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MICROBIOLOGY LABORATORY - 4 Back at Montana State University, Dr. Ward opened his teaching laboratory to us. He prepared the microbial mat samples we had collected for optical microscopy, and we saw what kinds of cells were in the mats. The colors on these images are not necessarily right, and the striping is from interference between the video
monitor and the digital camera and the overhead lights. |
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Zygogonium, a true green alga, from the TB View Spring microbial mat at Mammoth Hot Springs. These are eukaryote cells (with distinct nuclei), which are larger (5-20 micrometers) than most prokaryotic cells. Most bacteria and archaea are typically < 2 micrometers in diameter, but several types are larger. Many cyanobacteria ("blue-green algae") are larger, ~ 5 micrometers in diameter; Oscillatoria cells are ~15 micrometers across! |
Closeup of a single Zygogonium cell from a filament. We can see some of
its internal structure, like the spotty gray nucleus, the dark green chloroplasts
(where the chlorophyll is), and clear vacuoles filled with water.
Prokaryote cells do not have internal organs (like these) bounded by membranes.
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A Euglena wanders by! Euglena is a common mobile green alga, found in warm or cool water nearly everywhere. Like Zygogonium, it is a eukaryote. Chloroplasts are quite clear in closeup. Cloroplasts are similar to blue-green algae, and may be descendants of ancient photosynthetic algae that joined other cells to live together (symbiosis). |
Chromatium microbes from New Pit. This is a purple sulfur bacterium, which takes sulfur from the water and gains energy by reducing it to pure sulfur. Chromatium stores that waste inside its cells as 'pearls' which appear as bright circles in the cells. |
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