Mercury in fish from Norwegian lakes: The complex influence of aqueous organic carbon

摘要: Mercury (Hg) concentrations in water and biota are often positively correlated to organic matter (OM), typically measured as total or dissolved carbon (TOC/DOC). However, recent evidence suggests that higher OM inhibit bioaccumulation of Hg. Here, we test how TOC impacts the Hg accumulation fish a synoptic study Methyl-Hg (MeHg) (THg) perch (Perca fluviatilis) 34 boreal lakes southern Norway. We found aqueous MeHg (r2 = 0.49, p < 0.0001) THg (r2 = 0.69, p < 0.0001), (r2 = 0.26, p < 0.01) were all related with TOC. declining factors (BAFMeHg) for increasing concentrations. The significant correlation between elevated levels regions associated humic lakes. BAFMeHg suggest increased promotes concentrations, but lowers relative bioaccumulation. A mechanistic understanding response from on might be metal-complexation properties OM, where complexation metals reduces their bioavailability. Hence, suggesting becomes less effective at TOC, which is particularly relevant when assessing potential responses predicted future changes inputs ecosystems. Increased browning waters may affect opposite directions: an increase food web exposure Hg, reduced bioavailability species. negative relationship challenging interpret, carries great deal uncertainty, since this driven by underlying (i.e. spurious correlations). Our results trade-off will have important implications effects lake transport, bioavailability, trophodynamics.