Fate, Distribution and Limnological Effects of Volcanic Tephra in the St. Joe and Coeur d'Alene River Deltas of Lake Coeur d'Alene, Idaho

摘要

The purpose of this research was to determine the effects of the tephra (volcanic ash) fallout from the May 18, 1980 eruption of Mt. St. Helens on a lake-river system 200 - 300 miles east of the volcano. Lake Coeur d'Alene in northern Idaho was chosen for the study as a water system which would reflect the more subtle impacts of ash fallout in contrast to the immediate and devastating impact to lakes and streams near the volcano. The specific objectives were to quantify and identify volcanic ash in the lake sediments and water columns, describe chemical conditions in the sediments and water columns, and to assess the effects of volcanic tephra on the benthic, phytoplankton, and zooplankton communities.