July Iridescence 2
August 17, 2015
While the rainbow colors of a more mature film of Leptothrix discophora, such as the one shown in last week’s post, may be more spectacular, I think there’s also something to say for the younger, more subtle, manifestations of this iron bacterium—especially when it’s housed in attractive shale formations. In the first photo, notice how the film seems to disappear when it’s in the shadow of the piece of shale. Sometimes the film becomes invisible in the shade, and sometimes the film can be seen only if a shadow falls across it. Whaaa??? I know the visibility of these films has something to do with the angle of the sun relative to the viewer’s eyes, but the phenomenon must be more complicated. Where is a physicist with special expertise in optics when you need one?
Romancing Reality 
You don’t need a physicist to appreciate the photos.
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August 17, 2015 at 6:47 AM
Yeah, but . . . (Thanks, Ken.)
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August 17, 2015 at 2:18 PM
Those are a couple of stunners!
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August 17, 2015 at 9:05 AM
Thank you, Leslie. I love how nature sometimes puts a leaf right where I want it.
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August 17, 2015 at 2:22 PM
I like the second one very much – what a great composition, and the iridescence adds a subtle finishing touch to the whole.
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August 23, 2015 at 9:35 PM
Thank you, Lynn. I’m sure I’d have taken this shot even if the film hadn’t formed there. The shapes of the shale always get to me.
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August 24, 2015 at 12:44 PM