This dataset contains time series observations of land surface-atmosphere exchanges of net ecosystem carbon dioxide exchange (NEE), sensible heat (H) and latent heat (LE), and momentum (τ) measured at the Wicken Sedge Fen, a conservation managed lowland fen (site code: EF-LN) in the Cambridgeshire Fens, UK. Turbulent flux densities (fluxes) were monitored using the micrometeorological eddy covariance (EC) technique between 2009-03-20 to 2009-12-31, and 2010-04-09 to 2011-01-16. The dataset includes ancillary weather and soil physics observations, as well as variables that characterise atmospheric turbulence.