Time-series for medium nitrogen (A and C) and population size (B and D) for Chlorella sp. reared in batch culture with either nitrate (A and B) or ammonium (C andD) as the only nitrogen sources. Each symbol type is an independent replicate culture and each point is the mean between three replicate measurements for that culture.Arrows show one-step ahead predictions for the best-fit model assuming process noise, where the observed values at time t (base of arrows) are used in Eqs. (6a–d) to predictvalues at time t + 1 (arrowheads; see Section 2.2.1). Line graphs beneath each panel connect the residuals between model predictions and observations for each day and are adifferent color for each different replicate culture. Vertical axes are scaled consistently across the two sub-panels. (For interpretation of the references to color in this figurelegend, the reader is referred to the web version of this article.)