Abstract
The Deep Biosphere is a major new area in Geosciences and the presence of possibly the largest prokaryotic biomass on Earth being in the deep subsurface is both astonishing and still controversial. This has fuelled wide interest and a string of papers in Nature and Science, as well as wide press and public interest. This project will investigate a new aspect of deep biosphere research by quantifying and investigating the role of prokaryotic spores, which could represent a very significant proportion of previously detected cells in deep sediments. As they do not show detectable metabolism, the presence of large number of spores could help to explain the paradox of large numbers of cells in the deep biosphere while only very little energy is available. Thus this research will have the same broad interest as previous Deep Biosphere studies.