Skip to main content
U.S. flag

An official website of the United States government

Big Soda Lake (Nevada). 1. Pelagic bacterial heterotrophy and biomass

January 1, 1987

Bacterial activities and abundance were measured seasonally in the water column of meromictic Big Soda Lake which is divided into three chemically distinct zones: aerobic mixolimnion, anaerobic mixolimnion, and anaerobic monimolimnion. Bacterial abundance ranged between 5 and 52 x 106 cells ml−1, with highest biomass at the interfaces between these zones: 2–4 mg C liter−1 in the photosynthetic bacterial layer (oxycline) and 0.8–2.0 mg C liter−1 in the chemocline. Bacterial cell size and morphology also varied with depth: small coccoid cells were dominant in the aerobic mixolimnion, whereas the monimolimnion had a more diverse population that included cocci, rods, and large filaments. Heterotrophic activity was measured by [methyl-3H]thymidine incorporation and [14C]glutamate uptake. Highest uptake rates were at or just below the photosynthetic bacterial layer and were attributable to small (<1 µm) heterotrophs rather than the larger photosynthetic bacteria. These high rates of heterotrophic uptake were apparently linked with fermentation; rates of other mineralization processes (e.g. sulfate reduction, methanogenesis, denitrification) in the anoxic mixolimnion were insignificant. Heterotrophic activity in the highly reduced monimolimnion was generally much lower than elsewhere in the water column. Therefore, although the monimolimnion contained most of the bacterial abundance and biomass (∼60%), most of the cells there were inactive.

Publication Year 1987
Title Big Soda Lake (Nevada). 1. Pelagic bacterial heterotrophy and biomass
DOI 10.4319/lo.1987.32.4.0781
Authors Jon P. Zehr, Ronald W. Harvey, Ronald S. Oremland, James E. Cloern, Leah H. George, Judith L. Lane
Publication Type Article
Publication Subtype Journal Article
Series Title Limnology and Oceanography
Index ID 70174325
Record Source USGS Publications Warehouse
USGS Organization San Francisco Bay-Delta; Toxic Substances Hydrology Program; Pacific Regional Director's Office