Accession Number : AD0726712

Title :   Investigation of Gas in Bottom Sediments.

Descriptive Note : Final rept. 1 Jan-31 Dec 69,

Corporate Author : TEXAS UNIV AUSTIN APPLIED RESEARCH LABS

Personal Author(s) : Anderson,Aubrey L. ; Harwood,Roderick J. ; Lovelace,Robert T.

Report Date : 07 JUN 1971

Pagination or Media Count : 40

Abstract : The occurrence of gas bubbles in sediments has been noted in several contexts in the past, particularly in the field of acoustics, where bubbles cause aberrations in the predicted behavior of sound waves. The presence of bubbles in sediments can be predicted from a theoretical model of the bottom sediment chemical system. The model developed in this investigation suggests that bubbles will form in any sediment that contains organic material, as a result of anaerobic bacterial activity. Thus, most naturally occurring sediments are likely to contain bubbles. Several steps have been made toward testing the model quantitatively, including the development of methods for collecting and analyzing uncontaminated samples of free and dissolved gas. Preliminary results from tests of these methods in general confirm the model's predictions of gas bubble occurrence. Measurements of acoustical attenuation (frequency range 40 to 80 kHz) in gas-bearing sediments ranged from 7 to 30 dB/ft. (Author)

Descriptors :   (*OCEAN BOTTOM, SEDIMENTATION), (*SEDIMENTATION, GASES), (*UNDERWATER SOUND, ATTENUATION), BUBBLES, SAMPLING, ORGANIC MATERIALS, BACTERIA, MATHEMATICAL MODELS, REVERBERATION, SOUND TRANSMISSION

Subject Categories : Physical and Dynamic Oceanography
      Acoustics

Distribution Statement : APPROVED FOR PUBLIC RELEASE