A reconnaissance investigation of a large meromictic lake in southeastern Alaska

Journal of Research of the U.S. Geological Survey
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Abstract

Redoubt Lake is one of the largest documented meromictic lakes in North America. The chemocline extends in depth from 80 to 100 m (meters) and the steepest gradient is between 98 and 100 m. The monimolimnion is anoxic, contains hydrogen sulflde, and has a salinity about two-thirds that of seawater. Turnover appears to introduce additional sodium chloride from the chemocline to the mixolimnion, but diffusion is probably the dominant mixing mechanism. Vertical profiles show a dichothermic temperature curve. A minimum temperature of 3°C in the chemocline is unexplained, but higher temperatures in the monimolimnion may be a result of solar radiation. At the lower limit of the chemocline there is a sharp decrease in pH, which could be due to bacterial action. Redoubt Lake is probably a relict fiord. The data presented herein support the hypothesis that the lake was gradually isolated from the sea by uplift. While seawater was entering the lake, it probably mixed with the freshwater in the mixolimnion and therefore the monimolimnion is less saline than seawater. Geologic and geophysical evidence support the speculation that significant amounts of saltwater inflow probably ceased about 650-800 years before the present.

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Publication type Article
Publication Subtype Journal Article
Title A reconnaissance investigation of a large meromictic lake in southeastern Alaska
Series title Journal of Research of the U.S. Geological Survey
Volume 5
Issue 3
Year Published 1977
Language English
Publisher U. S. Geological Survey
Description 6 p.
First page 319
Last page 324
Country United States
State Alaska
Other Geospatial Baranof Island, Kunaa Shak Áayi, Redoubt Lake
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