Stalked ciliate on mayfly nymph

[sreynolds]

I'm sampling aquatic invertebrates and have come across mayfly nymphs covered with 'fuzz' in some streams here in Vermont. I don't know enough about mayfly nymphs to know if this is normal, but I have also seen some that are 'clean'. There appear to be several things accounting for the fuzz, and this stalked ciliate is one of them. Any ideas? Video clip here

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[macnmotion]

Rigid stalks, colonial, check out Epistylis.

[sreynolds]

Rigid stalks,

Mac - The stalks are spirally contractile, as seen in the video clip.

Wikipedia says 'Carchesium is a genus of usually colonial peritrich ciliates in the Vorticellidae with a spirally contractile stalk.[1][2] The inverted bell-shaped cells have an oral lip as in Epistylis. The genus has a cosmopolitan distribution in freshwater and is a common part of the fauna of the aerobic stages of waste water treatment plants, such as activated sludge and trickling filters.'

Would this suggest that water with these organisms has been subjected to exposure to wastewater sludge pollution? My samples came from streams with known concentrations of farm manure pollution, and it is not impossible that adjacent fields were also used to dispose of wastewater treatment plant sludge.

[Bruce Taylor]

Yes, it's Carchesium (colonial, with spirally-contractile stalks).

[charlie g]

Thanks, steve, for this example of: 'epibionts' on their aquatic insect host.

You here for me ( charlie g) share an encounter and image capture of a colonial peritrich ciliate..? Carchesium'? ...before , in the frequent encounters I have enjoyed with genus: Carchesium ciliates ( peritrichs a sloppy often used term for this wonderful group of ciliates)....before the very dense ( like a collection of over twenty helium balloons tethered to a table at a childs birthday party!)..your microscopy shows only a few ciliates in each 'colony' of ciliates.

I wonder if this implies each of these 'small clusters' of colonial ciliates are genus: Carchesium? Everything starts somehow..are you sharing an encounter with a seasonal phase of 'low colonial colony density'? Or did traumatic collection and colony transport to your bench..shake out/ decimate naturally flush and dense colonies of Carchesium?

Or is this another genus of 'peritrich'? Seasonal observation of protozoan epibionts are rewarding in showing trends.

Carchesium dense colonies are evident to naked eye observation..on sides of collection bottles as rythmically pusating ' collections of tethered fuzz-balls '...but I never encountered literature thoughts to: how long are Carchesium colonies with sparse few members....do colonies start from one protozoan?..how long till ' maturity/ dense Carchesium colony'?

Your kind thread has me thinking about colony growth-maturity..dispersal...thank you, steve!

thanks for this shared encounter with ciliate epibionts...please keep an eye out for epibionts on algae, water fleas, worms, snails, etc. . charlie g, finger lakes/NY

[sreynolds]

please keep an eye out for epibionts

Charlie - Thanks for the kind response. I plan to keep sampling the two sites where I found these this spring, and to look at other substrates than the mayfly nymphs I found the ciliates on. This should shed some light on the presence of larger/denser colonies. The samples I first found were just attached to nymphs, as in the image below. I'm waiting for the snowmelt high water to go down; I also bought a pair of waders.

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[Bruce Taylor]

( peritrichs a sloppy often used term for this wonderful group of ciliates

Hi Charlie! You've raised some interesting points.

First, the term "peritrich" isn't sloppy at all! Peritrichia is a well-defined and strongly supported natural group (clade). In 2017, Eleni Gentekaki & her collaborators showed that peritrichs make up a single separate branch of the ciliate family tree: https://pubmed.ncbi.nlm.nih.gov/27659723/. So, no need to be bashful about using the word.

..your microscopy shows only a few ciliates in each 'colony' of ciliates.

Young colonies are sparser than mature ones. In my experience, it's not unusual to run across stalks of Carchesium bearing only a couple of zooids.

Or is this another genus of 'peritrich'?

