1.   Invitro, sulphate reducing bacteria compete with methanogenic bacteria for hydrogen when sulphate is present.

2.   These results further indicate that the formation of the siderite concretions is not associated with the activity of methanogenic bacteria.

3.   In vitro, sulphate reducing bacteria compete with methanogenic bacteria for hydrogen when sulphate is present.

4.   Breath methane was measured and viable counts and metabolic activities of methanogenic bacteria and sulphate reducing bacteria determined in faeces.

5.   Dietary sulphate may allow growth of sulphate reducing bacteria which inhibit the growth of methanogenic bacteria.

6.   Breath methane was monitored and metabolic activities of methanogenic bacteria and sulphate reducing bacteria studied in faecal samples.

7.   Viable counts of methanogenic bacteria were enumerated using the Hungate roll tube technique.