title: 454 sequencing of nosZ clade I: sandy sediment, habitat diversity level 2
design: DNA was extracted from sediments using the Fast DNA Spin Kit for Soil (MP Biomedicals, Santa Ana, USA). A two-step PCR was performed to amplify the nitrous oxide reductase gene nosZI (primers: 1840F/2090R, Henry et al., 2006) and introduce the barcode, sequencing key and adapter. Pyrosequencing was performed by Genoscreen (Lille, France) on a RocheÕs 454 FLX+ Sequencer.