The sediments of Morecambe Bay contain large numbers of salinity-tolerant, nitrogen-fixing Enterobacteriaceae (NFEs) mainly Klebsiella pneumoniae ) which appear to be derived from sewage. Sewage effluents, regardless as to whether they have received primary or secondary treatment, contain huge numbers of NFEs with salinity-tolerant and freshwater strains present in roughly equal quantities. The bacteria are discharged into the rivers and estuaries and carried out to sea. Once in the sea the salinity-tolerant strains retain their viability better than the freshwater strains so that the incoming tide, which doses the sediments, contains mainly salinity-tolerant NFEs. It is probable that similar processes occur all round the U.K. coast, as inshore coastal... |