title: Veracruz soil sample plus Anthracene and Surfynol 485 day 56 replicate 2
design: The soil sample was washed first with 0.15 M sodium pyrophosphate and 0.15 M phosphate buffer pH 8 to remove the organic material before the DNA was extracted (Ceja-Navarro et al., 2010). Three different methods were used to extract the DNA from soil. A first technique used a chemical and thermal shock for cell lysis (Ceja-Navarro et al., 2010). In a second technique cells were enzymatically lysed (Sambrook and Rusell, 2001) and in a third technique a detergent solution and mechanic disruption were used for cell lysis (Hoffman and Winston, 1987). Each technique was used to extract four times 0.5 g soil (a total 2 g soil) and pooled. As such, a total of 6 g soil was extracted for DNA.