» Home » HOT » Analytical Methods & Results
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 2007 determined from triplicate analyses are presented in the Table below.


Chlorophyll a Pheopigments
Cruise CV (%) SD (µg/l) N CV (%) SD (µg/l) N
189 10.3 0.011 6 11.4 0.013 6
190 3.1 0.003 6 9.1 0.013 6
191 7.2 0.008 6 14.8 0.027 6
192 4.3 0.007 2 2.6 0.004 2
193 10.4 0.008 6 28.4 0.027 6
194 3.7 0.006 6 6.4 0.010 6
195 10.2 0.018 6 9.1 0.045 6
196 6.5 0.008 6 14.5 0.033 6
197 3.3 0.004 6 6.8 0.006 6
198 17.6 0.017 6 17.9 0.028 6
Mean 7.7 0.009 10 12.1 0.021 10



Results

A contour plot of chlorophyll a concentrations measured using standard fluorometric techniques from 0 to 200 dbar during 1988-2007 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.