A Headspace Technique for Oxygen Measurements in Deep-Sea Sediment Cores

A headspace analysis technique is described for shipboard measurement of $O_2$ in deep-sea sediments. A subsample of a core is equilibrated with helium in a closed vial and a gas sample is taken for gas chromatographic determination of $O_2$. Air contamination, bubble formation, and microbial activity are minimized by careful design of procedures, rapid handling, and storage in the cold. The results are in agreement with a parallel series of $O_2$ measurements in porewaters collected by in situ filtration at the sea bottom. The technique is particularly useful in diagenetic studies of the sediments as oxygen can be determined in samples from the same core used for determination of all other diagenetically active chemical species.