Skin Bacterial Communities Similar Across Humpback Whale Populations
March 27, 2014

Skin Bacterial Communities Similar Across Humpback Whale Populations

Lawrence LeBlond for - Your Universe Online

The omnipresence of bacteria in the environment as well as on our own skin makes research on how they affect human health an important topic in the scientific and medical community. But little is known about the identity or function of skin bacteria that is found on other mammals.

Researchers, led by microbiologist Amy Apprill from the Woods Hole Oceanographic Institution, have conducted a widespread study on the bacterial communities found on humpback whales. The team found that humpback whales share a simplistic skin bacterial community across populations, which they suggest could help in determining the overall health of these endangered marine mammals.

"The skin is the interface between the animal and the ocean it lives in," Appril said in a statement. "By studying the bacterial species on the skin of humpbacks, we might be able to learn more about their health and the status of their environment."

In a published paper in the journal PLOS ONE, the researchers noted that the “overall bacterial communities [in humpback whales] differ by geographic area and by metabolic state, such as feeding versus starving during migration and breeding.”

Whales move thousands of miles through the ocean and are in contact with numerous bacteria throughout their journeys. For the study, Apprill and her colleagues collected 56 skin samples from humpback whale populations in the North Atlantic, North Pacific and South Pacific oceans. They obtained the samples from biopsy collecting darts that bounce off the whales’ skin and the skin that naturally sloughs off when the mammals breach the surface. The team’s studies provided important details about the individual humpback whales involved, such as age and sex.

Once the data were collected, the team sequenced, analyzed and identified more than a half million small-subunit ribosomal RNA genes from bacteria obtained from the humpback whale skin. They compared the data to bacterial sequences identified from the skin of deceased whales, whales with injuries and whales with compromised health.

The team found that the general bacterial community of healthy individuals consisted largely of Tenacibaculum and Psychrobacter spp., while the overall bacterial populations differed geographically and by metabolic state. As well, bacterial communities differed in stressed and deceased whales. The latter contained less core bacteria and more potential pathogens.

The researchers suggest that their results indicate that the bacterial skin community may act as an indicator of whales’ health and status of the environment. They acknowledge that the results are preliminary and more research needs to be conducted. Still, they believe their work can help other researchers monitor the population health and conservation status of other endangered marine mammals.

"It is astonishing that we find Tenacibaculum and Psychrobacter spp. bacteria on whale skin regardless of animal age, sex, metabolic state, geographic region or population. These bacteria may be involved in an important interaction with the whales," Apprill said. "With further development, we might be able to gain insight into the health of whales by examining their skin-bacteria."

"The next step is to figure out what the core bacteria are doing—and if they're doing anything that benefits the whales," Apprill added. "There's a spectrum of things they could be doing, such as keeping the whale clean of fouling organisms or producing antibiotics to fend off potential pathogens."

"This work represents a productive blend of fundamental and applied research," said Michael Moore, director of the WHOI Marine Mammal Center, which funded the work.

Researchers from the Marine Biological Laboratory, The Dolphin Institute, and the International Fund for Animal Welfare also contributed to the study.