Ozone Hole Consequences

The Southern Ocean is one of the world's most productive marine ecosystems, home to huge numbers of penguins, seals, and bottom plants, and a major supplier of nutrients carried to other parts of the world by undersea currents. Little is known about the effect of UV-B on marine life, particularly the microscopic algae called phytoplankton that form the foundation of the undersea food chain. These tiny plants capture the sun's energy through photosynthesis, providing food for microscopic animals. 

phytoplankton images

They are eaten by krill, which sustain the Antarctic's abundant seals, penguins, and baleen whales.

Antarctic Krill

Photo Courtesy of

http://www.ecoscope.com

Less phytoplankton means less food for these animals to eat. It is estimated that a 16 % ozone depletion could result in further losses in Phytoplankton, which would lead to a loss of about 7 million tons of fish per year. With the human food supply already strained due to demands of an ever-increasing population, small reductions resulting from UV damage may be disastrous to many people, especially the poor and indigenous people.

UV Rays enter the human body

Researchers say it's clear that UV-B harms Antarctic microbes. Dr Patrick Neale, of the Smithsonian Environmental Research Center, has predicted that phytoplankton photosynthesis declines by as much as 8.5 per cent under the worst conditions.

DNA

It also damages the DNA of marine bacteria and the larvae of starfish and urchins, they say. And it even alters ocean chemistry, creating potentially dangerous substances in the water itself. 

"This refers to the fact that UV radiation is involved in a number of photochemical reactions in seawater (including the hydrolysis/splitting of water molecules) that produce radicals (hydroxyl, peroxide, superoxide, etc.). These radicals are very reactive and can cause biological damage by oxidizing biological molecules. It's really dramatic what the changes in ozone levels will do to rates of DNA damage and inhibited development," says biologist Deneb Karentz of the University of San Francisco. "If you have a 30 per cent decline in ozone, that doesn't mean a 30 per cent decline in a given biological process - it could be a lot more than that". Experts predict that an estimated 10 % reduction in the ozone layer will result in a 25 % increase in non-melanoma skin cancer rates for temperate latitudes by the year 2050.

Deneb Karentz of the University of San Francisco

Professor of Environmental Science and Biology Chair, Department of Biology

Photograph taken near Palmer Station, a US research base on Anvers Island along the Antarctic Peninsula

The burning goes deeper however, than sunburn, skin cancers, and cataracts. Wearing certain sunglasses may enhance exposure of the lens and retina to harmful UV rays, because the iris opens wider to compensate for the reduced visible light and then more penetration of UV can reach the retina. Through other similar mechanisms, UV rays can suppress the human immune system leaving the body vulnerable to many diseases caused by bacteria and viruses entering through or affecting the skin. While darker skinned individuals are less likely to contract a skin cancer from sun exposure, dark skin is not a protection against immune suppression by UV. But dark skin does require a greater dosage of UV than white skin to initiate immune suppression.

Increased exposure to UV rays in animals and humans has been linked to elevated risk from the following diseases: the herpes viruses, the human immunodeficiency virus HIV- 1, a variety of papilloma viruses, leishmaniasis, malaria, forms of tuberculosis, leprosy, lupus erthematodes, dermatitis, E. coli, and Staphylococcus aureus. Since UV rays readily damage DNA in all cells, it is not unrealistic to hypothesize that this will play an additional role in the mutation of existing disease bacteria and viruses and may produce totally new strains of pathogens. Physicians are finding that infection and disease is a greater global challenge than cancer, as people of all skin pigmentation are at equal risk from the effects of immuno-suppression. Geographic areas of poor public health are at even greater risk.

Australian Skin Cancer

Australians suffer the highest rates of skin cancer in the world. Each year, around 1,200 Australians die from what is an almost totally preventable disease. Everyone can develop skin cancer; however, some people may be at higher risk than others, due to a range of factors.

Australia exposed to more UV
Ultraviolet (UV) radiation levels in Australia are higher than in Europe, even during summer. Being located close to the ozone hole over the Antarctic means much higher, more severe levels of UV radiation get through to ground level.

During summer, the earth's orbit brings Australia closer to the sun than Europe during its summer, resulting in an additional seven per cent solar UV intensity. This, coupled with our clearer atmospheric conditions, means Australians are exposed to up to 15 per cent more UV than Europeans.

First launched by a cartoon seagull singing ‘Slip! Slop! Slap!’ on  TV screens in 1980, 

SunSmart adopted its name and mission in 1988. An initiative of The Cancer Council Victoria and supported by the Victorian Health Promotion Foundation, SunSmart was developed to combat spiralling skin cancer incidence and mortality rates.

Since then, attitudes towards tanning and sun protection have changed dramatically. Australians have realised the pitfalls of their sun-loving, outdoor lifestyle and are taking preventative measures to reduce their risk of sun damage and skin cancer. Research by The Cancer Council Victoria shows SunSmart’s messages have reached a majority of Australians and had a stong impact on their behaviour.

Consequently, skin cancer deaths have slowed and for females, have even started to decline. More Australians are detecting skin cancers early, increasing their chances of surviving the disease.

http://www.sunsmart.com.au/index.htm

2007 United States Skin Cancer Facts & Figures 

• More than 1 million new cases of skin cancer will be diagnosed in the United States this year
• 1 in 5 Americans will develop some form of skin cancer during their lifetime
• There will be about 108,230 new cases of melanoma in 2007 — 48,290 in situ (noninvasive) and 59,940 invasive (33,910 men and 26,030 women).
•  In 2007, at current rates, a person has a one in 33 chance of developing melanoma (both in situ and invasive). The risk of developing invasive melanoma is one in 63.
• Invasive melanoma is the sixth most common cancer in men and women.
• Melanoma is the second most common cancer in women aged 20-29.
• One American dies of melanoma almost every hour (every 65 minutes). 
• In 2007, 8,110 deaths will be attributed to melanoma — 5,220 men and 2,890 women. Older Caucasian males have the highest mortality rates from melanoma.
• An estimated 10,850  people in the United States will die of skin cancer this year, 8,110 from melanoma and 2,740 from other skin cancers.
• The incidence of melanoma has increased 690 percent from 1950 to 2001, and the overall mortality rate increased 165 percent during this same period.
• More than 75 percent of skin cancer deaths are from melanoma.
• Both basal cell carcinoma and squamous cell carcinoma have a better than 95 percent five-year cure rate if detected and treated early.
• The five year survival rate for people whose melanoma is detected and treated before it spreads is 99 percent.
• Between 1996 and 2002, the five year survival rate for melanomas detected at all stages increased to 92 percent from 82 percent between 1975 and 1977.

Credit: American Cancer Society's 2007 Facts & Figures

The World Health Organization estimates that as many as 60,000 people a year worldwide die from too much sun, mostly from malignant skin cancer. Of these deaths, 48,000 are from melanoma, and 12,000 are from other skin cancers. About 90 percent of these cancers are caused by ultraviolet light from the sun.

Health Effects of Overexposure to the Sun