More Critters From The Plankton Net

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KurtM
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More Critters From The Plankton Net

#1 Post by KurtM » Fri Mar 04, 2022 6:39 pm

Here are a few more weird and wonderful characters from the zooplankton in Upper Galveston Bay, that I've been hauling in with my plankton net over the past couple months. All except image #4 were shot through the 20/.70 Splanapo, and #4 through the 10/.40 Splanapo lens, on an Olympus BHS BH-2 using DIC, LED illumination, and speedlite flash. Camera is Canon T7i/800D, NFK 2.5x relay lens. All are single frames as these are living critters that are in constant motion, making stacks impossible.

Image #1 is what I call a 'UFO', which is just my own term for critters I haven't yet managed to identify. If it were in freshwater I'd say it's a rotifer, and as many freshwater critters have marine counterparts perhaps that's just what it is. In any case I thought the picture came out pretty good so here it is. Incidentally, the spiny little thing with a brownish-yellow center just to the left of the animal is a Chaetoceros diatom chain as seen end-on.

Images #2 and #3: I believe this is a bristle worm, of which there are a great many species. This particular one exhibits loads of personality, a real charmer who reminds me of the gastrotrichs in freshwater as he moves about in similar fashion, appearing curious and inquisitive as he busily tends to a complete inspection of his surroundings. I assume the name 'bristle worm' comes from the lengthy appendages at his sides which stream in trail as he glides about, and which he fans out at each encounter with a neighbor, which is quite frequently in a busy wet mount on a microscope stage. I can't decide if he's startled by the encounters, if it's a greeting, perhaps a salute, or maybe he's just proud to be a bristle worm and wants everyone to know it; whatever the case, it's quite a comic effect and endless fun to watch. A nice little pair of "eyes" don't hurt the "cute" look either.

The last two images show what I thought might be a microscopic Texas longhorn at first, until I figured out this creature actually sports a trio of horns, the third one gracing its tail end. Such a distinctive appearance made it easy to identify as a barnacle larva. If you've been around saltwater your whole life as I have, you will know barnacles as one of the most terrible pests ever, as in adult form they encrust anything and everything that's in the water for even just a couple weeks. They're the devil to clear off, and can be sharp as razors should you be so unfortunate as to brush against a colony. But seeing them in this way adds a whole new dimension to the things, and suddenly they're fascinating animals that are well worth studying. The larva is pretty thick in the Z axis, and because it's in constant motion you only get one shot and can forget about stacked images; so image #4 is focused on the animal's foot, and image #5 focuses on the third, or posterior, spine or horn. The foot and posterior horn are situated one on top of the other, and this is the only way I could think of to show both features.
Attachments
1-18-22 UFO poss Marine Rotifer 20x.jpg
1-18-22 UFO poss Marine Rotifer 20x.jpg (90.3 KiB) Viewed 6251 times
1-19-22 Bristle Worm 20x 01.jpg
1-19-22 Bristle Worm 20x 01.jpg (140.03 KiB) Viewed 6251 times
1-19-22 Bristle Worm 20x 02.jpg
1-19-22 Bristle Worm 20x 02.jpg (164.84 KiB) Viewed 6251 times
1-23-22 Barnacle Larva 10x.jpg
1-23-22 Barnacle Larva 10x.jpg (52.55 KiB) Viewed 6251 times
1-23-22 Barnacle Larva 20x.jpg
1-23-22 Barnacle Larva 20x.jpg (136.91 KiB) Viewed 6251 times
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Re: More Critters From The Plankton Net

#2 Post by imkap » Fri Mar 04, 2022 8:50 pm

I like your catch and the images, really nice...

My son has a DIY plankton net, made from leggings and home sewage tubes. Always trying to find Pteropods or Heteropods... He wants me to buy him a real plakton net, but I think he's better off doing some DIY :mrgreen: He had some nice results with it, managed to find the same one once as on your last picture and some others. I actually don't know as much about the subject so can't say which ones.

