Contaminant pathways in Port Curtis: Final report - OzCoasts

Contaminant pathways in Port Curtis: Final report8: Effect of pulse eventsobserved data and Model 2 (Figure 8.5b, r 2 = 85) for the pulsed exposureexperiments was better than Model 1 (Figure 8.5a, r 2 = 0.67). While neither modelprovided a completely accurate description of effects the copper exposure had onalgal growth, in general the models reasonably predicted effects due to the variouspulsed copper exposure scenarios (Figure 8.5).72 h Yield, % Control100%90%80%70%60%50%40%30%20%10%0%Measured Model 1 (dissolved Cu exposure)Time averaged concentration, µg/L9 7 8 8 5 4 4 5 6.5 7 7 7 7 11 12 16 21C 2 4 8 C 1 4 8 C 1 4 8 C 1 2 4 8Exposures: C, 1, 2, 4, 8 = continuous, 1 h, 2 h, 4 h, 8 h pulses(a)72 h Yield, % Control100%90%80%70%60%50%40%30%20%10%0%Measured Model 2 (intracellular Cu exposure)C 2 4 8 C 1 4 8 C 1 4 8 C 1 2 4 8Exposures: C, 1, 2, 4, 8 = continuous, 1 h, 2 h, 4 h, 8 h pulses(b)Figure 8.5a,b. Measured and predicted effect of copper exposure scenariostested with equivalent copper ‘dose’, but varying duration and magnitudeThe models treated the ‘exposure’ causing the toxicity as (a) the external copperconcentration (Model 1), and (b) the internalised copper concentration (Model 2).The discrepancies (Figure 8.5) between the measured effects of copper on algalgrowth and the predictions from Models 1 and 2 for the pulsed copper experiments106