Page 59 - Microbial methane cycling in a warming world From biosphere to atmosphere Michiel H in t Zandt

Road Dike
Sheet Pile
Water
Sediment
0m 3m
BS
AS DL
3
Figure 2. Overview of the sheet pile sampling procedure. The sheet pile is located at the boundary between the dike and the canal. The bulk sediment (BS) sample was taken at the top of the sediment layer; the surrounding/adjacent sediment (AS) and the deposit layers (DL) were sampled at 3 m below the sediment water interface. The AS samples were taken 1-5 cm away from the DL.
Physicochemical parameters (total C and S, SiO2, AlO3, TiO2, Fe2O3, MnO, CaO, MgO, Na2O, K2O, P2O5, soil organic matter, Cr, Ni, Sr, Ba, Zr, Si, Al, Ti, Fe, Mn, Ca, Mg, Na, K, and P) were analyzed by Deltares (Utrecht, the Netherlands) using X-ray fluorescence (XRF). Total C and S were determined by flash combustion and CO2 analysis with a LECO SC-632 IR detector. Additional parameters were determined for the sites Giessenburg and Nieuwlekkerland (see Kip et al. [2017] for extensive details).
Molecular analysis
(i) DNA extraction and sequencing. DNA was extracted from 0.25-0.30 g of (ground) sample using a PowerSoil DNA isolation kit (Qiagen, Venlo, the Netherlands) according to the manufacturer’s protocol, with 10-min bead beating at 30 Hz instead of vortexing. The DNA concentration of each sample was measured using an ND-1000 spectrophotometer (Thermo Fisher Scientific, Waltham, MA). Sequencing libraries were constructed using a TruSeq Nano
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