I was asked once on the forum to put a photo of a DIY plankton net, but I forgot :mrgreen: and we usually keep them out of town...I'll shoot all the tools once as I think they are useful.
It's either bad weather here (on weekends) or lot of work (weekdays) lately so we didn't go anywhere much, therefore plankton is scarce in our house lately. Soon it will be spring :D
Last edited by imkap on Sat Mar 05, 2022 4:32 pm, edited 1 time in total.

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Re: More Critters From The Plankton Net

#3 Post by zzffnn » Fri Mar 04, 2022 9:13 pm

Fascinating images, thank you for sharing, Kurt!

Where did you buy you plankton net? I should also buy one. Do I just drag it behind a boat or kayak?

You made me read about barnacles:
http://courses.washington.edu/mareco07/ ... shome.html

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Re: More Critters From The Plankton Net

#4 Post by Javier » Fri Mar 04, 2022 11:57 pm

Impressive images.

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Re: More Critters From The Plankton Net

#5 Post by tlansing » Sat Mar 05, 2022 12:09 pm

Nice photos, Kurt!

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Re: More Critters From The Plankton Net

#6 Post by KurtM » Sat Mar 05, 2022 3:03 pm

Thanks, y'all!

The plankton net I use is this one:

Image

https://shop.sciencefirst.com/wildco/st ... -80um.html

At ~$110 it's inexpensive as ready-made plankton nets go, and no matter your opinion of the price I can attest to its impressive quality and value - I seriously doubt anyone would be disappointed with what you get.

Fan, yes, just drag it around a bit and see what you get (at slow speed, it's a very fine mesh). How long to drag it around will depend on how much plankton there is to catch; sometimes I make 4 passes, other times just one will do. Just one of those things you gotta learn by doing.

I imagine there are lots of ways to use a plankton net; one way, for instance, might be to drag it a set distance at the same location every time to learn population density. Or 'trawl' different depths. Or who knows, I'm no scientist - I just play one.
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Re: More Critters From The Plankton Net

#7 Post by zzffnn » Sat Mar 05, 2022 5:29 pm

[youtube]https://youtu.be/ziGtmjiUlJQ[/youtube]

The above is a short and nice documentary about plankton.

Thank you, Kurt. I will get one for these floaters. My usual collection method only catches protists attached to plants and bottom soil.

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Re: More Critters From The Plankton Net

#8 Post by KurtM » Sun Mar 06, 2022 3:03 pm

That's a great video Fan, thanks for posting! David Attenborough narrates - bonus!!
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Re: More Critters From The Plankton Net

#9 Post by Wes » Tue Mar 08, 2022 8:13 am

Kurt, you have inspired me to get a plankton net. Great catch and write-up.
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Re: More Critters From The Plankton Net

#10 Post by Phill Brown » Tue Mar 08, 2022 9:07 am

Screenshot_20220308-085954.png
Screenshot_20220308-085954.png (61.88 KiB) Viewed 6016 times
This is for UK marine diatoms,hope it's relevant or of some interest.
Maybe March/April is ideal for northern waters.
Would have linked the reference but that is beyond my skill set.

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Re: More Critters From The Plankton Net

#11 Post by zzffnn » Tue Mar 08, 2022 3:32 pm

Thanks to Kurt's continued inspiration, I finally bought a 5" 80um Fieldmaster net from eBay as well, which is slightly easier to handle for my sons (7yo and 11yo) than the 8" net.

Our soccer friends would take us to boating in Galveston Bay soon and I plan to take both my AO series 10 scope and plankton net onto their boat. It is time to pretend to be an ecologist for me :mrgreen:

I can also tow the net behind my kayak when I go birding in Horsepen Bayou, and use it with a pocket microscope on the kayak.

Looks like timing is about right too.

