Stentor coeruleus under a cover slip

In my last water sample from the La Salle river I was lucky enough to capture a number of Stentor coeruleus. These large bluish-purple Stentors can be spectacular when observed under a stereoscope with a higher power but the detail doesn't show up till you get them under a coverslip. With careful observation you can see the moniliform macronucleus, the oral ciliature and membranelles, cortical rows and the contractile vacuole.

New water samples after a long winter...

The ice on the river had only recently broken up and plant growth has not yet been evident so I wasn't really anxious to get a water sample yet. At my wife's prodding I filled a couple of jars with river water and mud from the bottom and was I ever glad I did. Had a wonderful couple of hours at the microscope and saw a few specimens for the first time.

 

 

Possibly Genus Litonotus

Possibly Genus Pandorina

 

Stentor coeruleus

 

Genus Asterionella

Diatom

 

 

 

 

 

 

 

 

 

 

Synura

 

 

 

 

 

 

Phacus

 

 

 

Ciliate division, possibly from the genus Stylonychia

 I have witnessed this a number of time but have always lost the couple at the end when they seem to zoom off very quickly just as they divide. This time I seem to have caught them in the act of separating.

Isolating and selecting microscope specimens

Deliberately selecting specimens to view under a microscope has always been a challenge for me...but I'm getting better! I thought I'd share my methodology in the hope that someone else can benefit from my experience. But before I get to the basics of what I do it's important to share that reading about techniques will only get you so far, you have to practice to get better. In my experience, the more you practice, the better you get.

There are two methods I employ, one involves a stereoscope, the other a microscope. My favorite method employs the stereoscope, an LED goose neck lamp and a watch glass. I add 5 to 6 ml of water to my watch glass, apply some side lighting with the LED lamp and start hunting for specimens. My zoom stereoscope can employ powers ranging from 7X to 180X by using various accessory lenses but I generally work in the 14X to 90X range to isolate specimens. First, using a higher power I dial in to a critter that I want to examine with the microscope. possibly clean away debris with a needle, and suck up the specimen using a micro-pipette (20 to 40 ul) with a rubber bulb. This is then transferred to another area of the watch glass and viewed to confirm a successful transfer. If unsuccessful, repeat. When you have the specimen in a water drop, transfer it to a slide, put on a cover slip and start viewing under the microscope.

 

For those that don't own a stereoscope a similar technique can be employed using your microscope. In this case, a small volume of water, perhaps a couple of ml, is picked up with a dropper or micro-pipette and ejected along the length of a slide. Your specimen is then searched for under a low power, say 4X or 5X, and once found treated just like the critter in the previous paragraph.

Bonus tips: Cover slips float and specimens like to attach themselves to the bottom of them. I use the illustrated tweezers to drop them and pick them up.  

 

And stereoscopes can be as much fun to view protists as microscopes are. 3D and really fun to watch once you become familiar with what you're looking at.

Euglenids exibiting metaboly and flagellum motility

Euglena

  One of the jars I had been sampling from all winter           became quite green. I took a fairly large sample from the mid jar water and included some bottom sediment and ran it through the centrifuge at 800 RPM for about ten minutes. Out of the resulting pellet came a significant number of algae, a large number of which were various species of euglenids.

 

 

 
 

Phacus

 

 

 

There are now reports of over 1500 species so identification for the layperson is almost impossible.

But I did find some interesting movement types of one particularly numerous species, probably from Family Peranemidae, showing both metaboly and flagellum motility.

 

 

 

Also an image of a similar group in darkfield.
 

 

 

 

 

 

Pass the Pollen, Honey

          

I watched a video about pollen extraction by Oliver of MicrobeHunter fame yesterday and thought it might be fun to duplicate what he did on his live-stream. He essentially put a small (2 ml) sample of honey with about 10 ml of water into a 15 ml vial and thoroughly mixed up the two into solution. Then about a 5 minute spin in a centrifuge at 4000 RPM, pour off the liquid and drop the pellet onto a slide with cover-slip. The result was a number of different pollen grains and at least one insect part, which according to Oliver, at one time belonged to a bee. All the pollen cells I found were in the range of 7 to 40 um long.

 

   

 

  

I also tried stacking a couple of the images with Picolay.

 

And here is the insect part, ostensibly from a bee. The piece is about 1/10 mm long.

                              

Spring, old specimen jars and new opportunities.

After a long winter of limited access to fresh specimens, my river is again open, at least near the banks. However, the winter was an enlightening season since it taught me much about protist cultures, how to maintain them and how to sample them.

It all started last fall when I filled a standard “fish bowl” with water, mud and a few plants taken from the small river I live on. I began with a relatively large collection of microscopic specimens, including some larger types like gammarus, copepods, ostracods, fairy shrimp and daphnia. The bowl was placed in an east facing windowsill where it received direct morning light. This little micro environment provided a large number of critters for observation but after some time the plants died and things slowed down. Luckily I had a 30 gallon tank that had gone wild and in cleaning it up I was able to add a large matt of algae to my bowl, again rejuvenating it.

The fish bowl on the extreme left was the container that started it all

It was at that point I started a jar collection, seeding them with soil, water and algae from the fish bowl. These jars were “fed” with dried oak leaves, dead grasses from under the snow, vegetable scraps and various grains, cereals or even garden dirt. Most of these jars developed in different ways and provided a source of interesting, but limited, species over the winter. Another jar collection was started in a north facing window with none getting direct light. I had noticed the jars on the sunny sill were getting quite warm on clear days.

My north facing jars

One jar in which I was doing a Walstad experiment developed an algae explosion that I used to feed several of the jars with larger inhabitants. What I found interesting was that some of my best microbe sources were the smallest containers I  used, old 35 mm film containers. I even had a population explosion of several ciliate species under a cover slip on a slide I was keeping in a “wet” container to watch the development of snail eggs. 

After providing a winter of enjoyment under the microscope the jars will soon be emptied back into the river, cleaned up and readied for some new, springtime populations.