On October 17, 2024 at the Arctic Circle Assembly, PhD and master students from Québec and Nordic UArctic universities had an opportunity to present their work through lightning talks. My Northern Project is a science popularization contest in which each student has a maximum of five minutes to introduce their research to a broad audience, with the aim to summarize potentially complex topics into easily understandable presentations and promote the transfer of knowledge.
The audience selected Henna Kangosjärvi and her presentation as their favourite. We asked Henna to tell more about her research and why her topic is important:
"Imagine you’re hiking through the Scandinavian mountains and come across a series of lakes. The first lake you encounter lies near the seashore. It’s large and deep, surrounded by dense forests, with fields and buildings visible in the distance. After taking in the scenery, you continue your hike further up into the mountains. There, you find a second lake. The air is noticeably colder, and the water is crystal clear. The landscape is rocky and barren, with no trees or large plants in sight. You decide to continue a bit further and come across a third lake. Similar to the second lake, the air is cold, and the landscape is treeless and rocky. However, you can see that the shoreline is very rocky and worn down. Soon you also find out why: there is a hydropower dam at the outlet river of the lake, which is controlling the water level and causing erosion of the shoreline.
In my PhD research, I study the food webs of these diverse cold-water lakes across Norway, Sweden, and Finland. A food web maps out "who eats whom," offering a powerful lens for understanding northern lake ecosystems. It not only reveals the biodiversity within these systems by identifying the species present but also explains the ecosystem's functioning—how species interact and how energy flows through the ecosystem.
The key question guiding my research is: What shapes these cold-water lake ecosystems? Specifically, I examine the factors that influence the diets of two top predators: Arctic charr and brown trout. By understanding what drives the feeding habits of these species, we can gain valuable insights into the structure of the entire food web.
Food web studies can help us to predict how these fragile ecosystems might respond to environmental changes. For example, it allows us to compare food webs in lakes with varying temperatures or examine how human activities, such as the introduction of invasive species or hydropower-related water-level fluctuations, affect the diets of charr and trout. These shifts can have cascading effects on the entire food web and ultimately, the ecosystem.
By building a comprehensive understanding of how food webs vary across different lakes—whether shaped by natural factors like size, temperature, or species composition, or by human impacts—we can develop informed strategies for managing and preserving northern lake ecosystems in the face of future challenges."
Photos courtesy of Henna Kangosjärvi
My Northern Project is a cooperation between Québec and the Nordic countries in Culture, Society, Research and Innovation supported by Nordic Council of Ministers.