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Re: More Critters From The Plankton Net

#12 Post by apochronaut » Tue Mar 08, 2022 5:07 pm

For those who want to spend a little less, the silk ones from India on ebay are quite good, especially for around 30.00. Silk is stronger than nylon and based on the thread count they use, 125 x 125 and the average diameter of woven 8 strand silk thread ( 90 microns), the mesh is just around 100 microns.

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Re: More Critters From The Plankton Net

#13 Post by KurtM » Wed Mar 09, 2022 12:58 am

I need to be getting commissions on plankton net sales! Seriously though, it's great to hear that my strange little adventures inspire others. Now I can tell people who know me pfffft.

Phil Brown, if you can't quite post a link the next best thing is to say the name of the site, and often Google can do the rest for us. In the meantime, please find a 14 year old to teach you copy-and-paste; this one trick will make all the difference in the world to your computer life.

Fan, when are you coming down here next?
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Re: More Critters From The Plankton Net

#14 Post by zzffnn » Wed Mar 09, 2022 3:38 am

Kurt, I still reside about 15 minutes of driving from you. Will stay here for maybe a year.

apochronaut, thank you, I saw those eBay silk nets but wasn’t sure about their pore size, so I didn’t buy it. Next time I will remember.

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Re: More Critters From The Plankton Net

#15 Post by Phill Brown » Wed Mar 09, 2022 7:38 am

Title to google is
An illustrated guide to the diatoms of British coastal plankton.

Seem to remember reading that the zooplankton eat many of the diatoms in the water sample in a matter of hours.
We get Gulf stream and Labrador current mostly in the UK from my understanding which is minimal.

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Re: More Critters From The Plankton Net

#16 Post by KurtM » Thu Mar 10, 2022 2:00 am

zzffnn wrote:
Wed Mar 09, 2022 3:38 am
Kurt, I still reside about 15 minutes of driving from you. Will stay here for maybe a year.
Did I move to Boston??? :shock:
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Re: More Critters From The Plankton Net

#17 Post by zzffnn » Thu Mar 10, 2022 3:29 am

KurtM wrote:
Thu Mar 10, 2022 2:00 am
zzffnn wrote:
Wed Mar 09, 2022 3:38 am
Kurt, I still reside about 15 minutes of driving from you. Will stay here for maybe a year.
Did I move to Boston??? :shock:
Not yet; I probably don't have to. The problem is, my main DIC scope and carbon kayak are there in Boston; I would have to either move them back or move my home to them. It is long and complicated story. I am doing well though, thank you.

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Re: More Critters From The Plankton Net

#18 Post by MicroBob » Thu Mar 10, 2022 7:16 pm

Hi Kurt,
nice photos! I like the third best as it shows the dynamic movement best.

Plancton nets can be made from mesh used for silk screen printing. This can be bought quite cheaply from China or from a printing company in the area it one has a contact person there. I wasn't able to buy it in small amounts from european manufacturers.
The mesh is fairly slippery so one should have a bit of experience in sewing to do this. It is very useful to have a bottle at the bottom and a supply of spare bottles.When I asked the nurse whether I could have four more urine bottles I was eyed suspiciously though! :lol:
I mostly use a plancton sieve I made from stainless steel mesh and a plastic jar, compact, easy to clean, robust.

Bob

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Re: More Critters From The Plankton Net

#19 Post by Dubious » Thu Mar 10, 2022 8:10 pm

Kurt, does the net come with that bottle attached to the end in the photo? I see that WildCo also has the net in a smaller 5" size. Is the mesh woven or one solid piece? I am wondering how it compares to those less expensive silk nets mentioned, which are woven; and WildCo seems to suggest its material has an advantage as to fixed mesh size: "All nets are of durable Nitex® nylon, known for the accuracy of its mesh size."

Anyway, thanks for posting--I am going to have to get one!

