Low-molecular-weight organic molecules such as methane and carbon 

 dioxide are produced during the microbiological decomposition of 

 organic matter, but few measurements of these gases have been made 

 in the sedimentary column. Their presence in the overlying waters 

 could affect life processes in them. An inventory of such gases and 

 flux calculations should be made, for in addition to contributing to the 

 properties of the overlying waters as mentioned above, it is postulated 

 that layers of gases (possibly as clathrates) are responsible for certain 

 strong acoustic reflectors observed in sediments. 



The recent development of in situ interstitial water samplers allows 

 for measurements of these gases dissolved in the interstitial waters in 

 the top of the sedimentary column, and makes possible the calculation 

 of fluxes. The methods for the analysis of these gases by mass spectros- 

 copy and by gas chromatography are well developed. However, sampling 

 devices for deeper portions of the sedimentary column still need to be 

 developed. 



43 



