Eddy covariance flux measurements has taken place at the site MM2 since 2007. The mast (3 m high) is located on a wet fen area called Rylekæret, about 1.5 km North of the Climate station (operated by ClimateBasis). Between 2007 and 2011 the system consisted of a LI6262 and Gill R2. Since 2012 a LI7200 and Gill HS are used. Data from LI6262+Gill R2 was logged at 20 Hz in Edisol software and fluxes calculated on halfhourly basis using EdiRe software, whereas data from LI7200+Gill HS is logged at 20 Hz on LI7550 and fluxes calculated on halfhourly basis using EddyPRO software.