Effects Of Ultraviolet Radiation Exposure Research Articles

Properties and safety of topical dihydroxyacetone in sunless tanning products: A review.

Sunless tanning products have risen in popularity as the desire for a tanned appearance continues alongside growing concerns about the deleterious effects of ultraviolet radiation exposure from the sun. Dihydroxyacetone (DHA) is a simple carbohydrate found nearly universally in sunless tanning products that serves to impart color to the skin. The Food and Drug Administration (FDA), which regulates sunless tanning products as cosmetics, allows DHA for external use while maintaining that its ingestion, inhalation, or contact with mucosal surfaces should be avoided. Given its widespread use and a paucity of reviews on its safety, we aim to review the literature on the topical properties and safety profile of DHA. Available data indicate that DHA possesses only minimal to no observable photoprotective properties. In vitro studies suggest that, while DHA concentrations much higher than those in sunless tanning products are needed to induce significant cytotoxicity, even low millimolar, nonlethal concentrations can alter the function of keratinocytes, tracheobronchial cells, and other cell types on a cellular and molecular level. Instances of irritant and allergic contact dermatitis triggered by DHA exposures have also been reported. While no other side effects in humans have been observed, additional studies on the safety and toxicity of DHA in humans are warranted, with a focus on concentrations and frequencies of DHA exposure typically encountered by consumers.

Ozone Layer Depletion and Emerging Public Health Concerns - An Update on Epidemiological Perspective of the Ambivalent Effects of Ultraviolet Radiation Exposure.

Solar ultraviolet (UV) radiation exposure is the primary etiological agent responsible for developing cutaneous malignancies. Avoiding excessive radiation exposure, especially by high-risk groups, is recommended to prevent UV-induced photo-pathologies. However, optimal sun exposure is essential for the healthy synthesis of about 90% of vitamin D levels in the body. Insufficient exposure to UV-B is linked to vitamin D deficiency in humans. Therefore, optimal sun exposure is necessary for maintaining a normal state of homeostasis in the skin. Humans worldwide face a major existential threat because of climate change which has already shown its effects in several ways. Over the last 4 to 5 decades, increased incidences in skin cancer cases have led international health organizations to develop strong sun protection measures. However, at the same time, a growing concern about vitamin D deficiency is creating a kind of exposure dilemma. Current knowledge of UV exposure to skin outweighs the adverse effects than the beneficial roles it offers to the body, necessitating a correct public health recommendation on optimal sun exposure. Following an appropriate recommendation on optimal sun exposure will lead to positive outcomes in protecting humans against the adverse effects of strict recommendations on sun protection measures. In this short review, we spotlight the ambivalent health effects of UV exposure and how ozone layer depletion has influenced these effects of UVR. Further, our aim remains to explore how to lead towards a balanced recommendation on sun protection measures to prevent the spurt of diseases due to inadequate exposure to UV-B.

A virtual classroom activity for teaching sunlight‐initiated DNA damage and its protection

As a consequence of COVID-19 pandemic, most of classroom teaching went virtual in the academic year 2020-21. We took this opportunity to create a virtual activity for a biochemistry course for undergraduate nursing students at Milwaukee School of Engineering. It is well understood that prolonged exposure to sunlight is one of the major causes of skin cancer due to mutations in the keratinocyte DNA. Skin cancer is one of the most common forms of cancer in the US. UV-B radiation in the region of 290-320 nm is absorbed by skin cells resulting in mutated DNA which can lead to cancer. We developed the virtual activity with a dual purpose in mind. First, the activity would enhance their learning experience about DNA mutations using a 3D-printed model showing the biochemical DNA damage which could lead to skin cancer. Second, the activity could increase general awareness among students about the dangers of UVB-radiation exposure and protection strategies by directly testing everyday products such as sunscreens. We randomly picked nine commercially available sunscreens with various SPF values and tested their ability to protect from UVB radiation. Testing for protection from UVB radiation was performed using an in-house created customized chamber equipped with a UVB light source emitting a single wavelength at 310 nm. A thin, even layer of sunscreen was applied on a thin clear plastic wrap and exposed to UVB light. The sunscreens’ ability to block UVB radiation was quantitated compared to a control sample with no sunscreen.Further, using a 3D model of a DNA segment created by 3D printing at the Center for Biomolecular Modeling, we explained molecular-level changes. We created a two-part video. Part I narrates details of the sunscreen protection experiment. Part II explains the molecular details of DNA damage using 3D-printed model including (i) location of a broken A-T hydrogen bond (ii) location ofa T-T dimer and discussion of possible impact of the change in the DNA structure and (iii) explaining the formation of a ‘kink’ in the DNA strand as a result of the T-T photoproduct. The video will be accompanied by a student survey questionnaire on Canvas LMS. The goal of this study is to quantitatively test students’ understanding of this biochemistry topic before and after watching the virtual activity. Further, it is our hope that the activity will also increase general awareness among nursing students about the harmful effects of ultraviolet radiation exposure.

