Abstract:
Here, we report on the spatial and temporal variation in sulphate-reducing bacterial community structure
and activity in three hypersaline coastal pans. Community structure was determined using denaturing gradient
gel electrophoresis (DGGE). Cluster analysis of DGGE patterns indicated that similar microbial populations
were generally found in individual pans but varied from one pan to the other. Sulphate reducing bacteria
(SRB) were quantified by competitive polymerase chain reaction based on the amplification of the dsrAB
genes. Cell numbers and in situ sulphate reduction activities varied between seasons and pans but in general
showed low variation in depth. Sulphate reduction activity was not correlated with microbial population size
indicating that community composition is relevant for specific microbial processes. Principal component analysis
coupled with correlation analyses suggested that salinity, sulphate concentration, C/N ratio and pH were
the most important factors in explaining variations in SRB community composition. Most sequences derived
from DGGE amplicons belonged to members of the Desulfobacteraceae and Desulfohalobiaceae families.
