A method is needed by which biomass production resulting from non-photosynthetic micro-organisms in natural aquatic ecosystems can be included in microbial production measurements. Both laboratory cultures and field samples were used for examining the suitability of measuring sulfate uptake as a yardstick of microbial production. Sulfate uptake, using 35SO4, was com pared with 14CO2 uptake and it was found that sulfate uptake measures significantly more microbial production than does 14CO2 uptake. With further study, the use of sulfate uptake may become a very satisfactory method for better estimating the total planktonic microbial production under aerobic conditions.
Inorganic carbon uptake (primary production) and sulfate uptake were studied in axenic cultures of a Chlorella sp., a Nannochloris sp., and a Scenedesmus sp. All of the cultures took up significant amounts of sulfate in the dark, and it is concluded that the direct use of dark sulfate uptake as a measure of in situ bacterial heterotrophic production is probably not valid. The C:S uptake ratios of the algal cultures in the light also varied widely so that the indirect use of a single C:S value for calculating microbial heterotrophic production is also not valid. Carbon:sulfur uptake ratios appear to have some regular but complex relationship to primary production.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.