Volume 16, Number 21: 22 May 2013
As Llabres et al. (2013) note in discussing the results of their important new study, "the formal exploration of elevated UVB radiation as a possible cause of the accelerated declines in marine biota - despite evidence that UVB may induce coral bleaching (Gleason and Wellington, 1993) and significant phytoplankton mortality in the ocean (Llabres and Agusti, 2006; Agusti and Llabres, 2007; Labres et al., 2010)" - is likely a consequence of the "widespread misconception" that the Montreal Protocol "solved the problem of elevated UVB radiation." Although the protocol was indeed successful in helping to avoid further deterioration of the stratospheric ozone layer and laying the foundations for its recovery, this recovery, in their words, "has not yet occurred," with the result that the problem of elevated UVB radiation is still with us.
In an attempt to assess the scope of this ongoing threat to earth's marine life, the seven scientists analyzed the findings of 1,784 experimental assessments of the impacts of UVB that have been "performed with natural radiation and organisms from different geographical areas, as well as with artificial radiation and cultured organisms at many laboratories around the world." And this meta-analysis revealed, as they describe it, that "increased UVB radiation leads to a sharp increase in mortality rates across marine taxa, with protists, corals, crustaceans and fish eggs and larvae being most sensitive."
As a result of their meta-analysis, Llabres et al. (2013) did indeed find that "mortality rates of marine biota increase rapidly in response to elevated UVB radiation," and they thus conclude that "elevated UVB may have played a role in enhancing biological declines in the ocean" - citing "recent widespread declines in the abundance of marine organisms ranging from corals to fish and krill" - by "inducing synergies with the more proximal drivers," such as rising water temperatures and declining pH values. We agree; and we thus suggest that until the stratospheric ozone layer makes a full recovery, we ought not buy into the climate-alarmist claim that global warming and ocean acidification are - in and of themselves - the demons they make them out to be.
Sherwood, Keith and Craig Idso
References
Agusti, S. and Llabres, M. 2007. Solar radiation-induced mortality of marine pico-phytoplankton in the oligotrophic ocean. Photochemistry and Photobiology 83: 793-801.
Gleason, D.F. and Wellingon, G.M. 1993. Ultraviolet-radiation and coral bleaching. Nature 365: 836-838.
Llabres, M. and Agusti, S. 2006. Picophytoplankton cell death induced by UV radiation: evidence for oceanic Atlantic communities. Limnology and Oceanography 51: 21-29.
Llabres, M., Agusti, S., Alonso-Laita, P. and Herndl, G. 2010. Synechococcus and Prochlorococcus cell death induced by UV radiation and the penetration of lethal UVR in the Mediterranean Sea. Marine Ecology Progress Series 399: 27-37.
Llabres, M., Agusti, S., Fernandez, M., Canepa, A., Maurin, F., Vidal, F. and Duarte, C.M. 2013. Impact of elevated UVB radiation on marine biota: a meta-analysis. Global Ecology and Biogeography 22: 131-144.