Hello from Oregon

What is your microscopy history? What are your interests? What equipment do you use?
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gastrotrichman
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Location: Oregon, USA

Hello from Oregon

#1 Post by gastrotrichman » Mon Nov 12, 2018 4:57 pm

I am a 73-year-old man with a serious interest in freshwater gastrotrichs (microscopic worm-like metazoans). I use primarily a Nikon Microphot with DIC and a tethered PaxCam 5+ digital camera, and a Wild M8 stereo microscope. I sometimes use a Leitz Orthoplan with DIC and a tethered PaxCam 2+ digital camera, and a Bausch & Lomb MicroZoom stereo microscope. I have BA and MS degrees in biology. I worked as a biologist early on, but eventually pursued a career as a lawyer. I returned to my biological roots when I retired from law about a decade ago.

Any other freshwater meiofauna students out there?
gastrotrichman

Nikon Microphot
Leitz Orthoplan
Wild M8
Bausch & Lomb MicroZoom

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75RR
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Re: Hello from Oregon

#2 Post by 75RR » Mon Nov 12, 2018 8:05 pm

You have some very nice equipment there!

Agree gastrotrichs are pretty cool. You most probably have this key then, but just in case:

viewtopic.php?f=15&t=1320
Zeiss Standard WL (somewhat fashion challenged) & Wild M8
Olympus E-P2 (Micro Four Thirds Camera)

MicroBob
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Re: Hello from Oregon

#3 Post by MicroBob » Mon Nov 12, 2018 8:24 pm

Welcome to the forum!
It would be nice to see more from your meiofauna work, how you collect, prepare, and what you find.
I haven't had a look at the meiofauna, but I spent some time collecting information on it. A while ago I was offered a lecture on this topic by a professor who has worked a lot on the topic, but for our group meetings I always need a practical part too. So I will dive into this topic sooner or later and it would be nice if you could write a bit about how to get a good start.

Bob

gastrotrichman
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Re: Hello from Oregon

#4 Post by gastrotrichman » Mon Nov 12, 2018 10:42 pm

Thanks for the attachment. It is from the third edition of Thorp and Covich, which I don't happen to have (I have the first, second, and fourth editions). The key is to the freshwater genera, which are "relatively" easy to identify. The fourth edition is divided into two volumes, with biology in volume I (2015) and keys in volume II (2016). The 2016 key to gastrotrichs extends down to species reported from North America. Species identifications can be challenging, particularly for the large genus Chaetonotus. The inventory of North American species is far behind that of European species, so the volume II key should be used with caution … many North American species presumably remain to be discovered and described. DIC really helps with morphological identifications.

gastrotrichman
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Re: Hello from Oregon

#5 Post by gastrotrichman » Mon Nov 12, 2018 11:17 pm

Bob --

Sorry, I'm learning how to use this site. I thought I was responding to a particular person, but guess I was responding to the topic.

Regarding methods, I recommend checking the gastrotrich section in Thorp and Covich (any edition, including the one 75RR posted in this string), which has a general description of the methods most seem to use. Each worker seems to have his or her favorite modifications. The goal is to get an undamaged specimen slightly compressed under the coverslip with either the dorsal side up or the ventral side up. DIC is very helpful, and often allows one to see the uppermost side, but also to see through the specimen to the opposite side. Measurements are essential, so a camera and measurement software are desirable, although there is nothing wrong with a calibrated ocular reticle.
gastrotrichman

Nikon Microphot
Leitz Orthoplan
Wild M8
Bausch & Lomb MicroZoom

charlie g
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Re: Hello from Oregon

#6 Post by charlie g » Wed Nov 14, 2018 8:33 pm

Welcome 'gastrotrich man', thanks for your intro! I have tons to ask..but as a freshwater meiofauna/protist microscopy amateur myself..I'm eager for your thoughts:

1) Do you serendipitously encounter varied Genus/species of gastrotrichs...or do you have predictable locals to collect from to encounter your variety of gastrotrichs? I have encountered perhaps five species of these elongated 'porkypines' ( vertebrate conceit...whoops).

2) Do you go to any particular current listserves of meiofauna biologists to opine your ID's with images included..or do you mostly yourself posit an ID and have your sources to bolster your opinion?

3) I fancy my next upgrade will be a DIC system, I'm curious about your stand. Do you have the DIC sequence of objectives on your nosepiece which you are quite satisfied with...or do you have an eye out to aquire a specific DIC objective for your stand?

4) Is the water table under your coverslip a fleeting moment prior to specimen squash...or does your DIC protocol permit a water film thickness tolerable for your live gastrotrichs?

