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Xue Yu and Charles Driscoll*, Syracuse University

Patterns of Mercury in the Aquatic Food Chain in Lakes of the Adirondack Region of New York. Xue Yu and Charles Driscoll*, Syracuse University Melissa Duron, Nina Schoch and David Evers, BioDiversity Research Institute. Content. Background/objectives Approach/study sites

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Xue Yu and Charles Driscoll*, Syracuse University

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  1. Patterns of Mercury in the Aquatic Food Chain in Lakes of the Adirondack Region of New York Xue Yu and Charles Driscoll*, Syracuse University Melissa Duron, Nina Schoch and David Evers, BioDiversity Research Institute

  2. Content • Background/objectives • Approach/study sites • Atmospheric Hg deposition • Hg in lake water • Spatial pattern of Hg in biota • Factors influencing spatial patterns • Conclusions

  3. Background • Despite moderate wet Hg deposition, the Adirondacks has been shown to be a biological Hg hotspot • Factors that contribute to elevated Hg in biota: forest and wetland cover, unproductive lakes, elevated inputs of acidic deposition and surface water acidification

  4. Objectives • Evaluate the spatial patterns of Hg in Adirondack lakes • Evaluate the factors that contribute to these spatial patterns

  5. Approach • 44 Adirondack lakes with populations of common loon sampled during summers 2003-2004 • THg and MeHg in water and littoral sediments • THg and MeHg in bulk zooplankton • Crayfish • Prey fish (golden shiner, creek chub, banded killifish) • Fish (yellow perch, pumpkinseed, smallmouth bass. largemouth bass converted to yellow perch equivalent)

  6. Study sites

  7. Atmospheric Hg deposition • Atmospheric Hg deposition is the main source of Hg to Adirondack lakes • Atmospheric Hg deposition is weakly correlated with Hg concentrations in lake water

  8. Hg in lake water • pH was negatively correlated with MeHg in water • DOC was positively correlated with THg in water

  9. Sediment chemistry effect • Percentage of organic carbon in littoral sediments has relationships with THg and MeHg concentrations, and percentage of THg as MeHg.

  10. Mercury concentrations in biota • Generally, Hg concentrations in biota increase from zooplankton to prey fish to fish.

  11. A relationship between MeHg in zooplankton and THg concentration in fish may reflect the importance of zooplankton in the food chain

  12. Hg spatial patterns in biota

  13. Factors influencing spatial patterns • Landscape characteristics, such as lake elevation, land cover use type (near lake wetlands) • Lake chemistry, such as pH and DOC • Biology, such as trophic status, fish length

  14. Water chemistry effects • Lake chemistry influences Hg bioavailability • pH is generally negatively correlated with Hg concentrations in biota

  15. Distribution patterns of log10 based BAF by fish

  16. Elevation is positively correlated with Hg bioaccumulation factor (BAF) in biota

  17. Conclusions • The spatial patterns occur in Hg concentrations in lake water, zooplankton and fish in the Adirondacks • Low pH and high DOC in lake water in the western Adirondacks appears to influence elevated mercury concentrations in zooplankton and fish • Sensitivity of lakes to acidic deposition and interactions of lakes with wetlands appears to be an important controller of mercury in biota

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