Ref ID : 2769
W.T. Edmondson; Eutrophication effects on the food chains of lakes. Memorie dell'Istituto Italiano di Idrobiologia (Mem.Ist.Ital.Idrobiol.) 52:113-132, 1992
Reprint
In File
Notes
Much of the attention given to eutrophication has concerned lakes fertilized with domestic sewage, and is focused on the abundance of primary producers, especially planktonic Cyanobacteria. Disposal of domestic waste is not the only change made by increased human populations. Land development precedes and accompanies the growth of cities, changing the input through the inlets and the air. These inputs are chemically different from those in sewage, and may have different biological effects. Turbidity increases from erosion, reducing light penetration. Major changes in the community structure of plankton or benthos are produced by the inadvertent or deliberate introduction of keystone species, grazers or predators. Such changes may mask or accentuate changes in nutrition. Toxic effluents may prevent phytoplankton from responding to increased nutrition. Thus, many accounts of the effect of eutrophication by sewage confound the effects of different processes, some of which do not directly have to do with nutrients. We can use episodes of pollution as experiments to clarify the way in which lakes respond to different kinds of impacts. For example, when pollutants are diverted, the post-pollution episode exposes the continuing effects of land development. A long-term study of Lake Washington is summarized to illustrate this point.