ISSN:0031-8655    

DOI:10.1111/j.1751-1097.1989.tb05547.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

AbstractThe biologically effective ultraviolet irradiance at the earth's surface varies with the elevation of the sun, the atmospheric ozone amount, and with the abundance of scatterers and absorbers of natural and anthropogenic origin. Taken alone, the reported decrease in column ozone over the Northern Hemisphere between 1969 and 1986 implies an increase in erythemal irradiance at the ground of four percent or less during summer. However, an increase in tropospheric absorption, arising from polluting gases or particulates over localized areas, could more than offset the predicted enhancement in radiation. Any such extra absorption is likely to be highly regional in nature and does not imply that a decrease in erythemal radiation has occurred on a global basis. The Antarctic ‘ozone hole’ represents a special case in which a portion of the earth has experienced ultraviolet radiation levels during spring that are far in excess of those which prevailed prior to the present dec

ISSN:0031-8655    

DOI:10.1111/j.1751-1097.1989.tb05548.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

AbstractSeveral ultraviolet (UV) action spectra that typify the responses of higher plants to irradiation by wavelengths between 280 nm and 380 nm are shown. An attempt is made to generate common spectra that may be used, at least temporarily, to represent the effects of UV on such important biological parameters as photosynthesis. The goal is to provide an estimate of plant response to solar UV and to the potential increase in ground level UV postulated for a depleted stratospheric ozone layer. Solar plant damage effectiveness curves are generated under “normal” solar UV conditions, and under an assumed UV increase corresponding to a 16% depletion in total ozone. Additional effects due to ozone depletion are concentrated in the UV‐B region, especially at wavelengths between about 297 nm and 315 nm. Common features of these effectiveness curves are noted, and limitations are pointed out. As expected, no common spectrum has been found that can substitute for any specific spectrum nor that is unique enough to provide more than a limited first approximation of a plant damage spectrum. Additional information must be generated to fulfill this

ISSN:0031-8655    

DOI:10.1111/j.1751-1097.1989.tb05549.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

AbstractMarine organisms in the upper layers of the sea may be endangered by increased ultraviolet radiation resulting from declines in the thickness of stratospheric ozone. Evidence supporting this hypothesis includes the fact that wavelengths of potentially damaging ultraviolet radiation can penetrate to ecologically significant depths and laboratory findings that many marine organisms are extremely sensitive to this radiation. Estimated effects of increased ultraviolet radiation on populations of marine organisms range from insignificant to catastrophic. Direct estimation of population effects have not been made, although this is the only adequate measure of the potential impact. The extreme diminution of ozone during the Antarctic spring, coupled with the dynamics of phytoplankton production in this region, may provide conditions suitable for an environmental test of the hypotheses that marine organisms are endangered by reduced stratospheric ozone. There is an urgency to the testing of this hypothesis since these populations may be directly impacted at the present time.

ISSN:0031-8655    

DOI:10.1111/j.1751-1097.1989.tb05550.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

AbstractIncreases in UV‐B radiation resulting from ozone depletion during austral spring could potentially alter the balance of the Southern Ocean marine ecosystem. A quantitative assessment ol the effects of UV‐B enhancement requires knowledge of (1) the wavelength‐dependent fluxes of UV‐B in the upper ocean, (2) action spectra for UV‐B damage to Antarctic phytoplankton and zooplankton, and (3) depth‐dependent distributions and residence times of Southern Ocean phytoplankton and zooplankton during austral spring. Unfortunately, only limited data arc currently available to address this impact directly. To provide some of the information required for such an assessment, available data regarding plankton distributions and their photophysiological characteristics have been summarized. A preliminary assessment of the available literature suggests that Antarctic phytoplankton and krill receive very low doses of UV‐B during austral spring. The high spectral attenuation coefficients associated with the environments in which most plankton arc found during springtime precludes the possibility of UV damage. Future research directions are described which should provide a better understanding of the ecological consequences of the “ozone hole” which resides over the Antarctic continent duri

ISSN:0031-8655    

DOI:10.1111/j.1751-1097.1989.tb05551.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

AbstractThe potential impacts of an increase in solar UV‐B radiation reaching the Earth's surface due to stratospheric ozone depletion have been investigated by several research groups during the last 15 years. Much of this research has centered on the effects of plant growth and physiology under artificial UV‐B irradiation supplied to plants in growth chambers or greenhouses. Since these artificial sources do not precisely match the solar spectrum and due to the wavelength dependency of photobiol‐ogical processes, weighting functions, based on action spectra for specific responses, have been developed to assess the biological effectiveness of the irradiation sources and of predicted ozone depletion. Recent experiments have also utilized artificially produced ozone cuvettes to filter natural solar radiation and simulate an environment of reduced UV‐B for comparative purposes.Overall, the effectiveness of UV‐B varies both among species and among cultivars of a given species. Sensitive plants often exhibit reduced growth (plant height, dry weight, leaf area, etc.), photosynthetic activity and flowering. Competitive interactions may also be altered indirectly by differential growth responses. Photosynthetic activity may be reduced by direct effects on photosynthetic enzymes, metabolic pathways or indirectly through effects on photosynthetic pigments or stomatal function. The fluence response of these changes has yet to be clearly demonstrated in most cases. Plants sensitive to UV‐B may also respond by accumulating UV‐absorbing compounds in their outer tissue layers, which presumably protect sensitive targets from UV damage. Several key enzymes in the biosynthetic pathways of these compounds have been shown to be specifically induced by UV‐B irradiation.Few studies have documented the effects of UV‐B on total plant yield under field conditions. One notable exception is a 6‐yr study with soybean demonstrating harvestable yield reductions under a simulated 25% ozone depletion. These effects are further modified by prevailing microclimatic conditions. Plants tend to be less sensitive to UV‐B radiation under drought or mineral deficiency, while sensitivity increases under low levels of visible light. Further studies are needed to understand the mechanisms of UV‐B effects and the interactions with present stresses and future projected cha

