River oxygen uptake by benthic microorganisms
type: CreativeWork
description: The factors influencing benthic microbial uptake of river dissolved oxygen (DO) and dissolved organic matter (DOM) were investigated in 4 New Zealand rivers receiving organic waste discharges from dairy factories and a pulp and paper company. A chamber system for in situ use was developed and tested against segment oxygen mass balances in 3 rivers. Benthic oxygen uptake rate (BUR) was found to be strongly affected by circulation velocity, electron acceptor (oxygen) concentration and in some instances electron donor (glucose) concentration. Satisfactory agreement between calculated BUR values and those obtained using the chamber was obtained with matching boundary velocities (0.05 m above bed) in the 2 shallow (<0.5 m) rivers, with low chamber values in the deep (>1.5 m) river. Thus chamber devices must adequately simulate the natural flow and turbulence conditions in order to obtain realistic BUR measurements. Maximum BUR was measured for filamentous ‘sewage fungus’ colonisation at 70.2 g O₂ m⁻² day at 7.0 g O₂ m⁻³. Benthic oxygen penetration depths were estimated from chamber and sediment intrinsic activity measurements and ranged from 0.32 to 32 cm, with minimum values for ‘sewage fungus’ biofilms. Actual measurements of interstitial DO for 2 pumice bed rivers, showed DO present down to at least 10 cm in the Waiotapu River and down to 15 cm in the Tarawera River. The estimated oxygen penetration depths were used to calculate benthic dispersion coefficients. These values ranged from 0.38-16.30 x 10⁻³ cm⁻² s⁻¹ which are several orders of magnitude higher than previously reported maxima. Such high values imply that a high rate of sediment-water exchange was sustained by turbulent mass transfer processes rather than molecular diffusion. Benthic biomass values by ATP extraction ranged from 0.67-4.95 μg ATP cm⁻³, with higher maximum values for the rivers studied than have been reported for sediments in other aquatic systems, and suggesting greater levels of metabolic ac…
abstract: The factors influencing benthic microbial uptake of river dissolved oxygen (DO) and dissolved organic matter (DOM) were investigated in 4 New Zealand rivers receiving organic waste discharges from dairy factories and a pulp and paper company. A chamber system for in situ use was developed and tested against segment oxygen mass balances in 3 rivers. Benthic oxygen uptake rate (BUR) was found to be strongly affected by circulation velocity, electron acceptor (oxygen) concentration and in some instances electron donor (glucose) concentration. Satisfactory agreement between calculated BUR values and those obtained using the chamber was obtained with matching boundary velocities (0.05 m above bed) in the 2 shallow (<0.5 m) rivers, with low chamber values in the deep (>1.5 m) river. Thus chamber devices must adequately simulate the natural flow and turbulence conditions in order to obtain realistic BUR measurements. Maximum BUR was measured for filamentous ‘sewage fungus’ colonisation at 70.2 g O₂ m⁻² day at 7.0 g O₂ m⁻³. Benthic oxygen penetration depths were estimated from chamber and sediment intrinsic activity measurements and ranged from 0.32 to 32 cm, with minimum values for ‘sewage fungus’ biofilms. Actual measurements of interstitial DO for 2 pumice bed rivers, showed DO present down to at least 10 cm in the Waiotapu River and down to 15 cm in the Tarawera River. The estimated oxygen penetration depths were used to calculate benthic dispersion coefficients. These values ranged from 0.38-16.30 x 10⁻³ cm⁻² s⁻¹ which are several orders of magnitude higher than previously reported maxima. Such high values imply that a high rate of sediment-water exchange was sustained by turbulent mass transfer processes rather than molecular diffusion. Benthic biomass values by ATP extraction ranged from 0.67-4.95 μg ATP cm⁻³, with higher maximum values for the rivers studied than have been reported for sediments in other aquatic systems, and suggesting greater levels of metabolic ac…
author: Hickey, Christopher W.
license: https://researchcommons.waikato.ac.nz/bitstreams/beb143df-0407-4e94-be2d-b5f2072d8c33/download
date published: 1985
date modified: 2026-07-24T05:57:24Z
provider: University Waikato
publisher: Networked Digital Library of Theses and Dissertations
type: WebPage
source organization: The University of Waikato