Exploring the Blueprint of Photoprotection in Mycosporine-like Amino Acids.

Microorganisms require protection against the potentially damaging effects of ultraviolet radiation exposure. Photoprotection is, in part, provided by mycosporine-like amino acids (MAAs). Previous reports have proposed that nonradiative decay mediates the impressive photoprotection abilities of MAAs. In this letter, we present the first ultrafast dynamics study of two MAAs, shinorine and porphyra-334. We demonstrate that, in aqueous solution, these MAAs relax along their S1 coordinates toward the S1/S0 conical intersection within a few hundred femtoseconds after photoexcitation and then traverse the conical intersection and vibrationally cool in approximately 1 ps through heat transfer to the solvent. This new insight allows a quintessential component of microbial life to be unraveled and informs the development of molecular photon-to-heat converters for a myriad of applications.

The Association of Socioeconomic Status with the Burden of Cataract-related Blindness and the Effect of Ultraviolet Radiation Exposure: An Ecological Study

ObjectiveTo assess the association of socioeconomic status with the burden of cataract blindness in terms of year lived with disability (YLD) rates and to determine whether ultraviolet radiation (UVR) levels modify the effect of socioeconomic status on this health burden. MethodsNational and subnational age-standardized YLD rates associated with cataract-related blindness were derived from the Global Burden of Disease (GBD) study 2017. The human development index (HDI) from the Human Development Report was used as a measure of socioeconomic status. Estimated ground-level UVR exposure was obtained from the Ozone Monitoring Instrument (OMI) dataset of the National Aeronautics and Space Administration (NASA). ResultsAcross 185 countries, socioeconomic status was inversely associated with the burden of cataract blindness. Countries with a very high HDI had an 84% lower age-standardized YLD rate [95% confidence interval (CI): 60%–93%, P < 0.001] than countries with a low HDI; for high-HDI countries, the proportion was 76% (95% CI: 53%–88%, P < 0.001), and for medium-HDI countries, the proportion was 48% (95% CI: 15%–68%, P = 0.010; P for trend < 0.001). The interaction analysis showed that UVR exposure played an interactive role in the association between socioeconomic status and cataract blindness burden (P value for interaction = 0.047). ConclusionLong-term high-UVR exposure amplifies the association of poor socioeconomic status with the burden of cataract-related blindness. The findings emphasize the need for strengthening UVR exposure protection interventions in developing countries with high-UVR exposure.

Impact of solar ultraviolet radiation on daily outpatient visits of atopic dermatitis in Shanghai, China.

The potential roles of solar ultraviolet radiation (UVR) as an environmental risk factor in inducing atopic dermatitis (AD) have not been well quantified. To determine the short-term associations between UVR and AD outpatient visits, we obtained daily outpatient visits of AD in Shanghai Skin Disease Hospital from 2013 to 2018. Data of hourly ground UVR were collected. We applied overdispersed generalized additive model to explore its associations. We found that daily exposure to UVR-A rather than UVR-B was positively associated with AD outpatient visits. The visits increased on the present day (lag 0 days) and decreased appreciably with longer lags and became insignificant at lag 4 days. For 10 w/m2 increase in daytime mean and noontime mean exposure to overall UVR and UVR-A from lag 0 to 6 days, the cumulative relative risk of AD was 1.12/1.13 and 1.08/1.08, respectively. Stronger effects of UVR exposure on AD occurred in patients aged 0-7 and > 45 years and in the cold seasons. This study contributed to the few epidemiological evidences that acute exposure to solar UVR may elevate the risks of AD.

