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Carmichael’s Concise Review Coming Events


2019 ISPM 2019 – International Scanning


Probe Microscopy Conference May 26–29, 2019


Louvain-la-Neuve, Belgium http://uclouvain.be/en/research- institutes/libst/ispm-2019.html


Lehigh Microscopy School June 2–7, 2019


Bethlehem, PA www.lehigh.edu/microscopy


MAS Topical Conference: QMA 2019 June 24–27, 2019


Minneapolis, MN www.microbeamanalysis.eu/events/ event/58-mas-topical-conference-qma-2019


mmc2019: Microscience Microscopy Congress 2019 July 1–4, 2019


Manchester, UK www.mmc-series.org.uk


Gordon Research Conference - Tissue Microstructure Imaging July 7–12, 2019


South Hadley, MA www.grc.org/ tissue-microstructure-imagingconference/2019


NextTEM: Next-Generation Transmission Electron Microscopy Workshop August 4, 2019


Portland, OR www.microscopy.org/MandM/2019/program/ NexTEM_2019_Announcement.pdf


Microscopy & Microanalysis 2019 August 4–8, 2019


Portland, OR www.microscopy.org


2020 Microscopy & Microanalysis 2020 August 2–6, 2020


Milwaukee, WI www.microscopy.org


2021 Microscopy & Microanalysis 2021 August 1–5, 2021


Pittsburgh, PA www.microscopy.org


2022 Microscopy & Microanalysis 2022 July 31–August 4, 2022


Portland, OR www.microscopy.org


2023 Microscopy & Microanalysis 2023


July 24–28, 2023 Minneapolis, MN www.microscopy.org


2024


Microscopy & Microanalysis 2024 July 28–August 1, 2024


Cleveland, OH www.microscopy.org


More Meetings and Courses Check the complete calendar near the back of this magazine.


8 Until now the earliest evidence of moving life forms was from half a billion years


ago. In an intriguing new study by Abderrazak El Albani, Donald Canfield, and a large international scientific team, evidence is presented that could suggest moving organisms existed from a much earlier time [1]. Examining exquisitely preserved fossils from the Francevillian Basin in Gabon, Africa, El Albani et al. found string-shaped formations or structures up to 6 mm in diameter and extending up to 170 mm through the layers (Fig- ure). Tese fossils are thought to be 2.1 billion years old and were formed at that time in an oxygenated shallow-marine environment. Oxygen levels could have been high at that time and then became much lower, consistent with life forms at this time later dying out. El Albani et al. used scanning electron microscopy (SEM) in combination


with microtomographic, geochemical, and sedimentologic analyses. It is suggested that the structures underwent fossilization during early changes to sedimentary rock near the sediment-water interface. Morphological and 3D tomographic reconstructions suggest that the structures were produced by a multicellular or syncytial organism that was able to migrate laterally and vertically to reach food resources. El Albani et al. suggested that a possible modern analog could be something similar to colonial amoeba or slime molds, organisms that normally live separately. An interesting series


of studies were done using X- ray microcomputed tomog- raphy (micro-CT). Analysis of these images revealed the presence of string-shaped structures within the layers of the fossils. Some of these structures were close to layers of pyrite (iron sulfate, com- monly called fool’s gold) sug- gesting an association with organic-rich mats where mi- crobial sulfate reduction was enhanced. Tis and other features indicate compaction of soſt, fine-grained sediment around a relatively rigid ob- ject and show that the strings were in place and mineral- ized when the sediments were still compacting. Combined SEM back-


scattered electron imaging and energy-dispersive X-ray


Evidence of an Organism Moving 2.1 Billion Years Ago!


Stephen W. Carmichael Mayo Clinic, Rochester, MN 55905 carmichael.stephen@mayo.edu


Figure: Micro-CT-based reconstructions of string-shaped struc- tures from the Francevillian Series, Gabon. (top) Contorted strings; box denotes location of the cross section shown in bottom image; image width = 19 cm. (bottom) Virtual cross section of contorted strings; image width = 2 cm.


doi:10.1017/S1551929519000464 2019 May


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