Carchesium is common, widespread, and known to colonize insects. However, it is true that there are a couple of other colonial members of Vorticellidae (sessile peritrichs with spirally-contracting stalks, featuring "sinusoidal" spasmonemes). Apocarchesium is one, but we can rule that out because it carries its zooids in distinctive rosettes, which we don't see here. Epicarchesium is more difficult to rule out. Like Pseudovorticalla, it has a pellicle featuring a "reticulate silverline system", which looks somewhat like brickwork in stained specimens. It can be hard to see this feature without a close examination of the pellicle. So, you've raised a useful point. If we're being very careful, we should keep identification at family level: Vorticellidae. (That said, I don't see any sign of pellicular bumps or raised granules in the critters shown above, and believe they are probably Carchesium).

do colonies start from one protozoan?..how long till ' maturity/ dense Carchesium colony'?

Yes, the colonies are clonal, and develop from a single migratory telotroch (swarmer) that lands on a suitable substrate and begins secreting a stalk. Once established, the cell begins feeding and dividing, and the colony grows.

Here's a chart showing colony growth rates in Carchesium polypinum (source: https://link.springer.com/article/10.1007/BF00376971):

[Sure Squintsalot]

Pretty cool stuff....these nymphs were alive when you collected them? What led you to investigate them in the first place? Do you plan on making permanent mounts of these?

[charlie g]

Great thread, thank you OP, and bruce.
well I use peritrich as a label for oh so many different organisms..cutting down loose meaning I intend from using term 'ciliate'...I guess it sharpens focus..but not by much ( thank goodness I do'nt concern myself with the categories of beetles). Classmates in high school teased me with the then modern and proper notion that: 'protozoans are to be termed: 'protists' ( to clear up the muddle of both unicellular/ acellular plants and animals often preying/eatting engulfed foods heterozoic nutrition...as well as using chlorophyls for sunlight nutrient production.) . I always liked that word protozoa!

So in 1966 (Kudo,5th ed.) recognized: Subclass: Peritricha...but had: suborder: Sessilina, suborder: Mobilina.

Both 1985/JohnJ.Lee ( a neighborbor of mine in NJ, conducted a model-rocket outing for children..including my son)....and in 1990/Lynn Margulis & John O.Corliss still recognized: Subclass: Peritrichia.

Expanded ( 1985 and 1990 texts)Sessilida to Order level, Mobilida to:Order level.

Yup I like term : 'protozoa', and yes bruce, I dissed the term: 'peritrich'...go figure.

Thanks for a great microscopy thread, charlie guevara

[Bruce Taylor]

> I always liked that word protozoa!

I do, too! As an informal term for non-photosynthetic unicellular organisms, it hits the spot. "Protist" is fine, too, as a catch-all term for "eukaryotic critters that are not animals, plants, or fungi."

However, things get weird if we retain these old terms as formal taxa. People get confused! The "protozoan" Salpingoeca (a choanoflagellate) is much more closely related to you and me than it is to the "protozoan" Giardia. Formally classifying both in "Protozoa" obscures that important and amazing fact, and cuts us off from our little sisters in Choanoflagellatea. It impoverishes our understanding. And in its reduced, modern form, "Kingdom Protozoa"--as proposed by Thomas Cavalier-Smith and adopted by many online databases such as Catalogue of Life, WoRMS and iNaturalist (where I am a curator, and often have to explain this stuff to users!)--is even more confusing, since it excludes classic "protozoans" such as ciliates, dinoflagellates and rhizarian amoebae! What kind of "Kingdom Protozoa" excludes ciliates?

Luckily, many traditional groupings have held up very well, in the era of molecular phylogeny! Ciliates are a rock-solid clade. Within that group (normally ranked as a phylum), peritrichs form a monophyletic subclass (Peritrichia), and the old orders Sessilida & Mobilida are here to stay.

[charlie g]

First off...my apologies to steve for this hijack of his wonderful thread on epibionts observed on late winter mayfly nymphs. Please keep watching for epibionts on all sorts of protists and meiofauna, steve.

