Extant life detection using label-free video microscopy in analog aquatic environments
Fig 6
Biosignatures in the Salton Sea hot spring.
(A-C) Amplitude reconstructions of large microbes. (A) Large microbe with dark absorption characteristic of chlorophyll. (B) Elongated filaments without chlorophyll. (C) Arrangement of several filaments with a cloud of putative cells/organics. (D-F) HELM motion history images (MHI) with color-coding indicating time lapse of selected areas at different temperatures. (D) At 25ºC, a single motile small microbe is observed making a complex trajectory in the imaging volume over a 675 frame (45 s) recording period. (E) At least 3 highly motile small microbes are seen in 35 s at 30ºC. (F) At 42ºC, the large microbes are highly active, though moving slowly as this 45 s recording period shows (the upper part of this panel corresponds to Panel C). (G, H) Chemotaxis and possible predation. (G) A needle filled with serine at the beginning of the recording. (H) Panel G after 60 min. Blue is a maximum projection of the frame-to-frame changes over the recording period. The arrow indicates a motile large microbe possibly preying on the small microbial cloud.