by episodic input of organic matter Abstract-We report the first seasonal time-series observations of porewater composition obtained for deep-sea sediments. We observed considerable temporal variability of O,, NO,-, and Mn2+ profiles at the French JGOFS site DYFA-MED (western Mediterranean) in response to a pulsed input of organic matter. A delivery of reactive organic matter representing only 1 % of the average organic C content of surface sediments (0.6 % wt/wt) was required in order to fuel the observed changes in porewater composition. The perturbation resulted in dramatic changes in integrated reaction rates and sediment-water fluxes. O2 uptake rates increased from 1.26 to 1.82 mmol m- * d-l, while nitrification rates rose from 0.13 to 0.18 mmol m- * d-l. These changes were paralleled by a decrease in NO,- effluxes across the sediment-water interfac
To submit an update or takedown request for this paper, please submit an Update/Correction/Removal Request.