Outflow lake catchment

Fig. 9.6. Model simulation for Hg. Curve 1 gives the values for Hg-concentration in lake water. The values do not reach a perfect steady-state level due to the fact that so much Hg has been accumulated in the catchment area during the last 50 years (initial amount in the catchment is 15 000 g in the entire catchment situated in central Sweden data for our "mean" lake), the outflow rate from the catchment is 0.0025 (1/year). Curve 5 illustrates a simulated liming during year 20 which would increase pH from 6 to 6.7. Curves 2, 3 and 4 show the effects of such a liming on Hg-concentrations in phytoplankton, prey (bottom fauna, zooplankton, small fish) and predatory fish (pike, large perch, etc.)...

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