One would think that collecting genetic material from Arctic marine mammals would be a big challenge. Large amounts of technical material, scientifically trained personnel and a lot of luck and patience to find the animals would be necessary to finally get hold of a few suitable samples. A Danish-Greenlandic research team has now shown that all this is not necessarily needed to obtain clean and meaningful data on bowhead whales and their genetic diversity.
The group, led by Morten Tange Olsen, assistant professor at the University of Copenhagen, together with fishermen and hunters from the West Greenlandic village of Qeqertarsuaq, collected samples from bowhead whales by simply dipping 1-litre bottles into the water where bowhead whales had surfaced and dived shortly before. Floating in the water was so-called eDNA (environmental DNA), genetic material of the whales in the form of skin and other cells that had been scraped off by movement. “The water samples contain enough DNA from bowhead whales to determine their presence, genetic diversity, the composition of the population and patterns of migration,” Olsen explains in a press release. “This way, we are able to keep an eye on how humans and climate changes impact the bowhead whale and other marine life in the Arctic.”
The massive marine mammals were chosen because they spend their lives along the edge of the Arctic sea ice, where they catch fish and other small creatures. The changes at work in the Arctic are therefore also affecting bowhead whales. In Disko Bay, the study site of the research team, the animals are always foraging in spring. But this is also one of the most human-influenced regions of Greenland. Until now, the people here lived with and from the whales. Therefore, the region offered itself as a place of study.
“You can find bowhead whale DNA in a footprint at least 10 minutes after the whale dove.”Natasja Lykke Corfixen, University of Copenhagen
More than one hundred samples were obtained, which then had to be cleaned and sequenced in the laboratory. “There is a lot more bowhead whale DNA in such a footprint (small waves caused by the whales diving) than in a random water sample collected at the same time in the same area,” explains master student and co-author of the study, Natasja Lykke Corfixen from the University of Copenhagen. “You can find bowhead whale DNA in a footprint at least 10 minutes after the whale dove.” The researchers were thus able to gain a first impression for the method and the genetic diversity in the region. Their work has appeared in the journal Environmental DNA.
“The field of eDNA is seeing rapid development“Morten Tange Olsen, University of Copenhagen
The scientists hope that the eDNA will help to clarify many more questions. However, the protocols and DNA extraction still need to be optimized for this purpose. This is because only fragments of genetic information have been obtained so far. The goal is to be able to extract the entire genetic sequences of the whales and also genetic information of their prey from the samples. “The field of Environmental DNA is seeing rapid development and is increasingly used for biodiversity monitoring in lakes, rivers, wetlands and, to some extent, the sea. We have shown that the method is also useful in the Arctic,” Olsen explains. “It can be used to monitor not just the presence of a species, but also its diversity and patterns of movement. By further developing this simple method we are able to significantly increase our knowledge of marine biodiversity, and hopefully the impact of both climate changes and human activities.”
Dr Michael Wenger, PolarJournal
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