A scanning electron microscopic study of periphyton colonization in a small stream subjected to sodium chloride addition

Summary

The addition of 1,000 ppm sodium chloride to a small stream in order to simulate road salt loading resulted in a reduction in algal density and an increase in bacterial density during a four week exposure period.

The scanning electron microscope was used to identify changes in the spatial pattern of periphyton community structure using specially prepared slate substrates which were placed in the stream at the onset of the study.

Phytophagous invertebrates increased algal diversity at the control station by preventing the dominant alga, Cocconeis placentina, from crowding out the other algal colonizers. Algal diversity remained lower at the salt stressed station as did algal density, fungal parasitism and invertebrate herbivory throughout the four week experiment.