POTENTIAL EFFECTS OF UV‐B RADIATION ON MARINE ORGANISMS OF THE SOUTHERN OCEAN: DISTRIBUTIONS OF PHYTOPLANKTON AND KRILL DURING AUSTRAL SPRING

Increases in UV-B radiation resulting from ozone depletion during austral spring could potentially alter the balance of the Southern Ocean marine ecosystem. A quantitative assessment ol the effects of UV-B enhancement requires knowledge of (1) the wavelength-dependent fluxes of UV-B in the upper ocean, (2) action spectra for UV-B damage to Antarctic phytoplankton and zooplankton, and (3) depth-dependent distributions and residence times of Southern Ocean phytoplankton and zooplankton during austral spring. Unfortunately, only limited data arc currently available to address this impact directly. To provide some of the information required for such an assessment, available data regarding plankton distributions and their photophysiological characteristics have been summarized. A preliminary assessment of the available literature suggests that Antarctic phytoplankton and krill receive very low doses of UV-B during austral spring. The high spectral attenuation coefficients associated with the environments in which most plankton arc found during springtime precludes the possibility of UV damage. Future research directions are described which should provide a better understanding of the ecological consequences of the “ozone hole” which resides over the Antarctic continent during austral spring.