Two dynamic regimes in the human gut microbiome
Fig 1
Time series stationarity and non-stationarity.
Grey lines depict time series, with the mean plotted in red. The top left time series is stationary, with a stable mean (i.e. mean-reverting) and variance (i.e. non-heteroskedastic). The top right trace shows a non-stationary time series where the mean and variance change monotonically. The bottom left trace shows a time series with non-stationary variance (i.e. a sudden bloom event). The bottom right trace shows a non-stationary time series with both a changing variance and a non-monotonically changing mean.