The production of bacteria attached to particles suspended in a freshwater pond1

The biomass and activity of particle‐bound bacteria in a small freshwater pond were examined during 2 years. The percentage of total bacteria attached to particles was highest (3%) in the months of July through October. During this period the number of bacteria per particle and the number of particles per milliliter were also relatively high. An average attached bacterium was larger than an unattached bacterium in July and August but not in February and May. Cell volumes of both populations were larger in summer than in winter. The uptake of three 14 C‐labeled compounds and the incorporation of 3 Hthymidine into macromolecules were also examined. Although there was no seasonal pattern in the percentage of activity contributed by the >3.0‐ µ m fraction, this fraction took up relatively more glucose (21% of total uptake) than glutamate (12%) or acetate (6.8%). Thymidine incorporation by the large bacteria was relatively low (2.8%). The production of bacteria attached to particles was estimated from rates of thymidine incorporation and used to estimate the remineralization rate of detrital carbon by particle‐bound bacteria. Detrital carbon in Ice House Pond was apparently not remineralized substantially by particle‐bound bacteria.