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#           Using carbon, nitrogen, and mercury isotope values to distinguish mercury sources to Alaskan lake trout      

      March 21, 2022    

Lake trout (Salvelinus namaycush), collected from 13 remote lakes located in southwestern Alaska, were analyzed for carbon, nitrogen, and mercury (Hg) stable isotope values to assess the importance of migrating oceanic salmon, volcanic activity, and atmospheric deposition to fish Hg burden. Methylmercury (MeHg) bioaccumulation in phytoplankton (5.0–6.9 kg L–1) was also measured to quantify the basal uptake of MeHg to these aquatic food webs. Hg isotope values in lake trout revealed that while the extent of precipitation-delivered Hg was similar across the entire study area, volcanic Hg is likely an important additional source to lake trout in proximate lakes. In contrast, migratory salmon (Oncorhynchus nerka) deliver little MeHg to lake trout directly, although indirect delivery processes via decay could exist. A high level of variability in carbon, nitrogen, and Hg isotope values indicates niche partitioning in lake trout populations within each lake and that a complex suite of ecological interactions is occurring, complicating the conceptually linear assessment of the contaminant source to the receiving organism. Without connecting energy and contaminant isotope axes, we would not have understood why lake trout from these pristine lakes have highly variable Hg burdens despite consistently low water Hg and comparable age-length dynamics.

## Citation Information

## Related Content

                  -              Data           
                  -              Connect           

March 18, 2022

####                 Assessment of mercury sources in Alaskan lake food webs (version 1.1, September 2023)              

Upper Midwest Environmental Sciences Center, Upper Midwest Water Science Center, Mercury Research Laboratory

#### Jacob M Ogorek

##### Biologist

Upper Midwest Water Science Center

##### Mercury Research Laboratory Manager

Mercury Research Laboratory

jmogorek@usgs.gov

608-663-5160

#### Sarah E Janssen

##### Research Chemist

Upper Midwest Water Science Center

##### Mercury Research Laboratory Team Lead

Mercury Research Laboratory

sjanssen@usgs.gov

608-663-5162

#### Collin Eagles-Smith

##### Supervisory Research Ecologist

Forest and Rangeland Ecosystem Science Center

ceagles-smith@usgs.gov

541-750-0949

#### David P Krabbenhoft

##### Scientist Emeritus

Mercury Research Laboratory

Mercury Research Laboratory

dpkrabbe@usgs.gov

608-335-4234

## Related Content

March 18, 2022

####                 Assessment of mercury sources in Alaskan lake food webs (version 1.1, September 2023)              

Upper Midwest Environmental Sciences Center, Upper Midwest Water Science Center, Mercury Research Laboratory

#### Jacob M Ogorek

##### Biologist

Upper Midwest Water Science Center

##### Mercury Research Laboratory Manager

Mercury Research Laboratory

jmogorek@usgs.gov

608-663-5160

#### Sarah E Janssen

##### Research Chemist

Upper Midwest Water Science Center

##### Mercury Research Laboratory Team Lead

Mercury Research Laboratory

sjanssen@usgs.gov

608-663-5162

#### Collin Eagles-Smith

##### Supervisory Research Ecologist

Forest and Rangeland Ecosystem Science Center

ceagles-smith@usgs.gov

541-750-0949

#### David P Krabbenhoft

##### Scientist Emeritus

Mercury Research Laboratory

Mercury Research Laboratory

dpkrabbe@usgs.gov

608-335-4234

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####               Upper Midwest Water Science Center - Madison, WI, Office          

1 Gifford Pinchot DriveMadison, WI53726United States

608-828-9901

608-821-3817

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