The effect of dissolution from particulates into the supernatant solution in sediment trap sample cups has been measured for fatty acids. A mooring array with time series sediment traps was deployed in the northeast Atlantic Ocean (59¿N, 21¿W) for 14 months. Selected representative samples from the trap at 2200 m (poisoned with NaN3) were analyzed for total and free fatty acids in both the solution and particulate phase by means of gas chromatography-mass spectrometery with an ion trap detector. The flux contribution of the dissolved total fatty acids (&Sgr;DTFA) was found to be between 15 and 75% of the total flux (&Sgr;TTFA, sum of the fluxes of total fatty acids in both particles and supernatants).

Dissolved free fatty acids (&Sgr;DFTA) represented 25--88% of the total flux of free fatty acids (&Sgr; TFFA). Absolution concentrations of total and free fatty acids in both compartments are discussed in terms of the processes controlling the distribution between the two phases, for example, readsorption. Sample handling, poisoning, bacterial activity, and swimmers may also affect fatty acid distribution. Flux data (sum of particulate and dissolved fluxes) are presented for individual fatty acids. Also, the degree of dissolution of individual fatty acids is shown for one sample (dissolved fraction ranging between 16 and 98% of total flux). ¿ American Geophysical Union 1994