We are looking at some fossil samples on SEM-EDS and have located several different species of mucroorganisms. Some are rich in C, but in some I also find Fe, Ti, Si, Al, Ca, Mo etc. We were wondering if you could help us by telling us what kind of chemical elements we should be expecting to find on chemiolithotroph, biomineralising and other microorganisms found on stone. The fossil we are looking at is a silicified tree from Thailand found in ancient river sediments. Any help and relevant papers would be more than useful. Thank you.
Are you claiming fossilized microorganisms? If so, how did you determine species? In any case, I advise caution in interpretation. NASA observations of meteorites interpreted as showing life forms were subsequently rejected by most scientists. Think yo should define the criteria by which you'd claim fossilized microorganisms before examination.
Dear Phil, sorry for the delay in responding. Thank you for the concerns you expressed. As a matter of fact, we are talking about both contemporary as well as fossil ones. We've only found one fossilised microorganism so far, and lots of different types of contemporary one). We are pretty sure we are indeed talking about microorganisms. Their features are very distinct.
The first findings of our research were presented in the 4th ARC_RNT Archaeological Research & New Technologies Symposium (1-3 October 2014) in Kalamata, Greece. ; Kyriazi E., Zacharias N., Palamara E., Boonchai N. “Preliminary SEM-EDS Observations on Microorganisms present on Petrified Wood Samples from the possibly World’s Longest Fossil Tree”
However we still have a long way to go and any kind of help is highly appreciated.
Thank you Phil for this interesting paper.
Most of the microorganisms detected are living ones (or at least used to be until put in the SEM-EDS and started "bombarding" them!) . We cannot proceed to any assumptions about biological classification, as none in our team is a microbiologist. We have detected more than a dozen of formations that look like contemporary microorganisations that have the appearance of bacteria, fungi and algae, and we think we may also have some amoebas.The formations detected are of various sizes and shapes and with different chemical compositions.
The preprints with the abstracts of the presentations of the 4th ARCH_RNT have been published. The following 2 paragraphs include copy-pasted information from the submitted abstract and from the texts in the presentation.
Morphologically, they can be grouped into longitudinal, branched, sheet and spherical formations. Some are found as individual appearances and others form colonies. Their location and agility also vary: some seem to be attached on amorphous fossil surface, certain types are attached on silica crystals, while others seem to pertain the ability to move on the fossil surfaces either by rolling, or through the use of thin "strings", covering long distances in relation to their size. In some cases, trace marks were observed, while needle-form cavities were also observed. Qualitative analysis indicates that chemically, the types of microorganisms may be grouped into carbon-rich, silicon-rich and iron-rich formations
Limitations using SEM-EDS are that this method is unable to detect chemical elements lighter than Na, therefore it cannot be trusted for N, H detection; it cannot be trusted for C detection; there are high limits of detection; it is a semi-quantitative analysis and most taxonomic errors are due to visual observations. However, using SEM-EDS has its advantages as it was possible to study surface structures
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