In some areas, the saturation levels reached at least 250 times that of background levels in the summer and 1,400 times higher in the winter. (skepticalscience.com)
At some locations, methane concentrations reached 100 times background levels. (realclimate.org)
There are usually several such plots on one site, some with elevated CO2 and a number of control plots in which CO2 remains at normal background levels. (carbonbrief.org)