Science Serving Maryland's Coasts

R/CBT-11

Microbial degradation of chlorinated hydrocarbons under alternating redox conditions in Chesapeake Bay sediments

Principal Investigator: 

Douglas G. Capone

Start/End Year: 

1991 to 1994

Institution: 

Chesapeake Biological Laboratory, University of Maryland Center for Environmental Science

Co-Principal investigator: 

Jay Gooch, Joel E. Baker, Chesapeake Biological Laboratory, University of Maryland Center for Environmental Science

Description: 

To examine the effect of altering redox conditions and length of exposure to halogenated organics on the capacity of the bacterial flora of surficial sediments to transform and degrade chlorinated hydrocarbons. For two sites in Chesapeake Bay which experience seasonal anoxia and have differing organic contaminant loads, samples will be collected before, during and after seasonal anoxia and examined for the chlorinated hydrocarbon concentration. The effect of anoxia in conditioning (through dechlorination) model chlorinated hydrocarbons for subsequent oxic catabolism will be determined in manipulative laboratory experiments of these sediments using a combination of 14C-tracer, GC/MS and HPLC. Sediments will also be returned to the laboratory for microcosm experiments. Microcosms will be dosed with specific compounds, held anoxic for periods comparable to the in situ duration of bottom water anoxia and then aerated. Rates of degradation will be determined on subsamples at various times during anoxia and after aeration.