2026
March 2026
Seasonal Variation of δ13C and δ15N in a Boreal Lake Fish Community—Year-Round Patterns and Explanatory Variables
Eerola, E. S., B.Hayden, A. J.Piro, and K. K.Kahilainen. 2026. “Seasonal Variation of δ13C and δ15N in a Boreal Lake Fish Community—Year-Round Patterns and Explanatory Variables.” Ecology of Freshwater Fish35, no. 2: e70043. https://doi.org/10.1111/eff.70043.
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Fish diets change with the seasons, even under the ice :
This study shows that fish don’t feed the same way year-round: their food sources and position in the food web shift between summer and winter, including during ice-covered months that are often overlooked.
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Ignoring winter can lead to incomplete conclusions:
Because fish isotope signatures vary significantly across seasons, studies that only sample in summer may miss important ecological dynamics. Year-round monitoring is key to truly understanding freshwater food webs.
February 2026
Freshwater biodiversity in a rapidly changing Arctic: An expert horizon scan of key research questions
Culp, J.M., Power, M., Christoffersen, K.S., Kimmo K. Kahilainen, Milla Rautio, Raoul-Marie Couture, Catherine Girard, Danny C. P. Lau, Sally MacIntyre et al. Freshwater biodiversity in a rapidly changing Arctic: An expert horizon scan of key research questions. Ambio (2026). https://doi.org/10.1007/s13280-025-02331-5
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Climate change is the dominant driver of Arctic freshwater biodiversity change. Experts identified it as the central factor affecting ecosystems across all major research themes, from hydrology and food webs to permafrost and winter ecology.
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There is an urgent need for coordinated, long-term monitoring across Arctic countries. Harmonized international research and stronger circumpolar collaboration are essential to fill major knowledge gaps and support effective policy and conservation decisions.
January 2026
Double diffusion in an ice-covered freshwater lake
MacIntyre, S. (2026), Double diffusion in an ice-covered freshwater lake. Limnol Oceanogr, 71: e70305. https://doi.org/10.1002/lno.70305
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This study provides the first field evidence that “salt fingers” can form under ice in freshwater lakes, even at very low salt levels (as low as ~50 μS/cm), changing how water mixes in winter.
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Most of the salt increase after freeze-up comes from ice formation itself, which concentrates salts in the water and drives unexpected circulation and mixing beneath the ice.
2025
November 2025
Patterns in mercury biomagnification in boreal and subarctic lake food webs.
Piro, A., Kozak, N., Keva, O., Eerola, E.S., Kulo, K., Ruokonen, T.J., Weckström, J., Malinen, T., Kiljunen, M., Taipale, S.J., & Kahilainen, K.K. 2025. Patterns in mercury biomagnification in boreal and subarctic lake food webs. Environmental Research 285: 122352. https://doi.org/10.1016/j.envres.2025.122352
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Mercury builds up in fish through the food web in all subarctic and boreal lakes, but the strength of this buildup varies by region.
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Warmer, nutrient-rich northern lakes show less mercury buildup, while boreal lakes are more strongly influenced by environmental changes and human activity.
August 2025
Impacts of Changing Winter Conditions on Lake Ecosystems Will Increase With Latitude
Ozersky T, Poste A, Rautio M, Leu E. 2025. Impacts of Changing Winter Conditions on Lake Ecosystems Will Increase With Latitude. Ecology Letters. doi.org/10.1111/ele.70200
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Northern lakes are especially vulnerable to climate change, because winter ice and light conditions shift more dramatically at high latitudes.
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Losing ice could strongly affect fish and food webs in the Arctic, as changes in light and temperature reduce the balance needed for healthy lake productivity.
August 2025
Terrestrial carbon inputs drive methylmercury accumulation in zooplankton of boreal and subarctic lakes
Graves, S.D., Kidd, K.A., Arts, M.T., Veiteberg Braaten, H.F., de Wit, H.A., Borgå, K., Åkerblom, S. and Poste, A.E. 2025. Terrestrial carbon inputs drive methylmercury accumulation in zooplankton of boreal and subarctic lakes. Limnology and Oceanography. https://doi.org/10.1002/lno.70185
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Lake browning raises risk: Higher DOC means more mercury in water and zooplankton.
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Food webs matter: Zooplankton diet shifts help drive mercury build-up, impacting fish and wildlife.
May 2025
Summer temperatures, autumn winds, and thermal structure under the
ice in arctic lakes of varying morphometry
Schwefel, R., MacIntyre, S. and Cortés, A. (2025), Summer temperatures, autumn winds, and thermal structure under the ice in arctic lakes of varying morphometry. Limnol Oceanogr, 70: 1817-1834. https://doi.org/10.1002/lno.70064
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Winter lake temperatures (1.5–3.1 °C) vary widely between nearby lakes, mainly depending on lake size, shape, summer warmth, and conditions just before freeze-up.
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Sediment heat and fall sunlight play a major role under the ice, especially when snow cover is low, driving warming and mixing that had not been previously observed in Arctic lakes during early winter.
May 2025
Biomagnification of mercury in brown-water boreal lake – year-round assessment using bulk and compound specific nitrogen stable isotope of amino-acids
Piro, A.J., Taipale, S.J., Eerola, E.S., Megyeri, E., & Kahilainen, K.K. 2025: Biomagnification of mercury in brown-water boreal lake – year-round assessment using bulk and compound specific nitrogen stable isotope of amino-acids. Environmental Pollution 372: 125933. https://doi.org/10.1016/j.envpol.2025.125933
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Mercury builds up in fish and other animals in northern lakes all year round, even under the ice.
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Different scientific methods give slightly different baseline values, showing the need to refine how we measure mercury in food webs.