Structural variations in derivatives of the bacteriochlorophylls of Chlorobiaceae: impact of stratigraphic resolution on depth profiles as revealed by methanolysis

• Published in: Organic Geochemistry
• Main Authors: Wilson, Michael A., Hodgson, Dominic A., Keely, Brendan J.
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: Elsevier 2004
• Subjects: Biology and Microbiology; Ecology and Environment; Earth Sciences; Antarc*; Antarctica
• Online Access: http://nora.nerc.ac.uk/id/eprint/12524/; http://www.sciencedirect.com/science/article/pii/S0146638004001548

Bacteriochlorophylls c and d, recovered from two sedimentary sequences, were converted to bacteriophaeophorbide methyl esters by methanolysis and analysed by atmospheric pressure chemical ionisation liquid chromatography-multi-stage mass spectrometry (APCI LC-MSn). The distributions in both settings, a moderately consolidated sediment from Kirisjes Pond, Antarctica, and in a finely laminated microbial mat from Les Salines de la Trinitat, Spain, show significant variations within a narrow depth interval. The overall bacteriophaeophorbide c to d ratios in the two sediments are different, as are the ratios of particular C-3(1) diastereoisomers, indicating distinct differences between the bacterial communities that contributed to each sediment. Furthermore, a shift towards more extensive alkylation in homologues within each sediment is consistent either with changing environmental conditions in the depositional environments, or development-related changes in the structure of the bacterial community, leading to increased competition for light or nutrients.