Effects of ultraviolet radiation on periphyton in an alpine lake

Abstract

Many alpine lakes have low concentrations of ultraviolet (UV) radiation-absorbing dissolved organic matter, yet receive higher UV radiation flux than low-elevation lakes. We tested whether ambient UV radiation affected periphyton development in a small alpine lake in Banff National Park, Canada. After 30 d, total periphytic biomass and chlorophyll accrual on artificial substrates were enhanced -100% (t-test, P < 0.05) by removal of UV radiation (~400 nm). The inhibitory effect of UV radiation was species-specific, significantly suppressing (Bonferroni-adjusted t-test, P < 0.05) Achnanthes minutissima Kiitzing but not other colonists. Although taxa apparently differed in their sensitivity to UV radiation, periphyton communities remained dominated by early successional taxa, especially A. minutissima (75% of total biovolume). In contrast, natural epilithic communities were dominated by cyanobacteria (Anabaena subcylindrica Borge, Calothrix sp.). These findings suggest that ambient UV radiation at alpine sites can suppress periphyton development by inhibiting littoral diatom production during the short ice-free season (July-September).

Impact of particulate and dissolved material on light absorption properties in a High-Altitude Lake in Tibet, China

“…Also, lakes on the TP are exposed to high fluxes of UV radiation (Norsang et al, 2009;Norsang et al, 2011;Norsang et al, 2014) due to the natural increase of UV radiation with altitude (Blumthaler et al, 1992;Alexandris et al, 1999) and the existence of a low total ozone column during summer (June-September) (Zhou et al, 2006). UV radiation has impact on both zooplankton and phytoplankton in aquatic ecosystems (Vinebrooke & Leavitt, 1996;Tartarotti et al, 1999;Helbling et al, 2001;Sommaruga, 2001).…”

Noeffects of ambient UV radiation detected in periphyton and grazers

“…The pelagic zones of marine and lacustrine ecosystems contain a variety of organisms sensitive to current levels of UV (Hader et al 1995). In freshwater benthic habitats, UV effects have not been as widely investigated, but Bothwell et al (1993) and Vinebrook and Leavitt (1997) both report that ambient UV inhibited biomass accumulation in developing periphyton communities. In more mature periphyton communities, biomass accumulation appeared to be enhanced by UV because grazing chironomids were more sensitive than periphyton to UV, grazing pressure was reduced accordingly by ambient UV (Bothwell et al 1994).…”

Effects of UV Radiation on Wetland Periphyton: Algae, Bacteria, and Extracellular Polysaccharides

“…Prior studies have observed reductions in algal photosynthesis and biomass accumulation in freshwater periphyton under full ambient light (+UV) as compared to -UV treatments (e.g., Vinebrooke and Leavitt 1996), whereas other studies have observed no affect of UV radiation (Hill et al 1997, Hodoki 2005. Shifts in algal species composition have also been observed in longer-term studies, with sensitivity to UV varying by taxon (Bothwell et al 1993, Vinebrooke and Leavitt 1996, Francoeur and Lowe 1998, Higley et al 2001).…”

“…Shifts in algal species composition have also been observed in longer-term studies, with sensitivity to UV varying by taxon (Bothwell et al 1993, Vinebrooke and Leavitt 1996, Francoeur and Lowe 1998, Higley et al 2001). …”