Changes In UV-B Radiation Research Articles

Ultraviolet-B radiation in relation to agriculture in the context of climate change: a review.

Over the past few decades, the amount of ultraviolet-B radiation (UV-B) reaching the earth's surface has been altered due to climate change and stratospheric ozone dynamics. This narrow but highly biologically active spectrum of light (280-320nm) can affect plant growth and development. Depletion of ozone and climate change are interlinked in a very complicated manner, i.e., significantly contributing to each other. The interaction of climate change, ozone depletion, and changes in UV-B radiation negatively affects the growth, development, and yield of plants. Furthermore, this interaction will become more complex in the coming years. The ozone layer reduction is paving a path for UV-B radiation to impact the surface of the earth and interfere with the plant's normal life by negatively affecting the plant's morphology and physiology. The nature and degree of the future response of the agricultural ecosystem to the decreasing or increasing UV-B radiation in the background of climate change and ozone dynamics are still unclear. In this regard, this review aims to elucidate the effects of enhanced UV-B radiation reaching the earth's surface due to the depletion of the ozone layer on plants' physiology and the performance of major cereals.

Twenty-five years of spectral UV-B measurements over Canada, Europe and Japan: Trends and effects from changes in ozone, aerosols, clouds, and surface reflectivity

Spectral UV records of solar irradiance at stations over Europe, Canada, and Japan were used to study long-term trends at 307.5nm for a 25-year period, from 1992 to 2016. Ground-based measurements of total ozone, as well as satellite measurements of the Aerosol Index, the Total Cloud Cover and the surface reflectivity were also used in order to attribute the estimated changes of the UV to the corresponding changes of these factors. The present study shows that over the Northern Hemisphere, the long-term changes in UV-B radiation reaching the Earth's surface vary significantly over different locations, and that the main drivers of these variations are changes in aerosols and total ozone. At high latitudes, part of the observed changes may also be attributed to changes in the surface reflectivity. Over Japan, the UV-B irradiance at 307.5nm has increased significantly by ∼3%/decade during the past 25 years, possibly due to the corresponding significant decrease of its absorption by aerosols. It was found that the greatest part of this increase took place before the mid-2000s. The only European station, over which UV radiation increases significantly, is that of Thessaloniki, Greece. Analysis of the clear-sky irradiance for the particular station shows increasing irradiance at 307.5nm by ∼3.5%/decade during the entire period of study, with an increasing rate of change during the last decade, possibly again due to the decreasing absorption by aerosols.

Effect of increased UV-B radiation on biological control of the gray mold by Clonostachys rosea and on the expression of strawberry defense-related enzymes

Changes in UV-B radiation can have large effects on the management of the pathogen Botrytis cinerea, especially on strawberry production in Brazil. The aim of this work was to investigate the effect of the increased UV-B radiation on biological control of gray mold by Clonostachys rosea and on the expression of plant defense-related enzymes. The experiments were laid out in randomized complete blocks in a split-plot design. The whole-plot factor was represented by UV-B treatments: 1. ambient solar UV; 2. ambient solar UV reduced by 80% (UV-); 3 ambient solar UV supplemented with UV-B lamps (UV+). The split-plot factors were: 1. plants sprayed with water (control); 2. plants exposed to B. cinerea; 3 plants sprayed weekly with an inoculum suspension of C. rosea and exposed to B. cinerea. The latent infection of B. cinerea was evaluated during five weeks per season, after which leaves were collected to assess the peroxidase, polyphenoloxidase and chitinase activities. No significant effect on B. cinerea incidence for irradiation treatments were observed during both seasons, although C. rosea treatments have been able to control gray mold on fruits. The enzymatic activity was related to the ambient condition, not to the exposure of the plants to these micro-organisms. Only UV+ conditions led to an increase of polyphenoloxidase activity in season 2. The results indicate that the increase of UV-B radiation has no influence on the ability of C. rosae to control the gray mold on strawberry.

