Ambient Levels Of Solar Radiation Research Articles

Sun Protection and Skin Examination Practices in a Setting of High Ambient Solar Radiation: A Population-Based Cohort Study.

Primary prevention and early detection are integral strategies to reduce the burden of skin cancer. To describe the prevalence of sun protection and skin examination practices in a population exposed to high levels of ambient solar radiation and to identify associated factors. Cross-sectional analyses of baseline data from a prospective cohort of 40,172 adults aged 40 through 69 years from Queensland, Australia, recruited in 2011. We obtained data on all melanoma diagnoses through 2009 via record linkage with the Queensland Cancer Registry (notifications have been mandatory since 1982). We calculated prevalence proportion ratios to compare prevalence of sun protection and skin examination practices in 3 separate groups: those with a history of melanoma (group 1), those with a self-reported history of treated actinic lesions (group 2), and those without either (group 3). We used multivariate generalized linear models to identify factors associated with each practice. Participants with a previously confirmed melanoma (group 1; n = 1433) and/or treated actinic lesions (group 2; n = 24,006) were more likely than those without (group 3; n = 14,733) to report sun protection practices, including regular use of sunscreen (53.3%, 45.1%, and 38.1%, respectively) and wearing hats (74.7%, 68.2%, and 58.2%, respectively). They were also more likely to have had a whole-body skin examination by a physician in the past 3 years (93.7%, 83.4%, and 52.1%, respectively). Within all 3 groups, the strongest association with sun protection practices was with sun-sensitive skin type. Within group 3 (no history of treated skin lesions), the strongest factor associated with clinical skin examinations was self-reported nevus density at 21 years of age, whereas a family history of melanoma was a significant factor in groups 2 and 3. In this large sample exposed to high levels of ambient solar radiation, sun protection and skin examination practices were most frequent among those with a history of treated skin lesions or sun-sensitive skin types.

High mortality of Red Sea zooplankton under ambient solar radiation.

High solar radiation along with extreme transparency leads to high penetration of solar radiation in the Red Sea, potentially harmful to biota inhabiting the upper water column, including zooplankton. Here we show, based on experimental assessments of solar radiation dose-mortality curves on eight common taxa, the mortality of zooplankton in the oligotrophic waters of the Red Sea to increase steeply with ambient levels of solar radiation in the Red Sea. Responses curves linking solar radiation doses with zooplankton mortality were evaluated by exposing organisms, enclosed in quartz bottles, allowing all the wavelengths of solar radiation to penetrate, to five different levels of ambient solar radiation (100%, 21.6%, 7.2%, 3.2% and 0% of solar radiation). The maximum mortality rates under ambient solar radiation levels averaged (±standard error of the mean, SEM) 18.4±5.8% h−1, five-fold greater than the average mortality in the dark for the eight taxa tested. The UV-B radiation required for mortality rates to reach ½of maximum values averaged (±SEM) 12±5.6 h−1% of incident UVB radiation, equivalent to the UV-B dose at 19.2±2.7 m depth in open coastal Red Sea waters. These results confirm that Red Sea zooplankton are highly vulnerable to ambient solar radiation, as a consequence of the combination of high incident radiation and high water transparency allowing deep penetration of damaging UV-B radiation. These results provide evidence of the significance of ambient solar radiation levels as a stressor of marine zooplankton communities in tropical, oligotrophic waters. Because the oligotrophic ocean extends across 70% of the ocean surface, solar radiation can be a globally-significant stressor for the ocean ecosystem, by constraining zooplankton use of the upper levels of the water column and, therefore, the efficiency of food transfer up the food web in the oligotrophic ocean.