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Re: More Critters From The Plankton Net

#20 Post by zzffnn » Thu Mar 10, 2022 9:54 pm

Dubious wrote:
Thu Mar 10, 2022 8:10 pm
Kurt, does the net come with that bottle attached to the end in the photo? I see that WildCo also has the net in a smaller 5" size. Is the mesh woven or one solid piece? I am wondering how it compares to those less expensive silk nets mentioned, which are woven; and WildCo seems to suggest its material has an advantage as to fixed mesh size: "All nets are of durable Nitex® nylon, known for the accuracy of its mesh size."

Anyway, thanks for posting--I am going to have to get one!
Dubious , I bought the 5'' net from eBay (which costs slightly less in US) and consider it slightly overbuilt (I think it can take quite some abuse). I am not sure what you would define as woven or one piece; it looks durably woven to me. It feels tougher to regular silk, but I don't think I need a really tough plankton net for my casual use.

Yes, mine came with a screw-on vial / bottle. The female screw vial receptacle part is zip-tied tightly onto the net.

Was it cheap for a net? No. Am I happy with the purchase? Yes.

I did not buy the silk net because that Indian eBay listing does not say its pore size. The silk net may be a better deal, if it is made durably. Please, someone buys one and report back!

I am aware it can be made DIY cheaply, but I don't have the material, time or patience to make it in this case. Bob, I would tell the nurse, eh, I pee quite a lot :mrgreen:

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Re: More Critters From The Plankton Net

#21 Post by KurtM » Fri Mar 11, 2022 12:57 am

I have a DIY plankton net made from filter fabric I obtained from a swimming pool supply store, and it works fine. I believe you can make plankton nets from a wide variety of materials. Using women's hosiery has the advantage of requiring no sewing, but learning to operate a sewing machine isn't difficult and opens up lots of options.

I agree with Fan's assessment: the Wildco net is overbuilt, and slightly pricey ... but as I said before, you surely get what you pay for, no problem there, it's certainly robust and durable.

I can't recall where I saw it, but I seem to recall that Nitex® is first woven, then heat pressed to fuse the fibers. It doesn't look like typical woven material under the microscope, so I think this is correct. At any rate, one of the things I like about it is the fabric rinses easily and cleanly, which means it "releases" the critters into the receptacle quite nicely, much better than my other nets of "lesser" mash fabrics. Back home it cleans up perfectly back to snow white in the kitchen sink, and doesn't require "blasting" with the hose outside like my others.

Yes, it comes with the bottle, but I'm not crazy about it and will likely replace it one of these days with one of my own design and fabrication. But it works, and I'm just being a connoisseur about it. :geek:
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Re: More Critters From The Plankton Net

#22 Post by Crater Eddie » Fri Mar 11, 2022 3:15 pm

Great images and informative comments.
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Re: More Critters From The Plankton Net

#23 Post by nematos » Fri Mar 11, 2022 3:31 pm

Great image and subject!

Compliments!

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Re: More Critters From The Plankton Net

#24 Post by KurtM » Fri Mar 11, 2022 8:03 pm

Thanks, fellas!

I started a new thread for plankton net discussion, and want to cross reference it here: viewtopic.php?f=10&t=15132
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Re: More Critters From The Plankton Net

