Thursday, November 11, 2010

Whales vs. Sun

A subject that has been receiving a lot of attention over the past few years is that of skin cancer. This attention is for a good reason, for over 73 000 Canadians in 2007 were diagnosed with it, so it is a real problem. As many people know, one of the main causes of skin cancer is exposure to Ultra Violet (UV) radiation. Exposure to UV radiation has increased greatly over the years as a result of air pollution and the resulting negative effects on the ozone layer. However, despite all of the research done in humans, of all the species on the planet humans are probably exposed to the least amount of UV radiation due to the amount of time spent indoors and technologies such as sunscreen that have been developed to help prevent skin cancer. The majority of all species are exposed to these increasing levels of UV every day. One of these animals is whales, especially due to the amount of time they spend near the surface doing such basic activities as breathing and eating. The theory is that because whales do not have any fur or feathers to protect their bodies, they have nothing to prevent the UV radiation from damaging their skin. However, I believe that this issue is greatly over rated.

First of all, one of the greatest dangers regarding sun exposure is when the sun is avoided for long periods of time, and then suddenly, the organism is exposed to the sun for hours at a time. An excellent example in humans is somebody who works in an office, and then goes to beach for the day. They are likely going to have very bad sunburn, whereas somebody like a farmer who spends a great deal of their time outside, does not experience hardly any negative effects from a day spend at the beach. This is greatly the case for whales. They spend every day of their lives exposed to this ultraviolet radiation, so they are very likely going to build up some sort of resistance to it.

Even in the actual study itself, most of the data that they collected was from the air through the use of photography. They used this to determine any sort of skin discolouration, and found that there was more damage to whales with lighter coloured skin compared to whales with darker coloured skin. However, this is probably just an effort to darken the whale’s skin to help protect it if the UV rays are getting stronger. Therefore this skin discolouration is more of an adaptation, something that organisms do all the time, rather than a disease.

The researchers also had no way of knowing whether or not the discolorations that were appearing on the whales skin were actually a result of UV or due to some other external factor that nobody has yet considered. Just because humans have certain reactions to overdoses of UV radiation, it does not mean that an animal which has a much tougher and thicker skin would experience the same effects.

A thinning ozone layer is by no means a good thing. However, I believe that the study on the effects of UV was bias because they wanted to find UV damage in the whales, and did not really investigate other possible causes of the discolorations. There is still a lot of work to do as far as research is concerned before we will be able to know for sure what the effects of increased UV levels have on whales and other similar wildlife.

Adam Gibson (0705733)





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