Some Components of Sediment Oxygen Demand in Lake Erie Sediments
Loading...
Date
1981
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
Ohio State University. Water Resources Center
Abstract
We have examined SOD of Lake Erie sediments with and without macrobenthic infauna, and with high and low macrobial activity, and have modeled the penetration of oxygen into sediments, since the depth of oxygen penetration is not easily measured. SOD of western and central basin sediments (95% silt clay, 3% organic carbon, 70-80% water content) ranges from 1.25-2.5 um 02/hr
in laboratory microcosms. When tubificid oligochaetes are added to laboratory
microcosms (30,000 m^-2 ), SOD rises to 1.5-3.5 um 02/hr. SOD is greater than
the simple sum of organism respiration plus sediment SOD. The extra enhanced demand is due to enhanced microbial activity, the transport of 02 to greater depths in the sediment, and to the transport by feeding of FeS to the sediment-water interface. Enhanced demand over sediment plus respiration values appear to be proportional to the number of oligochaetes present, which would implicate FeS transport as a major factor in enhanced demand. Thus, tubificids enhance the rate of organic decay not only through aiding the transport of dissolved
oxygen, but also by transporting reduced sulphur to be oxidized to SO4^2- at the sediment-water interface. Sediment sterilization techniques were not successful; these techniques probably result in the release of additional oxygen demanding substances as a result of sterilization. There is a pattern of decreasing SOD for a period of about 10-14 days after the start of an experiment
until an equilibrium SOD is reached. This is due to the liberation of bacterial nutrients when sediments are added to microcosms and mixed. Thus experiments done soon after introduction of sediments into an SOD apparatus are likely to be in error by as much as a factor of two.
Description
Research on which this report is based was financed in part by the U. S,
Department of Interior as authorized by the Water Resources and Development Act of 1978, (P. L. 95-467).
(print) 40 leaves : ill. ; 28 cm.
Item lacks publicaton date. Date supplied from WorldCat bibliographic record
(print) 40 leaves : ill. ; 28 cm.
Item lacks publicaton date. Date supplied from WorldCat bibliographic record