Mercury concentrations in landlocked Arctic char (Salvelinus alpinus) from the Canadian Arctic. Part II: Influence of lake biotic and abiotic characteristics on geographic trends in 27 populations

Abstract

Among-lake variation in mercury (Hg) concentrations in landlocked Arctic char was examined in 27 char populations from remote lakes across the Canadian Arctic. A total of 520 landlocked Arctic char were collected from 27 lakes, as well as sediments and surface water from a subset of lakes in 1999, 2002, and 2005 to 2007. Size, length, age, and trophic position (delta(15)N) of individual char were determined and relationships with total Hg (THg) concentrations investigated, to identify a common covariate for adjustment using analysis of covariance (ANCOVA). A subset of 216 char from 24 populations was used for spatial comparison, after length-adjustment. The influence of trophic position and food web length and abiotic characteristics such as location, geomorphology, lake area, catchment area, catchment-to-lake area ratio of the lakes on adjusted THg concentrations in char muscle tissue were then evaluated. Arctic char from Amituk Lake (Cornwallis Island) had the highest Hg concentrations (1.31 microg/g wet wt), while Tessisoak Lake (Labrador, 0.07 microg/g wet wt) had the lowest. Concentrations of THg were positively correlated with size, delta(15)N, and age, respectively, in 88, 71, and 58% of 24 char populations. Length and delta(15)N were correlated in 67% of 24 char populations. Food chain length did not explain the differences in length-adjusted THg concentrations in char. No relationships between adjusted THg concentrations in char and latitude or longitude were found, however, THg concentrations in char showed a positive correlation with catchment-to-lake area ratio. Furthermore, we conclude that inputs from the surrounding environment may influence THg concentrations, and will ultimately affect THg concentrations in char as a result of predicted climate-driven changes that may occur in Arctic lake watersheds.

The fate of mercury in Arctic terrestrial and aquatic ecosystems, a review

“…Mercury levels in Arctic char from 19 lakes were positively correlated with watershed-to-lake area ratios, which explained approximately one-quarter of the variation in length-adjusted Hg concentrations in fish. [206,207] MeHg concentrations in fresh water aquatic invertebrates (Diptera, Chironomidae) from 22 lakes and ponds were found to be only weakly correlated with measures of Hg supply (i.e. watershed-to-lake area ratios, MeHg concentrations in water and sediment).…”

“…[226] Recent d 15 N data on insectivorous char show low variability in THg and d 15 N among Cornwallis Island lakes. [206,207] On Ellesmere Island, larger char fed selectively on pupae at the lake surface during the period of emergence, whereas smaller char (,20 cm) inhabited very shallow areas and fed mostly on chironomid larvae. [228] Life stage-related differences in habitat use and diet of the fish, which exposed them to different stable N isotope ratios and MeHg concentrations among larval, pupal and adult chironomids, [208] could explain some of the variability in d 15 N and Hg concentrations of char, particularly the differences between juvenile and adult fish.…”

“…In four southern and more productive lakes with diverse food webs on Kent Peninsula (698N), char THg concentrations were lower than in the low productivity northern lakes (,758N), which again could suggest a biodilution effect. [207] The dominance of benthic prey in the char diet may mean that newly deposited atmospheric Hg is less likely to be directly reflected in Arctic char Hg concentrations. Responses of fish Hg levels to inputs from the surrounding environment may be delayed until Hg is taken up by chironomids from lake sediments.…”

Mapping Human Dimensions of Climate Change Research in the Canadian Arctic

“…The majority of these studies are conducted in Nunavut and reflect research effort in a small number of settlements (Igloolik, Arctic Bay, Cape Dorset, Clyde River) and by a cluster of researchers from a geography background. Health and well-being is examined in 25 % (n = 29) of studies, mostly examining food systems and safety of land-based activities, with recent publications examining the fate of contaminants in light of climate change (McKinney et al 2009;Gantner et al 2010;Kuzyk et al 2010;Macdonald and Loseto 2010). Mental health and vector-and water-borne diseases have received limited attention.…”

Physical and Biological Factors Affecting Mercury and Perfluorinated Contaminants in Arctic Char (<i>Salvelinus alpinus</i>) of Pingualuit Crater Lake (Nunavik, Canada) + Supplementary Appendices (See Article Tools)

“…Contaminant accumulation can vary among species Lockhart et al, 2005;swanson et al, 2011), making genetic identification highly relevant. Arctic char have been used as a species for monitoring contaminants undergoing long-range atmospheric transport because of their circumpolar distribution Muir et al, 2006;evenset et al, 2007;Gantner et al, 2010b;swanson et al, 2011). however, char are highly variable in terms of life history patterns (growth and age at maturity), habitat use (freshwater or marine), the role they play in those ecosystems (predator or prey), and their food sources (benthic or pelagic) (klemetsen et al, 2003;Power et al, 2008).…”