Document Type

Article

Publication Date

1-1-1993

Abstract

Glucose uptake was monitored on a seasonal basis, using [6-3H]glucose and undisturbed cores collected from an intertidal mud flat. The fate of glucose carbon, including the formation of CO2 and biomass, was assayed by using undisturbed cores and [U-14C]glucose; the production of short-chain fatty acids was monitored with [U-14C]glucose and sediment slurries. Rate constants for glucose uptake varied temporally, with temperature accounting for much of the variability; turnover times ranged from about 2 to 10 min. Rate constants decreased with increasing sediment depth and in the following order for several common monosaccharides: glucose>galactose>mannose~fucose. Time course analyses of 14CO2 production provided evidence of significant isotopic dilution; although pore water glucose turnover times were on the order of minutes, 14CO2 did not plateau until after approximately 6 h of incubation. At this time a maximum of about 40% of the added radioglucose had been respired. The extent of respiration varied as a function of sediment depth and season, with the highest values below the surface (4 to 7 cm) and in summer and fall. Incorporation of radiolabelled glucose into biomass also varied seasonally, but the greatest extent of incorporation (about 40%) was observed in the fall and for the 0- to 1-cm depth interval. The production of short-chain fatty acid end products was largely limited to acetate, which accounted for only a small percentage of the added radiolabel. Other organic acids, pyruvate in particular, were observed in pore water and were due to artifacts in the heat-kill procedure used to terminate incubations. An accurate assessment of the distribution and importance of short-chain fatty acids as end products required the use of an enzymatic technique coupled with high-pressure liquid chromatography to verify qualitative identities.

Publication Source (Journal or Book title)

Applied and Environmental Microbiology

First Page

120

Last Page

128

Plum Print visual indicator of research metrics
PlumX Metrics
  • Citations
    • Citation Indexes: 28
  • Usage
    • Downloads: 74
  • Captures
    • Readers: 25
see details

COinS