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Denitrification in a soft bottom lake: evaluation of laboratory incubations

1999; Inter-Research Science Center; Volume: 17; Linguagem: Inglês

10.3354/ame017279

1616-1564

Nils Risgaard‐Petersen, S Skårup, Lars Peter Nielsen,

Soil and Water Nutrient Dynamics

AME Aquatic Microbial Ecology Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsSpecials AME 17:279-287 (1999) - doi:10.3354/ame017279 Denitrification in a soft bottom lake: evaluation of laboratory incubations Nils Risgaard-Petersen*, Susanne Skårup, Lars Peter Nielsen Institute of Biological Sciences, Department of Microbial Ecology, University of Aarhus, DK-8000 Århus C, Denmark *E-mail: nils.risgaard-petersen@biology.aau.dk ABSTRACT: Annual benthic denitrification in a shallow soft bottom lake was estimated in laboratory-incubated sediment cores, using the isotope pairing technique. Rates were <30% of the estimate calculated from nitrogen mass balance of the lake. To investigate this discrepancy, in situ measurements were performed in flexible enclosures to which 15NO3- was added. Accumulation of 29N2 and 30N2 in the sediment and water column was measured and the loss to the atmosphere was estimated from depletion of argon, added in excess to the water of the enclosures. The calculated denitrification activities in the enclosures were 6 to 26 times higher than the activity in the incubated cores. We suggest that denitrification in situ was enhanced by wave forces, increasing the transport of oxygen and nitrate into these soft sediments. Such transport is not simulated by conventional stirring of the water column in laboratory incubations, which consequently may underestimate the in situ activity. KEY WORDS: Rigid core tubes · Flexible enclosures · In situ measurements · Nitrogen mass balance Full text in pdf format PreviousNextExport citation RSS - Facebook - Tweet - linkedIn Cited by Published in AME Vol. 17, No. 3. Publication date: June 18, 1999 Print ISSN: 0948-3055; Online ISSN: 1616-1564 Copyright © 1999 Inter-Research.