| Summary: | The aim of this study was to characterise waterlogged burial environments and to assess their potential for the in situ preservation of organic archaeological remains. To characterise these environments, environmental parameters were monitored through the soil profile and integrated with a study of the composition and activity of the microbial community. Soil cores were taken from two wetland sites located in the Humberhead Levels in Yorkshire: Hatfield Moor and Sutton Common. Cores were subsampled at depth intervals down to 100 cm depth, to allow for the examination of the vertical distributions of the variables being studied. Redox potential, water level variation and other physico-chemical parameters were measured down the soil profile. Bacterial abundance was determined by direct counts; activity was assayed by extracellular enzyme activity and leucine assimilation. The physiological profile of the microbial community was analysed using BIOLOG and the bacterial community structure was examined by PCR-DGGE. Redox potential readings were positive above the water table and negative below. The bacterial abundance and activity were greatest at the soil surface and, in general, decreased with depth. BIOLOG showed both depth variation and between site variation in microbial physiological profile. DGGE gels presented a different bacterial community structure with depth and between-sites. The results from monitoring of redox potential combined with water table height and determination of bacterial abundance and activity allowed the recognition of stratigraphic horizon where there was less potential for microbial degradation of organic archaeological artefacts. The information from BIOLOG and DGGE holds the potential for the development of a more subtle understanding of between-depth and between-site differences in the degradation process. The physico-chemical and the conventional and molecular microbiological results presented in this thesis have shown that microbial activity is implicated as a key factor that could lead to compromised in situ preservation conditions at the sites studied.
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