Figure 2

Solution curves for systems (5.1) and (5.2). The parameters are defined in Table 1, and the initial conditions are \(x=0.5 \mbox{ mg C/L}\) and \(y=0.25 \mbox{ mg C/L}\). (\(a_{i}\)) and (\(b_{i}\)) denote the dynamics of (5.1) and (5.2) with different \(P_{T}\), respectively. Producer and grazer densities (mg C/L) are given by dashed and solid lines, respectively