Details

Autor(en) / Beteiligte

• Kidd, Karen A.
• Muir, Derek C.G.
• Evans, Marlene S.
• Wang, Xioawa
• Whittle, Mike
• Swanson, Heidi K.
• Johnston, Tom
• Guildford, Stephanie

Titel

Biomagnification of mercury through lake trout (Salvelinus namaycush) food webs of lakes with different physical, chemical and biological characteristics

Ist Teil von

• The Science of the total environment, 2012-11, Vol.438, p.135-143

Ort / Verlag

Kidlington: Elsevier B.V

Erscheinungsjahr

2012

Quelle

MEDLINE

Beschreibungen/Notizen

• Mercury (Hg) biomagnification in aquatic ecosystems remains a concern because this pollutant is known to affect the health of fish-eating wildlife and humans, and the fish themselves. The “rate” of mercury biomagnification is being assessed more frequently using stable nitrogen isotope ratios (δ15N), a measure of relative trophic position of biota within a food web. Within food webs and across diverse systems, log-transformed Hg concentrations are significantly and positively related to δ15N and the slopes of these models vary from one study to another for reasons that are not yet understood. Here we compared the rates of Hg biomagnification in 14 lake trout lakes from three provinces in Canada to understand whether any characteristics of the ecosystems explained this among-system variability. Several fish species, zooplankton and benthic invertebrates were collected from these lakes and analyzed for total Hg (fish only), methyl Hg (invertebrates) and stable isotopes (δ15N; δ13C to assess energy sources). Mercury biomagnification rates varied significantly across systems and were higher for food webs of larger (surface area), higher nutrient lakes. However, the slopes were not predictive of among-lake differences in Hg in the lake trout. Results indicate that among-system differences in the rates of Hg biomagnification seen in the literature may be due, in part, to differences in ecosystem characteristics although the mechanisms for this variability are not yet understood. ► Mercury biomagnifies through aquatic food webs to toxic levels in top predator fishes. ► Among-system differences in mercury transfer through food webs occur but have not been explained. ► Diverse lakes supporting lake trout were compared to understand the ecosystem processes that affect mercury biomagnification. ► Higher biomagnification of mercury was found in larger, higher nutrient lakes. ► Results show that the food web processing of mercury is related to ecosystem properties.