Morphological and chemical transformations of Microcoleus chthonoplastes during early diagenesis in hypersaline microbial mats

In microbial mats, the growth of constituent populations and sediment accretion are accompanied by burial of phototrophic organisms in sediment layers that are anoxic and not reached by light. Nevertheless, cyanobacterial remains are often preserved in the sedimentary column. In the virtual absence of bioturbation, the original stratigraphy remains conserved in the sedimentary record. Hence, sediments with microbial mats often comprise an actively growing mat on top of a laminated system corresponding to buried mats of previous years, as described for Solar Lake (Egypt) by Jørgensen et al (1988). We have studied similar laminated systems in solar saltern ponds that have been exploited for more than one century.