Effect of solar radiation on dairy cattle behaviour, use of shade and body temperature in a pasture-based system

Our aim was to understand how protection from solar radiation influenced the behaviour and physiology of Holstein Friesian dairy cattle. We compared the behaviour and body temperature of pastured dairy cattle kept in 1of 4 treatments: no shade or free access to shade that blocked either 25, 50 or 99% of solar radiation (n=3 groups per treatment, 3animals/group). Within each group, cows were categorized as predominantly black, black and white or white in colour (n=1 of each coat colour per group). Shade use increased with higher levels of protection from solar radiation (total shade use, 25%: 1.3h, 50%: 3.0h, 99%: 3.3h/15.5 day-time h, S.E.M.: 0.22h, P<0.001). As average ambient solar radiation increased, total use of the shade structures increased (26 of 27 cows had a positive relationship between solar radiation and total use of shade structures, P<0.001). This pattern was particularity apparent for the 50 and 99% treatments (P=0.009). Cows were more likely to use the shade structures when ambient solar radiation levels were highest within a day, highlighting the importance of providing enough shade for all cows to simultaneously use this resource. Standing was the most common behaviour under shade (25%: 1.1h, 50%: 2.7h, 99%: 2.9h/15.5 day-time h, S.E.M.: 0.21h, P=0.001). Treatments had no effect on time spent lying or grazing over 24h (lying: no shade: 9.0h, 25%: 9.1h, 50%: 9.5h, 99%: 8.8h/24h, S.E.M.: 0.33h, P=0.630; grazing: no shade: 9.0h, 25%: 9.4h, 50%: 9.1h, 99%: 9.3h/24h, S.E.M.: 0.19h, P=0.231). Cows with more protection from solar radiation had lower minimum body temperature (no shade: 37.9°C, 25%: 37.9°C, 50%: 37.9°C, 99%: 37.7°C, S.E.M.: 0.05°C, P=0.004). Together, these results demonstrate that the degree of protection from solar radiation is an important design feature of effective shade for dairy cattle.

Ambient Solar UV Radiation Causes Mortality in Larvae of Three Species of Rana Under Controlled Exposure Conditions†¶

Recent reports concerning the lethal effects of solar ultraviolet-B (UV-B) (290–320 nm) radiation on amphibians suggest that this stressor has the potential to impact some amphibian populations. In this study embryos and larvae of three anuran species, Rana pipiens,Rana clamitans and Rana septentrionalis, were exposed to full-spectrum solar radiation and solar radiation filtered to attenuate UV-B radiation or UV-B and ultraviolet-A (UV-A) (290–380 nm) radiation to determine the effects of each wavelength range on embryo and larval survival. Ambient levels of solar radiation were found to be lethal to all three species under exposure conditions that eliminated shade and refuge. Lethality was ameliorated by filtration of UV-B radiation alone, demonstrating that ambient UV-B radiation is sufficient to cause mortality. Although several studies have qualitatively demonstrated the lethality of UV-B to early life stage amphibians this study demonstrates that the larval life stages of the three species tested are more sensitive than the embryonic stages. This suggests that previous reports that have not included the larval life stage may underestimate the risk posed to some anuran populations by increasing UV-B exposure. Furthermore, this study reports quantitative UV-B dosimetry data, collected in conjunction with the exposures, which can be used to begin the assessment of the impact of environmental changes which increase UV-B exposure of these anurans.

Effects of elevated ultraviolet radiation and endophytic fungi on plant growth and insect feeding in Lolium perenne, Festuca rubra, F. arundinacea and F. pratensis

