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THE EFFECTS OF DIFFERENT SAMPLE CONCENTRATIONS ON THE STRUCTURE OF MICROBIAL COMMUNITIES USING PHOSPHOLIPID FATTY ACID ANALYSIS
Citation:
Philip, N. AND M Molina. THE EFFECTS OF DIFFERENT SAMPLE CONCENTRATIONS ON THE STRUCTURE OF MICROBIAL COMMUNITIES USING PHOSPHOLIPID FATTY ACID ANALYSIS. Presented at 55th Southeast Regional Meeting of the American Chemical Society, Atlanta, GA, November 16-19, 2003.
Impact/Purpose:
Improve the scientific understanding of the processes controlling nutrient distributions in surface waters. Produce a suite of enhanced models for characterizing nutrient distributions in surface waters by incorporating improved process understanding in existing models (e.g., WASP), by developing new models (e.g., WHAM, reactive transport), and improving linkages between model components.
Description:
Phospholipid fatty acid (PLFA) analysis is a powerful tool for determination of microbial community structures in soils and sediments. However, accurate determination of total microbial biomass and structure of the microbial community may be dependent on the concentration of the soil extracted. In this study we tested the general protocol for PLFA analysis to determine whether different sample concentrations result in a change in PLFA profiles, percent composition of individual PLFAs, and types of PLFAs that can be identified. Samples were obtained from a small stream draining a cattle pasture in the South Fork Broad River watershed in Georgia. Sample concentrations were 1, 5, 10, and 20g of sediment. Total PLFA abundance in the 1g sample was approximately 93 ug/g, while 20g had an abundance of 18ug/g. It was observed however, that a group of fatty acids (18:1w7, cy17:0, 10Me18:0 and 16:1w7) had a general decrease in % composition as the sediment concentration decreased from 20 to 1g. The fatty acid i15:00 had an approximate 70% decrease in total abundance as the sample went from 20 to 1g. It appears from the data that maintaining a sample concentration of 20g is necessary to obtain the most accurate PLFA profiles for microbial structure determination and microbial abundance in sediment samples.