SMELTER IMPACT ON LAKE VEGETATION
FIGURE 13.20 (a) The sulfate concentrations in lakes near Sudbury, Ontario, decreased with distance from metal smelters. (b) In an opposite pattern, the number of aquatic plant species in the same lakes increased with distance from smelters. (c) Combining the patterns in parts (a) and (b) reveals a negative relationship between sulfate concentrations in these lakes and number of aquatic plant species. (Data from Gorham & Gordon, 1963)