REDUCTION OF MARINE SEDIMENT OXYGEN-UPTAKE - PRETREATMENT FOR THE DETERMINATION OF INFAUNAL RESPIRATION RATES

Biological oxygen demand (BOD) in samples of sandy marine mud sediments from North Inlet, South Carolina, USA, was significantly reduced by irradiating sediment samples with 66 240 cGy of ionizing radiation from a cesium-137 gamma source. Chemical oxygen demand (COD) was significantly reduced by bubbling ambient air through the sediment for 6 to 10 h. Combined treatments lowered the sediment oxygen uptake to a level which was not statistically different (p < 0.0001) from 0.2 mu m filtered seawater. The described method is useful for sufficiently reducing sediment oxygen consumption (BOD and COD) to measure respiration of infaunal organisms, including ophiuroids, bivalves and polychaetes, in a more natural, buried setting.