UV-B as a Photoacclimatory Enhancer of the Hermatypic Coral <i>Stylophora pistillata</i>

Photoacclimation processes are crucial for the survival of all photosynthetic organisms in the photic zone. Changes in photosynthetic active radiation (PAR) are however simultaneous to changes in UV-B radiation. The influence of UV-B levels on bio-optical and physiological parameters of deep (30 m) corals from the species Stylophora pistillata and their symbiotic algae, zooxanthellae, was examined during their gradual, stepwise acclimation to a shallow depth (3 m). Drastic exposure of deeper corals to higher UV-B levels in shallower depths is usually fatal. Hence, the acclimation process lasted 118 days and included 10 intermediate stations with an addition of similar amount of PAR at each depth transfer. Concomitantly, in an on-shore experiment, fragments from the same colonies were acclimated by changing shading nets corresponding in PAR levels to each in situ station. Since UV-B is attenuated more efficiently than PAR in seawater, the PAR: UV-B ratio changes in the depth experiment while remaining constant under the neutral density nets. This provided the opportunity to evaluate the importance of UV-B to photoacclimation. In both experiments all fragments survived, in spite of a four-fold difference in levels of PAR and a 140-fold difference in UV-B flux between the initial and final conditions. Both experimental designs resulted in reduction of zooxanthellae density, photosynthesis rates, and quantum yields of PSII, while cellular chlorophyll content remained unaffected. Zooxanthellae density and maximal photosynthetic rate was found decreased in correlation with UV-B radiation, whether it was elevated logarithmically with reducing depths or linearly with reducing shades. Conversely, quantum yields of PSII were adjusted according to the enhancement of PAR rather than UV-B. We conclude that UV-B enhances the magnitude of photoacclimation to higher PAR. This novel aspect of photoacclimation can provide the basis for our understanding of the underlying mechanisms that result in UV-related bleaching.

UV-B radiation effects on terrestrial plants – A perspective

Both terrestrial and aquatic plants, the primary producers supporting life on earth, can be threatened by global climate change and particularly by UV-B radiation due to the depletion of the ozone layer in both Poles. The injurious effects of UV-B have been assessed mainly through in vitro studies and vary greatly according the dose received, the exposition period and the sensitivity of the species. Adaptive responses can include for example, synthesis of new compounds, increases of UV-B absorbing compounds or anti-oxidant enzymes. Morphological consequences are also documented such as reduced growth and thickening of leaves and cuticule. The main response of UV-B irradiation in indoor experiments is the formation of UV-B absorbing compounds such as phenolic compounds and flavonoids which function as protective screens, although in the natural habitat plants living at higher altitudes and latitudes are tolerant to UV-B due to the natural selection. The main conclusion derived from studies with terrestrial plants is that photosynthesis is not significantly affected by changes in UV-B radiation when plants grow under natural conditions. Moreover, due to the successful implementation of the Montreal Protocol the increase of UV-B radiation in most populated regions of the world (i.e., outside the regions affected by the Antarctic ozone hole) has been modest.

Anthropogenic changes in the surface all-sky UV-B radiation through 1850–2005 simulated by an Earth system model

Abstract. The historical anthropogenic change in the surface all-sky UV-B (solar ultraviolet: 280–315 nm) radiation through 1850–2005 is evaluated using an Earth system model. Responses of UV-B dose to anthropogenic changes in ozone and aerosols are separately evaluated using a series of historical simulations including/excluding these changes. Increases in these air pollutants cause reductions in UV-B transmittance, which occur gradually/rapidly before/after 1950 in and downwind of industrial and deforestation regions. Furthermore, changes in ozone transport in the lower stratosphere, which is induced by increasing greenhouse gas concentrations, increase ozone concentration in the extratropical upper troposphere and lower stratosphere. These transient changes work to decrease the amount of UV-B reaching the Earth's surface, counteracting the well-known effect increasing UV-B due to stratospheric ozone depletion, which developed rapidly after ca. 1980. As a consequence, the surface UV-B radiation change between 1850 and 2000 is negative in the tropics and NH extratropics and positive in the SH extratropics. Comparing the contributions of ozone and aerosol changes to the UV-B change, the transient change in ozone absorption of UV-B mainly determines the total change in the surface UV-B radiation at most locations. On the other hand, the aerosol direct and indirect effects on UV-B play an equally important role to that of ozone in the NH mid-latitudes and tropics. A typical example is East Asia (25° N–60° N and 120° E–150° E), where the effect of aerosols (ca. 70%) dominates the total UV-B change.

