Novel chlorophyll-related compounds in marine phytoplankton: distributions and geochemical implications

The distributions of chlorophyll-related pigments in marine phytoplankton are surveyed to document their occurrence, reevaluate their use as biological markers, and suggest precursor-geoporphyrin relationships. Newly identified chlorophyll c related pigments were widely distributed among the marine phytoplankton clones examined in this study. Two of the recently described chlorophyll c like pigments (chlorophyll c{sub 3} and a phytylchlorophyll c derivative) were found to be associated with common bloom-producing chromophytes, thus having potential for preservation in the sedimentary record. The taxonomic specificity and apparent geological stability of chlorophyll pigments suggest that geoporphyrins are excellent candidates as indicators of paleooceanographic/depositional environments. The high structural diversity observed among geoporphyrins may be explained by the complexity of precursor pigments found in marine phytoplankton and bacterioplankton and not by extensive diagenetic transformations. The introduction of methods providing greater resolution (liquid chromatography/mass spectrometry and supercritical fluid chromatography/mass spectrometry) of complex chlorophyll mixtures and specific detection should lead to the discovery of an even more diverse collection of chlorophyll pigments.