Denitrification in San Francisco Bay intertidal sediments

Journal Article · Tue May 01 04:00:00 EDT 1984 · Appl. Environ. Microbiol.; (United States)

OSTI ID:6585593

Oremland, R S; Umberger, C; Culbertson, C W; Smith, R L

The acetylene block technique was employed to study denitrification in intertidal estuarine sediments. Addition of nitrate to sediment slurries stimulated denitrification. During the dry season, sediment-slurry denitrification rates displayed Michaelis-Menten kinetics, and ambient NO/sub 3//sup -/ + NO/sub 2//sup -/ concentrations (less than or equal to26 ..mu..M) were below the apparent K/sub m/ (50 ..mu..M) for nitrate. During the rainy season, when ambient NO/sub 3//sup -/ + NO/sub 2//sup -/ concentrations were higher (37 to 89 ..mu..M), an accurate estimate of the K/sub m/ could not be obtained. Endogenous denitrification activity was confined to the upper 3 cm of the sediment column. However, the addition of nitrate to deeper sediments demonstrated immediate N/sub 2/O production, and potential activity existed at all depths sampled (the deepest was 15 cm). Loss of N/sub 2/O in the presence of C/sub 2/H/sub 2/ was sometimes observed during these short-term sediment incubations. Experiments with sediment slurries and washed cells suspensions of a marine pseudomonad confirmed that this N/sub 2/O loss was caused by incomplete blockage of N/sub 2/O reductase by C/sub 2/H/sub 2/ at low nitrate concentrations. Areal estimates of denitrification (in the absence of added nitrate) ranged from 0.8 to 1.2 ..mu..mol of N/sub 2/ m/sup -2/ h/sup -1/ (for undisturbed sediments) to 17 to 280 ..mu..mol of N/sub 2/ m/sup -2/ h/sup -1/ (for shaken sediment slurries). 32 references

• Research Organization: Geological Survey, Menlo Park, CA
• OSTI ID: 6585593
• Journal Information: Appl. Environ. Microbiol.; (United States), Journal Name: Appl. Environ. Microbiol.; (United States) Vol. 47:5; ISSN AEMID
• Country of Publication: United States
• Language: English

Related Subjects

520200* -- Environment
Aquatic-- Chemicals Monitoring & Transport-- (-1989)
54 ENVIRONMENTAL SCIENCES
BACTERIA
CHALCOGENIDES
CHEMICAL ANALYSIS
CHEMICAL REACTIONS
DENITRIFICATION
ECOLOGICAL CONCENTRATION
ENZYMES
ESTUARIES
INHIBITION
KINETICS
MICROORGANISMS
NITRATES
NITROGEN COMPOUNDS
NITROGEN DIOXIDE
NITROGEN OXIDES
OXIDES
OXIDOREDUCTASES
OXYGEN COMPOUNDS
PACIFIC OCEAN
POLLUTION
PSEUDOMONAS
SAN FRANCISCO BAY
SEAS
SEDIMENTS
SINKS
SURFACE WATERS
WATER POLLUTION