Biomagnification of Monomethylmercury in Carnegie Lake H2O • x 104 Are there differences in MMHg uptake for different species of phytoplankton? Which characteristics might be related to increased uptake? Size Fractioning Target Group Filter pore size Phytoplankton and particulates 0.4−20 μm Herbivorous zooplankton >20 μm Flow Cytometry Target Group Signal Live Autotrophs DNA & chlorophyll Live Heterotrophs DNA Detritus None Within each site: Does the concentration of MMHg increase with increasing trophic level? Clams Amphipods Blood worms Snails Comparing the 5 sites: Is there a correlation between the density of phytoplankton and the concentration of mercury in the biota? • Phytoplankton density based on fluorescence of chlorophyll (mg of chlorophyll L-1) High Plankton Densities Reduce Mercury Biomagnification Chen & Folt, 2005 Total Mercury in Plankton based on Volume filtered 6/23/10 Total Mercury in Plankton based on Volume Filtered 7/27/10 4 0,35 0,3 Phytoplankton 6/23/10 0,25 0,2 0,15 Zooplankton 6/23/10 0,1 0,05 0 CL01 CL04 CL06 CL09 CL14 Concentration HgT (ng/L) Concentration HgT (ng/L) 0,4 3,5 3 Phytoplankton 7/27/10 2,5 2 Zooplankton 7/27/10 1,5 1 0,5 0 CL01 CL04 CL06 CL09 CL14 Question: Is there a correlation between the density of phytoplankton and the concentration of MMHg in the biota? Total Mercury in Plankton based on Volume Filtered 7/27/10 Chlorophyll Concentration in Unfiltered Water 30 3,5 3 Phytoplankton 6/23/10 Zooplankton 6/23/10 Phytoplankton 7/27/10 Zooplankton 7/27/10 2,5 2 1,5 1 0,5 Chlorophyll fluorescence Concentration HgT (ng/L) 4 25 20 6/23/2010 15 7/27/2010 10 5 0 0 CL01 CL04 CL06 CL09 CL14 CL01 CL04 CL06 CL09 CL14 Total Mercury 6/23/10 Total Hg in Water, Carnegie Lake 7/27/10 7 8 5 4 Unfiltered 3 Filtered 2 1 0 CL01 CL04 CL06 CL06 DUP CL06 TRIP CL09 CL14 Concentration HgT (ng/L) 6 7 6 5 4 Filtered 3 Unfiltered 2 1 0 CL01 CL04 CL06 CONTAMINATED FILTER Total Hg in Unfiltered Water Carnegie Lake 3,5 Concentration HgT (ng/L) HgT Concentration (ng/mL) 8 3 2,5 2 Unfiltered 6/23/10 1,5 Unfiltered 7/27/10 1 0,5 0 CL01 CL04 CL06 CL09 CL14 CL09 CL14 Total Hg Concentration in Invertebrates & Fish 200 180 Concentration HgT (ng/g) 160 140 CL01 120 CL04 CL05 100 CL06 80 CL09 CL14 60 40 20 0 Backswimmers Snails Amphipods Clams Limpet Fish Total Hg Concentration in Amphipods 180 Concentration HgT (ng/g) 160 140 120 100 80 60 40 20 0 CL01 Amphipods CL04 Amphipods CL09 Amphipods 705.6 ppb HgT 312.4 ppb HgT Total Mercury in Fish Mean Mercury Concentrations in Freshwater Fish Species Mean concentration (ppb) 200 180 Bottom Feeders Carp White sucker 110 Channel catfish 160 140 120 110 90 100 Predator Fish Largemouth bass Smallmouth bass Walleye Brown trout 140 80 60 40 20 0 CL01 Spotted Sunfish CL09 Largemouth Bass 460 340 520 a EPA National Study of Chemical Residues in Fish 1987; b Concentrations are reported on wet weight basis Source: Bahnick et al., 1994. Biomagnification of Total Mercury X8 X2 X 20,000 Concentration HgT (ppb) Total Mercury at Site CL01 800 700 600 500 400 300 200 100 0 Thanks to PEI, Dr. Eileen Zerba, Dr. Francois Morel, Frank Black, Nejma Piagentini, and my fellow interns for all your help this summer!