Effect of UV radiation on the global carbon cycle: the influence of marine phytoplankton's response to UV-B increase

In this report, model calculations are presented of the potential UV effect on global primary production for recent ozone layer conditions compared to those of 18 years ago. During the appearance of the ozone hole above the Antarctic (September-December), the calculated decrease in dept-integrated primary production over the past 18 years amounts to 2.2 percent. In the Arctic, a decrease of up to 0.6 percent is estimated during the period March-May.

The ozone related change in total global export production over the past decades was no more then marginal. Locally, however, Negative effects can be significant. The maximum change in export production appeared in November in the Southern Ocean it was lowered with 1.2% for this month. Due to many uncertainties, large errors may occur in these kind of assessments. For instance, more information is needed about the adaptation of algal species to UV radiation, their differential sensitivity to UV radiation, and consequent changes in the entire ecosystem. Further, more insight has to be gained in the role and functioning of the biological pump, both on a spatial and temporal scale. Only then, future developments can be predicted with some certainty.