Plants of perennial ryegrass ( Lolium perenne L.), red fescue ( Festuca rubra L.), tall fescue ( F. arundinacea Schreb.) and meadow fescue ( F. pratensis Huds) were exposed at an outdoor facility located in Edinburgh, UK to modulated levels of UV-B radiation (280–315 nm) using banks of cellulose diacetate filtered UV-B fluorescent lamps that also produce UV-A radiation (315–400 nm). The plants were derived from a single clone of each species and were grown both with and without colonization by naturally-occurring fungal endophytes. The UV-B treatment was a 30% elevation above the ambient erythemally-weighted level of UV-B during July to October. Growth of treated plants was compared with plants grown under elevated UV-A radiation alone produced by banks of polyester filtered lamps and with plants grown at ambient levels of solar radiation under banks of unenergized lamps. At the end of the treatment period, sample leaves were collected for feeding trials with the desert locust Schistocerca gregaria (Forsk). The UV-B treatment produced no effects on the aboveground biomass of any of the four grasses. The UV-B treatment and the UV-A control exposure both increased plant height and the number of daughter plants formed by rhizome growth in F. rubra. There were significant effects of endophyte presence on the total fresh and dry weights of F. arundinacea and F. rubra, on fresh weight only in F. pratensis, and on the fresh and dry weights of inflorescence in F. arundinacea and L. perenne. There were no effects of UV treatments on the absolute amounts of leaf consumed or on the feeding preferences of locusts for leaves with or without endophyte in three species: F. rubra, F. arundinacea and L. perenne. In F. pratensis there was no effect of UV treatment on the weight of leaves consumed but a significant UV×endophyte interaction caused by a marked change in feeding preference between leaves with and without endophyte that differed between the UV-B treatment and UV-A control exposures. The alkaloid compounds known as lolines were analysed in leaves of F. pratensis and were only found in plants grown with endophyte. However, there was no significant relationship between total loline content and insect feeding preference. These effects illustrate the potential complexities of species interactions under increasing levels of UV-B. The experiment also demonstrates the importance of appropriate controls in UV lamp supplementation experiments for interpretation of both plant growth and insect feeding effects.

UV‐B radiation constrains the photosynthesis of Quercus robur through impacts on the abundance of Microsphaera alphitoides

Summary Quercus robur saplings were exposed at an outdoor facility in the UK to supplemental levels of UV‐B radiation (280–315 nm) under arrays of cellulose diacetate‐filtered fluorescent lamps which also produced UV‐A radiation (315–400 nm). Saplings were also exposed to supplemental UV‐A radiation under arrays of polyester‐filtered lamps and to ambient levels of solar radiation under arrays of unenergized lamps. The UV‐B treatment was modulated to maintain a 30% elevation above the ambient level of erythemally weighted UV‐B radiation. Naturally occurring infections by oak powdery mildew (Microsphaera alphitoides) were more abundant, and developed more rapidly, on lammas leaves of saplings which were exposed to treatment levels of UV‐B radiation than on leaves of saplings exposed to supplemental UV‐A or to ambient levels of solar radiation over 12 weeks in summer and autumn 1996. An analysis of leaf photosynthetic capacities revealed that M. alphitoides infection reduced the quantum efficiency of photosystem (PS) II by 14% at moderate irradiance. Although there was no direct effect of UV‐B radiation on PSII photochemistry, exposure of saplings to supplemental UV‐A radiation under polyester‐filtered lamps resulted in a 17.5% decrease in PSII quantum efficiency, compared with saplings exposed to ambient solar radiation. The results from our study suggest that photosynthesis of Q. robur may be constrained by exposure to UV‐B radiation in the natural environment through impacts on the abundance of M. alphitoides.

Effects of elevated ultraviolet radiation on Quercus robur and its insect and ectomycorrhizal associates

SummarySaplings of pedunculate oak (Quercus robur L.) were exposed at an outdoor facility to modulated levels of elevated UV‐B radiation (280–315 nm) under treatment arrays of cellulose diacetate‐filtered fluorescent lamps which also produced UV‐A radiation (315–400 nm). Saplings were also exposed to UV‐A radiation alone under control arrays of polyester‐filtered lamps and to ambient levels of solar radiation under arrays of unenergized lamps. The UV‐B treatment corresponded to a 30% elevation above the ambient level of erythemally weighted UV‐B radiation. Sapling growth and the occurrence of associated organisms were examined over two years. In both years, leaves of saplings exposed to UV‐B treatment were thicker and smaller in area relative to leaves exposed to ambient and control levels of radiation. UV‐B treatment also retarded bud burst at one sampling in the first year of the study. Some responses were recorded which were common to both treatment and control arrays, implying that UV‐A radiation, or some other factor associated with energized lamps, was responsible for the observed effects. Saplings under treatment and control arrays were taller in the first year of the study, suffered greater herbivory from chewing insects, and had lower root dry weights and greater insertion heights of secondary branches than saplings exposed to ambient levels of radiation. Exposure of saplings to elevated UV‐A radiation alone under control arrays increased estimated leaf volumes in the second year of the study and reduced the number of secondary branches and the total number of branches per sapling after two years, relative to both treatment and ambient arrays. There were no effects of elevated ultraviolet radiation on shoot or total plant weight, root/shoot ratios, stem diameter, the numbers or insertion heights of primary or tertiary branches, total leaf number, timing of leaf fall or frequency of ectomycorrhizas. Our study suggests that any increases in UV‐B radiation as a result of stratospheric ozone depletion will influence the growth of Q. robur primarily through effects on leaf morphology.

