Whales, solar UV radiations and some research suggestions

Photograph showing, from top to bottom, a blue whale (pale grey skin colour, the lightest species), a sperm whale (dark grey skin colour) and a fin whale (black skin colour, the darkest species). (Credit: Martinez-Levasseur et al./Scientific Reports)
Photograph showing, from top to bottom, a blue whale (pale grey skin colour, the lightest species), a sperm whale (dark grey skin colour) and a fin whale (black skin colour, the darkest species). (Credit: Martinez-Levasseur et al./Scientific Reports)

Main Points:

Researchers have reported that large whales use different strategies to counteract the damaging effects of high level of solar ultraviolet radiation (UV). Moreover, they can also modulate their responses to changing levels of UV.

Published in:

Scientific Reports

Study Further:

Ultraviolet (UV) radiation:

UV radiation/light refers to the electromagnetic radiation of wavelengths from about 5 to about 400 nanometers, beyond the violet end of the visible light spectrum.

UV may result in cellular changes in human beings and other living creatures. Mitochondrial DNA (mtDNA) is an important biomarker of UV-exposure as it has higher rate of mutation as compared to nuclear DNA and reduced capacity to repair damage. mtDNA lesions caused by UV exposure accumulate throughout life that can result in cancer.

Researchers have found that UV-induced acute damage is commonly found in whales. They found that fewer melanocytes can result in more UV-related skin lesions and fewer apoptotic cells amongst whale species, and darker pigmentation provides cellular protection from sun irradiation and plays a role in the elimination of potentially precancerous cells in whales.

Present Research:

In the present study, researchers have reported that UV exposure results in mitochondrial DNA damage in the skin of seasonally sympatric fin, sperm, and blue whales, and this damage increases with time in the body of the animal.

Researchers have also reported that

  1. Sperm whales that spend most of the time at the sea surface activate genotoxic stress pathways in response to UV exposure.
  2. Paler blue whales take help from increased pigmentation (higher level of melanin) to counteract the seasonal changes and the damaging rays.
  3. Fin whales showed the lowest prevalence of sunburn lesions as compared to the other two studied whales.

Whales can also change their responses to changing levels of UV rays as found in humans and other animals.

Research Suggestions:

Although, researchers have worked on the genetic nature of the damage in whales as a result of UV rays but still this phenomenon needs further research. Moreover, the strategies used by the whales can be used in biomimetic technologies.

“Despite the opportunity to study these long-lived oceanic predators over decades, our findings demonstrate how poorly we understand the impact of UV exposure and the basic processes that are engaged by this environmental insult,” Researchers wrote in the paper.

Reference:

Laura M. Martinez-Levasseur et al. (2013). Whales Use Distinct Strategies to Counteract Solar Ultraviolet Radiation Scientific Reports DOI: 10.1038/srep02386

Usman Zafar Paracha

Usman Zafar Paracha is Assistant Professor, Pharmaceutics, in Hajvery University, Lahore, Pakistan.