| مستخلص: |
This paper is addressed to the following questions: 'How accurately does in vivo chlorophyll fluorescence of samples treated with Diuron (DCMU), notated FM estimate autotrophic standing stock?' and 'How accurately does the Diuron response, ΔF (= FM - FV), estimate primary production?'. Data are drawn from several cruises in the western Tasman Sea, ranging between latitudes 25S. and 53S. The prediction of chlorophyll (g chl u I-1) from FM (standard chl a fluorescence units) is given by Chl= 2 × 10-3 FM. The standard error is about 6 × 10-4 FM so the 'true' value will usually be within 60% of the estimated mean value. The production parameter, PA(g Cl-1), as measured by 14C uptake under saturating light conditions, may be predicted for the euphotic zone other than the surface layer by PA = 3 × 10-2ΔF. If mean ΔF values are used the 'true' value will usually lie within 25% of the estimate. A strong diel effect was found in the parameter Φ( =ΔFFM-1), the 'photochemical quantum efficiency', an estimator of relative growth rate. The diel cycle has the form of a major midday minimum, a minor midnight minimum, and pre-dawn and post-sunset maxima. This cycle must be removed before comparisons of Φ of samples taken at different times can be made. |