Elevated UV‐B radiation effects on experimental grassland communities

SummaryExperimental grassland communities (turves) were exposed to supplemental levels of UV‐B radiation (280–315 nm) at an outdoor facility, under treatment arrays of cellulose diacetate‐filtered fluorescent lamps which also produce UV‐A radiation (315–400 nm). Control treatments consisted of arrays of polyester‐filtered lamps, which allowed for exposure to UV‐A radiation alone, and arrays of unenergized lamps allowing for exposure to ambient levels of solar radiation.

Neotyphodium lolii, a Fungal Leaf Endophyte, Reduces Fertility ofLolium perenneExposed to Elevated UV-B Radiation

Plants ofLolium perenne, grown with and without the balansoid fungal leaf endophyteNeotyphodium lolii, were exposed to three ultraviolet radiation treatments at an outdoor facility in the UK for 172 d. Plants were exposed to either (a) a 30% elevation above the ambient erythemally-weighted level of UV-B (280–315 nm) radiation under banks of cellulose diacetate filtered fluorescent lamps that also produce UV-A (315–400 nm) radiation (UV-B+A); (b) elevated UV-A radiation alone under banks of polyester filtered lamps; or (c) ambient levels of solar radiation under banks of unenergized lamps. The fertility of plants grown withN. loliiwas significantly reduced by the elevated UV-B+A exposure. After 172 d, these plants produced 70% fewer spikes, 75% fewer seeds, 71% lower total weight of seed and 78% fewer seeds per g d. wt of plant tissue than plants colonized byN. loliiwhich were exposed to ambient radiation. There was no discernible effect of elevated UV-B+A exposure on the fertility of endophyte-free plants. Plants irradiated with UV-B+A developed 14% thicker leaves than those exposed to ambient radiation. Those which were irradiated with elevated UV-A alone produced seeds that were 20% heavier than plants exposed to ambient levels of radiation. Plants grown withN. loliihad 7% thicker leaves, 4% thicker stem bases and 7% fewer tillers than those grown without it. The fresh mass of tillers of plants grown withN. loliiwas 11% greater than those of endophyte-free plants, owing to their higher moisture contents. These results suggest that the fertility ofL. perennecolonized byN. loliiin the natural environment could be deleteriously affected by elevated fluxes of UV-B radiation associated with stratospheric ozone depletion and that this may affect the population dynamics of the species.

Direct Effects of Elevated UV-B Radiation on the Decomposition of Quercus robur Leaf Litter

