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Diurnal variation of denitrification and nitrification in sediments colonized by benthic microphytes
Author(s) -
Petersen Nils Risgaard,
Rysgaard Suren,
Nielsen Lars Peter,
Revsbech Niels Peter
Publication year - 1994
Publication title -
limnology and oceanography
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.7
H-Index - 197
eISSN - 1939-5590
pISSN - 0024-3590
DOI - 10.4319/lo.1994.39.3.0573
Subject(s) - denitrification , water column , nitrification , nitrate , benthic zone , anoxic waters , environmental chemistry , bioturbation , environmental science , sediment , chemistry , oceanography , nitrogen , geology , geomorphology , organic chemistry
Diurnal variation of denitrification in sediments with benthic microphytes was investigated by a 15 N isotope‐pairing technique in order to distinguish between coupled nitrification‐denitrification and denitrification of nitrate supplied from the water column. Sediments were incubated in a continuous flow‐through system and exposed to diurnal light and dark cycles. Illumination of both limnetic and estuarine sediments doubled the rate of coupled nitrification‐denitrification but reduced the rate of denitrification of nitrate supplied from the water column by ∼50%. Photosynthesis in the uppermost sediment layers during illumination led to deeper oxygen penetration and a resultant stimulation of nitrification. This stimulation may explain the increased rate of coupled nitrification‐denitrification during illumination. The rate of denitrification of nitrate supplied from the water column was reduced during illumination due to a longer diffusion path between water and the anoxic denitrification zone.