UVB-Based Mate-Choice Cues Used by Females of the Jumping Spider Phintella vittata

Although there are numerous examples of animals having photoreceptors sensitive to UVA (315-400 nm) [1] and relying on UVA-based mate-choice cues [2-5], here we provide the first evidence of an animal using UVB (280-315 nm) for intraspecific communication. An earlier study showed that Phintella vittata, a jumping spider (Salticidae) from China, reflects UVB [6]. By performing six series of binary mate-choice experiments in which we varied lighting conditions with filters (UVB+ [no filter] versus UVB-, UVB+ versus ND1, UVB+ versus ND2, UVB- versus ND1, UVB- versus ND2, and UVB- versus UVA-), we show that significantly more UVB + males than UVB- males are chosen by females as preferred mates. Female preference for UVB-reflective males is not affected by differences in brightness or by UVA.

Interactive effects of solar UV radiation and climate change on biogeochemical cycling

This report assesses research on the interactions of UV radiation (280-400 nm) and global climate change with global biogeochemical cycles at the Earth's surface. The effects of UV-B (280-315 nm), which are dependent on the stratospheric ozone layer, on biogeochemical cycles are often linked to concurrent exposure to UV-A radiation (315-400 nm), which is influenced by global climate change. These interactions involving UV radiation (the combination of UV-B and UV-A) are central to the prediction and evaluation of future Earth environmental conditions. There is increasing evidence that elevated UV-B radiation has significant effects on the terrestrial biosphere with implications for the cycling of carbon, nitrogen and other elements. The cycling of carbon and inorganic nutrients such as nitrogen can be affected by UV-B-mediated changes in communities of soil organisms, probably due to the effects of UV-B radiation on plant root exudation and/or the chemistry of dead plant material falling to the soil. In arid environments direct photodegradation can play a major role in the decay of plant litter, and UV-B radiation is responsible for a significant part of this photodegradation. UV-B radiation strongly influences aquatic carbon, nitrogen, sulfur and metals cycling that affect a wide range of life processes. UV-B radiation changes the biological availability of dissolved organic matter to microorganisms, and accelerates its transformation into dissolved inorganic carbon and nitrogen, including carbon dioxide and ammonium. The coloured part of dissolved organic matter (CDOM) controls the penetration of UV radiation into water bodies, but CDOM is also photodegraded by solar UV radiation. Changes in CDOM influence the penetration of UV radiation into water bodies with major consequences for aquatic biogeochemical processes. Changes in aquatic primary productivity and decomposition due to climate-related changes in circulation and nutrient supply occur concurrently with exposure to increased UV-B radiation, and have synergistic effects on the penetration of light into aquatic ecosystems. Future changes in climate will enhance stratification of lakes and the ocean, which will intensify photodegradation of CDOM by UV radiation. The resultant increase in the transparency of water bodies may increase UV-B effects on aquatic biogeochemistry in the surface layer. Changing solar UV radiation and climate also interact to influence exchanges of trace gases, such as halocarbons (e.g., methyl bromide) which influence ozone depletion, and sulfur gases (e.g., dimethylsulfide) that oxidize to produce sulfate aerosols that cool the marine atmosphere. UV radiation affects the biological availability of iron, copper and other trace metals in aquatic environments thus potentially affecting metal toxicity and the growth of phytoplankton and other microorganisms that are involved in carbon and nitrogen cycling. Future changes in ecosystem distribution due to alterations in the physical and chemical climate interact with ozone-modulated changes in UV-B radiation. These interactions between the effects of climate change and UV-B radiation on biogeochemical cycles in terrestrial and aquatic systems may partially offset the beneficial effects of an ozone recovery.

