FINE-SCALE DISTRIBUTION OF NITROUS-OXIDE IN MARINE-SEDIMENTS

Vertical profiles of nitrous oxide and other inorganic nitrogen compou nds in the sediments in Tokyo Bay and its vicinity were measured using the whole core squeezing method. Within the bay area, vertical profil es of nitrous oxide in the interstitial waters showed one or two disti nctive peaks around the depth of 2-4 cm, which corresponded to the pea ks of nitrite and nitrate. In situ formation of nitrous oxide through nitrification was suggested in those sediments, which was possibly act ivated by the presence of benthic animals. On the other hand, at the d eep sediment off Tokyo Bay the profiles of nitrous oxide, nitrite and nitrate gave a monotonous single peak, indicating less bioturbated con dition. Denitrification or dissimilatory nitrate reduction might be im portant for the formation of nitrous oxide peaks in the latter type of sediment.