Biosensor determination of the microscale distribution of nitrate, nitrate assimilation, nitrification, and denitrification in a diatom-inhabited freshwater sediment

Journal Article · Tue Sep 01 04:00:00 EDT 1998 · Applied and Environmental Microbiology

OSTI ID:658979

Lorenzen, J; Larsen, L H; Kjaer, T; Revsbech, N P ^[1]

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1. Univ. of Aarhus (Denmark). Dept. of Microbial Ecology

High-resolution NO{sub 3}{sup {minus}} profiles in freshwater sediment covered with benthic diatoms were obtained with a new microscale NO{sub 3}{sup {minus}} biosensor characterized by absence of interference from chemical species other than NO{sub 2}{sup {minus}} and N{sub 2}O. Analysis of the microprofiles obtained indicated no nitrification during darkness, high rates of nitrification and a tight coupling between nitrification and denitrification during illumination, and substantial rates of NO{sub 3}{sup {minus}} assimilation during illumination. Nitrification during darkness could be induced by purging the bulk water with O{sub 2} gas, indicating that the stimulatory effect on nitrification by illumination was caused by algal production of O{sub 2}. NH{sub 4}{sup +} addition did not stimulate nitrification during darkness when O{sub 2} was restricted to the upper 1-mm layer, and there was thus a low nitrification potential in the permanently oxic top 1 mm of the sediment.

• OSTI ID: 658979
• Journal Information: Applied and Environmental Microbiology, Journal Name: Applied and Environmental Microbiology Journal Issue: 9 Vol. 64; ISSN AEMIDF; ISSN 0099-2240
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
56 BIOLOGY AND MEDICINE
APPLIED STUDIES
BIOLOGICAL INDICATORS
DENITRIFICATION
DIATOMS
FRESH WATER
NITRATES
NITRIFICATION
SEDIMENTS
WATER POLLUTION