A Spectrophotometer view of Photosynthetic Organisms in our Tanks

[taricha]

Anyone got any reading material on possible pigment differences (or a lack of) between zooxanthellae clades?

 

[oreo54]

A quote from that paper:
>>In Chlorella, energy transfer from PSII to PSI appears to play an important role in balancing excitation between PSII and PSI.<<
Really?

I'm just the messenger...

. All samples examined showed prominent distribution of delayed fluorescence in PSII and PSI, which suggests that a certain amount of PSII attaches to PSI to share excitation energy in red algae. The energy transfer from PSII to PSI was found to be dominant when the amount of phycoerythrobilin was increased.

https://www.sciencedirect.com/science/article/pii/S000527281100065X

 

[Dana Riddle]

I'm just the messenger...




https://www.sciencedirect.com/science/article/pii/S000527281100065X

My initial take on that sentence I quoted was that electrons flow from PSII to PSI. Well, yes. Upon further consideration, I think they meant to say that energy transfer is from a 'state transition' (aka 'spillover'.) This is known to happen in at least some zoox clades.

 

[taricha]

Odd little tid bit to go w/ this................

https://www.britannica.com/science/algae/Photosynthesis-and-light-absorbing-pigments

Related:
https://www.sciencedaily.com/releases/2014/09/140926085816.htm

Don't think either really "apply' here though..

Hopefully the second link about cryptomonas will apply to the thread. I've had them in my sand before. Slightly redder than cyano, until you hit them with peroxide. Then they turn highlighter pink.

 

[taricha]

Extracting zoox pigments from a few different corals. Been doing softies, as it's fairly easy to squeeze a few drops out and be reasonably free from interference from the host coral.
Thus far all the pigment profiles have been quite similar. My favorite part is that even a photosynthetic flatworm (Waminoa) that has symbiodinium dinoflagellates and a few amphidinium has an indistinguishable profile from the rest of the soft corals.

Compared to the large variations from pigments of the other classes (faded lines) these differences are very small and mostly just test inconsistencies. See differences in the two samples from same cabbage leather. Slight shifts in the location of the left peak indicate minor differences in ratios of Chl A, C, and carotenoids extracted.

The consistency gives me some confidence in what I should expect and that I'll be able to spot something weird if I run across it in a sample from a hard coral.

 

[Dana Riddle]

Extracting zoox pigments from a few different corals. Been doing softies, as it's fairly easy to squeeze a few drops out and be reasonably free from interference from the host coral.
Thus far all the pigment profiles have been quite similar. My favorite part is that even a photosynthetic flatworm (Waminoa) that has symbiodinium dinoflagellates and a few amphidinium has an indistinguishable profile from the rest of the soft corals.

Compared to the large variations from pigments of the other classes (faded lines) these differences are very small and mostly just test inconsistencies. See differences in the two samples from same cabbage leather. Slight shifts in the location of the left peak indicate minor differences in ratios of Chl A, C, and carotenoids extracted.

The consistency gives me some confidence in what I should expect and that I'll be able to spot something weird if I run across it in a sample from a hard coral.

I'm surprised the red cyanobacterium strongly absorbs red light since it reflects it.

 

[oreo54]

https://www.researchgate.net/figure...p-In-vivo-absorption-spectra-of_fig3_26652345
https://www.researchgate.net/figure...pectra-of-Synechococcus-PCC7942_fig1_26652345
https://www.researchgate.net/figure...-two-phycoerythrin-rich-and-two_fig5_23567573

 

[Dana Riddle]

Just for fun, let's compare the light absorption and action spectrum of zooxanthellae. An 'action spectrum' demonstrates the response (such as oxygen production) of a photosynthetic organism to wavelength (using a monochromator which splits full spectrum light into narrow bandwidths.)

 

[Dana Riddle]

Anyone got any reading material on possible pigment differences (or a lack of) between zooxanthellae clades?

These works don't address clades but do look at photoadaptation:

Titlyanov, E.A. and Y.Y. Latypov, 1991. Light dependence in scleractinian distribution in the sublittoral zone of South China Sea islands. Coral Reefs 10:133-138.


Titlyanov, E.A., 1981. Adaptation of reef-building corals to low light intensity. Proc. 4th Int. Coral reef Symp., Manila. 2:39-43.


Titlyanov, E.A., M.G. Shaposhnikova and V.I. Zvalinskii, 1980. Photosynthesis and adaptation of corals to irradiance. I. Contents and native state of photosynthetic pigments in symbiotic microalga. Photosynthetica 14 (3):413-421.


Titlyanov, E., T. Titlyanova, K. Yamazato and R. van Woesik, 2001. Photoacclimation dynamics of the coral Stylophora pistillata to low and extremely low light. J. Exp. Mar. Biol. And Ecol., 263 (2): 211 – 225. (Abstract).

 

[taricha]

I'm surprised the red cyanobacterium strongly absorbs red light since it reflects it.

The acetone is misleading, especially with cyano, because it doesn't get the phycobilins (phycoerythrin, phycocyanin) that determine the color and absorption profile.
It's also misleading for me to call them "green" "red" they are both brown under neutral light. The "green" is very brown, and the "red" is reddish brown.