The effect of varying ozone concentration on surface UV-B radiation: a Fiji perspective

Projects studying the effect of column ozone levels on UV-B radiation reaching the surface of the Earth as part of a wider global observation of vertical profiling were initiated by NASA/NOAA in the 1990s. A comparison of the changes in UV-B radiation as a function of ozone concentration revealed a negative correlation. We have shown for the first time in Fiji that a similar trend exists but with more scatter. Previous studies at this site (USP) have shown that the atmospheric concentration of aerosols varies seasonally and this may have a bearing on the scatter of the results.

Physiological changes and UV protection in the aquatic liverwort Jungermannia exsertifolia subsp. cordifolia along an altitudinal gradient of UV-B radiation.

Here we report the effects of a natural altitudinal gradient of UV-B radiation, from 1140 to 1816 m altitude, on the physiology of the aquatic liverwort Jungermannia exsertifolia Steph. subsp. cordifolia (Dumort.) Váña collected in mountain streams. Photosynthetic pigments, net photosynthesis and dark respiration rates, chlorophyll fluorescence, protein concentration, sclerophylly, and UV-absorbing compounds [both global UV absorbance of methanol-extractable UV-absorbing compounds (MEUVAC) and concentrations of five individual compounds] were measured. Two new caffeic acid derivatives were discovered: 5″-(7″,8″-dihydroxycoumaroyl)-2-caffeoylmalic acid and 5″-(7″,8″-dihydroxy-7-O-β-glucosyl-coumaroyl)-2-caffeoylmalic acid, whereas three additional compounds were already known in other species: p-coumaroylmalic acid, phaselic acid (both compounds in their cis- and trans- forms) and feruloylmalic acid. Most physiological variables changed considerably along the altitudinal gradient, but only six showed significant linear relationships with altitude: MEUVAC levels, the concentrations of the two new secondary compounds, the maximal apparent electron transport rate through PSII (ETRmax) and the maximal non-photochemical quenching (NPQmax) increased with altitude, whereas photoinhibition percentage decreased. A principal components analysis (PCA) was conducted to rank the values of the physiological and ecological variables obtained along the altitudinal transect, showing that those variables correlated with altitude were responsible for the ordination of the sampling points. The liverwort was not adversely affected by the changing conditions along the altitudinal gradient and, in particular, by the increasing UV-B irradiance, probably because the characteristics shown by high-altitude populations may confer tolerance to high UV-B levels. The response to UV-B of the two new compounds suggests that they could be used as indicators of the spatial changes in UV-B radiation.

Possible impacts of changes in UV-B radiation on North American trees and forests

Approximately 35 species representing 14 tree genera have been evaluated for responses to UV-B radiation in North America. The best representation has been in the conifers where some 20 species representing three genera have been studied. Overall, about 1/3 of these have demonstrated some deleterious response to UV-B. However, most negative impacts have been observed under controlled environment conditions where sensitivity may be enhanced. Therefore, it seems unlikely that expected levels of ozone depletion will result in direct losses in productivity. However, the role that ambient or enhanced levels of UV-B may play in forest ecosystem processes is more difficult to access. One possible indirect response of forests to changes in UV-B radiation levels could be via alterations in plant secondary metabolites. Increases in phenolics and flavonoids that enhance epidermal UV-screening effectiveness may also influence leaf development, water relations or ecosystem processes such as plant–herbivore interactions or decomposition.

