Bacteria with different cell sizes respond differently to various carbon supply patterns
'Low nucleic acid content (LNA) bacteria' and 'high nucleic acid content (HNA) bacteria' have different cell sizes. Nutrient input modes vary in environments, causing nutrient availability heterogeneity. We incubated them with equal amounts of total glucose added in a continuous/pulsed mode. Finally, the pulse-treated LNA bacteria exhibited twice the cell abundance and four times the viability of the continuous-treated LNA, while HNA didn't show an adaptation to pulsed treatment. In structural equation modeling (SEM), LNA bacteria had higher path coefficients than HNA, between growth and carbon-saving metabolic pathways, intracellular ATP and the inorganic energy storage polymer, polyphosphate, indicating their low-cost growth, and flexible energy storage and utilization. After incubation, the pulse-treated LNA bacteria contained more proteins and polysaccharides (0.00064 ng.cell-1, 0.0012 ng.cell-1) than the continuous-treated LNA (0.00014 ng.cell-1, 0.00014 ng.cell-1), conferring endurance and rapid response to pulses. Compared to LNA, HNA keystone taxa had stronger correlations with the primary glucose metabolism step, glycolysis, and occupied leading positions to explain the random forest model. They are essential to introduce glucose into the element cycling of the whole community under both treatments. Our work outlines a systematic bacterial response to carbon input.