Effect of ultraviolet radiation exposure on optical nonlinearity and switching traits of SnO2 thin films deposited by thermal evaporation

Highly transparent amorphous SnO2 thin films were deposited using the thermal evaporation method and characterized. The influence of the UV radiation exposure (for approximately 2 h) on the morphology, linear and nonlinear optical properties of the films was evaluated for the first time. The optical switching performance of the as-deposited thin films was examined using the pump–probe technique. A continuous wave (CW) diode-pumped solid-state laser (532 nm with maximum power of 100 mW) and He-Ne laser (633 nm with maximum power of 35 mW) was used for the pump and probe beam, respectively. The band gap energies of the films were calculated using the Mott and Davis model fitting procedure. The films transmittance was increased and band gap was decreased upon the UV exposure. The signal modulations in the films were observed with the increase in the pump power. The signal intensities of both as-deposited and UV radiation exposed films were correspondingly dropped from 7.58 to 7.47 mW and from 8.16 to 8.05 mW, when the pump power was raised beyond 20 mW. The achieved SnO2 films displayed unaltered dynamic range under the UV radiation exposure. In addition, the nonlinear absorption coefficients of the UV radiation exposed films were increased from 0.10139 to 0.36435 cm W−1. This indicated the stabilization of the films upon the UV exposure and subsequent removal of the excess oxygen. The higher value of the nonlinear absorption by the films satisfied their figure of merit. The proposed SnO2 thin films may be effective for the development of the nonlinear optical devices working in the UV region.

The acute effects of ultraviolet radiation exposure on solar dermatitis in Shanghai, China.

Ultraviolet radiation (UVR) has long been considered associated with solar dermatitis, but the associations have not been well quantified. To depict the full-range exposure-response association between daily UVR exposures and daily outpatient visits of solar dermatitis. We collected the daily number of outpatient visits of solar dermatitis and monitored hourly ground data of UVR (the sum of A- and B-band) from 1 January 2013 to 31 December 2017 in Shanghai, China. The data were analyzed using the time-series approach, in which overdispersed generalized additive model was used and time trends and weather conditions were controlled for. During the study period, we recorded a total of 15,051 outpatient visits of solar dermatitis. There was a consistently increasing risk of solar dermatitis associated with stronger UVR without a discernible threshold. The effects occurred on the present day, increased to the largest at lag 1 or 2days, and attenuated to the null at lag 5days or more. A unit (w/m2) increase in daily maximum-hour UVR was associated with 1.70% (95%CI: 1.19%, 2.20%) increase of outpatient visits of solar dermatitis. Stronger effects occurred among the young people, females, and in the warm season. The risks of solar dermatitis due to UVR exposure would be overestimated if ambient temperature was not adjusted. This study provides quantitative epidemiological estimates for the positive associations between short-term exposure to UVR and increased risks of solar dermatitis. The associations were more prominent among young people, females, and in warm seasons.

Towards symmetry driven and nature inspired UV filter design

In plants, sinapate esters offer crucial protection from the deleterious effects of ultraviolet radiation exposure. These esters are a promising foundation for designing UV filters, particularly for the UVA region (400 – 315 nm), where adequate photoprotection is currently lacking. Whilst sinapate esters are highly photostable due to a cis-trans (and vice versa) photoisomerization, the cis-isomer can display increased genotoxicity; an alarming concern for current cinnamate ester-based human sunscreens. To eliminate this potentiality, here we synthesize a sinapate ester with equivalent cis- and trans-isomers. We investigate its photostability through innovative ultrafast spectroscopy on a skin mimic, thus modelling the as close to true environment of sunscreen formulas. These studies are complemented by assessing endocrine disruption activity and antioxidant potential. We contest, from our results, that symmetrically functionalized sinapate esters may show exceptional promise as nature-inspired UV filters in next generation sunscreen formulations.

Unveiling the Impact of Distinct Melanosome Arrangements on the Attenuation of Cancer-Inducing Ultraviolet Radiation.

The exposure of human skin to ultraviolet radiation (UVR) can trigger a wide array of biological responses, including photocarcinogenesis. Melanin, either in colloidal form or encapsulated into melanosomes, is known to be the main UVR attenuation substance acting within the cutaneous tissues. Although many studies have addressed the protective role of this pigment against the harmful effects of UVR exposure, the impact of different melanosome arrangements on the mitigation of these effects remains to be quantitatively verified. The difficulties to resolve this open question can be mainly attributed to the intrinsic practical limitations of in vivo and in vitro experiments involving skin specimens. In this paper, we describe controlled in silico experiments that allowed us to overcome such limitations and provide quantitative evidence for the clarification of this question. Besides contributing to a more robust understanding of the physiological parameters associated with cutaneous UVR attenuation, our findings can be incorporated into the development of more effective strategies for the evaluation of individuals' susceptibility to UVR exposure. Such strategies are essential for the prevention of UVR-induced pathologies, particularly skin cancer.

