Effect of soil sample preparation on fatty acid biomarker content

Abstract

Different techniques for the pre-treatments were applied at various time frames to evaluate their impact on fatty acid biomarkers content for the soil sampled from Suurmetsa, Põlva County, Estonia, one from the arable field the other from grassland. The fatty acids were extracted by the PLFA method and analysed by using GC-FID. The study included eight bacterial biomarkers (i15:0, a15:0, i16:0, a17:0, 17:0, 10Me17:0 ,10Me18:0, cy19:0),total fungal biomass 18:2ꙍ6,9 and AM fungal biomass by group specific NLFA (16:1ꙍ5). Three pre-treatment methods ( Freezing and Lyophilization, Silica gel, and Hot Air Oven) on four different time frame (0, 8, 24, 48) was carried out. Comparing different pre-treatment methods showed both freezing and lyophilization, and the silica gel method is adequate to identify fatty acid biomarkers content. Still, soil pre-treatment should be done as early as possible to get better results. However, for studying general ecological patterns, whichever approaches, or treatment methods can be chosen.