Growth responses to ultraviolet-B radiation of two Carex species dominating an Argentinian fen ecosystem

Solar ultraviolet-B radiation (UV-B, 280–315 nm) in the Southern Hemisphere has been increasing over the last few decades due to seasonal stratospheric ozone depletion associated with the ‘ozone hole’ and a more general erosion of the stratospheric ozone layer. We studied the effect of UV-B radiation on growth responses of Carex curta and C. decidua , the two most dominant sedges in a fen ecosystem in Tierra del Fuego (Argentina) in field plots and growth chambers where UV-B radiation was manipulated using different transparent plastic films that either transmitted or attenuated UV-B radiation. In the field, leaf and spike elongation of both species was unaffected by UV-B treatments in all four seasons studied (1997/98 through 2000/2001). Specific leaf areas (SLA) were only measured in the last two seasons and remained unaffected by UV-B for both species in the third field season. However, SLA decreased for C. curta in the fourth season but increased for C. decidua under near-ambient UV-B. Ecosystem specific root length was unaffected by UV-B. Although UV-B did not have a statistically significant effect on biomass production, there was a trend for a 15% higher production under near-ambient UV-B in the fourth year (P = 0.064). In the growth chambers, simulated ambient UV-B approximately equivalent to ambient UV-B in Tierra del Fuego stimulated seedling emergence of C. curta but reduced emergence of C. decidua ; leaf elongation remained unaffected in both species. While plant morphology of C. curta remained unaffected by UV-B radiation, C. decidua had fewer tillers per plant, however tillers had more leaves and biomass under simulated ambient UV-B than under reduced UV-B radiation. The SLA of C. curta was unaffected by UV-B treatments; however, it was significantly lower for C. decidua under simulated ambient UV-B. Root morphology remained unaffected by UV-B for C. curta but roots of C. decidua were significantly thicker under simulated ambient UV-B. Taken collectively, our findings demonstrate that even moderate changes in UV-B radiation (e.g., corresponding to those expected with current stratospheric ozone depletion) may influence growth, morphology and biomass allocation in a species-specific manner for these native sedges in growth chambers and might also affect competitive relationships of these species in the field. Die ultraviolett-B-Strahlung (UV-B, 280–315 nm) über der Südhemisphäre ist in den letzten Dekaden bedingt durch eine saisonale Abnahme an stratosphärischem Ozon (“Ozonloch”) und einer zusätzlichen, eher generellen Erosion der stratosphärischen Ozonschicht angestiegen. Wir untersuchten den Effekt von UV-B-Strahlung auf verschiedene Wachstumsparameter von Carex curta und C. decidua , den zwei dominierenden Seggenarten in Seggenried-Ökosystemen in Tierra del Fuego (Feuerland, Argentinien) in einem Feldversuch (Versuchsdauer: vier Saisonen von 1997/1998 bis 2000/2001) und in Wachstumskammern (Versuchsdauer: 3 Monate). Die Manipulation der UV-B-Strahlung erfolgte dabei durch transparente Kunststofffilm-Filter, welche die solare UV-B-Strahlung entweder transmittieren (Behandlung: “normale UV-B-Strahlung”) oder abschwächen (Behandlung: “reduzierte UV-B-Strahlung”). Im Feldversuch war das Längenwachstum von Blättern und hren beider Seggen-Arten in keiner der vier Vegetationsperioden von den UV-B Behandlungen beeinflusst. Die spezifische Blattfläche der beiden Seggen wurde nur in den letzten beiden Vegetationsperioden gemessen und war in der dritten Vegetationsperiode für beide Seggen-Arten unbeeinflusst von der UV-B-Strahlung. Im vierten Jahr jedoch war die spezifische Blattfläche unter normalem UV-B bei C. curta reduziert und bei C. decidua erhöht. Die spezifische Wurzellänge im Ökosystem war unbeeinflusst von der UV-B-Strahlung. Die Biomasse-Produktion des Ökosystems war im dritten Versuchsjahr unbeinflusst von der UV-B-Strahlung, im vierten Jahr war jedoch ein Trend zu einer um 15% höheren Produktion bei normalem UV-B im Vergleich zu reduziertem UV-B erkennbar (P = 0.064). In den Wachstumskammern hat eine die Feldbedingungen in Tierra del Fuego simulierende UV-B-Strahlung das Aufkommen von C. curta -Keimlingen erhöht aber jenes von C. decidua reduziert; das Längenwachstum der Blätter war bei beiden Arten unbeeinflusst von der UV-B-Strahlung. Während die Morphologie von C. curta von der UV-B-Strahlung unbeeinflusst war, zeigte C. decidua weniger Sprosse pro Pflanze, diese Sprosse hatten jedoch mehr Blätter und Biomasse unter simulierten normalen UV-B Bedingungen als unter reduziertem UV-B. Die spezifische Blattfläche von C. curta war unbeeinflusst von der UV-B-Strahlung, hingegen war sie bei C. decidua unter simuliertem normalen UV-B-signifikant kleiner. Die Wurzelmorphologie von C. curta blieb unbeeinflusst von der UV-B-Strahlung, die Wurzeln von C. decidua waren jedoch signifikant dicker unter simuliertem normalen UV-B. Zusammenfassend zeigen unsere Ergebnisse, dass selbst moderate nderungen in der UV-B Strahlung, wie sie beispielsweise im Zuge der gegenwärtigen stratosphärischen Ozonabnahme vorkommen können, artenspezifische Modifikationen im Wachstum, der Morphologie und der Biomasse-Allokation dieser Seggen in Wachstumskammern bewirken und somit potentiell auch die Konkurrenzbeziehungen dieser Arten in den Seggenriedern beeinflussen können.

