Fresh discoveries by Edinburgh scientists could one day help inform the search for life on other worlds.
Researchers have shed new light on how bacteria influence the formation of minerals - and help determine their shape.
Their discoveries could help analyse minerals found in strange environments - such as other planets - and identify whether bacteria, which is a form of life, were present at the time of mineral formation.
The shape of a mineral can tell us where life might once have existed.
Minerals can be formed from waste products excreted by bacteria, but until now it was not clear whether bacteria could control the shape of the mineral deposits formed.
Researchers from the University examined the role played by bacteria in forming a mineral recovered from a river in Sardinia.
Using high magnification techniques, they were able to show that the mineral formed in tiny spheres on the surfaces of bacterial cells.
The bacteria trigger formation of the mineral in this shape because spaces between the spheres enable the bacteria to continue to absorb nutrients from the water.
Researchers say the presence of life on early earth and other planets may be deduced from examining the shape of minerals formed in this way.
The study, published in the Royal Society journal Interface, was supported by the Natural Environment Research Council.
For a microbe cell, controlling the shape of the mineral that grows around it is very important for its survival.