November 17, 2019
This post might have included 34 photographs, but my better judgement intervened. I still want to show you a lot of what I saw on the annual fall downriver walk that my husband and I take. But I’ll break up the photos into three separate posts, one today, one tomorrow, and one Tuesday. This batch is all about the iridescent evidence I saw of the benign bacterium Leptothrix discophora. As you know if you’ve followed this blog for very long, the iron bacteria, of which L. discophora is one, are obsessions of mine (and the subject of my book They Breath Iron: Artistic and Scientific Encounters with an Ancient Life Form). So here we go again: 19 images of L. discophora films, preceded by an overall photograph of the river as it flows downstream.
12 The orange material you see on the ground beneath the water in this photograph and others is iron oxide, which L.discophora precipitates out of the water.
14 This photograph and the one following show L. discophora‘s film on top of a pudding-like substance that is probably the product of another iron bacterium called Leptothrix ochracea.
16 Notice the iridescence on the leaf- and algae-covered shale in the middle of the photograph. It indicates that the film-covered water recently receded from this area. Click on the photograph to see it larger.
19 This is a crop of the previous photo.
20 And this is a tighter crop. Click on the photograph to see even more detail.
August 4, 2019
Two years ago, during a visit to my friend’s farmstead in southwestern Pennsylvania, we took a short trip to the Ohiopyle State Park, where the Youghiogheny River leaps over rocks, forming the Ohiopyle Falls. Here’s some context, photographed in 2017. The river was just as exciting last month, when I took myriad pictures of its rushing water. I’ve winnowed them down for you. And as thrilling as the river is, so—in a far quieter way—are the still pools of water captured by depressions in the rock banks. My personal pleasure was finding Leptothrix discophora on the foot trail.
July 21, 2019
A week ago Sunday David and I walked downriver along the Vermilion. We’d had very little rain in Oberlin for maybe two weeks and expected the river to be low. We had forgotten that, even though the locations are only eight miles apart, weather at Schoepfle Garden—where we approach the river—and weather in Oberlin don’t always match. Alas, they must have had rain we didn’t. The river was too high, too fast, too wide, and the bedrock shale probably too slippery to walk across. I prefer the other side because it is where I always find lovely outbreaks of Leptothrix discophora films as well as interesting shale formations. On the less-interesting side we saw a little film, but nothing spectacular. Casting about for something that would warrant the rather tortuous trek along the river, I became fascinated by the shale at my feet where we usually cross over. Even there, the rock fractures along lines that look human made. I’d love to know why it does that.
August 11, 2018
Here you can see the Youghiogheny River in the distance, muddy from recent rains.
August 9, 2018
You may remember, from reading this blog, that my friend’s farm in southern Pennsylvania is near the Ohiopyle Falls on the Youghiogheny River. This year the adventure leaving from the farmhouse was to a tributary of the Youghiogheny called Cucumber Run, which turns into the Cucumber Falls on its way to the big river.
August 1, 2018
July 30, 2018
As promised, here come the photos of the Leptothrix discophora biofilms I saw along the Vermilion River July 14. Those of you new to this blog may find a brief introduction to what you see in this photograph useful. Those wanting to know more may care to explore some links.
July 29, 2018
Two weeks ago I made my way to the Vermilion River, something I do less often than I used to now that we are living back in town. The river still charms me, I’m happy to say, and I was in special good luck July 14 because the river’s water level was low and its banks embellished with iridescent patches of Leptothrix discophora. When the water is low, I get to wade across to the other side, where I usually can find more colonies of my favorite bacterium (photos to come). The wade itself is a treat, though, and I love seeing the ripples filled with sunshine at my feet.
June 5, 2018
June 4, 2018
June 2, 2018
April 11, 2018
Walking along the opposite bank, eyes mostly on the ground in front of me, I wasn’t expecting this.
April 10, 2018
November 12, 2017
November 11, 2017
November 16, 2016
November 13, 2016
November 12, 2016
Sometimes a shadow reveals a less-visible Leptothrix discophora film. Someone explained to me why this happens, but I’m afraid I didn’t quite get it. Perhaps one of you knows and can explain it again?
November 11, 2016
I found some of what I had come looking for last month when I waded across the river. The first image is the way I saw the patch of Leptothrix discophora film as I approached. It was surprisingly large for such a young film. Young films look blue or silver or silver blue. The prismatic colors arise when the film thickens as a result of more of its being produced by the Leptothrix discophora bacteria or when the film is broken and pieces of it slide over and under other pieces. The second image is the same patch of film seen from the opposite side. You can appreciate the importance of the angle of the sun relative to the viewer in how the film appears.
November 9, 2016
November 8, 2016
November 7, 2016
November 3, 2016
November 2, 2016