Isolation and characterization of chlorophyll and carotenoids in Florida Bay: Phytoplankton, microphytobenthos and sediments

An analysis of the waters, microphytobenthos, and carbonate marl sediments of Florida Bay was performed using ion-paired RP-HPLC-PDA for chemotaxonomic characterization of past and present photoautotrophic, communities. Application of regression formulae was determined to be applicable for the waters, microphytobenthos, and surficial sediments (0--5 cm) of Florida Bay using chemotaxonomic principles. Loss of chemotaxonomically important pigments with depth prevented similar application in deeper strata (>5 cm), however, past oxic and anoxic trends could be determined. Sedimentary alteration of pigments are characterized by: rapid conversion of chlorophylls-alpha and bacteriochlorophylls-alpha to their respective pheophytins-alpha, creation of a 'carotenoid diol-cluster', equilibrium isomerization of beta-carotene (15-cis and trans), and rapid conversion of pyropheophorbide-alpha to cyclopheophorbide-alpha. An abundant presence of pyropheophorbide-alpha steryl/hopanoid esters and an unusual relationship between organic carbon and water content providing the sediments with polymeric characteristics were also found.