Community-wide Interventions to Prevent Skin Cancer: Two Community Guide Systematic Reviews.

Skin cancer is a preventable and commonly diagnosed cancer in the U.S. Excessive ultraviolet radiation exposure is a known cause of skin cancer. This article presents updated results of two types of interventions evaluated in a previously published Community Guide systematic review: multicomponent community-wide interventions and mass media interventions when used alone. Studies assessing multicomponent community-wide and mass media interventions to prevent skin cancer by reducing ultraviolet radiation exposure were evaluated using Community Guide systematic review methods. Relevant studies published between 1966 and 2013 were included and analyzed for this review. Seven studies evaluating the effectiveness of multicomponent community-wide interventions showed a median increase in sunscreen use of 10.8 (interquartile interval=7.3, 23.2) percentage points, a small decrease in ultraviolet radiation exposure, a decrease in indoor tanning device use of 4.0 (95% CI=2.5, 5.5) percentage points, and mixed results for other protective behaviors. Four studies evaluating the effectiveness of mass media interventions found that they generally led to improved ultraviolet protection behaviors among children and adults. The available evidence showed that multicomponent community-wide interventions are effective in reducing the deleterious effects of ultraviolet radiation exposure by increasing sunscreen use. There was, however, insufficient evidence to determine the effectiveness of mass media interventions alone in reducing ultraviolet radiation exposure and increasing ultraviolet protection behaviors, indicating a continuing need for more research in this field to improve assessment of effectiveness.

Sebum, inflammasomes and the skin: current concepts and future perspective.

Increasing evidence has identified ultraviolet radiation (UVR) as the skins most potent mutagen as over exposure results in sunburn, inflammation and DNA damage, thus contributing to a photo-ageing phenotype and possibly skin carcinogenesis. The lipid-rich sebum secreted onto the surface of the skin plays an important physiological role in protecting the skin against external challenges. When skin is photosensitised by UVR, the lipid constituents of sebum are easily oxidised, generating several lipid photo-oxidative products (e.g. squalene peroxides). These photo-oxidative products have been shown to exert diverse toxicological, biological and immunological effects in the skin and have therefore been implicated in several detrimental skin alterations including premature skin ageing. The involvement of lipid peroxidation products in UVR-induced inflammatory responses has been inadequately studied and highly controversial. Furthermore, it is unclear to what extent these oxidative products contribute to the underlying mechanisms of skin photo-ageing. Therefore, this viewpoint essay will discuss the current knowledge on the effect of UVR exposure on skin surface lipids and how these may mediate UVR-induced inflammatory responses which may be key contributors to photo-damage in skin. This essay will also examine the potential role of inflammasomes (innate immunecomplexes) in the inflammatory response associated with UVR-induced lipid peroxidation. Limited evidence is available on the interactions between sebaceous lipids, downstream mediators and concomitant immune response in sun-exposed skin and clearer elucidation may lead to novel biomarkers of photo-ageing and the incorporation of new molecules into current skin therapies which better target oxidised lipids and or downstream mediators/pathways.

Photoimmunology.

The discipline that investigates the biologic effects of ultraviolet radiation on the immune system is called photoimmunology. Photoimmunology evolved from an interest in understanding the role of the immune system in skin cancer development and why immunosuppressed organ transplant recipients are at a greatly increased risk for cutaneous neoplasms. In addition to contributing to an understanding of the pathogenesis of nonmelanoma skin cancer, the knowledge acquired about the immunologic effects of ultraviolet radiation exposure has provided an understanding of its role in the pathogenesis of other photodermatologic diseases.

Site-specific louvered shells for shading harmful ultraviolet radiation

Excessive Ultraviolet (UV) radiation exposure results in various health hazards for humans. The United States Environmental Protection Agency maintains that moderate health risk starts at a UV Index of three, where protection such as built shade should be sought. However, commercially available shading structures often fail to take into account varying solar positions at different geographic locations and times of the day. They are typically designed with a “one-design-fits-all” mentality which ignores the site-specificity and time dependency of the position of the sun. This paper proposes and tests a design methodology for a large span louvered shell system that mitigates the harmful effects of UV radiation exposure. The structural beams of the presented grid shell are integrated and optimized as louvers that block out harmful UV radiation only when it poses health risks. The design approach incorporates algorithms that allow for the identification of critical solar positions using a UV Index algorithm, shade analysis, structural form finding and definition of louver orientations and depth. To validate the methodology, a physical prototype is designed, built, equipped with UV sensors and monitored over a period of four months. The presented and tested approach allows for the design of site-specific louvered shells that effectively shade large scale urban spaces (such as public squares, outdoor play and sports grounds and entertainment areas). The resulting novel shades offer an effective strategy for the prevention of UV radiation health risks through the interaction of the built environment.

