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Fluorometric Pigments
 Chlorophyll Filtration
FTP View Data
To assist in the interpretation of the data, it can be displayed using the Hawaii Ocean Time-series Data Organization & Graphical System (HOT-DOGS©).


Analytical Method

Samples for Chlorophyll a (chl a) and pheopigments were collected onto 25 mm GF/F glass fiber filters and measured fluorometrically on a Turner Designs Model 10-AU flourometer with 100% acetone as the solvent using standard techniques (Strickland and Parsons, 1972). The average precisions during 2009 determined from triplicate analyses are presented in the Table below.


Chlorophyll a Pheopigments
Cruise CV (%) SD (µg/l) N CV (%) SD (µg/l) N
208 3.6 0.006 6 3.1 0.011 6
209 2.9 0.005 6 5.2 0.010 6
210 4.5 0.004 6 11.5 0.009 6
211 5.3 0.006 6 6.9 0.013 6
212 5.8 0.008 6 10.7 0.011 6
213 10.0 0.004 4 9.4 0.006 4
214 4.3 0.005 12 3.8 0.005 12
215 8.9 0.011 6 7.4 0.014 6
216 26.0 0.008 6 26.1 0.020 6
217 6.3 0.009 6 4.6 0.008 6
Mean 7.8 0.007 10 8.9 0.011 10



Results

A contour plot of chlorophyll a concentrations measured using standard fluorometric techniques from 0 to 200 dbar during 1988-2009 is shown in Figure 45. A chlorophyll maximum with concentrations up to about 0.3 mg/m3 is observed at approximately 110m depth. The magnitude of this feature exhibits significant interannual variability, with a pronounced period of low chlorophyll concentration lasting from 1992-1998. Chlorophyll a concentrations at depths shallower than 50m display an annual cycle with winter maxima and summer minima.