Bucket of water can reveal impacts of climate change on Arctic marine life – sciencedaily



Climate change raises many important questions. In particular how it affects animals and plants: do they adapt, do they gradually migrate to different areas or do they disappear? And what is the role played by human activities? This applies in particular to Greenland and the rest of the Arctic, which are expected to experience the greatest effects of climate change.

“We know surprisingly little about Arctic marine species and ecosystems, as it is often expensive and difficult to conduct fieldwork and monitor biodiversity in this area,” says the associate professor of marine mammals and GLOBE study instigator Morten Tange Olsen. Institute of the Faculty of Health and Medical Sciences, University of Copenhagen.

To answer these questions, researchers from the University of Copenhagen, Aarhus University and the Greenland Institute of Natural Resources collected water samples in West Greenland with the help of local hunters and fishermen. Their method is simple: go out to sea in a small boat and collect water in bottles. The content is much more complex, however. Seawater bottles contain what is called environmental DNA, which can provide insight into the impact of climate change and human activities on biodiversity. The researchers chose to focus on the bowhead whale, which is a key species in the Arctic ecosystem and is therefore a good indicator of changes in water temperature and sea ice cover.

“Water samples contain enough DNA from bowhead whales to determine their presence, genetic diversity, population composition and migration patterns. In fact, you can monitor Arctic marine biodiversity simply by going out in a small boat and collecting water in bottles, which is then analyzed in the DNA lab. This way we are able to keep an eye on the impact of humans and climate change on bowhead whales and other arctic marine species, ”says Morten Tange Olsen.

Footprint in a bottle

Working with local hunters and fishermen in Qeqertarsuaq (Godhavn), researchers collected more than 100 one-liter water samples from Disko Bay in West Greenland in May 2017 and 2018. In May, the pack ice has just broken up and bowhead whales are visiting the foraging area. Samples were collected from small boats along transects and in particular in the bowhead whale ‘footprint’ – the small ripples on the surface of the water created when whales come up to breathe and dive again.

“There is much more bowhead whale DNA in such a print than in a random water sample collected at the same time in the same area. You can find bowhead whale DNA in a print at least 10 minutes after the whale dove, ”says Natasja Lykke Corfixen, who helped launch the study as part of her master’s thesis at the Faculty of sciences from the University of Copenhagen and the Greenland Institute of Natural Resources.

By optimizing DNA methods in the laboratory, researchers hope to be able to sequence the entire whale genome from water samples. “So far, we have been successful in sequencing the mitochondrial genomes of water samples, and we are currently testing various methods to capture the entire whale genome, as well as the genomes of algae and crustaceans that are part of it. their food chain “, explains the PhD Student at the GLOBE Dóra Székely Institute.

Health and genetics from a water sample

The researchers hope that by optimizing DNA extraction and sequencing protocols and learning more about the link between genes, behavior, and health, they can eventually use the method to monitor the state of health of the patient. the bowhead whale and many other animals.

“The field of environmental DNA is developing rapidly and is increasingly used for monitoring biodiversity in lakes, rivers, wetlands and, to some extent, the sea. We have shown that the This method is also useful in the Arctic and can be used to monitor not only 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 climate change and human activities, ”says Morten Tange Olsen.


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