Bruce...ahem... I never touted 'formal taxonomic use' of my appeal, my enchantment for the term: 'protozoa'. Since you turn my originally stated silly fondness for the term 'protozoa' ( I even put this enchantment for term: 'protozoa' into a fond high school scenario of classmates ribbing me), you grace this thread, bruce,.with a keen and thoughtful discussion on clarity of thought in embracing our worlds biota into sensible relationships. Since you mention a wonderful professor: Dr. Thomas Cavalier-Smith....well I'm cheered we share this professors significant contributions to understanding our biota, our neighbor biota close and globally.

Professor Cavalier-Smith senses..the first..the primordial eukayotes were indeed protozoans...'phagotrophic uniciliate, unicentriolar, aerobic zooflagellates that arouse from a neomuran bacterial ancestor by the simultaneous origin of the cytoskeleton, endomembrane system, nucleus, and cilium, coupled with overlapping symbiogenetic origin of mitochondria from an intracellular alpha-proteobacterium'. Thomas Cavalier-Smith, september/2003.

I promise, bruce, I will thoughtfully state when I attempt 'formal taxonomic terms'...btw..your use of term: 'clades' does not contribute to my silly diss of: subclass: Peritrichia...my use of term: 'peritrichs' as personally a sloppy label.

Thanks for this late winter microscopy, steve, and thanks bruce for your posting, charlie guevara

[Bruce Taylor]

my apologies to steve for this hijack of his wonderful thread on epibionts observed on late winter mayfly nymphs

Yes, sorry for the detour! We've wandered a long way from Carchesium.

Since you mention a wonderful professor: Dr. Thomas Cavalier-Smith....well I'm cheered we share this professors significant contributions to understanding our biota, our neighbor biota close and globally.

T C-S was a great protistologist, and his work in the deep phylogeny of eukaryotes was dazzling and original. The tree you posted is a phylogenetic one, and very different from the ranked taxonomic schemes he created, which currently form the taxonomic backbone of Catalogue of Life, Algaebase, WoRMS and iNaturalist. His "Kingdom Protozoa" only appears in the latter, as a "wastebasket taxon" containing a mix of organisms that don't fit into his other "kingdoms." He excludes ciliates, dinoflagellates and cercozoan amoeboids from that taxon (which often befuddles users on iNat).

That tree is an interesting snapshot of eukaryote phylogenetics in 2003. Much has changed! The "Cabozoa" clade didn't hold up: it turned out that Rhizaria formed a group with the ciliates and stramenopiles/heterokonts (a group now called SAR), so the Cabozoa hypothesis was abandoned. Apusozoa is now on the opposite side of the tree, in the group T C-S called Unikonts. The Unikont hypothesis itself turned out to be mistaken: members of the group are ancestrally biflagellate, so Unikonta has largely been superseded by a similar group called Amorphea.

The "neomuran model" of eukaryote origins has fallen from favor, too. The discovery of the "Asgard archaea" in 2015 supports the view that our kind of complex cells emerged within the Archaea. That is, the "host" cell for the bacterial mitochondrion was itself an archaean, possibly from the same lineage as the Asgard group.

[actinophrys]

Sorry to add to the derail, but as far as eukaryotes developing from within archaea, I would say the matter does not seem as settled as that. See for instance Devos, 2021 for an alternate look at Asgardarchaeota and what we can learn from them.

[Bruce Taylor]

Thanks for the link to that fascinating paper, Josh! I don't know nearly enough to have opinions about the arguments Devos makes, but I take your point: the jury is still out on Neomura.

[sreynolds]

Pretty cool stuff....these nymphs were alive when you collected them? What led you to investigate them in the first place? Do you plan on making permanent mounts of these?

