Data from: Complex transient dynamics of stage-structured populations in response to environmental changes

Stage structures of populations can have a profound influence on their
dynamics. However, not much is known about the transient dynamics that
follow a disturbance in such systems. Here we combined chemostat
experiments with dynamical modeling to study the response of the
phytoplankton species Chlorella vulgaris to press perturbations. From an
initially stable steady state, we altered either the concentration or
dilution rate of a growth-limiting resource. This disturbance induced a
complex transient response—characterized by the possible onset of
oscillations—before population numbers relaxed to a new steady state.
Thus, cell numbers could initially change in the opposite direction of the
long-term change. We present quantitative indexes to characterize the
transients and to show that the dynamic response is dependent on the
degree of synchronization among life stages, which itself depends on the
state of the population before perturbation. That is, we show how
identical future steady states can be approached via different transients
depending on the initial population structure. Our experimental results
are supported by a size-structured model that accounts for interplay
between cell-cycle and population-level processes and that includes
resource-dependent variability in cell size. Our results should be
relevant to other populations with a stage structure including organisms
of higher order.