Biological Systems, Global Change and Ozone Recovery.

DIAZ; S.B; PALADINI; A; DIÉGUEZ, M.C; BUITRAGO, L; DEFERRARI, G.A; VRALOVICH, J., ; VERNET, M.

Aveiro

Simposio; Congreso; ESP Congress 2015. Symposium Global change and quantitative modelling of photobiological responses; 2015; 2015

European Society of Photobiology

While trespassing the atmosphere andreflecting on the ground, solar ultraviolet radiation (UVR) is affected byscattering and absorption processes. Themain factors that determine ground-level radiationare: sun-Earth distance, atmospheric gases and aerosols, solar zenith angle(SZA), clouds cover and type, and surface albedo. Some of these parameterspresent well established variations with time and location, which will remainunchanged in the future (i.e.: SZA and sun-Earthdistance), while others are expected to change as consequence of ozonerecovery and global change. According tothe most recent report on the ozone layer, decreases in the atmosphericabundance of controlled ozone depleting substances have been observed, derivedfrom actions taken under the Montreal Protocol, enabling a future return of theozone layer toward 1980 levels. In addition, globalchange is expected to produce climatological variations in cloud cover andtypes, earth reflectivity (albedo) and aerosols. The above mentioned variationswould lead to spectral, geographical and seasonal changes in solar radiation atthe earth surface, resulting in increases or decreases of beneficial anddetrimental effects of UV on living organisms (erythema, vitamin D production,DNA damage, etch). Due to the spectral dependence of the action spectraand the parameters under consideration, not all ecosystems would be equallyaffected. We have analyzed the changes in four biologically effectiveirradiances, for three situations, when one or more of the parameters thataffect UV changed. The situations we considered were: ozone recovery atdifferent latitudes in the Southern Hemisphere, a volcanic eruption andaltitude effect. The selected action spectra were DNA, erythema, phytoplanktonand vitamin D production. Except when considering the effect of clouds,biologically effective irradiances with action spectra more sensitive to lowerwavelengths (DNA, vitamin D) were the most affected, while those with flatteraction spectra (phytoplankton) would almost suffer no effect.enviar mensaje