Denitrification and photosynthesis in stream sediment studied with microsensor and whole-core techniques
Journal Article
·
· Limnology and Oceanography; (United States)
- Univ. of Aarhus (Denmark)
The effect of light on benthic photosynthesis, denitrification, and assimilation of NH{sub 4}{sup +} and NO{sub 3}{sup {minus}} in stream sediments was studied with whole-core techniques and with O{sub 2} and N{sub 2}O microsensors. Photosynthetic oxygen production increased the thickness of the aerobic surface layer from 1.5 mm in the dark to {approximately} 3.5 mm at a light intensity saturating photosynthesis. The O{sub 2} flux change concurrently from net uptake to net release and the overall rate of denitrification was reduced by 70%. Denitrification was always restricted to a narrow zone immediately below the aerobic-anaerobic interface. Calculated NO{sub 3}{sup {minus}} microprofiles showed that overall denitrification was primarily dependent on the thickness of the aerobic layer which acted as a barrier for diffusion of NO{sub 3}{sup {minus}} from the overlying water. In the light, algal NO{sub 3}{sup {minus}} assimilation could exceed NO{sub 3}{sup {minus}} consumption by denitrification when availability of NH{sub 4}{sup +} was low. Assimilation of NO{sub 3}{sup {minus}}, however, had no influence on the flux of NO{sub 3}{sup {minus}} to the denitrification zone, since assimilation occurred relatively close to the sediment surface.
- OSTI ID:
- 5945461
- Journal Information:
- Limnology and Oceanography; (United States), Journal Name: Limnology and Oceanography; (United States) Vol. 35:5; ISSN LIOCA; ISSN 0024-3590
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
54 ENVIRONMENTAL SCIENCES
540320* -- Environment
Aquatic-- Chemicals Monitoring & Transport-- (1990-)
550200 -- Biochemistry
59 BASIC BIOLOGICAL SCIENCES
AEROBIC CONDITIONS
ALGAE
AMMONIUM COMPOUNDS
AQUATIC ORGANISMS
BENTHOS
BIOCHEMICAL REACTION KINETICS
BIOLOGICAL ACCUMULATION
CHEMICAL REACTIONS
CHEMISTRY
DENITRIFICATION
DRILL CORES
KINETICS
NITRATES
NITROGEN COMPOUNDS
OXYGEN COMPOUNDS
PHOTOCHEMICAL REACTIONS
PHOTOSYNTHESIS
PLANTS
REACTION KINETICS
SEDIMENTS
STREAMS
SURFACE PROPERTIES
SURFACE WATERS
SYNTHESIS
WATER CHEMISTRY
540320* -- Environment
Aquatic-- Chemicals Monitoring & Transport-- (1990-)
550200 -- Biochemistry
59 BASIC BIOLOGICAL SCIENCES
AEROBIC CONDITIONS
ALGAE
AMMONIUM COMPOUNDS
AQUATIC ORGANISMS
BENTHOS
BIOCHEMICAL REACTION KINETICS
BIOLOGICAL ACCUMULATION
CHEMICAL REACTIONS
CHEMISTRY
DENITRIFICATION
DRILL CORES
KINETICS
NITRATES
NITROGEN COMPOUNDS
OXYGEN COMPOUNDS
PHOTOCHEMICAL REACTIONS
PHOTOSYNTHESIS
PLANTS
REACTION KINETICS
SEDIMENTS
STREAMS
SURFACE PROPERTIES
SURFACE WATERS
SYNTHESIS
WATER CHEMISTRY