Thanks for your intro, again welcome to a terrific forum. Charlie Guevara finger lakes/US

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RobBerdan
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Re: Hello from Oregon

#7 Post by RobBerdan » Sun Nov 25, 2018 3:50 am

Welcome from Oregon - I think you will find lots of microscopists interested in fresh water meiofauna - I love to photograph ciliates, rotifers, diatoms, desmids, cladocera, hydra, Gastrotrichs etc. I am semi-retired but doing as much photomicrography as possible. Have a few pictures posted on this forum and also write lots of photo-articles on my web site about nature and photomicrography. If you get a chance hope you wild drop by my site to see some pictures. Some articles are by guests.
https://www.canadiannaturephotographer.com

I even have an article and pictures of Gastrotrichs:
https://www.canadiannaturephotographer. ... richs.html

I purchased a new Zeiss Axioscope with DIC last year, and it wasn't cheap. Best price I could find for a used one was $10,000 US so thought what the heck- only live once, sold a bunch of my stuff and purchased the Zeiss Axioscope A1. I love it, but I will be paying for it for a few years I think, but I always wanted to own a DIC microscope - it has also has phase contrast. I would also like to own a scanning electron microscope, but don't see that happening unless I win the lottery.

I am hoping to promote microscopy more in Alberta, I am located not too far from you as I live in Calgary.

Welcome hope you find something of interest here and make new friends.

PNWmossnerd
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Location: Corvallis, Oregon

Re: Hello from Oregon

#8 Post by PNWmossnerd » Sun Nov 25, 2018 4:27 am

Hello from Corvallis!

gastrotrichman
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Location: Oregon, USA

Re: Hello from Oregon

#9 Post by gastrotrichman » Fri Nov 30, 2018 5:45 am

To: RobBerdan, Charlie Guevara, PNWmossnerd

From: Jim Kirk, aka gastrotrichman


RobBerdan

Thanks for the links. I looked at your website and your gastrotrich piece. Very nice images. You could easily capture sets of images that would allow you to identify gastrotrichs to species.

I’m not familiar with the Axioscope A1. Given the price, I’m guessing it is an “infinity tube length” scope. But it does make nice images.



Charlie –

I remember you from another microscope forum about a decade ago. Nice to meet again. I’ve pasted your points below with some thoughts.

1) Do you serendipitously encounter varied Genus/species of gastrotrichs...or do you have predictable locals to collect from to encounter your variety of gastrotrichs? I have encountered perhaps five species of these elongated 'porkypines' ( vertebrate conceit...whoops).

I’ve been focused on gastrotrichs for just over a decade … basically, since retiring. Early encounters were somewhat serendipitous, but gastrotrichs are so widespread that diligent searching will reveal them in almost any aquatic environment. In the last few years I’ve focused almost exclusively on gastrotrichs in moving water; seeps, streams, small rivers. Gastrotrich species diversity and population density seem to be lower in moving water habitats, but those habitats have been less studied than standing water habitats, and therefore invite attention.

2) Do you go to any particular current listserves of meiofauna biologists to opine your ID's with images included..or do you mostly yourself posit an ID and have your sources to bolster your opinion?

I rely primarily on the scientific literature for identifications. I’ve collected much of the world literature on freshwater gastrotrichs. Identifications of species are often challenging, particularly in the large genus Chaetonotus. Molecular methods are frequently used by modern workers, but there are so many descriptions that predate molecular methods that morphological identifications are still necessary (and of course desirable for those of us addicted to light microscopy).

3) I fancy my next upgrade will be a DIC system, I'm curious about your stand. Do you have the DIC sequence of objectives on your nosepiece which you are quite satisfied with...or do you have an eye out to aquire a specific DIC objective for your stand?

I have two DIC scopes. I first bought a Leitz Orthoplan with “Interf.-Kontrast S.” As I recall, the oil top lens gives the DIC condenser a numeric aperture of 1.3. The DIC objectives are all Leitz (170mm tube length) and include a 25x 0.50, a 40x 0.65, and a 100x 1.30 … all cemented in what is presumably their original factory position in the nosepiece so that the objective prism has the appropriate orientation relative to the condenser prism. My other DIC scope is a Nikon Microphot. The DIC condenser has a top lens that yields a numeric aperture of 1.4. Since the Nikon DIC system does not have a prism associated with each objective, it is possible to use virtually any 160mm tube length objective of the appropriate magnification. My Microphot DIC objectives are all Nikon and include a 20x 0.75, 40x oil 1.0, 60x oil 1.4, and 100x oil 1.4. None are branded as DIC objectives, but I’ve yet to see a strain-related problem with the images they produce. So far the Microphot produces better DIC images than the Orthoplan, which may be due to the superior (i.e., larger numeric aperture) Nikon objectives, operator (me) error with the Orthoplan, or a combination of both. Note that I have not seen a Labophot-Optiphot-Microphot DIC condenser with an oil top lens (oil top lenses are available for later Nikon DIC condensers), so immersion oil incursion into the condenser lens assembly is a risk. However, “oiling the condenser” is essential for better images.


