The cycling of iron and manganese in the water column of Lake Sammamish, Washington

Limnology and Oceanography
By: , and 



Processes controlling the distribution and mobility of Fe and Mn in Lake Sammamish, Washington, a seasonally anoxic lake, are deduced from a year‐long monthly study of physical, chemical, and biological parameters in the lake. Inventories of dissolved Mn and Fe in the bottom waters increase as the redox potential lowers with dissolved Mn inventories during stagnation being much larger than inventories of dissolved Fe. The shapes of the dissolved metal profiles indicate that dissolved Fe is supplied to the hypolimnion during stratification by diffusion of Fe(II) from the sediments into the overlying anoxic water as well as reduction of Fe oxide particles settling through the anoxic water column, while the dominant source of dissolved Mn to the anoxic bottom waters during most of the stratification period appears to be reduction of settling Mn‐oxide particles. Inventories of particulate Fe in the hypolimnion during the latter stages of stratification are significantly larger than inventories of particulate Mn. Peaks of particulate Fe and Mn occur in the water column from July through November and particulate Mn peaks always occur at shallower depths than peaks of particulate Fe. Flux calculations suggest that there is a sufficient supply of both oxygen and reduced metal to the particulate zones for metal‐oxide precipitation to occur. Thermodynamic calculations suggest that during the sulfidic phase of stagnation dissolved Fe concentrations in the very bottom waters may be controlled by FeS precipitation.

Study Area

Publication type Article
Publication Subtype Journal Article
Title The cycling of iron and manganese in the water column of Lake Sammamish, Washington
Series title Limnology and Oceanography
DOI 10.4319/lo.1992.37.3.0510
Volume 37
Issue 3
Year Published 1992
Language English
Publisher American Society of Limnology and Oceanography
Contributing office(s) Geology, Minerals, Energy, and Geophysics Science Center
Description 19 p.
First page 510
Last page 528
Country United States
State Washington
County King County
Other Geospatial Lake Sammamish
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