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I live in Austin Texas. My grass is in pretty bad shape but I have noticed small luminous spots on some areas after I step on them.

I'm guessing this will be seasonal so, for the record, this is during November and December that I've noticed it. It's been quite wet and about 40F to 60F at night. I've seen it a dozen times over the last several weeks. I've attempted to collect samples and when I bring it inside to study it, there is nothing there but grass and maybe some young root systems. I've googled and haven't seen anything like this discussed. Does anybody have an explanation?

I can see about 5 spots after trampling a few square feet of my grass. Using a DSLR and a time exposure, this is the best photo I've been able to get of one: enter image description here

On one attempt, I pinched the glowy part, held it in my hand, confirmed it was glowing, brought it inside, and this is what I had: enter image description here

Can anyone explain this? Is this significant? Or perhaps the right question is where should I go for a question like this?

PaulC
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  • Neat! How long does the glowing last? And can you not see the luminescence when under artificial lighting? – theforestecologist Jan 08 '16 at 03:53
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    I'd guess that you have some kind of glow worms/fire flies - when you walk across the grass you are disturbing them causing light to be emitted. It's going to need a much better photograph to capture the luminescence event (I appreciate that is very difficult!) to be answerable. – rg255 Jan 08 '16 at 07:49
  • It lasts for about 30 to 90 seconds. It's conceivable that I'm squishing something, like glow worms. Are glow worms tiny like a quarter of an inch? And would this be the right season, weather, and location for there to be several of them per square foot? And would their ..uhm.. juices glow when they get squished? Oh, and this is so faint that anything more than moonlight and you wouldn't see it. – PaulC Jan 08 '16 at 09:50
  • I know this is a late reply, but I observed the same phenomenon this morning. I live on 12 acres with horses. It is my ritual to jog with my horse in the morning early before I get started with my day. It was before sunrise and very dark (the moon wasn't out). I had a red-filter flash light so I could see what I was doing, but once I started my jog I turned it off. I saw a speck on the ground that I thought at first had to be the neighbor's security light shining through some trees. After I looked closer I was certain it was it's own light source, so maybe a firefly then? A firefly usually has – Justin R Nov 17 '18 at 12:22
  • first of all, this is not an answer to the question. This is also not a question on its own.Usually, I vote to remove these kind of answers but in your case, I will make an exception since its a well written anecdote and others get to know that this is not an uncommon occurrence. – The Last Word Nov 17 '18 at 18:24

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If it were fireflies or glow-worms, you would have seen them pretty quickly with your searching and collection of grass. I would guess that this is some kind of bioluminescence caused by bacteria or Dinoflagellate. I have seen this effect when walking on wet sand at the ocean. It is quite fascinating and fun to watch. According to wikipedia, bioluminescent bacteria and Dinoflagellate can exist in fresh water. The moisture in your yard might be enough to support their growth.

https://en.wikipedia.org/wiki/Bioluminescent_bacteria

https://en.wikipedia.org/wiki/Dinoflagellate :

The luminescence occurs as a brief (0.1 sec) blue flash (max 476 nm) when stimulated, usually by mechanical disturbance. Therefore, when mechanically stimulated—by boat, swimming, or waves, for example—a blue sparkling light can be seen emanating from the sea surface.[66]

Cara Wogsland
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