Table 4.
Prediction of the in situ balance between net DOP production and DOP consumption during 5-day, simulated phytoplankton blooms at four stations on the Oregon Coasta.
| Conditions | Upwelling |
Relaxation |
||
|---|---|---|---|---|
| Station | CP-1 | CP-4/5 | CH-6 | CP-4 |
| Initial (in situ) [DOP] μMb | 0.27 (0.02) | 0.25 (0.02) | 0.23 (0.02) | 0.22 (0.02) |
| Observed [DOP]control (μM) @ day-5c | 0.45 (0.02) | 0.40 (0.04) | 0.26 (0.03) | 0.34 (0.03) |
| (+P) TREATMENT | ||||
| Maximum net DOP production rate (nmol P/L/h)c,d | 14.33 (0.58) | 18.39 (9.11) | 14.35 (2.15) | 20.75 (2.02) |
| Predicted net DOP accumulated over 5-day incubation (μM)e,f | 1.72 (0.07) | 2.21 (1.09) | 1.72 (0.26) | 2.49 (0.24) |
| Maximum predicted net [DOP] concentration at day-5 (μM)g,h | 1.99 (0.07) | 2.46 (1.09) | 1.95 (0.26) | 2.71 (0.24) |
| Difference between Maximum predicted net and observed [DOP]control concentration @ day-5 (μM)i | 1.54 (0.07) | 2.06 (1.09) | 1.69 (0.26) | 2.37 (0.24) |
| Observations | [DOP]predicted > [DOP]obsd | [DOP]predicted > [DOP]obsd | [DOP]predicted > [DOP]obsd | [DOP]predicted > [DOP]obsd |
| Implications for [DOP] | Production > consumption | Production > consumption | Production > consumption | Production > consumption |
| (+N) TREATMENT | ||||
| Minimum net DOP production rate (nmol P/L/h)c,d | 0.39 (0.46) | 0.06 (0.35) | 0.29 (0.44) | −0.25 (0.36) |
| Predicted net DOP accumulated over 5-day incubation (μM)e,f | 0.05 (0.06) | 0.01 (0.06) | 0.04 (0.06) | −0.03 (0.04) |
| Minimum predicted net [DOP] concentration at day-5 (μM)g,h | 0.32 (0.06) | 0.26 (0.06) | 0.27 (0.06) | 0.19 (0.04) |
| Difference between Minimum predicted net and observed [DOP]control concentration @ day-5 (μM)i | −0.13 (0.06) | −0.14 (0.07) | 0.01 (0.07) | −0.15 (0.05) |
| Observations | [DOP]predicted > [DOP]obsd | [DOP]predicted > [DOP]obsd | [DOP]predicted ≈ [DOP]obsd | [DOP]predicted > [DOP]obsd |
| Implications for [DOP] | Consumption > production | Consumption > production | Consumption ≈ production | Consumption > production |
aValues in parentheses are uncertainties, estimated as described in the Section “Materials and Methods” and according to the Table notes for each parameter.
bUncertainty in Initial DOP is the analytical uncertainty (±0.02 μM), as described in Note b to Table 2.
cUncertainties for Observed day-5 DOP concentrations and for net DOP Production Rates are estimated as the standard deviation about the mean calculated over concentrations and rates determined on triplicate bottles.
dRates are from Table 3.
ePredicted net [DOP] accumulation over the 5-day incubation is calculated as rate (nM-DOP/h) × 120 h = [DOP] (nM), where 5-days equates to 120 h.
fUncertainty in Predicted net [DOP] production over the 5-day incubation is calculated according the standard error propagation formulation: ({square root [(Δrate/Rate)2 + (Δtime/Time)2]} × [DOP]predicted day-5 net [DOP]), where Δrate is calculated as described in Note c, above, and Δtime (the uncertainty in time of sample collection during the time course incubation) is ±0.5 h.
gPredicted net [DOP] concentration is calculated as the initial (in situ) [DOP] + {predicted day-5 net [DOP]}. Concentrations are identified as ‘net’ owing to the fact that the rates are calculated based on subtraction of initial from day-5 DOP concentrations, and the latter reflect both production and consumption that occurred over the 5-day incubation time-course; see text for further discussion.
hUncertainty in the Predicted Net [DOP] concentration at day-5 is calculated by propagating the error in the initial [DOP] and the Predicted net [DOP] production at day-5, according to the following standard error propagation formulation: square root {(Δinitial [DOP])2 + (Δpredicted net [DOP] production at day-5)2}, where Δinitial [DOP] and Δpredicted net [DOP] production at day-5 are calculated as described in Notes b and f, above.
iUncertainty in the difference between Predicted net [DOP] and Observed [DOP]control @ day-5 is calculated by propagating the error associated with these two quantities according to the standard error propagation formulation: square root {(ΔPredicted net [DOP] @ day-5)2 + (ΔObserved control [DOP] @ day-5)2}, where (ΔPredicted net [DOP] concentration @ day-5), and (ΔObserved control [DOP] @ day-5) are calculated as described in notes h and c, respectively.