The effect of temperature and moisture on lag phase length of bacterial growth in soil after substrate addition

Publication date: Available online 8 August 2019Source: Soil Biology and BiochemistryAuthor(s): Lidia Nicola, Erland BååthAbstractMicroorganisms in soil are commonly limited by available substrate, and removing the limitation will increase activity and growth, with predictable dynamics in growth. The initial phase with a lag period (λ) will usually be followed by exponential growth (also called log phase, with growth rate μ). These two growth phases may be differently affected by environmental conditions, like temperature and moisture. Using glucose addition as a model of a sudden increase in labile C, we studied the effect of temperature (0oC to 30oC) and soil moisture (10% to 35%) on bacterial growth dynamics (estimated using leucine incorporation). Decreasing temperature resulted in decreased μ and increased λ. The latter increased from a minimum around 6h at 25oC to>100h at 0oC. The square root of μ increased linearly with temperature below Topt according to the Ratkowsky equation, with an apparent Tmin of -11oC. The square root of 1/λ also increased linearly with temperature (the inverse Ratkowsky equation), with a Tmin of -10oC. Thus, there was a close correlation between μ and 1/λ, suggesting that the length of λ at different temperatures was entirely determined by the rate of growth after adding glucose. Increasing soil moisture increased μ and decreased λ (at 20oC), with the latter decreasing from 14-21h at 15% moisture to 8-14h at 35% moisture. No expon...
Source: Soil Biology and Biochemistry - Category: Biology Source Type: research