A1 Journal article (refereed)
Environmental and biological factors are joint drivers of mercury biomagnification in subarctic lake food webs along a climate and productivity gradient (2021)
Kozak, N., Ahonen, S. A., Keva, O., Østbye, K., Taipale, S. J., Hayden, B., & Kahilainen, K. K. (2021). Environmental and biological factors are joint drivers of mercury biomagnification in subarctic lake food webs along a climate and productivity gradient. Science of the Total Environment, 779, Article 146261. https://doi.org/10.1016/j.scitotenv.2021.146261
JYU authors or editors
Publication details
All authors or editors: Kozak, Natalia; Ahonen, Salla A.; Keva, Ossi; Østbye, Kjartan; Taipale, Sami J.; Hayden, Brian; Kahilainen, Kimmo K.
Journal or series: Science of the Total Environment
ISSN: 0048-9697
eISSN: 1879-1026
Publication year: 2021
Volume: 779
Article number: 146261
Publisher: Elsevier
Publication country: Netherlands
Publication language: English
DOI: https://doi.org/10.1016/j.scitotenv.2021.146261
Publication open access: Openly available
Publication channel open access: Partially open access channel
Publication is parallel published (JYX): https://jyx.jyu.fi/handle/123456789/74892
Abstract
Subarctic lakes are getting warmer and more productive due to the joint effects of climate change and intensive land-use practices (e.g. forest clear-cutting and peatland ditching), processes that potentially increase leaching of peat- and soil-stored mercury into lake ecosystems. We sampled biotic communities from primary producers (algae) to top consumers (piscivorous fish), in 19 subarctic lakes situated on a latitudinal (69.0–66.5° N), climatic (+3.2 °C temperature and + 30% precipitation from north to south) and catchment land-use (pristine to intensive forestry areas) gradient. We first tested how the joint effects of climate and productivity influence mercury biomagnification in food webs focusing on the trophic magnification slope (TMS) and mercury baseline (THg baseline) level, both derived from linear regression between total mercury (log10THg) and organism trophic level (TL). We examined a suite of environmental and biotic variables thought to explain THg baseline and TMS with stepwise generalized multiple regression models. Finally, we assessed how climate and lake productivity affect the THg content of top predators in subarctic lakes. We found biomagnification of mercury in all studied lakes, but with variable TMS and THg baseline values. In stepwise multiple regression models, TMS was best explained by negative relationships with food chain length, climate-productivity gradient, catchment properties, and elemental C:N ratio of the top predator (full model R2 = 0.90, p < 0.001). The model examining variation in THg baseline values included the same variables with positive relationships (R2 = 0.69, p = 0.014). Mass-standardized THg content of a common top predator (1 kg northern pike, Esox lucius) increased towards warmer and more productive lakes. These results indicate that increasing eutrophication via forestry-related land-use activities increase the THg levels at the base of the food web and in top predators, suggesting these sources of nutrients and mercury should be considered in future bioaccumulation and biomagnification studies.
Keywords: aquatic ecosystems; environmental toxins; accumulation; mercury; food chains; fishes; invertebrates; climate changes; land use; isotope analysis
Free keywords: climate change; fish; food chain length; invertebrates; land-use; stable isotopes
Contributing organizations
Ministry reporting: Yes
Reporting Year: 2021
JUFO rating: 2