Decomposing Quercus robur L. leaf litter was exposed for 64 weeks at an outdoor facility to supplemental levels of UV-B radiation (280-315 nm) under treatment arrays of cellulose diacetate-filtered fluorescent lamps which also produce UV-A radiation (315-400 nm). Litter was also exposed to UV-A radiation alone under control arrays of polyester-filtered lamps and to ambient levels of solar radiation under arrays of unenergised lamps. The treatment corresponded to a 30% elevation above the ambient erythemally-weighted level of UV-B radiation. Litter was sampled after 11, 39 and 64 weeks and was examined for differences in mass loss, decomposition constants (k), chemical composition and the abundances of saprotrophic fungi. No effects of UV radiation on k values were recorded, but after 11 weeks, percentage mass loss of litter exposed to UV-B radiation under treatment arrays was 3% lower than under control arrays and 2% lower than under ambient arrays. After 39 weeks, litters exposed to UV-A radiation under control arrays had 10% lower total nitrogen contents and 13% higher C:N ratios than those litters exposed beneath ambient arrays. At the last sampling, litters exposed to supplemental UV-B radiation had 5% higher carbon contents than those under ambient arrays. A 2.4-fold increase in the frequency of lamina particles of litter that were uncolonised by fungi was recorded in litter exposed to UV-B radiation under treatment arrays, compared to ambient arrays. The abundances of the saprotrophic fungi Cladosporium spp. and Acremonium persicinum (Nicot) W. Gams were decreased by 50% and 91%, respectively, under UV-B treatment arrays compared to ambient arrays, and the abundance of coelomycete conidiomata recorded on leaves was increased by 12% under treatment arrays, compared to ambient. Dactylella spp. were not recorded on litter exposed to UV-A radiation under control arrays and UV-A radiation applied under control and treatment arrays apparently increased the abundance of Polyscytalum fecundissimum Riess. on litter. UV radiation had fewer effects on the abundances of decomposer fungi that develop in leaf tissues than it did on those that develop on leaf litter surfaces. We conclude that increased fluxes of UV-B radiation as a result of stratospheric ozone depletion will have subtle but wide-ranging impacts on the decomposition of litters in oak woodlands.

Ultraviolet‐B radiation influences the abundance and distribution of phylloplane fungi on pedunculate oak (Quercus rohur)

SUMMARYThe effects of u. v.‐B radiation (280–315 nm) on the fungi occurring on the lammas leaves of pedunculate oak (Quercus robur L.) were examined using saplings that were exposed at an outdoor facility to supplemental levels of u. v.‐B radiation under treatment arrays of cellulose diacetate‐filtered fluorescent lamps, which also produce u. v.‐A radiation (315–400 nm). Saplings were also exposed to u. v.‐A radiation alone under control arrays of polyester‐filtered lamps, and to ambient levels of solar radiation under arrays of unenergized lamps. The u. v.‐B treatment corresponded to a 30 % elevation above the ambient level of erythemally‐weighted u. v.‐B radiation. The fungi were examined weekly over a 4–month‐period in summer and autumn 1995 using two techniques, the spore fall and leaf impression methods, which differentiated between those fungi occurring on the upper (adaxial) and lower (abaxial) surfaces of the leaves. The abundances of Aureobasidium pullulans (De Bary) Arnaud and Sporobolomyces roseus Kluy. et van Niel, two leaf yeasts which had adaxial: abaxial ratios of &lt; 1 under ambient levels of u. v.‐B radiation, were negatively correlated with increasing ambient levels of u. v.‐B radiation and were significantly reduced on adaxial leaf surfaces by supplemental levels of u. v.‐B. There were few effects of supplemental u. v.‐B radiation on the abundances of these yeasts on abaxial leaf surfaces. The abundances of the dematiaceous hyphomycetes, Cladosporium spp. and Epicoccum nigrum Link., species with adaxial: abaxial ratios of ≥ 1 under ambient levels of u. v.‐B radiation, were not correlated with ambient levels of u. v.‐B radiation, nor were they usually affected on either leaf surface by supplemental u. v.‐B radiation. Alternaria spp. and Microdochium nivale (Fr.) Samuels &amp; Hallet showed consistent responses on adaxial leaf surfaces to u. v.‐A radiation applied under control and treatment arrays. Our results suggest that current levels of shortwave radiation already influence the distribution of fungi on leaf surfaces and that future increases in u. v.‐B radiation will directly affect the abundances of specific phylloplane fungi.

Systems Model Analysis of Hot Weather Housing for Livestock

ABSTRACT A mathematical model was developed to predict a Temperature-Humidity Index and a Black Globe Humidity Index as indicators of comfort for livestock ex-posed to ambient levels of solar radiation. Field research was conducted at the Central Farm Experimental Station in Belize. The Black Globe Humidity Index provided an indicator of comfort which included the significant ra-diant heat load under hot weather conditions.