#25 Post by Sure Squintsalot » Mon Dec 05, 2022 5:57 pm

Me and my ghetto-built, plexiglass, half-baked DIY DIC set-up have finally yielded some results.....and I have many questions. But first:
Screenshot 2022-12-05 093452.jpg
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Disclaimers:
1) Photos taken handheld, through a 10x eyepiece and 40x DIC objective, using Pixel 4a with limited post processing, largely to replicate what I saw through the eyepiece after a couple of glasses of wine: lots of cropping, a little added sharpness and saturation. No stacking, no AI-enhanced resolution. Hell, I didn't even clean the optics. Scope is an 80s era Optiphot.
2) I've not yet done any identification, though I am collecting the graphic database to help me with this project. So, DON'T go ruining my future easter egg hunt!
3) These samples were collected by dragging a fabric shopping bag behind a kayak in Puget Sound. I'd fogotten the actual plankton net at home. In addition to making an acceptable net, the shopping bag also makes a superlative sea anchor.
4) Sample prep: right after the drag, the bag was placed in a ziploc and allowed to ferment in a hot car for a few days until it smelled like a fine Swedish canned fish product. The bag was cut flat and rinsed of its contents with isopropyl alcohol and allowed to settle, drained, rinsed with some arbitrary lye solution, then rinsed 3x with distilled water. I also made a DIY centrifuge with a hand drill to speed the process along.
5) Samples were then placed on a cover slip and dried. Permount was placed on a slide and degassed under vacuum before placement of the cover slip. With some slides, I degassed the entire slide and watched the cover slip foam up, amazed by how much invisible air gets trapped in those nooks and crannies. The cover slips were then weighted with about 4oz., to flatten out and minimize sample depth; the finished slide was then set on a drugstore heating pad overnight to allow the Permount to fix.

Questions:
1) Is oblique lighting preferable to DIC for viewing plankton?
2) Should I pursue immersion oils and better, high mag/high aperture objectives?
3) What's the sweet spot for viewing plankton? 60x Plan HA-fluoro-BD-apo-PHP-chromo-DIC? or 20x chinesium? I get to make this decision exactly twice (wife is getting a little impatient with the purchases).
4) I used "Permount" with a RI = 1.52. Safety aside, is there a better mounting medium for Plankton?
5) What do you people do with your plankton information? Build a life list? Conversation starters? Framed portraits? Citizen science?

My aim is to better understand this largely invisible part of the ocean and I'm super interested in plankton diversity, census data, biology, and morphology. My stare-at-the-ceiling dream is to build a buoy-mounted, solar powered, sat-linked, in-situ device that records high resolution plankton information in real time. I guess just seeing the damn things is a first step.

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Re: More Critters From The Plankton Net

#26 Post by Hobbyst46 » Mon Dec 05, 2022 8:38 pm

Sure Squintsalot wrote:
Mon Dec 05, 2022 5:57 pm
Questions:
1) Is oblique lighting preferable to DIC for viewing plankton?
2) Should I pursue immersion oils and better, high mag/high aperture objectives?
3) What's the sweet spot for viewing plankton? 60x Plan HA-fluoro-BD-apo-PHP-chromo-DIC? or 20x chinesium? I get to make this decision exactly twice (wife is getting a little impatient with the purchases).
4) I used "Permount" with a RI = 1.52. Safety aside, is there a better mounting medium for Plankton?
5) What do you people do with your plankton information? Build a life list? Conversation starters? Framed portraits? Citizen science?

My aim is to better understand this largely invisible part of the ocean and I'm super interested in plankton diversity, census data, biology, and morphology. My stare-at-the-ceiling dream is to build a buoy-mounted, solar powered, sat-linked, in-situ device that records high resolution plankton information in real time. I guess just seeing the damn things is a first step.
Great catch, nice variety and interesting photos.
The illumination (seems to me oblique, mixed with significant other effects) helps a lot here because Permount is not an ideal medium.
Naphrax, Pleurax, some UV curable glass cements will afford better visibility in brightfield, but great DIC images can be done even on water-mounted diatoms.
I think that the "sweet spot" for medium size diatoms is the 60X (or 63X) 1.3-1.4 NA oil objective.
Live plankton creatures are of interest by themselves, besides diatoms (which are algae).

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Re: More Critters From The Plankton Net

#27 Post by imkap » Mon Dec 05, 2022 11:22 pm

Plankton is super interesting, in some cases might be a good conversation starter. :D
Yesterday we had a family visit to a 97 year old marine biologist, a renowned expert. She still knows everything about plankton movements in the Mediterranean and Atlantic. Very lucid old lady with first hand info, I didn't talk much, was mostly taking some footage of her and my son exchanging info about their findings. Maybe all this plankton info is keeping her so lucid, or long term formalin exposure...
Tried to get some info about which microscopes they used, but she wasn't very interested in that, just said they didn't have all the tech that is available now.
Probably the meeting of the oldest and the youngest planktonologist around. :D

I like your photos...

