September 17, 2013
Whale Earwax Reveals Secrets Of Their Past
[ Watch the Video: Blue Whale Earwax Tells A Tale Of A Lifetime ]
Brett Smith for redOrbit.com - Your Universe Online
Earplugs made of wax and fats are common to blue and other large whales and resemble the waxy buildup in our own ears – except on a much, much larger scale.
To learn more about the history of individual whales, marine biologists from Baylor University and the Natural Museum of History have developed a unique method for analyzing these earplugs. The technique reveals a whale’s chronological hormone levels and exposure to chemicals, according to a new report in Proceedings of the National Academy of Sciences of the United States of America.
"Scientists in the past have used this waxy matrix as an aging tool, similar to counting tree rings,” said Sascha Usenko, assistant professor of environmental science at Baylor. “Then, the question arose: Could whale earwax chronologically archive chemicals, such as man-made pollutants?"
Over the past two years, Usenko and his colleague Steven Trumble have been working to answer just that question.
"The type of information we can derive from these earplugs along with our methodology is exceptionally valuable," Usenko said. “There is nothing like it. It really should be classified as a new field of research.”
Previous studies have looked at whale blubber to establish a whale’s hormone and chemical exposure. However, those studies have only yielded information on limited periods of time. Moreover, these results were difficult to obtain and cost-prohibitive.
"Whales are free-ranging animals and you can't get these types of profiles or information on free-ranging animals in any part of the world," said Trumble, an assistant professor of biology at Baylor. “This has never been done before.”
With their novel method, the Baylor researchers said they can also see the human impact on individual whales across multiple generations and various ecosystems.
"You have this 100-year-old question: How are we impacting these animals? There is ship traffic, environmental noise, climate change and contaminants. Now, we are able to provide definitive answers by analyzing whale earwax plugs," Usenko said.
Besides determining human impact on these whales, the scientists were also able to find out information about specific hormonal events that occur during a whale’s lifetime.
"Our research was able to improve upon estimates of sexual maturity for blue whales," Trumble said. “Previous estimates provided a 10-year range of maturity and we have been able to pinpoint exactly when the whale in the study hit sexual maturity. Our research was able to shed new light on the life cycle of whales.”
Usenko added that their newly developed technique could be used on historical samples to gain a better understanding of whales and human-whale interactions over time.
"We are able to go back in time and analyze archived museum earplug samples that were harvested in the 1950s and examine critical issues such as the effects of pollution, use of sonar in the oceans and the introduction of specific chemicals and pesticides in the environment over long periods of time," Usenko said.
"There are a myriad of ways that we can analyze plugs for a better understanding of marine ecosystems and these endangered animals. There is so much additional information that can be mined from studying earplugs."