DOES CHLOROPHYLLIDE-A REDUCE RELIABILITY OF CHLOROPHYLL-A MEASUREMENTS IN MARINE COASTAL SEDIMENTS

Pigment concentrations (chlorophyll a, chlorophyllide a and pheopigmen ts a) were measured by HPLC and spectrophotometry with acidification o n 57 samples collected in different marine coastal sediments, containi ng autochthonous microphytes, and with various organic matter contents (plant detritus, biodeposits or hydrocarbons). Statistical analysis s hows that the spectrophotometry with acidification, as compared to HPL C, gives reliable values for chlorophyll a. Chlorophyllide a concentra tions may be considered as negligible. Though spectrophotometric metho ds are sometimes questioned when applied to sediments they appear to g ive easy, quick and good estimates of Chla contents in benthic microph ytes for hydrobiological studies in coastal areas.