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Re: More Critters From The Plankton Net

#28 Post by Sure Squintsalot » Wed Dec 07, 2022 2:26 am

Hobbyst46 wrote:
Mon Dec 05, 2022 8:38 pm
The illumination (seems to me oblique, mixed with significant other effects) helps a lot here because Permount is not an ideal medium.
Naphrax, Pleurax, some UV curable glass cements will afford better visibility in brightfield, but great DIC images can be done even on water-mounted diatoms.
I think that the "sweet spot" for medium size diatoms is the 60X (or 63X) 1.3-1.4 NA oil objective.
I agree, the lighting does seem oblique, but isn't that the point of DIC? Highlighting subtle differences in refractive index in a visually useful way minus bogus artefacts?

Can you elaborate as to why Permount is not ideal? It seemed to me that the Permount RI is right in line with a lot of other plankton mounting mediums used in published mounting procedures, (not to mention far more easily available).
imkap wrote:
Mon Dec 05, 2022 11:22 pm
Plankton is super interesting, in some cases might be a good conversation starter. :D
At thanksgiving, I ran into a PhD who just wrapped up his thesis on Pacific copepod population evolution. If I hadn't been yakking ceaselessly about my new toys, we'd have never met!

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Re: More Critters From The Plankton Net

#29 Post by Hobbyst46 » Wed Dec 07, 2022 1:18 pm

Sure Squintsalot wrote:
Wed Dec 07, 2022 2:26 am
Hobbyst46 wrote:
Mon Dec 05, 2022 8:38 pm
The illumination (seems to me oblique, mixed with significant other effects) helps a lot here because Permount is not an ideal medium.
Naphrax, Pleurax, some UV curable glass cements will afford better visibility in brightfield, but great DIC images can be done even on water-mounted diatoms.
I think that the "sweet spot" for medium size diatoms is the 60X (or 63X) 1.3-1.4 NA oil objective.
I agree, the lighting does seem oblique, but isn't that the point of DIC? Highlighting subtle differences in refractive index in a visually useful way minus bogus artefacts?

Can you elaborate as to why Permount is not ideal? It seemed to me that the Permount RI is right in line with a lot of other plankton mounting mediums used in published mounting procedures, (not to mention far more easily available).
[/quote]Because of the relatively low RI. Diatoms are very transparent, since their own RI is near 1.4 or 1.5 (can't remember exactly). Visibility grows with the difference in RI between the specimen and media, i. e. RI difference between the diatom and mounting medium. So the letter should be as high as possible. An RI of 1.52 does not provide good visibility. Naphrax, Pleurax and other resins have RI's of ~1.6 or higher, and are proven good media for visibility of diatoms on the slide. These resins are useful for clean thin flat frustules, not whole-body ( ;) ) creatures...

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Re: More Critters From The Plankton Net

#30 Post by zzffnn » Thu Dec 08, 2022 3:45 pm

Sure Squintsalot, to answer your questions #1-#3:

1) No, compared to DIC, oblique cannot achieve the same image effect at NA higher (larger aperture) than 0.65. DIC’s background cleanness and overall contrast and image clarity is superior in my opinion. Oblique may produce better resolution, but its background is oftentimes messy and lacks contrast. At under NA 0.65, that difference is not obvious.

2) I personally prefer immersion, water or oil; you seem to have more than sufficient skills, knowledge and patience, so I would suggest you try immersion and higher aperture (NA).

3) The sweet spot can vary depending on viewer and the exact plankton subject. For me, it is usually between 40x to 60x.

It would be nice to have an iris objective to instantly fine tune aperture at will. An iris helps you to arrive at a good compromise between resolution, viewable depth and contrast; that good compromise point can change from subject to subject.

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