Cast of Critters

One essential attribute of Hidden Ecologies is “community“. In our exploration of Hidden Ecologies, we sometimes talk about human communities, or plant communities, or animal communities, or Micro-communities. Micro-communities are composed of and dominated by microorganisms, but they share many properties with the other communities. Each community has a story, defined by “Who”, “What”, “When”, and “Where”. Like all stories, these values change with time.
As spectators viewing these Hidden Ecologies, we can think of each community story as a “play”. That is why we used the term “Cast of Critters“. Some critter actors in the cast have starring roles. These are the critters that define the community. Others have walk-on parts. Sometimes the play has a brief run, sometimes a long run. Increasingly, we are coming to understand that many of these community plays return year-after-year for a limited engagement, defined, not by the audience, but by climate.

The page “Cast of Critters” will be used to identify these players. Click-on the Cyanobacterial Mat picture, or any other picture, to view our Cast and the plays they act in.

Cyanobacteria used to be called “blue-green algae,” but they are actually large photosynthetic bacteria. Here, Cyanobacterial filaments of the genus Oscillatoria form a Cyanobacterial Mat in the salt marsh at Heron’s Head Park, San Francisco.

Cyanobacteria from Heron's Head Sample Site mat.

Diatoms Diatoms are algae in a glass box. They appeared on Earth at about the same time as Mammals and flowering plants, so they are newcomers compared to Cyanobacteria. Each Diatom is an individual algal cell inclosed in a pair of silica shells called “tests”, or “valves”.

Diatom - this diatom is common in salt marshes and salt flats.

Sulfide Oxidizing Bacteria Salt marsh areas that smell of “rotton egg” because of hydrogen sulfide production are likely to be “home” to one or both of the Gamma Proteobacteria Beggiatoa and Chromatium. Here both are captured in one photomicrograph: The giant filament is probably Beggiatoa sp. and the smaller, but still giant rod sticking up near its lower end is probably Chromatium sp.

Beggiatoa and Chromatium from HH09

Spirochetes Although many San Francisco Bay salt marsh micro-community critters appear strange, the most strange are the Spirochetes [properly, Spirochaetae]. Long, skinny disjointed rods, their “jittery” movement is comic. Normal bacteria have a “length” and a “width”… Spirochetes also have a “wavelength” and an “amplitude”…! Making still photomicrographs of Spirochetes is somewhat like making a group photo of kittens. Here I managed to capture three Spirochetes dancing around a Cyanobacterial filament [just barely shown at the top].

Spirochetes dancing - reduced to 1300W

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