
antarctica. This species dominates spring blooms in polynyas
(ice-free region in an otherwise ice-covered ocean) that develop,
for example, in the southern Ross Sea in October and November. This
polynya has particular interest because it results in open water
at a far southerly location in the spring, well within the "ozone
hole" and exposing plankton to elevated UV-B. The continuous
daylight characteristic of this time of year has also implications
for the regulation of DNA repair most of which normally occurs at
“night”. Another important factor is the depth and rate
of vertical mixing. These distinctive aspects of Southern Ocean
UV photobiology will be illustrated using results from our most
recent cruises.
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