What Is Ultraviolet Radiation?

Ultraviolet radiation is optical radiation with a wavelength range of about 10 to 400 nm. In this wavelength range, different wavelengths of ultraviolet radiation have different effects. In research and applications, ultraviolet radiation is often divided into: A-band (400-320nm); B-band (320-280nm); C-band (280-200nm). ); Vacuum ultraviolet band (200 ~ 10nm). Ultraviolet radiation with a wavelength of less than 200 nm cannot be transmitted in the air due to absorption by the atmosphere.

The ultraviolet radiation of the sun is the main body of ultraviolet radiation received by human beings.

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Impact on aquatic life

Aquatic biological systems provide a large amount of food for humans. About 30% of all animal proteins consumed by humans worldwide come from the ocean. In many countries, especially developing countries, this proportion will increase significantly. Therefore, it is important to understand how the increase in solar UVB radiation affects the production of aquatic ecological products. In addition, the ocean also plays a decisive role in the process of global warming. The plankton in the ocean is the main sink of carbon dioxide in the atmosphere and plays a decisive role in the trend of carbon dioxide concentration in the atmosphere.

Hader et al. Studied the effect of solar UVB on a plant of the genus Chlamydomonas and a plant movement of the genus Amoeba Continuously make necessary adjustments to changing environmental conditions and potentially dangerous situations.

Takeuchi et al.'S research shows that enhanced solar UVB radiation will reduce the productivity of marine plankton, which will have a huge impact on complex marine ecosystems and humans. Any reduction in this kind of marine productivity will undoubtedly affect the global food supply. Worrest also pointed out that enhanced UVB radiation will affect the growth and rhythm of many microorganisms. Dohler and other studies also found that UVB radiation strongly affects the nitrogen fixation process, which affects the reduction of many important plankton; while the reduction of some important plankton will seriously affect the complex food chain and total food production in the aquatic ecosystem. According to estimates, a loss of 16% of the ozone content in the atmosphere will lead to a 5% reduction in plankton biomass, which is equivalent to a reduction of 700,000 tons of annual fishing output worldwide.

Enhanced UVB results in decreased abundance of seagrass and redistribution in deep water. When the UVB intensity is increased relative to the PAR level, the seagrass community may become small and deficient, the population distribution is weakened, and the biomass is reduced. Therefore, the enhancement of UVB has the potential to change the structure and distribution of the seagrass population.

Increased UVB radiation can cause massive deaths of marine plankton, shrimp, crab larvae and shellfish, and even cause extinction of certain organisms. UVB radiation has a detrimental effect on the early developmental stages of fish, shrimp, crabs, amphibians and other animals. The most serious thing is to reduce their reproductive ability and damage the growth and development of larvae. In the late spring season of high latitudes, the enhancement of UVB radiation may affect some species, because the enhancement of UVB radiation occurs exactly at the critical stage of their growth and development. Even a small increase in UVB radiation or short-term fluctuations will seriously affect the relative Sensitive species.

Effects on plant mineral nutrition

Murali et al. Reported that the rate at which UVB affects soybean absorption of phosphorus is related to the amount of phosphorus used. When there is more phosphorus, UVB does not affect phosphorus absorption, and vice versa. Ambler et al. Found that in cotton without UVB supplemental irradiation, the speed at which Zn moves from cotyledons to young leaves is twice that of UVB treatment, which shows that UV can inhibit the operation of Zn in plants, and the mechanism is unknown. Dai found that rice treated with UVB had a reduced electrical conductivity in the leaves, and this inhibition would affect the absorption capacity of rice roots, plant nutrition and rice biological yield.

Doughty and Mope found that the cell membrane was polarized after irradiated by ultraviolet light, and the membrane resistance also decreased. Due to the damage of the membrane structure, Cl-, K +, and Na + in the cell are extravasated, and the active absorption of ions is continuously decreased. Wright et al. used cultured tobacco cells to absorb 86, Rb +, and 14C- and mannitol before UVB irradiation. As a result, there were a large amount of 86, Rb +, but no 14, C-, mannitol in the extravasation. It destroys some specific ion channels on the plasma membrane, but has little effect on the entire structure of the cell. This view has been confirmed by subsequent experiments. Zill and tolbert found that after UVB treatment of wheat, K-ATPase activity in root cells was inhibited. In general, there are few studies on the absorption and operation of mineral ions by UVB.

Impact on skin canceration

Using the daily solar radiation, cloud cover, solar zenith angle, ozone, water vapor pressure, air pollutants, and ultraviolet radiation data from September 2002 to October 2005 in Nanning, Guangxi, a model for estimating ultraviolet exposure based on meteorological elements was established. ; Using this model to reconstruct the daily UV exposure data from 1961-2007, and analyzing the characteristics of the reconstructed sequence from different scales of year, spring, summer, autumn, and winter; using the skin cancer incidence data from 1991-2003 to analyze the UV exposure and Correlation between the number of various types of skin cancer incidence; prospects for future changes in UV. The main conclusions are: from 1961 to 2007, the annual average daily ultraviolet exposure in Nanning was 95.83 Wh / m2; the absolute variability was highest in summer, the relative variability was highest in winter, and the absolute and relative variability were smallest in autumn; The average UV radiation in spring, summer, and autumn has a slight downward trend, and the downward trend is obvious in winter; the mutations mainly occur in the middle and late 1970s to the early 1980s and the early 1990s; the most significant cycle of the year and season is the standard In summer, there is still an obvious 11-year cycle; the number of squamous cell carcinomas from 1991 to 2003 is significantly correlated with the amount of ultraviolet exposure; basal cell carcinoma, squamous cell carcinoma, and malignant melanoma are all three types of skin cancers that occur frequently. Ultraviolet radiation time; looking at the changes of ultraviolet radiation before 2050, it is believed that the higher years may be around 2017, 2031, and 2045, and the lower years may be around 2010, 2024, and 2038 ^[4] .