3.1. The pattern of decay of the model soft-bodied organismArtemia salina in different sediments.
In our burial experiments, we used five different model sediments with various mineral and chemical compositions: chamosite, clinochlore, kaolinite, montmorillonite, and artificial silica (Table 2, see Materials and Methods). The experimental aqueous sediments with the buried nauplii of A. salina (see Methods) quickly (within the first week) changed their coloration (Figure 1). In the kaolinite, clinochlore, and chamosite, prominent light-colored spots formed around every carcass (Figure 1 C, F, I). In the silica, dead nauplii clustered in a subsurface layer which remained light-colored on the otherwise darkened background (Figure 1 K, L). In the montmorillonite, a bright red layer formed by the 5th month and stayed well visible to the end of the experiment (5 years, Figure 1 M). The patterns in the sediment controls (prepared by the same protocol but without any buriedArtemia ) differed dramatically: their coloration remained unchanged (Fig 1 A, D, G, J). This difference implies some active chemical, organic-mineral processes within the sediments that contain decaying soft-bodied organisms.