The nymphs were alive. I'm trying to assess the health of my local streams and looking for examples of the ranges of organisms I find, both in diversity and condition. I wondered what they were covered with. They were collected from a stretch of water surrounded by farm land which is heavily treated with manure as fertilizer. My imaging is hampered by not yet knowing how to slow down live specimens; I haven't tried making permanent mounts either.

[Sure Squintsalot]

I'm trying to assess the health of my local streams and looking for examples of the ranges of organisms I find, both in diversity and condition.

I wondered what they were covered with. They were collected from a stretch of water surrounded by farm land which is heavily treated with manure as fertilizer.

This is a good project. How are you establishing a baseline for "diversity and condition" given your observational "snapshot-in-time"?

My imaging is hampered by not yet knowing how to slow down live specimens; I haven't tried making permanent mounts either.

I've read of using dilute concentrations of various "poisons" like ethanol to slow the little buggers down, or at least using cold temperatures. That may mean some clever hardware for a stage specimen holder. Making permanent mounts is a science in and of itself and I'm always on the lookout for shortcuts because of, you know, laziness.

[sreynolds]

How are you establishing a baseline for "diversity and condition" given your observational "snapshot-in-time"?

Very good question. I live in the Champlain Valley of Vermont with several small rivers coming off the western slope of the Green Mountains. There are four such streams within a 30 minute drive. All of these originate in upland wooded forests, transition to floodplain streams meandering through agricultural land, and then enter Lake Champlain. There are comparable sites in terms of topography and flow on all four, and these are my sampling locations. I will take the superset of organisms found at comparable sites as my baseline for 'diversity', recognizing that this base superset may be already self-limited by water quality. I don't have a plan for assessing 'condition' aside from noting seemingly obvious situations like the mayfly nymphs above. There are 20 years of water quality data on all these streams collected by a local civic body, and all show elevated levels of e. coli and phosphorus at some sites across the years. I would like to test the correlation of organisms with water quality, comparing the organisms at historically polluted sites with those in clean water. I will probably get a Surber sampler and start taking quantitative observations, but for starters, I will be satisfied to get a time-lapse high level view of changes throughout year and a greater comfort level with my ID work.

[charlie g]

Hi, steve. Macroinvertebrate freshwater insects are a strong signal to freshwater quality status. Aquatic ( part of the indicator insects life cycle having an aquatic phase) insects have been grouped into tolerance levels for 'water pollution/ water fouling'.

Good water quality is indicated by mayflies (Ephemeroptera), stoneflies( Plecoptera), and caddisflies(Tricoptera). By use of these macroinvertebrate indicators...you avoid physico-chemical testing for: O2 saturation, pH, water temp., .


Prudent to still survey bacterial indicators of status of freshwaters: coliforms, fecal coliforms, E. coli and enterococci(presumptive tests are cheap and easy).

Alas..do understand...even pristine 'high quality fresh waters' may be tainted/ may be a threat for infective gut protozoan: Guiardia sp., from our neighborhood beavers and muskrats..guiardiasis is a parasitic infection we humans are often

at risk for getting ( recall: "Wash your hands" mantras for restrnt./ food workers...giving many meals to patrons..and at times, these food workers must use the ...err..bathroom).

Here in finger lakes/NY..we have been seeking best practices for how to spread cow-manure , on cropland adjacent to bodies of water...lots of 'stake holders/ lots of give and take'.

And worst of all ( IMHO) , steve..please keep track on simple year calenders...when snow, when warm...etc....I sense we are experiencing a 'new normal'...sighh

Love your citizen-science project. Please go slow on spending duckets for dedicated sample equipment...look/ see the drainage basins point sources of water influx...enjoy your macro/microscopy work...bravo for your activities. charlie guevara/ finger lakes, NY

[sreynolds]

Update - My stream project for the-now-past year included 78 samples taken from 10 streams in Addison County, Vt, which yielded about 1,000 images, some of which are in a photo album I posted on a website I put up to organize links to some helpful aquatic invert. sites - here. Having working microscope setups was key. 'Thank you' to the people on this forum who helped me with that.