Photo-oxidant chemistry in the polluted boundary layer under changing UV-B radiation

UV-B radiation is a driving factor for the chemistry of the polluted boundary layer. It is involved in the formation of radicals and consequently influences the formation and concentration of photo-oxidants. The 3-D mesoscale photochemical Metphomod model was employed to study the effect of changes in UV-B radiation on the concentration of photo-oxidants in the boundary layer over the Swiss Plateau. The model chemistry is based on the RACM mechanism and a two-stream approximation of radiative transfer. A summer (July) and a late winter (February) episode were simulated. All simulations were replicated with relatively large changes in the prescribed total ozone. The results for an increase in UV-B radiation show increases in PAN, HNO 3, and ozone at noon in NO x -rich areas and a decrease in NO x . In NO x -poor areas in summer the effect on ozone is weak and has a negative sign, the main effect being an increase in H 2O 2. The spatial variability of NO x concentrations in the Swiss Plateau in the summer case is such that the effect of increased UV-B radiation on ozone is spatially variable. The effect on the ozone production rate in summer is strongest positive at the surface in the NO x -rich regions in the morning and strongest negative at some altitude above ground in NO x -poor regions in the early afternoon. In the winter episode, NO x -rich conditions are found almost everywhere on the Swiss Plateau, the effect of increased UV-B radiation on the ozone production rate is positive all day long and is largest at 300 m above ground at noon. In this case, in contrast to the summer case, the increase in ozone is carried over to the next day. The model results for ozone are in good agreement with results from a case study and a time series analysis of surface ozone measurements. We estimate the effect of day-to-day changes in total ozone on surface ozone peaks to range from 4 to 6 ppb at most.

Indications of climate change in coastal areas: what may fish otoliths tell us?

