Summary of Crater Lake studies and comparison with the early stages of eutrophication of Lake Tahoe
Goldman CR. 1990. Summary of Crater Lake studies and comparison with the early stages of eutrophication of Lake Tahoe. Pages 213-221. In Goldman CR (ed): Crater Lake: An ecosystem study. Corvallis, Oregon. June 18-22, 1988. San Francisco. 69th Annual Meeting of the Pacific Division/American Association for the Advancement of Science
"This symposium brings together an array of studies focusing on limnological and geological aspects of this important caldera lake. Public law established in 1982 as a result of observed loss in water clarity from early Secchi measurements. These indicated a drastic decline in transparency from 38 m in 1937 to 21 m in 1978. Extensive geological investigations by USGS scientists and by Oregon State University oceanographers have been directed towards the possibility of geothermal inputs by remote, geochemical, and sediment studies of the basin. The ratio of Cl to Li and He isotope ratios provide additional support for input of thermal springs. Variable hydrothermal activity during the last 6900 years may have modified nutrient loading. Blooms of a single diatom species, Nitzschia gracilis, among the five highly diverse phytoplankton communities contributes most to the transparency loss and higher primary productivity rates than were encountered in the late 1960s. Two cladocerans and nine rotifers make up the zooplankton with possible ‘top-down’ effects of kokanee predation influencing cyclic phenomena of Daphnia. Food supply is partitioned between rainbow trout and kokanee with almost 100 m of water column utilized. Long-term weather data have been used to evaluate the systems water balance. Seasonal heating and cooling and what appears to be thermal input from the lake floor produce low stability in deep water. Like Lake Tahoe, nitrogen limitation of algae growth is indicated. Spring water contaminated by sewage seepage has been suggested as a possible cause of the loss of transparency. The intensive data set from Lake Tahoe provides comparison of nutrient response, primary productivity, and transparency change useful in predicting future conditions and management strategies for Crater Lake. Recommendations for addition studies are also included."
- Type
- Conference Proceeding Paper
- Authors
- Goldman, Charles
- Units
- CRLA
- Keywords
- Abundance (Biodiversity), Aquatic Ecology, Aquatic Sciences, Clarity (Water), Comparison studies, Distribution (Biodiversity), Eutrophication, Lake Tahoe, Limnology, Pollution, Presence (Biodiversity), Taxa List Only, Wastewater, Water characteristics, Water Management, Water Quality