Chlorophyll

Shore-based fluorometric detection of chlorophyll and phaeophtyin are available. Contact Susan Becker for details and pricing. 

Sampling

Filter enough water through a glass fiber filter that color is visible on the filter. 100-250 mL is usually sufficient. The filters should then be folded in half, with the sample facing in, and enclosed in aluminum foil. Freeze the filters until analyzed.

Equipment and Techniques

Analyses are performed on a Turner 10-005R fluorometer.

Filters are removed from the foil packets and placed in glass vials with 10 mL of 90% acetone and sealed with parafilm. They are refrigerated for 30 minutes and then sonicated for 15 minutes. The vials are returned to the refrigerator for 24-48 hours before the filters are removed and discarded. The vials are centrifuged for 5 minutes and then decanted (absent of filter particles) into smaller glass vials that fit into the fluorometer. The fluorescence is read, and the sample is then acidified with 2-3 drops of 1.2N HCl. A second reading provides phaeopigment values.  

Data Processing

The fluorometer is connected to a PC and the fluorescence is read by a software program developed by the team at CalCOFI. The Ra and Rb values, along with volume of water filtered, extraction volume, and blank, are put into a spreasheet with formulas that determine the chlorophyll and phaeophytin values, given in units of mg/m3.

Standards

A "blank" vial of 90% acetone from the same batch as used for the samples is refrigerated and sonicated along with the samples and then read before and after the sample analysis. Coproporphyrin standards are read before and after each run. Fluorometer calibration of the machine is performed on a regular basis and the mean F and mean tau values are used in the calculation.

References

Holm-Hansen, O., Lorenzen, C.J., Holms, R.W., Strickland, J.D.H. "Fluorometric Determination of Chlorophyll," J. Cons. Int. Explor. Mer. 30: 3-15 (1965).

Lorenzen, C. J. "Determination of chlorophylls and phaeopigments: spectrophotometric equations," Limnol. Oceanogr. 12: 343–346 (1967).

Yentsch, C.S., Menzel, D.W. "A method for the determination of phytoplankton chlorophyll and phaeophytin by fluorescence," Deep-Sea Res. 10: 221-231 (1963).