Nanoparticulate titanium dioxide (TiO(2)) is highly photoactive, and its function as a photocatalyst drives much of the application demand for TiO(2). Because TiO(2) generates reactive oxygen species (ROS) when exposed to ultraviolet radiation (UVR), nanoparticulate TiO(2) has been used in antibacterial coatings and wastewater disinfection, and has been investigated as an anti-cancer agent. Oxi...

Predicting where species invasions will occur remains a substantial challenge in ecology, but identifying factors that ultimately constrain the distribution of potential invaders could facilitate successful prediction. Whereas ultraviolet radiation (UVR) is recognized as an important factor controlling species distribution and community composition, the role of UVR in a habitat invasibility con...

Ultraviolet radiation (UVR) damages most biota, yet little evidence exists for its long-term effects on natural ecosystems. We used paleoecological techniques at three low-elevation lakes to show that algal abundance in lakes was depressed 10-fold by UVR during the first millennium of lake existence. Likewise, analysis of data from a lake near treeline showed that algal biomass declined 10–25-f...

Rising levels of ultraviolet radiation (UVR) striking the Earth’s surface have led to numerous studies assessing its inhibitory effects on phytoplankton and periphyton in aquatic systems. Mineral nutrients such as nitrogen (N) and phosphorus (P) have been shown to increase aspects of algal metabolism and compensate for UVR inhibition. An in situ substratum enrichment technique and UV shielding ...

While excessive exposure to ultraviolet radiation (UVR) is a significant cause of disease burden in Australia and the Western Pacific region, there are well documented beneficial as well as adverse effects of UVR exposure. Ambient UVR levels do not translate directly to personal UVR dose and thus to biological effect - each person's sun-exposure behaviour and pigmentation also play a role. Expo...

Laboratory exposures of embryos from the sea urchin Strongylocentrotus droebachiensis to ultraviolet B radiation (UV-B, 290-320 nm), equivalent to a depth of 1-3 m in the Gulf of Maine, resulted in significant damage to DNA measured as cyclobutane pyrimidine dimer formation. Cells with DNA damage caused by ultraviolet radiation (UVR, 290-400 nm) and oxidative stress can survive, but are often r...

Global warming and ozone depletion, and the resulting increase of ultraviolet radiation (UVR), have far-reaching impacts on biota, especially affecting the algae that form the basis of the food webs in aquatic ecosystems. The aim of the present study was to investigate the interactive effects of temperature and UVR by comparing the photosynthetic responses of similar taxa of Chlorella from Anta...

We present a mathematical model for a phytoplankton-zooplankton system, based on a predator-prey scheme. The model considers the effects of sinking in the phytoplankton, vertical mixing and attenuation of photosynthetically active radiation (PAR) and ultraviolet radiation (UVR) in the water column. In a first approach, the model was studied under conditions of average PAR irradiance and shows f...

Terrestrial life is dependent on radiant energy from the sun. Solar radiation is largely optical radiation [radiant energy within a broad region of the electromagnetic spectrum that includes ultraviolet (UV), visible (light) and infrared radiation], although both shorter wavelength (ionizing) and longer wavelength (microwaves and radiofrequency) radiation is present. The wavelength of UV radiat...

Biomass burning has an impact on atmospheric composition as well human health and wellbeing. In South Africa, the biomass season extends from July to October affects aerosol loading tropospheric ozone concentrations which in turn solar ultraviolet radiation (UVR) levels at surface. Using ground-based observations of aerosols, UVR (as modelled UVR) we investigated aerosols August, September, ove...