Are the intertidal fish highly resistant to UV-B radiation? A study based on oxidative stress in Girella laevifrons (Kyphosidae)

Sea chub, Girella laevifrons, is a coastal fish that inhabits high intertidal rockpools along the coast of Chile. The intertidal pools where the juveniles live, are an extreme environment with high levels of ultraviolet (UV) radiation, becoming harmful to the organisms, due to oxidative stress generated by reactive oxygen species. For this reason organisms develop adaptations that allow them to survive in this complex environment. The search of biomonitor species, sensitive to UV radiation is very important in aquatic ecosystems, mainly in the southern hemisphere where depletion of the ozone layer and the consequent increase of UV radiation, have become an environmental problem. The aim of this study was to evaluate the effect of ultraviolet radiation in G. laevifrons and its possible use as UV-B radiation biomonitor specie in intertidal systems, which are very important for the Chilean fisheries. The effect of UV radiation exposure on juvenile G. laevifrons was measured through oxidative stress parameters. Catalase's activity increased with the time of exposure, unlike superoxide dismutase's activity which peaked at 2h, decreasing towards the 5th hour of irradiation. The superoxide dismutase activity in muscle tissue did not show significant differences. The lipid peroxidation and DNA damage increased in relation to exposition times. Tissue muscle's DNA damage was shown only at 5h of exposure. Significant differences between the two organs in the antioxidant capacity were observed, the liver of G. laevifrons exhibited the higher antioxidant capacity. It can be concluded that this specie exhibits effective protection mechanisms against UV radiation exposure and it is not appropriate specie as a biomonitor in intertidal systems.

Effects of ultraviolet radiation exposure on FOXP3+ infiltration in cutaneous squamous cell carcinoma and basal cell carcinoma

To analyze the prevalence and significance of FOXP3+ infiltration into (pre)malignant skin carcinomas following ultraviolet radiation (UVR) exposure. The possible pathways that UVR impacts on FOXP3 are to be discussed. FOXP3+ regulatory T cells (FOXP3+ Tregs) are correlated to cutaneous squamous tumor progression. However, there is no information describing the prevalence of FOXP3+ infiltration in cutaneous premalignant and malignant squamous carcinomas with UVR exposure. We investigated the prevalence of FOXP3+ infiltration in 14 patients with Bowen's disease, 40 squamous cell carcinoma SCC patients and 21 patients with basal cell carcinoma (BCC) by immunohistochemistry. The percentages of FOXP3+ vs. total peri-neoplasm infiltration cells (FOXP3+ PCT) were significantly higher in Bowen's disease and well-differentiated SCC that were exposed to UVR than these diseases not exposed to UVR (t = 3.5776, P = 0.0038; t' = 5.9214, P < 0.01, respectively). FOXP3+ PCT was also higher in less pigmented than pigmented sites in BCC (t = 3.369, P = 0.0032). This study shed some light on the effect of UVR on FOXP3+ infiltration in skin (pre)malignant carcinomas. Our data suggested that FOXP3+ infiltration was positively related to UVR exposure. The mechanisms merit further investigation.

A Review: Role of Ultraviolet Radiation in Age-Related Macular Degeneration

Age-related macular degeneration (AMD) is a leading cause of blindness in the western world. The retina is highly susceptible to photochemical damage from continuous exposure of light and oxygen. The cornea and the lens block a major portion of the ultraviolet (UV) radiation from reaching the retina (<295 nm). The relationship between UV light exposure and AMD is unclear, although short wavelength radiation and the blue light induce significant oxidative stress to the retinal pigment epithelium. Epidemiologic evidence indicates a trend toward association between severity of light exposure and AMD. In this review, we discuss type 1 and type 2 photochemical damage that occurs in response to UV exposure. We examine the impact of different doses of exposure to UV radiation and the subsequent production of oxidative stress in AMD. Local and systemic protective mechanisms of the retina including antioxidant enzymes and macular pigments are reviewed. This article provides a review of possible cellular and molecular effects of UV radiation exposure in AMD and potential therapies that may prevent blindness resulting from this disease.

