Tuesday, September 30, 2014

No end to mysteries

I do routine maintenance on the aquarium, daily, and half the time, it seems that I have to say, "What on earth is that?"

Last week I emptied the tank, washed the sand, and replaced everything. As usual, I kept out the dirty water I'd washed the sand with, and let it sit overnight, just in case any tiny snails were hidden in the gunk. Normally, the dirt settles, and the snails climb to the top, where I catch them and return them to the tank, then dump the goopy mess.

But this time, there was a white network of fibers just on top of the settled gunk, below the inch or two of clear water. I stirred the water again, and let it sit. Two hours later, there was the net again. Three times I stirred it; every time, white lines made a road map along the top two hours later.

Monday evening

I looked at the clumps under the microscope: all I could see were tiny, straight threads. Watching one for a while, I could see it grow, lengthening at both ends. When I stirred the mix, I could still see shreds of threads, unconnected. But two hours later, there was the network again.

Monday evening, overview. The bowl is 6 inches across. This is about a 3 inch section.

I was gone for a day, and came back Wednesday afternoon. Part of the bowl was covered with a papery coat; the rest was still clumps of threads, some still making a road map.

Wednesday afternoon

Zooming in, Wednesday afternoon.

The filled-in areas looked like papier-mache pulp; all short, white fibers, arranged every which way.

Thursday afternoon. The "roads" are gone, replaced by individual clumps.

I looked at several of these clean clumps under the microscope. There was nothing to see but the white fibers, still short and straight, sticking out in all directions.

Zooming in. Nothing but white fibers on the dark background.

Over the weekend, the threads covered the whole area, without any organization into clumps or roads. When I shook the bowl Sunday night and again this morning, they disappeared, and returned in a couple of hours to the final, uniform covering. No roads, no clumps.

I don't even know where to start to find out what this was.


  1. Urk! A marine slime mould? (Are there marine slime moulds?) Or just a mould?

  2. I've never heard of a marine slime mould, but it does look sort of like that.

  3. There are marine slime moulds (or to be more accurate, there are marine organisms that look slime mould-ish), but I don't know if that's what you look at.

    To be honest, the pattern you describe makes me wonder if you're looking at some sort of mineral precipitation, particularly the fact that the stuff disappears when you shake the bowl (dissolves?) only to reappear soon afterwards. Perhaps some sort of salt in the water is reacting with something on the bowl?

  4. *you're looking at*, sorry. Me speak England good.

  5. "More things in Heaven and Horatio..." - that is what makes life so interesting!!!

  6. Christopher, Thanks! I spent an hour looking at photos and articles about Labyrinthuleans after Snail's comment, without finding any hint of those network arrangements.

    But the mineral precipitation idea makes a lot of sense. I'll see what I can find along those lines. And I'll have to set up another batch of dirty tank water in the same bowl to see if the pattern repeats.

  7. it really does look like a hairy mold of some kind. If you mix the water and pull a drop and allow it to dry on a slide you might be able to define budding from the branches.

    if I remember you have a microscope.

  8. Totally fascinating. You're such a scientist. =)

  9. Interesting that it didn't form in the tank as well. - Margy


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