4) Is the water table under your coverslip a fleeting moment prior to specimen squash...or does your DIC protocol permit a water film thickness tolerable for your live gastrotrichs?

I have a “typical” protocol for examining gastrotrichs for identification. I put a small bead of petroleum jelly on three edges of a 22 x 22mm No. 1 or 1.5 coverslip, put a very small drop of 1 percent magnesium chloride in the center of the coverslip, transfer a live gastrotrich to the drop with an Irwin loop, and carefully set the coverslip, petroleum jelly beads down, on a clean slide. The magnesium chloride anesthetizes most gastrotrichs; the concentration sometimes needs to be reduced to keep some gastrotrichs from rolling into a tight ball. Once the gastrotrich has stopped swimming, I carefully press down on the coverslip to slightly compress the specimen. Too much compression will cause the specimen to burst. Too little compression will yield images that may be difficult to use for identification. If you want to observe the gastrotrich alive, substitute water in place of the magnesium chloride, limit compression, and be patient. The reason for a very small drop is to keep the gastrotrich near the center of the coverslip and away from the edges. Toward the end of a viewing session, I sometimes run a small amount of dilute aceto-orcein under the open edge of the coverslip to bring out small scales that may not be visible otherwise, even with DIC. Every gastrotrich worker seems to have his or her own protocol. Permanent mounts of gastrotrichs are reputed to degrade over time, so that essential morphological features are lost … consequently, temporary mounts documented with good photomicrographs and line drawings are typical for gastrotrich descriptions.



PNWmossnerd

Howdy. I toyed with mosses in the distant past … even took a few identification courses in Portland, Eugene, and Berkeley. But gastrotrichs got under my skin.

I’d be interested in hearing what you do with mosses.
gastrotrichman

Nikon Microphot
Leitz Orthoplan
Wild M8
Bausch & Lomb MicroZoom

Rorschach
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Re: Hello from Oregon

#10 Post by Rorschach » Sat Apr 06, 2019 10:44 am

Hi,

Always nice to see another "optically oriented" biologist, especially one who is into critters living in water :) I'm into macrozoobenthos myself, but will enjoy reading about and seeing pics of meiofauna.

As a stream ecologist, I am well aware of how under studied meiofauna is. So many more people concentrate research efforts on fish, macroinverts and diatoms, heck, even on bryophytes and macrophytes!

I am building a fleet of a 1) a Wild compound (M20 currently in progress), 2) a Wild viewing stereo scope (currently a M5A but eventually a M10 I hope) and 3) for imaging of 3D stuff (as opposed to compound stuff on a glass slide) I am building a Wild M7S setup (but eventually will be replaced by a Wild macroscope). It's slow going because I am forced to hunt for true bargains and finds, not having the funds to just click on every 'buy-it-now' item of interest on the fleabay and other fora. It's the familiar story: my finances are devastated by two mortgages (unfortunately true for the time being) and several kids :)

Best regards,
Riku

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iconoclastica
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Re: Hello from Oregon

#11 Post by iconoclastica » Sat Apr 06, 2019 9:47 pm

gastrotrichman wrote:Any other freshwater meiofauna students out there?
Quite some years ago I worked with free-living nematodes. To say 'freshwater' would be to stretch the truth, for it was in a fresh to marine transect, so mainly brackish water. All these years since, I haven't looked at them again. But since a couple of months I have a much better microscope than I had before, so, who knows if I might pick it up again one day...

Wim

gastrotrichman
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Location: Oregon, USA

Re: Hello from Oregon

#12 Post by gastrotrichman » Sun Apr 07, 2019 3:00 pm

Hi Riku -

Good luck in expanding your equipment. Is your interest in the macrozoobenthos focused on any particular group?


Hi Wim -

I hope you return to nematodes. I see them all the time, but basically ignore them, as I do virtually everything other than gastrotrichs … too many critters and too little time.
gastrotrichman

Nikon Microphot
Leitz Orthoplan
Wild M8
Bausch & Lomb MicroZoom

Rorschach
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Re: Hello from Oregon

#13 Post by Rorschach » Wed Apr 10, 2019 4:41 am

gastrotrichman wrote:Hi Riku -

Good luck in expanding your equipment. Is your interest in the macrozoobenthos focused on any particular group?

Thanks! Not really, all the major groups living there are interesting. Well, Oligochaeta aren't all that interesting to me :-)

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