Environmental and biological factors are joint drivers of mercury biomagnification in subarctic lake food webs along a climate and productivity gradient
Publiceringsår
2021
Upphovspersoner
Kozak, Natalia; Ahonen, Salla A.; Keva, Ossi; Østbye, Kjartan; Taipale, Sami J.; Hayden, Brian; Kahilainen, Kimmo K.
Abstrakt
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.
Visa merOrganisationer och upphovspersoner
Helsingfors universitet
Kahilainen Kimmo K.
Publikationstyp
Publikationsform
Artikel
Moderpublikationens typ
Tidning
Artikelstyp
En originalartikel
Målgrupp
VetenskapligKollegialt utvärderad
Kollegialt utvärderadUKM:s publikationstyp
A1 Originalartikel i en vetenskaplig tidskriftPublikationskanalens uppgifter
Journal
Moderpublikationens namn
Volym
779
Artikelnummer
146261
ISSN
Publikationsforum
Publikationsforumsnivå
2
Öppen tillgång
Öppen tillgänglighet i förläggarens tjänst
Ja
Öppen tillgång till publikationskanalen
Delvis öppen publikationskanal
Licens för förläggarens version
CC BY
Parallellsparad
Ja
Parallellagringens licens
CC BY
Övriga uppgifter
Vetenskapsområden
Miljövetenskap; Ekologi, evolutionsbiologi
Nyckelord
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Publiceringsland
Nederländerna
Förlagets internationalitet
Internationell
Språk
engelska
Internationell sampublikation
Ja
Sampublikation med ett företag
Nej
DOI
10.1016/j.scitotenv.2021.146261
Publikationen ingår i undervisnings- och kulturministeriets datainsamling
Ja