CR Climate Research Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsSpecials CR 18:113-118 (2001) - doi:10.3354/cr018113 Indications of climate change in coastal areas: what may fish otoliths tell us? Rüdiger Berghahn* Umweltbundesamt, Versuchsfeld Marienfelde, Schichauweg 58, 12307 Berlin, Germany *E-mail: ruediger.berghahn@uba.de ABSTRACT: The relative occurrence of hyaline zones in the otoliths of the 0-group of certain flatfish species may serve as an indicator for changes in UV-B radiation in the course of climate change. The importance of factors other than UV-B, which are also related to climate change, is discussed. KEY WORDS: Climate change · Flatfish · Tidal flats · Environmental stress · UV-B radiation · Hydrogen peroxide · Otoliths · Biological tags Full text in pdf format PreviousNextExport citation RSS - Facebook - Tweet - linkedIn Cited by Published in CR Vol. 18, No. 1-2. Online publication date: October 18, 2001 Print ISSN: 0936-577X; Online ISSN: 1616-1572 Copyright © 2001 Inter-Research.

Growth seasonality, photosynthetic pigments, and carbon and nitrogen content in relation to environmental factors: a field study of Ulva olivascens (Ulvales, Chlorophyta)

Relative growth rate, photosynthetic pigment content, and internal carbon and nitrogen levels of Ulva olivascens P.A. Dangeard, were examined on a seasonal basis under natural conditions from December 1994 to February 1996. Biotic variables were correlated with abiotic factors, including phosphate and nitrate/nitrite [(NO3− + NO2−)] concentrations in the seawater, temperature, photosynthetically active radiation (PAR), and UV-A and UV-B radiation. The relative growth rate of the alga was 68% higher in spring and early summer than in mid summer. In the same spring-to-summer period, photosynthetic pigment concentrations (chlorophyll a, chlorophyll b, and carotenoids) decreased by 70–80%. From March to July, nitrogen and carbon content declined by 62% and 11%, respectively, which yielded a change in the carbon: nitrogen mass ratio from 12.9 to 39.4. In late summer, the alga disappeared from the field site. Seasonal variations in relative growth rate of U. olivascens were governed by changes in primary ecological factors, i.e., [NO3− + NO2−] concentration (70%), PAR (15%), UV-B (5%), and temperature (4%). UV-B and UV-A radiations and PAR, were primarily responsible for the seasonal changes in chlorophyll a and b and carotenoid contents. More than 78% of the changes in internal carbon and nitrogen levels could be explained by seasonal changes in UV-B radiation. These results suggest that the metabolic stress due to UV-B radiation has little impact on the seasonal growth cycle of U. olivascens but has significant impact on pigments and internal carbon and nitrogen content.

Possible changes in the dose of biologically active ultraviolet radiation received by the biosphere in the summertime Arctic due to total ozone interannual variability

Data for total ozone measurements since 1972 from the world ozone measuring network have been analyzed to study ozone interannual variability and estimate its possible effect on the UV-B dose received by the arctic biosphere. Possible interannual changes in the UV-B dose received by DNA associated with overall interannual ozone variability, as well as with the quasi-biennial oscillation (QBO) in total ozone were computed for different summer months. In general, the largest interannual variations in UV-B dose may occur in the Russian Arctic, whereas the possible variations in the Canadian Arctic are the smallest. Overall variations in the UV-B dose received by DNA can exceed 25% (2σ criterion) in the Taimyr and Severnaya Zemlya for June and July, and 30% in the Laptev Sea for August. In the European sector of the Arctic, the possible variations are greater than 10%, and can exceed 15% in the north Norwegian Sea for July and 20% in Spitsbergen for August. Possible overall variations in the Canadian Arctic and Alaska are ≤ 10%, reaching 15% in Alaska for August, however. The total ozone QBO can also cause essential and (statistically) predicted changes in UV-B radiation. In general, the UV-B dose received by DNA is found to be greater in the Arctic during the westerly phase of the QBO of the equatorial stratospheric wind at 50 mb level than during the easterly phase. The difference can reach or exceed 15% (relative to the mean value) in Taimyr for June and in Severnaya Zemlya for July and August. In northern Europe and Iceland, the difference can reach 10% for August. In the Canadian Arctic, the QBO-related effect is small. In Alaska, the appropriate difference in UV-B dose has an opposite sign for August, exceeding 5% in magnitude.