I didn't have enough red cyano in my tank to get a sample of the raw absorption from the cells. So above I have "red" and "green" in 90% acetone, and "green" mashed up raw. The prominent absorption in the middle of the spectrum in the raw sample is the phycobilins.
The raw sample can be compared with the graphic from the 3rd link in @oreo5457 post above

 

[taricha]

Just for fun, let's compare the light absorption and action spectrum of zooxanthellae. An 'action spectrum' demonstrates the response (such as oxygen production) of a photosynthetic organism to wavelength (using a monochromator which splits full spectrum light into narrow bandwidths.)

awesome. Dana, any thoughts on what's going on in the green with the relative decrease 515-530 or relative increase 535-550nm? I thought photoprotection from carotenoids but their absorption cuts off further blue than that.
Another thought: this is right at the location of green fluorescence (lyndby 2016 has a nice graphic) but I don't see how fluorescence at that wavelength would suppress zoox production there.

 

[Dana Riddle]

awesome. Dana, any thoughts on what's going on in the green with the relative decrease 515-530 or relative increase 535-550nm? I thought photoprotection from carotenoids but their absorption cuts off further blue than that.
Another thought: this is right at the location of green fluorescence (lyndby 2016 has a nice graphic) but I don't see how fluorescence at that wavelength would suppress zoox production there.

Again, good work! I suspect the increase of oxygen production seen in the action spectrum at ~550nm is due to chromatic adaptation of the cultured zooxanthellae - likely due to an increase in the peridinin/chlorophyll pool. I looked at the Lyndby graphic ('g') and the reflectance spectral signature is that of Hochberg's 'brown' coral (as opposed to his other category - 'blue' coral.) Fluorescence apparently had little, if any, impact on the reflectance.

 

[Dana Riddle]

awesome. Dana, any thoughts on what's going on in the green with the relative decrease 515-530 or relative increase 535-550nm? I thought photoprotection from carotenoids but their absorption cuts off further blue than that.
Another thought: this is right at the location of green fluorescence (lyndby 2016 has a nice graphic) but I don't see how fluorescence at that wavelength would suppress zoox production there.

Another, if late, thought. The differences could *possibly* be due to the photoadaptive capability of the zooxanthellae clade. I'm unsure if LaJeunesse or Smith are still looking at zoox DNA. Might be some clues there, but my attention has been elsewhere for quite a while.

 

[taricha]

Another, if late, thought. The differences could *possibly* be due to the photoadaptive capability of the zooxanthellae clade. I'm unsure if LaJeunesse or Smith are still looking at zoox DNA. Might be some clues there, but my attention has been elsewhere for quite a while.

That action spectrum data is from within favia coral tissue? or is it zoox isolated out of the tissue in culture? I tried to hunt down source, but I didn't have luck.

On the clade idea - forgive this digression. I looked at the flatworm tissue under the scope, and found no symbiodinium at all - only amphidinium. (Pic)
This genus has a few symbiotic species, but mostly free living and they show up as pest dinoflagellates in people's tanks.
Interesting for two reasons.
One, I was hoping to get some pest dino spectral data anyway and this is at least close.
Two, the flatworm absorption was near identical to the other zoox samples from corals I took even though it's not symbiodinium at all. So I'll be increasingly surprised if/when we find a symbiodinium clade in corals whose absorption doesn't look much like the rest.

 

[Dana Riddle]

I've got to find that paper - the primary's name started with an 'H' but he is not in my data base. If I recall correctly, the zoox were isolated from the Favia host. I'll also list all zoox photopigments as described Jeffrey. She died five years ago and I treasure the conversations I had with her.

 

[taricha]

I've got to find that paper - the primary's name started with an 'H' but he is not in my data base. If I recall correctly, the zoox were isolated from the Favia host. I'll also list all zoox photopigments as described Jeffrey. She died five years ago and I treasure the conversations I had with her.

Thanks so much! Is it Halldal?

 

[Dana Riddle]

Thanks so much! Is it Halldal?

Yes! I copy and paste references from my Word document into articles. I must have cut it accidentally. Thanks for refreshing my fading memory!

 

[csb123]

Just sitting hear with my mouth hanging open in awe!

 

[SDchris]

Just for fun, let's compare the light absorption and action spectrum of zooxanthellae. An 'action spectrum' demonstrates the response (such as oxygen production) of a photosynthetic organism to wavelength (using a monochromator which splits full spectrum light into narrow bandwidths.)

Is it possible to roughly translate pigment composition percentages to action spectra? When you look at the pigment concentrations in this study. It would appear that the action spectra would be very different between the acro and brain corals.

 

[Dana Riddle]

Is it possible to roughly translate pigment composition percentages to action spectra? When you look at the pigment concentrations in this study. It would appear that the action spectra would be very different between the acro and brain corals.

Thanks for sharing that paper - very interesting. I'm busy today, but will study it as soon as I can. Particularly interested in examining photopigments v. zoox clades. Fascinating.