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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 2006 determined from triplicate analyses are presented in the Table below.


Chlorophyll a Pheopigments
Cruise CV (%) SD (µg/l) N CV (%) SD (µg/l) N
177 1.9 0.002 3 3.6 0.006 3
178 3.0 0.001 6 4.1 0.005 6
179 23.9 0.018 6 11.7 0.028 6
180 2.8 0.003 6 0.9 0.002 6
181 3.7 0.004 6 14.7 0.027 6
182 2.6 0.003 6 5.4 0.009 6
183 4.5 0.003 6 5.3 0.007 6
184 17.2 0.010 6 19.1 0.023 6
185 7.2 0.005 6 5.8 0.006 6
186 1.9 0.002 6 3.0 0.010 6
187 6.7 0.005 6 15.3 0.020 6
188 2.1 0.003 6 8.0 0.009 6
Mean 6.46 0.005 12 8.1 0.013 12


Results

A contour plot of chlorophyll a concentrations measured using standard fluorometric techniques from 0 to 200 dbar during 1988-2006 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.


Underway Surface Chloropigment

Continuous in vitro chloropigment (fluorescence) from surface seawater was measured using a Turner Designs Model 10-AU fluorometer installed on the ship's seawater intake system. The underway measurements were calibrated by taking discrete samples from the outflow of the fluorometer and extracting the pigments according to standard fluorometric methods.