Big Soda Lake (Nevada). 2. Pelagic sulfate reduction

Limnology and Oceanography
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Abstract

The epilimnion of hypersaline, alkaline, meromictic Big Soda Lake contains an average 58 mmol sulfate liter−1 and 0.4 µmol dissolved iron liter−1. The monimolimnion, which is permanently anoxic, has a sulfide concentration ranging seasonally from 4 to 7 mmol liter−1. Depth profiles of sulfate reduction in the monimolimnion, assayed with a 35S tracer technique and in situ incubations, demonstrated that sulfate reduction occurs within the water column of this extreme environment. The average rate of reduction in the monimolimnion was 3 µmol sulfate liter−1 d−1in May compared to 0.9 in October. These values are comparable to rates of sulfate reduction reported for anoxic waters of more moderate environments. Sulfate reduction also occurred in the anoxic zone of the mixolimnion, though at significantly lower rates (0.025–0.090 µmol liter−1 d−1 at 25 m). Additions of FeS (1.0 mmol liter−1) doubled the endogenous rate of sulfate reduction in the monimolimnion, while MnS and kaolinite had no effect. These results suggest that sulfate reduction in Big Soda Lake is iron limited and controlled by seasonal variables other than temperature. Estimates of the organic carbon mineralized by sulfate reduction exceed measured fluxes of particulate organic carbon sinking from the mixolimnion. Thus, additional sources of electron donors (other than those derived from the sinking of pelagic autotrophs) may also fuel monimolimnetic sulfate reduction in the lake.

Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Big Soda Lake (Nevada). 2. Pelagic sulfate reduction
Series title Limnology and Oceanography
DOI 10.4319/lo.1987.32.4.0794
Volume 32
Issue 4
Year Published 1987
Language English
Publisher ASLO
Contributing office(s) Pacific Regional Director's Office, San Francisco Bay-Delta
Description 10 p.
First page 794
Last page 803
Online Only (Y/N) N
Additional Online Files (Y/N) N