Scoping Out II

Scoping Out II

March 21 and 28, 2014

Back on March 21, after the frequency of warm days began increasing, I decided to take some samples from Cottonwood Pond.  I wanted to see if anything was stirring yet, and I figured that this early start would serve as a sort of “baseline” as we moved further into spring, when much more would be quivering into action.

I took samples of water and mud as well as a twig and dead leaf that had been below water since last fall.  Besides an occasional Water Strider on the pond's surface, there had not been any visible stirring, to the naked eye.  Over the preceding winter there had been a great influx of fresh water from heavy rains and much snow melt.

As it happened, I did not have time to look at the samples until seven days later, on March 28, decreasing the possibility of seeing anything still alive.

I looked at samples under the stereoscope first.  The first water sample showed lots of particles, some long strands that could have been algae, and some obvious plant debris.  Some particles seemed to be what was left of very tiny aquatic animals.  I suspected that these were Bosmina which had spent last summer feeding on algae and one-cellular organisms (after grabbing them with their first pair of legs, then filtering them), spinning around in the water, and reproducing rapidly and prodigiously.  These particles were probably Bosmina that were not consumed by predators, but that simply came to the end of their short lives and disintegrated.  Various, bacteria, perhaps, were gradually breaking down the remains.

That's my theory, anyway.

There were also a number of objects, dark and the size of pinpoints, in rapid motion. I hoped I would be able to see them more clearly under higher magnification.

The second water sample yielded “something that might be a worm”, according to my lab notes.

I put a mud sample under the stereoscope and added a little distilled water to thin it out, then gently pushed it around with the point of a probe while looking through the lens.  There were tiny grains of sediment, some like silica.  I presumed these to be grains of fine sand among the clay particles.  There were also long, skinny, clear strands that appeared to have segments.

The most interesting thing in the mud sample was a critter.  It was a light peach color and appeared to be moving! It had dark eye spots and two filaments extending down from the head that seemed to be antennae. It also appeared to have six legs, like an insect.  I could only discern two body parts (insects have three), but maybe this was an undeveloped stage of an insect.

It was very tiny.  I nudged it very gently with the tip of the probe (which looked giant next to this creature) so that I was able to see it from other angles.  It was moving! In particular, its first pair of legs seemed to be very busy near its mouth.

Curious.

It moved in another way: it would lift its head and crane it back toward the lens, similar to the “Cobra Pose” in yoga.

Curious.

I let these images and observations roll around in my head for some days, then settle into the back of my head and rest there awhile.  Eventually, a thought emerged – could this have been Collembola (Springtail)? Could it be an immature form of the Springtail, or an unusual Collembola species, one that lives underwater in the mud? Many species of Springtails live in damp leaf litter on the forest floor.  Last year, I found a white one on the surface of Cottonwood Pond, hopping around on the surface film with the aid of its spring-like device under the body (see the Cottonwood Pond entry called “Color and Rain”).

Sometime after this thought, I was reading a chapter of a book called The Forest Unseen: A Year's Watch in Nature, by David George Haskell (a book I highly recommend).  In that particular chapter, he was talking about peering into the leaf litter and finding Springtails, observing these tiny creatures with a hand lens.  He found an unusual kind with “six stumpy legs protruding from the barrel-like body”.  Also, these particular Springtails, he reported, were “doughy white and wet, without eyes”.  These were members of a family of Collembola called Onychiurid.  Haskell stated that “their lack of pigment and blindness reflects the subterranean specialization of the group; unlike other springtails, these animals never wander above ground. The onychiurids have lost the jumping organ, the furca, that gives springtails their name.”  Another interesting fact he gave was that, unlike other Collembola who escape by springing away, these “deter predators by releasing noxious chemicals from glands on their skin”.

Could it be that the Collembola (if that's what it was) I found in the mud sample was a species in this group that is adapted to underwater mud? The “Cobra Pose” fits the nature of a Springtail.

There were two main differences though, between my possible Collembola and the oychiurids: the one in my sample appeared to have eyes, and it had some color, albeit a very pale color.  I could not see if it had the jumping mechanism, and, of course, did not know if it was toxic (I'm too large a “predator” to notice).

Ah, mysteries – curiouser and curiouser.

I put the twig under the stereoscope.  The outside of it was covered in a network of silky strands, some appearing broken, and some stretching across gaps like spider silk. A piece of old leaf from under water also had strands, but they appeared to be “growing” from a shiny surface.

I decided to put the leaf strands under the other microscope, using an indented slide without a slip cover. First, I used the lowest power on my scope (10/0.25). They appeared clear, segmented, and pointed at the ends.  On one, there seemed to be the remains of something, perhaps a Collembola.  Some strands had gelatinous, circular things attached to them.

I looked at the end of one strand through a stronger lens (40/0.65).

There was a long, narrow space visible within walls, and roughly triangular chambers after that. 

A section of another showed a roundish, bumpy mass along the side...

...and I could see a division between long spaces. The space in this division was amber-colored.

At this point, I wondered if these were the hairs that grow along leaf veins.

I looked at a sample of mud under the same lens. Here I found what may have been the remains of a kind of creature I found alive in the other mud sample (the one that may have been a Springtail).  There seemed to be remains of the main body as well as a segmented leg.  I did not know if the leg had belonged to this particular main body part, or even to the same kind of animal.

Also, I saw those round things again that had been dashing about in a water sample. In this magnification, they looked like two hemispheres stuck together, with an obvious slit of space between them.

That was all I had time for, unfortunately.  If I had nothing else to do (and sometimes I wish I hadn't), I could spend many hours with the scopes, exploring more and more samples of water,mud and debris.  A whole new world opens up under the lenses.

As far as a “baseline”, what I found from late March were the remains of things that were likely alive last year that had sunk to the mud, landed on debris, or were drifting in the water that had been stirred up now then then by a fresh influx.  The thing that I did find alive seemed to be a mud-dweller, perhaps waiting to mature into a form that would leave the mud when things warmed up, or maybe something that just lives in the mud all the time.

My goal is to take and view samples at least once a month and to be able to spend ample time looking at them the same day that I gather them.  Through this, I can watch the progression of the tiniest aspects of Cottonwood Pond.