Could stratospheric ozone depletion lead to enhanced aquatic primary production in the polar regions?

We study the effects of ozone depletion on primary production in ice-covered and open polar waters using a spectral radiative transfer model combined with a parameterization of the inhibition of marine photosynthesis by ultraviolet radiation. We find that ozone depletion might not have a negative influence on the aquatic algal community at high latitudes but instead could enhance primary production. For an ozone depletion of 50%, we estimate the yearly averaged enhancement to be about 1%. Even though ozone-destroying chemicals are mostly phased out of production, they will reside in the atmosphere for the next few decades and continue to deplete stratospheric ozone. In addition, global warming could indirectly, through increased formation of stratospheric ice clouds, increase the destruction of ozone (Austin et al. 1992; Staehelin et al. 2001). Various studies have suggested that one effect of ozone depletion on aquatic ecosystems could be a reduction in primary production because of increased ultraviolet B (UVB; 280 , l , 320 nm) radiation (Häder 1997). Smith et al. (1992) estimated a reduction in primary production of about 6– 12% in the marginal ice zone in the Southern Ocean with a stratospheric ozone reduction from 300 to 200 Dobson units (DU). At about the same time, Holm-Hansen et al. (1993) estimated the reduction in daily primary production under a well-developed ozone hole (150 DU) in Antarctica to be ,3.8%. Five years later, Neale et al. (1998b) predicted that an ozone depletion from 300 to 150 DU would lead to a reduction in primary production of between 8.5% and 0.7% for clear sky conditions and between 6.2% and 0.8%