Impact of wildfire and clear-cutting in the boreal forest on methyl mercury in zooplankton

Garcia, Édenise; Carignan, Richard

doi:10.1139/cjfas-56-2-339

Cited by 34 publications

(38 citation statements)

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“…Alternatively, the high phytoplankton biomass observed in the studied burnt lakes (Planas et al, 2000) may have caused a biological dilution of the available Hg (Pickhard, Folt, Chen, Klaue, & Blum, 2002). This alternative is supported by the significant negative correlation between chlorophyll a and MeHg observed during the first year following fire (Garcia & Carignan, 1999). Likewise, observed increases in biomass of crustacean organisms in the same group of burnt lakes (Patoine et al, 2000;Patoine, Pinel-Alloul, & Prepas, 2002) may have resulted in a growth dilution effect (Herendeen & Hill, 2004).…”

Section: Among-group Variations In Mehg In Zooplanktonmentioning

confidence: 71%

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Seasonal and Inter-Annual Variations in Methyl Mercury Concentrations in Zooplankton from Boreal Lakes Impacted by Deforestation or Natural Forest Fires

Garcia

Carignan

Lean

2006

Environ Monit Assess

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We compared the effects of natural and anthropogenic watershed disturbances on methyl mercury (MeHg) concentration in bulk zooplankton from boreal Shield lakes. MeHg in zooplankton was monitored for three years in nine lakes impacted by deforestation, in nine lakes impacted by wildfire, and in twenty lakes with undisturbed catchments. Lakes were sampled during spring, mid- and late summer. MeHg in zooplankton showed a seasonal trend: concentrations were the lowest in spring, then peaked in mid-summer and decreased in late summer. Over the three study years, MeHg concentrations observed in mid-summer in zooplankton from forest harvested lakes were significantly higher than in reference and fire-impacted lakes, whereas differences between these two groups of lakes were not significant. The pattern of distribution of MeHg in zooplankton during the different seasons paralleled that of dissolved organic carbon (DOC), which is known as a vector of Hg from watershed soils to lake water. Besides DOC, MeHg in zooplankton also showed a positive significant correlation with epilimnetic temperature and sulfate concentrations. An inter-annual decreasing trend in MeHg was observed in zooplankton from reference and fire-impacted lakes. In forest harvested lakes, however, MeHg concentrations remained higher and nearly constant over three years following the impact. Overall these results indicate that the MeHg pulse observed in zooplankton following deforestation by harvesting is relatively long-lived, and may have repercussions to the accumulation of MeHg along the food chain. Therefore, potential effects of deforestation on the Hg contamination of fish should be taken into account in forest management practices.

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Section: Among-group Variations In Mehg In Zooplanktonmentioning

confidence: 71%

“…In a previous study, we compared the effects of forest clearance by wildfire and logging on MeHg contamination of bulk zooplankton (Garcia & Carignan, 1999) one year after disturbances. MeHg levels were higher in zooplankton from forest harvested lakes relative to fire-impacted or undisturbed lakes.…”

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confidence: 99%

Seasonal and Inter-Annual Variations in Methyl Mercury Concentrations in Zooplankton from Boreal Lakes Impacted by Deforestation or Natural Forest Fires

Garcia

Carignan

Lean

2006

Environ Monit Assess

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“…Elevated levels of THg and CH 3 Hg + have been recorded in runoff and lake sediments near forested areas that are clear-cut (Roulet et al, 2000;Porvari et al, 2003). Increases in Hg in water are transferred into the food web, such that higher Hg concentrations have been seen in zooplankton (Garcia and Carignan, 1999) and periphyton from lakes in logged watersheds (Desrosiers et al, 2006). This effect is propagated through the food web because fish such as northern pike also show elevated Hg concentrations compared to fish from watersheds where forestry is not occurring Carignan, 2000, 2005).…”

Section: Watershed Characteristics and Human Activitiesmentioning

confidence: 99%

Bioaccumulation and Biomagnification of Mercury through Food Webs

Kidd

Clayden

Jardine

2011

Environmental Chemistry and Toxicology of Mercury

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“…In this study, light extinction coefficients were higher in harvested lake basins due to higher epilimnetic concentrations of colored DOC . Increased DOC export following harvesting could affect the transport and cycling of some contaminants, such as methyl mercury (Garcia and Carignan 1999 a Estimated from soil pits (forest floor and 0-20 cm mineral soil) in areas burnt during the 1995 Belleplage fire relative to nearby reference areas in 1996 (Brais et al 2000). Volatilization losses were approximated as the difference in nutrient mass between soil pits from burnt and reference areas minus the average nutrient export in runoff from burnt areas in 1996 (this study).…”

Section: Significance Of Nutrient Export In Runoff To Forest and Lakementioning

confidence: 99%

Element export in runoff from eastern Canadian Boreal Shield drainage basins following forest harvesting and wildfires

Lamontagne¹,

Carignan²,

D'Arcy³

et al. 2000

Can. J. Fish. Aquat. Sci.

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Element export rates from the drainage area of nine harvested, nine burnt, and 16 reference Boreal Shield lake basins in Haute-Mauricie, Québec, were estimated for the 3 years following harvesting or fires. Export rates from the drainage area of the basins were evaluated using lake sampling surveys, estimated hydrological budgets, and estimated nutrient retention during lake transit. Increases in K + , total N, and total P export rates were similar between harvested and burnt drainage areas. However, harvested drainage areas exported more dissolved organic C, while burnt drainage areas exported more Mg 2+ , NO 3 -, and SO 4 2-. Potassium cumulative losses in runoff during the 3 years of the study were of a similar magnitude as volatilization losses during fires and corresponded to -33% of the losses by biomass removal during harvesting. While the increased export rates for N and P following fires or harvesting represented negligible losses of nutrients for the forest, they were important supplementary inputs to lakes. The differences in element export rates observed between harvested and burnt drainage areas indicate that these disturbances have different impacts on biogeochemical cycles in the Boreal Shield forest.

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Impact of wildfire and clear-cutting in the boreal forest on methyl mercury in zooplankton

Cited by 34 publications

References 0 publications

Seasonal and Inter-Annual Variations in Methyl Mercury Concentrations in Zooplankton from Boreal Lakes Impacted by Deforestation or Natural Forest Fires

Seasonal and Inter-Annual Variations in Methyl Mercury Concentrations in Zooplankton from Boreal Lakes Impacted by Deforestation or Natural Forest Fires

Bioaccumulation and Biomagnification of Mercury through Food Webs

Element export in runoff from eastern Canadian Boreal Shield drainage basins following forest harvesting and wildfires

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