The effect of temperature and algal biomass on bacterial production and specific growth rate in freshwater and marine habitats

Abstract

We analyzed heterotrophic, pelagic bacterial production and specific growth rate data from 57 studies conducted in fresh, marine and estuarine/coastal waters. Strong positive relationships were identified between 1) bacterial production and bacterial abundance and 2) bacterial production and algal biomass. The relationship between bacterial production and bacterial abundance was improved by also considering water temperature. The analysis of covariance model revealed consistent differences between fresh, marine and estuarine/coastal waters, with production consistently high in estuarine/coastal environments. The log-linear regression coefficient of abundance was not significantly different from 1.00, and this linear relationship permitted the use of specific growth rate (SGR in day(-1)) as a dependent variable. A strong relationship was identified between specific growth rate and temperature. This relationship differed slightly across the three habitats. A substantial portion of the residual variation from this relationship was accounted for by algal biomass, including the difference between marine and estuarine/coastal habitats. A small but significant difference between the fresh- and saltwater habitats remained. No significant difference between the chlorophyll effect in different habitats was identified. The model of SGR against temperature and chlorophyll was much weaker for freshwater than for marine environments. For a small subset of the data set, mean cell volume accounted for some of the residual variation in SGR. Pronounced seasonality, fluctuations in nutrient quality, and variation of the grazing environment may contribute to the unexplained variation in specific growth.

Interactive network configuration maintains bacterioplankton community structure under elevated CO<sub>2</sub> in a eutrophic coastal mesocosm experiment

“…The average marine bacterial growth rates, mainly in oligotrophic seawaters, have been reported to be 1.1 day −1 ± 0.83 (Kirchman, 2016). However, the bacterial growth rates under eutrophic conditions are much higher than under oligotrophic conditions, and it has been reported to be on the order of per hour (White et al, 1991). The bacterial growth rate reached 16.2 day −1 (0.675 h −1 ) during a diatom bloom in a mesocosm experiment using seawater from Santa Barbara Channel amended with nutrients (Smith et al, 1995).…”

Isotope‐based Fluvial Organic Carbon (ISOFLOC) Model: Model formulation, sensitivity, and evaluation

“…where APOC col (kgC m 22 d 21 ) is the algal colonization rate and DEC APOC (kgC m 22 d 21 ) is the breakdown rate of coarse algae to fine sediment algae and is assumed to vary proportionally with heterotrophic bacterial growth [e.g., White et al, 1991], and Slough (kgC) is the carbon eroded from the algal mat. ISOFLOC models algal sloughing using shear and supply limited conditions as…”

Warm ocean processes and carbon cycling in the Eocene

“…Q 10 ≈ 2.0). This includes marine and terrestrial microbial decomposers, whose measured Q 10 activities lie between approximately 2 and 4 [28][29][30][31][32]. The Q 10 pattern can also be used to describe the temperature dependence of metabolic rates in a more diverse range of life forms, from unicellular ectotherms to large endothermic mammals, with other factors such as body size playing important additional roles.…”