Integrated Watershed Study: An Investigation of the Biota in the Emerald Lake System and Stream Channel Experiments

摘要

As part of the Integrated Watershed Study in the vicinity of Emerald Lake, Sequoia National Park, investigators conducted baseline monitoring of benthic invertebrates in the inflow streams and the outflow stream. During summer 1986 they carried out a series of acidification experiments in artificial stream channels located in the drainage of the Marble Fork of the Kaweah River. Twelve channels (2.4 m x 20 cm x 20 cm) were stocked with natural substrates, algae and invertebrates. In the treatment channels the pH was reduced to 4.6 and 5.2, using a mixture of nitric and sulfuric acids. Measurements of benthic densities, drift rates and algal densities were made before, during and after each acid treatment of 8 hours duration. Diatom populations declined in the acidified channels, while other periphyton species actually increased with the treatment.