Modeling
the Effects of Hydrodynamic Regimes on Microbial
Communities within Fluvial Biofilms: Combining Deterministic and Stochastic
Processes
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Abstract
To
fully understand the effects of hydrodynamics on a microbial
community, the roles of niche-based and neutral processes must be
considered in a mathematical model. To this end, a two-dimensional
model combining mechanisms of immigration, dispersal, and niche differentiation
was first established to describe the effects of hydrodynamics on
bacterial communities within fluvial biofilms. Deterministic factors
of the model were identified via the calculation of Spearman’s
rank correlation coefficients between parameters of hydrodynamics
and the bacterial community. It was found that turbulent kinetic energy
and turbulent intensity were considered as a set of reasonable predictors
of community composition, whereas flow velocity and turbulent intensity
can be combined together to predict biofilm bacterial biomass. According
to the modeling result, the bacterial community could get its favorable
assembly condition with a flow velocity ranging from 0.041 to 0.061
m/s. However, the driving force for biofilm community assembly changed
with the local hydrodynamics. Individuals reproduction within the
biofilm was the main driving force with flow velocity less than 0.05
m/s, while cell migration played a much more important role with velocity
larger than 0.05 m/s. The developed model could be considered as a
useful tool for improving the technologies of water environment protection
and remediation