ISSN:0031-8655    

DOI:10.1111/j.1751-1097.1989.tb05552.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

Abstract–The adverse effects of ultraviolet‐B (UV‐B) radiation on the eye have been suspected but only recently have they been quantified by epidemiologic studies in humans. These studies became possible as methods to qualify individual ocular UV‐B exposure were developed. A consistent dose‐dependent association between ocular UV‐B exposure and two common types of cataract (cortical and posterior subcapsular) has been shown. Although suggested by experimental studies, at present, evidence does not exist to link UV‐B exposure to senile macular degeneration. Ocular exposure to UV‐B is also associated with several corneal changes, pterygium, climatic droplet keratopathy, and acute photokeratitis (snow blindness). Significant reduction in ocular UV‐B exposure results from the use of ey

ISSN:0031-8655    

DOI:10.1111/j.1751-1097.1989.tb05553.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

Abstract–Malignant melanomas of the skin are becoming more common. Earlier diagnosis has led to better individual prognoses, but this has not prevented the death rate in the population from rising. This paper brings up‐to‐date studies on the etiology of malignant melanoma, and supplements various fuller but earlier reviews.Melanoma risk is increased in lightly pigmented people who burn in the sun and do not tan well. People with an increased number of nevi are also at increased risk. Latitude of residence is important, risk in white populations increasing with distance from the poles. Phenotypic factors can over‐ride location, so that Mediterranean people have lower rates than Scandinavians. Melanomas are concentrated on sites exposed by clothing, but this concentration is not as strong as for the other skin cancers. Migrants to sunny climates are at less risk than similar people born locally, provided that they migrated as adults. Outdoor work carries only a small excess risk of malignant melanoma, in contrast to the other skin tumors. Melanomas are commoner, and kill more often, among people of high socioeconomic status than low.The two most detailed contemporary reconciliations of these pieces of evidence are based on the ideas that intense brief exposure is the critical factor, or that exposure in childhood is of major importance.With the expected changes in the global concentration of ozone in the stratosphere, it is necessary to estimate the relationship between the intensity of sunlight and melano

ISSN:0031-8655    

DOI:10.1111/j.1751-1097.1989.tb05554.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

Abstract–Incidence of melanoma is certainly rising all over the world and this observation has been related to a more frequent and prolonged exposure to the rays of the sun.The authors critically review pertinent literature and conclude that descriptive epidemiology of melanoma does not give survival trends and does not support the claim that melanoma is ultraviolet (UV) dependent. Analytical epidemiology has not reached a consensus on this aspect.Experimental data available are also difficult to interpret because there are consistent differences of susceptibility to UV among different animals, among lamps used and methods of measuring employed in various laboratories.Information available shows that the maximal relative biological activity of UV in humans is at about 305 nm. This evaluation greatly depends on (1) thickness of the skin, (2) the quantity and quality of secretions that cover the skin, (3) cleaness of the skin, (4) the latitude, (5) the weather, (6) the hour of the day and (7) the presence of chemical carcinogens in the air and on the skin.The authors stress the importance of the criteria of clinical diagnosis recently introduced in clinical practice and higher public awareness as the causes of the increasing incidence of melanom

ISSN:0031-8655    

DOI:10.1111/j.1751-1097.1989.tb05555.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

Abstract–There is highly significant evidence that non‐melanoma skin cancers are primarily due to chronic repeated exposure to solar ultraviolet radiation, and that there is a significant, although somewhat different relationship between solar radiation and the development of cutaneous malignant melanoma.Recent experimental and epidemiologic studies show that the biologically most effective UVR wavelengths are in the segment of the solar UVR spectrum that would be significantly augmented by decreases in stratospheric ozone content.A recent report on measurements of column ozone changes in the stratosphere has shown that in the past 18 yr, there has been an ozone decrease between 2 and 3%, greater in the winter months, and somewhat differing with latitude in the Northern Hemisphere.Calculations of the relationship of ozone decrease to increase in biologically effective UVR show great dependence on the biologic action spectrum assumed.Based on extensive epidemiologic studies of skin cancer incidence, it appears that the estimated increase in biologically effective UVR due to the measured ozone decreases in the past (almost) two decades are not likely to be the cause of the sharp increase in skin cancer incidence which have been observed. Most likely these increases in incidence are the result of increasing personal exposure, due to striking changes in personal behavior that have taken place for social reasons.However, there is every reason to believe that increases in biologically effective UVR due to stratospheric ozone decreases will have significant impact on human skin cancer incidence in the fut

ISSN:0031-8655    

DOI:10.1111/j.1751-1097.1989.tb05556.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY