I would give the Letharia dye another try
Would love to... When I was in Oregon this lichen was super abundant. At the moment I am living in Amsterdam (Netherlands), and I see mostly Xanthoria, Evernia, Rhizocarpon, and a few other lichen species that grow on city trees, but they are very small and spotty, nothing compared to the wolf lichen in Oregon. I do miss the Oregon forests with the old growth sequoia redwood trees and all that lichen.
9ft of snow?! I only experienced such deep snow in an urban setting while living in Connecticut for a year. I spent a few years in Oregon but the snow in the area never got so deep while I was there. When I was in the US I was not yet able to identify many fungi as I was mainly obsessed with animals (especially salamanders) back then, so unfortunately I did not really appreciate the diversity of fungi there. Although once in Oregon I did attempt to dye some socks using a wolf lichen (Letharia vulpina) and a pressure cooker. That did not end well.
I see. So it is not necessarily that their mycelium are better at surviving the freezing temperatures, but rather that either they fruit quicker once conditions are acceptable or that their fruiting bodies are more cold tolerant. Thanks, it's interesting.
Cool! I just read their wiki page and it says
A snowbank fungus, it is most common at higher elevations after snowmelt in the spring.
Snowbank fungus is a new term for me. Not sure yet what makes a fungus thrive through snow. Maybe they have anti-freeze proteins?
Does your area get a lot of snow?
In many cases the tweet is important because it was tweeted by a specific person. If only a screenshot is provided then one needs to go through the hassle of verifying it is a real tweet. A good approach would be to do both: post screenshot + link to neutral frontend
This article is from earlier in the year but I missed until now!
>Abstract > >The emergence of Batrachochytrium salamandrivorans (Bsal) poses an imminent threat to caudate biodiversity worldwide, particularly through anthropogenic-mediated means such as the pet trade. Bsal is a fungal panzootic that has yet to reach the Americas, Africa, and Australia, presenting a significant biosecurity risk to naïve amphibian populations lacking the innate immune defenses necessary for combating invasive pathogens. We explored the capability of near-infrared spectroscopy (NIRS) coupled with predictive modeling as a rapid, non-invasive Bsal screening tool in live caudates. Using eastern newts (Notopthalmus viridescens) as a model species, NIR spectra were collected in tandem with dermal swabs used for confirmatory qPCR analysis. We identified that spectral profiles differed significantly by physical location (chin, cloaca, tail, and foot) as well as by Bsal pathogen status (control vs. exposed individuals; p < 0.05). The support vector machine algorithm achieved a mean classification accuracy of 80% and a sensitivity of 92% for discriminating Bsal-control (-) from Bsal-exposed (+) individuals. This approach offers a promising method for identifying Bsal-compromised populations, potentially aiding in early detection and mitigation efforts alongside existing techniques.
Alright! Some other tips:
- Your current microscope is a 160 mm system, so make sure that the objectives are 160 mm and not infinity.
- Make sure the objectives have an RMS thread
- Once you move into higher-end objectives, you will have objectives that are specialized. For example, 'phase contrast' objectives have a dark ring inside of them. For the olympus brand their name often ends in 'PL'. These work with bright-field too. My 40/1.30 objective is actually a phase-contrast objective because I did not know this and ChatGPT told me it meant something different 😂 However, the objective does work well for me and I am now considering upgrading to a phase contrast-capable microscope (the BH2), so I made a good choice by accident.
I first purchased some Plan objectives from China (40x, 60x), and they are alright. More recently I have been looking into objectives with high numerical apertures to increase the resolution of my images, and I think that the best source of good high-quality used objectives is Ebay. The Olympus apochromatic objectives with high NA are listed for a fraction of their original price, but they are still in the $200 - $500 range, so not very cheap.
Wow, those spores are so bumpy, they are very interesting! Thanks for sharing :D
Ah, I did miss this one! I am not sure that I was notified. This one would absolutely fit with the general theme, as it is a community about sharing useful math-based perspectives.
Thanks for the idea! That looks very nice, I like how the collection is organized in those storage containers. They look very well preserved so far so your well water + sun protocol seems to be working well. Perhaps I will too start a lichen collection!
A new species of salamander from Costa Rica, Bolitoglossa chirripoensis, has been described!
!Two photos of the newly described salamander, Bolitoglossa chirripoensis
KLANK, JEREMY, et al. "A new species of salamander of the genus Bolitoglossa (Caudata: Plethodontidae) from the highest massif of the Cordillera de Talamanca, Costa Rica." Zootaxa 5642.5 (2025): 427-450.
Always happy to talk about molecules interacting with light! 😄
This is an aspect of lichen I hadn’t really put much thought into before now.
I have some background is in studying how light interacts with molecules, so I probably put more thought and emphasis on these things than average.
Its been in storage for a couple of months so I may try to re-hydrate it a bit before lighting it up during the night.
That's cool! When keeping a collection, can you keep them alive for a long time dry?
Not sure how I managed to never hit this species with UV. I would describe the colour as a bright, hot, lipstick pink. I am unsure if this lichen is actually fluorescing or if something else to do with how the pigments show up under UV light - maybe @Sal@mander.xyz would know. Picture doesn’t quite do it justice.
You are pointing a UV lamp at it which probably sends out 365 nm or 395 nm photons. The lichen is shooting back photons with a broad range of wavelengths, and a lot of ~600 - 750 nm ones (red). So, the UV photons had to be "captured" by some molecular system, the system dissipated some energy, and then re-radiated some of these longer-wavelength photons.
The general term that covers the many different possibilities is "photoluminescence". In this case we can say for sure that the lichen exhibits "UV-induced photoluminescence", because it is re-emitting lower energy (longer-wavelength) photons. It is common to make the connection "photoluminescence" = "fluorescence", but technically fluorescence makes specific claims about how the light is re-emitted (singlet -> singlet emission), and it is not the only luminescence process. Other examples of luminescence are phosphorescence from a triplet state and luminescence via charge-recombination. So, to call it "fluorescence" in the strict sense we need know what the exact pathway is.
That said, when it comes to biological pigments fluorescence is generally the most common pathway. Triplets that live long enough to produce light are generally undesirable as they can react indiscriminately with molecules inside of the cell as well as produce reactive oxygen species, and good phosphorescent materials often combine metals and heavy atoms that are not as abundant in living tissue.
So, knowing nothing else, and seeing that red light comes out when you shine UV/blue light on a lichen, it is generally fair to call it "fluorescence".
Now, if we discuss this specific lichen... I have looked it up and it does get interesting! Do you have it with you? I suspect that its fluorescence might be different during the day than during the night.
I can find online two significant fluorescent components: parietin, which produces the fluorescent yellow pigment, and Chlorophyll a/b, which produces red fluorescence. There is an interesting paper exploring the idea that one functional purpose of parietin's fluorescence is that it can transfer energy to the algae to boost their photosynthesis. Their conclusions in the paper is that the idea is not supported by the evidence, so, a "negative result". It is a fun example of the type of research that is performed in photobiology and also an example to show that even negative results can be interesting enough to be published!
As for the difference between day and night - if what you see is a combination of the fluorescence of parietin and chlorophyll, then the color might change with the day/night cycle. Photosynthetic organisms regulate the flow of excess photon energy towards a safe non-radiative dissipation pathway in response to light. This is called the non-photochemical quenching pathway, and during the day this pathway tends to be active. During the night there is little light, and so this protective pathway shuts-off. This allows more of the absorbed photon energy to flow into the radiative fluorescence pathway, increasing the red fluorescence. You can actually see this easily with plants - you can dark adapt a leaf and then compare its fluorescence with that of a leaf that is being exposed to a bright light. The dark-adapted one will usually show significantly more red fluorescence.
This time you did ask, so I won't apologize for my essay 😆 But I am a bit sorry I didn't have the time to make it shorter.
No. I think they both lose more than they gain here. It doesn't make sense as a strategy. Ego clash is a simple explanation.
Too bad you don't get to bring your equipment, but at least you will get to see them :D Good luck finding some wild ancestors!
Hi! I’ve looked through /r/shittyaskscience and I think it leans too far into jokes with very little actual science content. The idea behind mander is to support specific, niche science-related communities, so a general joke-focused community doesn't really fit.
For 'science_memes', the mod is a very capable superstar and I agree with their vision of memes as a laid-back way to connect people to science. It’s plausible that a community like 'shittyaskscience' could achieve something similar, but honestly I think science_memes already covers that space well.
As for !askscience - it simply hasn’t been created yet. It would be more fitting than 'shittyaskscience', but I still prefer encouraging people to ask lichen questions in the lichen community, mushroom questions in the mushroom community, chemistry questions in the chemistry community, and so on. I support content flowing toward niche communities rather than having a centralized place for general questions. A general community would be more popular, but popularity isn’t a goal, and it works against the underlying philosophy. Niche spaces may be smaller, but they offer much better signal-to-noise for building meaningful connections.
cross-posted from: https://mander.xyz/post/31227704
> This weekend I did some experiments with turmeric powder. Here are some images of the results, and the description of how to create these microscopic chemical landscapes is given below. > > [!](https://mander.xyz/pictrs/image/032592b4-8643-42bc-bb28-447c0d4781b6.jpeg) > > [!](https://mander.xyz/pictrs/image/bec7b76e-f0da-4931-9a24-dcf8ceb7eb64.jpeg) > > [!](https://mander.xyz/pictrs/image/ca296d6b-719e-46e3-9616-a138869a1527.jpeg) > > [!](https://mander.xyz/pictrs/image/28ab3814-c8fc-4560-aea7-5a8afb2a8667.jpeg) > > [!](https://mander.xyz/pictrs/image/425347e4-8def-4433-9032-a426aa61f426.jpeg) > > [!](https://mander.xyz/pictrs/image/c4d7e3cf-7c8f-46c4-9943-cc14fdfee80a.jpeg) > > [!](https://mander.xyz/pictrs/image/fe24fa2f-79ec-4f5a-960e-c8f444a1233f.jpeg) > > [!](https://mander.xyz/pictrs/image/c7d6a44a-e4e1-4068-8375-521b2c29dc47.jpeg) > > [!](https://mander.xyz/pictrs/image/c96d710d-674e-4d93-bbe6-eb1c61378323.jpeg) > > [!](https://mander.xyz/pictrs/image/4feb9440-a880-47db-b8f3-b039213bc223.jpeg) > > [!](https://mander.xyz/pictrs/image/453618d1-9f0b-42ec-b8f5-e10d5c1fba70.jpeg) > > [!](https://mander.xyz/pictrs/image/c3973120-439d-4cfb-9206-25ec7124f702.jpeg) > > [!](https://mander.xyz/pictrs/image/9e8c3c1d-082b-4ea6-b5f3-f230dd990684.jpeg) > > [!](https://mander.xyz/pictrs/image/22f25807-630a-4cc4-a3e5-b89a72917f2a.jpeg) > > [!](https://mander.xyz/pictrs/image/57aa0bce-9cb6-44e4-8f06-41a03d763103.jpeg) > > [!](https://mander.xyz/pictrs/image/958a04c2-518f-4712-a01d-622fee5bbe01.jpeg) > > > > Turmeric powder is a fantastic material to play with. The powder has a high concentration of colored and fluorescent curcuminoids and volatile turmerone oils. > > When you use a polar solvent to extract these compounds, what you get is a kind of fluorescent oily resin called a turmeric 'oleoresin'. > > The curcuminoids are yellow at acidic and neutral pH, but they become bright red at high pH due to keto-enol tautomerization. There is a lot of cool things you can do with the curcuminoids in terms of photo/electrochemistry. > > I have been playing with very simple chemistry under the microscope, and I have noticed that you can create some cool-looking micro-landscapes. During this process you can also see different types of physico-chemical processes happening in real time. > > Procedure to do this: > > - Place a few grams of turmeric powder into a glass container > - Add enough isopropanol to cover the material, and a bit more > - Mix > - Wait for the solids to settle > - Collect a bit of the isopropanol liquid from the top and place on a glass coverslip > - Wait for the isopropanol to evaporate. > > At this time, you can see under the microscope that golden oil droplets have been deposited, and that the surroundings are also yellow. The drops are oleoresins, which consist of curcuminoids suspended in turmerones and other oily compounds. Thin curcuminoid films might also be forming in between these droplets. > > - Add a sprinkle of baking soda crystals (sodium bicarbonate) on top of the coverslip. You can blow on the coverslip if you accidentally add too much. > > - Add a small drop of water, and wait a bit. > > At this time you can see that the crystals are dissolving under the microscope, but the colors are not changing. The water and oils are not mixing, and so you get this film of alkaline water surrounding the oil droplets, but nothing is yet really changing. > > - After waiting a few minutes, add a drop of isopropanol. > > Now the isopropanol will re-dissolve the oleoresin and mix with the alkaline water. The carbonate ions are now able to react with the curcuminoids, and when they do, they go into the ketone form and instantly turn red. Under the microscope you can see quite dramatic movements of yellow and rad streaking as well as turbulent movements of the baking soda crystals. > > - Wait some time for the liquids to evaporate again > > - You will end up with a landscape that combines yellow resins, red resins, sodium bicarbonate crystals, and several different patterns. > > ----- > > You can vary the parameters - the amount of sodium bicarbonate, the position and size of the drops, you can pre-mix the water and isopropanol, etc. Small changes can drastically affect the resulting landscape. > > > > >
This weekend I did some experiments with turmeric powder. Here are some images of the results, and the description of how to create these microscopic chemical landscapes is given below.
[!](https://mander.xyz/pictrs/image/032592b4-8643-42bc-bb28-447c0d4781b6.jpeg)
[!](https://mander.xyz/pictrs/image/bec7b76e-f0da-4931-9a24-dcf8ceb7eb64.jpeg)
[!](https://mander.xyz/pictrs/image/ca296d6b-719e-46e3-9616-a138869a1527.jpeg)
[!](https://mander.xyz/pictrs/image/28ab3814-c8fc-4560-aea7-5a8afb2a8667.jpeg)
[!](https://mander.xyz/pictrs/image/425347e4-8def-4433-9032-a426aa61f426.jpeg)
[!](https://mander.xyz/pictrs/image/c4d7e3cf-7c8f-46c4-9943-cc14fdfee80a.jpeg)
[!](https://mander.xyz/pictrs/image/fe24fa2f-79ec-4f5a-960e-c8f444a1233f.jpeg)
[!](https://mander.xyz/pictrs/image/c7d6a44a-e4e1-4068-8375-521b2c29dc47.jpeg)
[!](https://mander.xyz/pictrs/image/c96d710d-674e-4d93-bbe6-eb1c61378323.jpeg)
[!](https://mander.xyz/pictrs/image/4feb9440-a880-47db-b8f3-b039213bc223.jpeg)
[!](https://mander.xyz/pictrs/image/453618d1-9f0b-42ec-b8f5-e10d5c1fba70.jpeg)
[!](https://mander.xyz/pictrs/image/c3973120-439d-4cfb-9206-25ec7124f702.jpeg)
[!](https://mander.xyz/pictrs/image/9e8c3c1d-082b-4ea6-b5f3-f230dd990684.jpeg)
[!](https://mander.xyz/pictrs/image/22f25807-630a-4cc4-a3e5-b89a72917f2a.jpeg)
[!](https://mander.xyz/pictrs/image/57aa0bce-9cb6-44e4-8f06-41a03d763103.jpeg)
[!](https://mander.xyz/pictrs/image/958a04c2-518f-4712-a01d-622fee5bbe01.jpeg)
Turmeric powder is a fantastic material to play with. The powder has a high concentration of colored and fluorescent curcuminoids and volatile turmerone oils.
When you use a polar solvent to extract these compounds, what you get is a kind of fluorescent oily resin called a turmeric 'oleoresin'.
The curcuminoids are yellow at acidic and neutral pH, but they become bright red at high pH due to keto-enol tautomerization. There is a lot of cool things you can do with the curcuminoids in terms of photo/electrochemistry.
I have been playing with very simple chemistry under the microscope, and I have noticed that you can create some cool-looking micro-landscapes. During this process you can also see different types of physico-chemical processes happening in real time.
Procedure to do this:
- Place a few grams of turmeric powder into a glass container
- Add enough isopropanol to cover the material, and a bit more
- Mix
- Wait for the solids to settle
- Collect a bit of the isopropanol liquid from the top and place on a glass coverslip
- Wait for the isopropanol to evaporate.
At this time, you can see under the microscope that golden oil droplets have been deposited, and that the surroundings are also yellow. The drops are oleoresins, which consist of curcuminoids suspended in turmerones and other oily compounds. Thin curcuminoid films might also be forming in between these droplets.
-
Add a sprinkle of baking soda crystals (sodium bicarbonate) on top of the coverslip. You can blow on the coverslip if you accidentally add too much.
-
Add a small drop of water, and wait a bit.
At this time you can see that the crystals are dissolving under the microscope, but the colors are not changing. The water and oils are not mixing, and so you get this film of alkaline water surrounding the oil droplets, but nothing is yet really changing.
- After waiting a few minutes, add a drop of isopropanol.
Now the isopropanol will re-dissolve the oleoresin and mix with the alkaline water. The carbonate ions are now able to react with the curcuminoids, and when they do, they go into the ketone form and instantly turn red. Under the microscope you can see quite dramatic movements of yellow and rad streaking as well as turbulent movements of the baking soda crystals.
-
Wait some time for the liquids to evaporate again
-
You will end up with a landscape that combines yellow resins, red resins, sodium bicarbonate crystals, and several different patterns.
-----
You can vary the parameters - the amount of sodium bicarbonate, the position and size of the drops, you can pre-mix the water and isopropanol, etc. Small changes can drastically affect the resulting landscape.
I just learned about hobby and read through some discussions about space weather in the spaceweatherlive forum.
It is not clear to me from those discussions where the data they discuss is coming from.
Are there tools that one can have at home to track space weather events? Through hobby-grade telescopes can one observe solar activity? Are diagnostic radio signals detectable with an SDR? Can an X-ray/gamma burst produce a strong enough diagnostic signal to detect with a radiation detector? Or are there some other type of detectors?
Is the main source of data used for interpreting solar activity patterns as a hobby the data that can be found here: https://www.spaceweatherlive.com/ ?
This is a stack of 7 images, you can click on the image to see the full resolution and guess what the subject is :D
The photos were taken using a Nikon D7500 camera connected through a T2 adapter tube with 2X magnification (NDPL-1(2X)). Microscope is the Swift SW380T. The objective is a 4x Plan objective.
For stacking the images together I use three tools: ImageMagick's mogrify to transform from the raw NEF files to .tif, Hugin's align_image_stack function to align the images, and enfuse to blend the images together.
The output .tif file was post-processed using rawtherapee in order to increase local contrast and tune some other parameters.
The process of focus stacking a set of images is rather simple in Linux. The programs above can be installed via the package manager. Then, you copy the raw files to focus-stack into a folder, and run the following sequence of commands:
``` (1) Convert from RAW to TIF:
mogrify -format tif *NEF
(2) Align images
align_image_stack -a aligned_ -v -m -g 10 -C *.tif
(3) Focus stack
enfuse -o result.tiff --exposure-weight=0 --saturation-weight=0 --contrast-weight=1 --hard-mask aligned_*
```
Below are the images used for the stack after alignment, for reference:
The linked video is about the open source 3D printable "Portable Upgradeable Modular and Affordable" (PUMA) microscope. The channel has several videos explaining fundamental concepts in microscopy and showing practical examples.
The github is here: https://github.com/TadPath/PUMA
The microscope can already perform many types of advanced techniques, and it is still being actively developed. The git states that the author is currently working on a motorized XYZ precision CNC stage. These precision stages are usually quite expensive, and they are very interesting because they enable some scanning microscopy techniques.
I am not associated with this in any way, I just watched a few videos and found them interesting enough to share.
This specimen came from a slimy film of algae that grew in one of my algal cultures. I think that it is a Nostoc. Objective is 40x/0.65
This image was taken through the 100x oil objective and a 2x camera adapter projecting the image into a Nikon D7500. The sample is a leaf from one of my plants (Dioscorea elephantipes, but I don't think this picture would look very different for other plant species)
The edges of he leaf were already yellowish brown. Here is a photo of that area with much less chlorophyll:
And here is a photo through the 40x objective using oblique illumination:
If you want to see some really fantastic photos of plant stomata I recommend having a look at Rolf Vossen's photographs here: https://microscopyofnature.com/stomata
I am looking through his documentation trying to understand how he managed to get those images. They are spectacular.
I prepared a 1:200 dilution of red blood cells using a ~1% NaCl solution. The imaged region contains 4 nano liters of the diluted sample. This image was taken using a 40x objective.
A count is performed by counting the number of red blood cells in a few of these sections, averaging the result, and then converting back to red blood cells per microliter by multiplying times 200 (dilution) and dividing by 0.004 (sampled volume in micoliters).
For this particular sample I estimated 3.8 million red blood cells per micro liter of blood.
I tested a few different types of hemocytometer/Neubauer chambers from China and I can recommend this specific one:
There are some even cheaper alternatives but the lines are very difficult to see.
I followed the Gram Staining tutorial from this video to prepare a sample of my cheek cells: https://www.youtube.com/watch?v=lMoT-FmhS6A
For preparing the staining solutions I purchased crystal violet, ethanol, potassium iodide, iodine, and an already prepared safranin solution from laboratorium discounter.
The slight 3D effect is achieved by displacing the filter holder to block the light coming from one direction and achieve oblique illumination to cast a shadow (https://www.youtube.com/watch?v=9btIpf5mjyA).
The image is post-processed using Rawtherapee to increase the contrast.
Here is another photo without using the oblique illumination trick, also post-processed with rawtherapee:
[!](https://mander.xyz/pictrs/image/01e6eb27-0e1f-4948-afc1-ee921b9bc713.jpeg)
In trying to isolate Trebouxia from an Evernia lichen. I found that some of the cultures are contaminated by a what I think are rotifers. I am not sure of what kind of rotifer (or other organism) is the one pictured, so if anyone has some idea please let me know.
I also recorded a video of what I think are belloid rotifers feeding on the same lichen culture:
https://peertube.uno/w/uoSCNagVVmbuMcgXdVfPGR
I don't have much hope that the algae will survive this attack, but I might turn those jars into rotifer cultures.
I left a slide with some algae and rotifers sitting on the microscope. After it dried up I was able to see several of these flower-like shapes. Not a pattern that I had seen before, and I a don't know what about the drying process lead to this particular shapes forming.
>Abstract > >Non-contact mechanical control of light has given rise to optical manipulation, facilitating diverse light-matter interactions and enabling pioneering applications like optical tweezers. However, the practical adoption of versatile optical tweezing systems remains constrained by the complexity and bulkiness of their optical setups, underscoring the urgent requirement for advancements in miniaturization and functional integration. In this paper, we present innovations in optical manipulation within the nanophotonic domain, including fiber-based and metamaterial tweezers, as well as their emerging applications in manipulating cells and artificial micro-nano robots. Furthermore, we explore interdisciplinary on-chip devices that integrate photonic crystals and optofluidics. By merging optical manipulation with the dynamism of nanophotonics and metamaterials, this work seeks to chart a transformative pathway for the future of optomechanics and beyond.
About two years ago I wanted to learn more about lichen. Since I cultivate mushrooms as hobby, I figured that attempting to isolate the wild lichen symbionts and then re-synthesizing the lichen would be a good way to learn about them. The experiment was not successful, in part because it is a long process and at one stage I did not give it the attention it needed. But at least I can share a bit of the process and observation.
Near where I live I can easily find Oakmoss (Evernia prunastri) and the Yellow Wall Lichen (Xanthoria parietina).
I collected small samples of each and placed very small pieces of them into many agar dishes. The idea here is that, coming from a wild source, contaminants will be present for sure. The process of isolation is an iterative process in which you observe the growth on the plate, pick out a small region where your target organism is growing strongly, and then move it into another plate.
This is an agar plate into which pieces of Evernia were added:
[!Wild cuture of evernia, contaminated](https://mander.xyz/pictrs/image/1e4ba003-8897-452f-b697-873002c0b286.jpeg)
In this image you can see that there is a wedge with fluffy white mycelium, which was consistent with the morphology for the mycelium of this species as described in the literature. So, I would pick a tiny piece from this region and transfer into a new plate, to obtain a clean mycelium after 1 or 2 transfers:
[!Pure culture of evernia](https://mander.xyz/pictrs/image/f1069ea8-43dc-48cf-ac41-7c38c6e56c68.jpeg)
This process was also performed for Xanthoria parietina.
After this step, I had plates with "clean" mycelium but not yet confirmation that the mycelium was truly the lichen's mycobiont. That is when microscopic identification comes into play. I was especially happy with the microscopic images I was able to get of the Xanthoria because they clearly show structures that are very characteristic structure of "septate, pluricellular, branched hyphae" described in the literature.
[!The microstructure of Xanthoria](https://mander.xyz/pictrs/image/bc92c71a-924f-4f6f-ac5f-b6ff21cf7d85.jpeg)
At this point I now had the fungal component isolated in agar plates. This was for me the easy part because I am familiar with growing mushrooms. But to build a lichen we need two parts: a fungus and an algae.
From a search I could find that both lichen species may use algae of the genus Trebouxia as a symbiont. I placed small pieces of each lichen into water and made the following observations:
- When placed in water, some of the algal cells become dislodged and float away
Photo: Algal cells floating away from a piece of Evernia prunastri
[!](https://mander.xyz/pictrs/image/11f675f2-b633-4a09-8b78-c7e1f175355f.jpeg)
- The algal cells can be seen held loosely in between the hyphae, rather than incorporated into the hyphal structure
Photo: Algal cells loosely bound to the hyphae of Evernia prunastri
[!](https://mander.xyz/pictrs/image/15816855-42c5-4420-9734-b5f652433152.jpeg)
Photo: Cluster of algal cells bound to the surface of a hypha of Xanthoria parietina
[!](https://mander.xyz/pictrs/image/4c804f00-fb24-40bc-8b8d-8f7b0033aca7.jpeg)
- Both species contained algar with similar if not identical round morphologies
Photo: Individual algal cell released from Xanthoria parietina
[!](https://mander.xyz/pictrs/image/d70cf479-ef35-4954-9dfb-d1c3990f3871.jpeg)
- The round morphology is consistent with Trebouxia
.... So, at this point I had successfully isolated the fungal partner and had some evidence to suggest that the binding between the fungus and the algae is loose. Since I saw that the algae could be released from a lichen, an easy thing try was to attempt to transfer the algae from a living lichen to the mycelium culture.
This is a photo of that attempt. Small pieces of wild Evernia were placed on top of a mycelium culture that was already several weeks old.
[!](https://mander.xyz/pictrs/image/a511f8cb-896e-4514-9475-9c8321cd665d.jpeg)
This... Did not work at all. The culture eventually became contaminated and was thrown away.
The next attempt was to try to grow the algae separately. One method was to place the wild lichen into agar dishes with no added nutrients end expose the dishes to the sun. The logic here is that the algae will survive from photosynthesis while the rest of the species do not have the nutrients to thrive on. I tried this on about 15 plates, different light conditions, but nothing grew other than a few weakly growing contaminants in some of the dishes...
Another method was to place the lichen into a glass jars filled with water and place those by the window at different levels of shade.
In the meantime, I decided to grow "grain spawn" jars out of the mycobiont thinking that this would give me a lot of material to work with once the algae grew. Both fungi did colonize the grain well. However, those jars were abandoned and eventually, after several months of storage, became contaminated and I had to toss them away.
It has been almost two years and I just had a look now at how the algae in jars are doing.
In the Xanthoria jar I can see significant algal growth. As for the Evernia, the algae did not make it but it looks like the mycelium did, as it has created a floating white blob.
[!](https://mander.xyz/pictrs/image/1f4f1413-e49b-4e24-8412-4702071b6901.jpeg)[!](https://mander.xyz/pictrs/image/6660000d-76ce-4739-8015-69f81d6748b1.jpeg)
A few months after having the algae jar sitting by the window I analyzed the mixture under the microscope and did observe a large amount of Trebouxia.
Right now I have checked another sample, and, while I do see what looks like a bit of Trebouxia (marked with a red arrow), unfortunately most of the mixture now consists of other unidentified algal species. Since Trebouxia is not the dominant species, it would probably be easier to re-isolate the algae from the wild instead of trying to isolate it from this mixture.
[!](https://i.imgur.com/F7MmjaX.jpeg)
I will give it a second try, and this time I will place more emphasis on culturing the algae first and keeping the cultures healthy and pure.
The SCD4x sensor from Sensirion measures CO₂, temperature, and humidity, and communicates these values via I²C.
The measurement principle for the CO2 is that of photoacoustic sensing. The fundamental principle is shown in the diagram below: shine light that the CO2 molecules absorb and use a microphone to listen to the pressure variations.
!Principle of the CO2 sensor via photoacoustic sensing
I ordered a batch of SCD41 sensors from China for various projects, including fermentation, mushroom and plant cultivation, and field monitoring.
Since I had extras, I sacrificed one for macro photography. I removed the cover with a dremel and pliers, then cleaned the internals using isopropanol.
[!](https://mander.xyz/pictrs/image/a24bbff2-f141-490a-9e97-b470b89a2610.jpeg)
Here is my take:
The temperature and humidity are measured by Sensirion’s SHT40, seen as the black square at the bottom right. It’s likely accessed by the internal microcontroller over an internal I²C bus.
The pink square at the top left is a MEMS IR emitter. The SCD4x datasheet doesn’t specify the emission wavelength, but 4.3 µm is standard for NDIR-based CO₂ detection. A similar emitter example is this one from Microhybrid. These emitters usually produce broadband IR, with a 4.3 µm band-pass interference filter on top. The pink hue likely comes from this filter. Filters like these are critical to target CO₂ absorption while avoiding spectral overlap with other gases. For further reading, see Infratec's application note and Delta Optical Thin Film’s technical explanation.
The gold component labeled “o119 ANC” is the MEMS microphone, used to detect pressure waves caused by gas molecules absorbing pulsed IR light—this is photoacoustic sensing. The vibration excited by 4.3 µm light occurs at ~70 THz, far beyond acoustic detection. However, the IR source is pulsed at a modulation frequency (typically 20–60 Hz, e.g. 40 Hz), and the microphone detects the resulting pressure variations at this frequency. The principle is outlined in patent US 2024/0133801 A1.
An example of a compatible MEMS microphone is Infineon’s IM72D128V01, which supports frequencies down to 20 Hz.
The final main component is the metal-shielded package. It likely contains a microcontroller responsible for:
- Driving the MEMS IR emitter with a modulated current (e.g., at 40 Hz)
- Capturing and analyzing the MEMS microphone signal to extract the amplitude of acoustic pressure oscillations (proportional to CO₂ concentration)
- Acting as an I²C master to retrieve temperature and humidity data from the SHT40
- Acting as an I²C slave to provide CO₂, temperature, and humidity data to an external controller
Here are top and bottom views of the sensor cap:
!Top view of cap of SCD41 !Bottom view of cap of SCD41
The cap has a circular gas inlet. The white material covering it is likely a hydrophobic ePTFE membrane, which allows gas exchange while blocking liquid water.
I hope someone else finds this interesting too!
---- EDIT: After posted this, I searched online and I found a photo from someone who went a deeper than me and did expose the microcontroller: https://www.hackteria.org/wiki/CO2_Soil_Respiration_Chamber
This is the photo borrowed from that site:
-----
The developers of Lemmy are currently under-funded and are asking for donations.
Community funding of projects like Lemmy offers an alternative to the commercial system in which projects are funded by investors looking to make a profit in the long run.
Unfortunately, community funding is not easy. Sometimes it might be because many of the users are unable and/or unwilling to donate, but sometimes it might also be that it is not clear that donations are needed, or users may underestimate the impact of their "small" donation. I am glad that the developers are explicitly asking for help at this point, and hope that they find support to continue.
Cross-posting and pinning this here to help them spread their call for help. I recommend placing comments directly to the original post so that it is visible to them.
cross-posted from: https://lemmy.ml/post/29579005
> An open source project the size of Lemmy needs constant work to manage the project, implement new features and fix bugs. Dessalines and I work full-time on these tasks and more. As there is no advertising or tracking, all of our work is funded through donations. Unfortunately the amount of donations has decreased to only 2000€ per month. This leaves only 1000€ per developer, which is not enough to pay my bills. With the current level of donations I will be forced to find another job, and drastically reduce my contributions to Lemmy. To avoid this outcome and keep Lemmy growing, I ask you to please make a recurring donation: > > Liberapay | Ko-fi | Patreon | OpenCollective | Crypto > > If you want more information before donating, consider the comparison with Reddit. It began as startup funded by rich investors. The site is managed by corporate executives who over time have become more and more disconnected from normal users. Their main goal is to make investors happy and to make a profit. This leads to user-hostile decisions like firing the employee responsible for AMAs, blocking third-party apps and more. As Reddit is a single website under a single authority, it means all users need to follow the same rules, including ridiculous ones like censoring the name "Luigi". > > Lemmy represents a new type of social media which is the complete opposite of Reddit. It is split across many different websites, each with its own rules, and managed by normal people who actually care about the users. There is no company and no profit motive. Much of the work is carried out by volunteer admins, mods and posters, who contribute out of enthusiasm and not for money. For users this is great as there is no advertising nor tracking, and no chance of takeover by a billionaire. Additionally there are no builtin political or ideological restrictions. You can use the software for any purpose you like, add your own restrictions or scrutinize its inner workings. Lemmy truly belongs to everyone. > > Dessalines and I work fulltime on Lemmy to keep up with all the feature requests, bug reports and development work. Even so there is barely enough time in the day, and no time for a second job. Previously I sometimes had to rely on my personal savings to keep developing Lemmy for you, but that can't go on forever. We partly rely on NLnet for funding, but they only pay for development of new features, and not for mandatory maintenance work. The only available option are user donations. To keep it viable donations need to reach a minimum of 5000€ per month, resulting in a modest salary of 2500€ per developer. If that goal is reached Dessalines and I can stop worrying about money, and fully focus on improving the software for the benefit of all users and instances. Please use the link below to see current donation stats and make your contribution! We especially rely on recurring donations to secure the long-term development and make Lemmy the best it can be. > > > Donate