Vitamin D Receptor Genotypes, Ultraviolet Radiation Exposure, and Risk of Non-Hodgkin Lymphoma

Ultraviolet radiation (UVR) exposure may influence risk of non-Hodgkin lymphoma (NHL) through vitamin D, with antineoplastic effects mediated through the vitamin D receptor (VDR). To explore the role of vitamin D in NHL risk and the potential interaction with UVR, the authors genotyped 10 VDR polymorphisms in 2,448 NHL patients and 1,981 controls from Denmark and Sweden who were recruited in 1999-2002. Odds ratios and 95% confidence intervals were computed with logistic regression. P values were 2-sided. Most VDR variants (e.g., rs731236/TaqI, rs15444410/BsmI) were not associated with overall risk of NHL, but there was some evidence of a positive association between rs4760655 and follicular lymphoma risk (nominal P(trend) = 0.004, corrected P(trend) = 0.24). There was no support for an effect of interaction between VDR variants and UVR exposure on risk of overall NHL or B-cell lymphoma subtypes. However, there was some evidence that rs731236 altered associations between UVR and T-cell NHL risk; while increasing UVR frequency lowered T-cell NHL risk among rs731236 TT carriers, an elevated risk was observed among rs731236 CC carriers (nominal P(interaction) ≤ 0.008, corrected P(interaction) ≥ 0.12). VDR does not appear to harbor major determinants of NHL risk, except perhaps for follicular lymphoma. Possible heterogeneity in effects of UVR exposure on T-cell lymphoma risk by VDR rs731236 genotype merits further investigation.

Albinism in Africa as a public health issue

BackgroundOculocutaneous albinism (OCA) is a genetically inherited autosomal recessive condition and OCA2, tyrosine-positive albinism, is the most prevalent type found throughout Africa. Due to the lack of melanin, people with albinism are more susceptible to the harmful effects of ultraviolet radiation exposure. This population must deal with issues such as photophobia, decreased visual acuity, extreme sun sensitivity and skin cancer. People with albinism also face social discrimination as a result of their difference in appearance. The World Health Organization is currently investigating the issues concerning this vulnerable population.MethodsSystematic electronic search of articles in PubMed concerning albinism in Africa. Furthermore, a World Health Organization (WHO) pilot survey of albinism was drafted in English, French and Portuguese, and distributed to African countries through WHO African Regional Offices (AFRO) in an attempt to gather further information on albinism.ResultsEpidemiologic data on albinism, such as prevalence, were available for South Africa, Zimbabwe, Tanzania and Nigeria. Prevalences as high as 1 in 1,000 were reported for selected populations in Zimbabwe and other specific ethnic groups in Southern Africa. An overall estimate of albinism prevalences ranges from 1/5,000 – 1/15,000. In addition, both the literature review and the survey underscored the medical and social issues facing people with albinism.ConclusionThe estimated prevalence of albinism suggests the existence of tens of thousands of people living with albinism in Africa. This finding reiterates the need for increased awareness of and public health interventions for albinism in order to better address the medical, psychological and social needs of this vulnerable population.

Interactive effects of temperature and nutrient limitation on the response of alpine phytoplankton growth to ultraviolet radiation

We performed bag-enclosure experiments fo r7di n alake in the Beartooth Mountains (in Montana and Wyoming) using natural phytoplankton assemblages. Ultraviolet radiation (UVR) (exposed or blocked), temperature (68C and 148C), and nutrients (nitrogen, phosphorus, and nitrogen plus phosphorus) were manipulated in a factorial design to determine how these factors interact to affect phytoplankton growth. Four major phytoplankton taxa (two diatoms, one chrysophyte, and one dinoflagellate) were found in the water samples across all treatments. Greater growth rates were observed at the higher temperature for all taxa, except the chrysophyte. UVR depressed the growth rates of all phytoplankton at 68C regardless of nutrient conditions. In contrast, at 14 8C, a negative effect of UVR was not observed for any species in the absence of nutrient additions; only with the addition of nutrients did UVR exposure depress the growth of one diatom species and the dinoflagellate. Our results suggest that in alpine lakes, the effects of UVR exposure on phytoplankton depend on temperature and nutrient availability, indicating that climate change and enhanced atmospheric nitrogen deposition are likely to alter UV‐temperature‐nutrient relationships of plankton in high-UV systems.