Neptune Aquatics

Zooxanthellae


@NanoCrazed reported good results on an anemone, with pics!

Bruce made a couple posts in the thread too...
 
Thanks for finding it. Stuff seemed to work. I'm amazed. I did talk to Chad at RN about it briefly, and he was aware of it, but had no knowledge of whether it would work at all.
 
I find this topic fascinating. I’m not personally convinced yet that this product is “working” vs natural re-accumulation of zoox after expulsion following a stressor. I haven’t seen any controlled studies with commercial products, but if anyone knows of any I’d be interested. Certainly plausible from a biology perspective since we know zoox can be taken up from the water by coral, but there are large quantities of zoox in reef tanks at all times, so I’m not sure if adding more necessarily helps.
 
But are corals somewhat species specific? Or is it any zooanthelle in a storm?
As far as I know no they aren’t specific.
I recall a speaker talking about gfp (green Flourecent pigment) “invading” other corals. He showed a pic of a monti setosa with green in it.
But then again I know next to nothing about this. Anyone know more?
 
I'm tempted to set up one of those IM divided tanks and brown out some corals. Use the Zooanthelle stuff on one side, and not the other. :)
That would be interesting- but I think you would want to bleach them out, not brown them out

Bleaching is when they expel all their zoox’s
Browning is when they have too many zoox’s

And just to make sure we are all on the same page, coral bleaching has nothing to do with bleach :)
 
But are corals somewhat species specific? Or is it any zooanthelle in a storm?
As far as I‘m aware, that is not well understood. Less than you would think is known about zoox/coral symbiosis, but it is a very active area of study.

This particular product claims to have 2 different strains of zoox, for what that’s worth.

We have a resident expert, I’m interested to hear his insight - @gaberosenfield ?
 
That would be interesting- but I think you would want to bleach them out, not brown them out

Bleaching is when they expel all their zoox’s
Browning is when they have too many zoox’s

And just to make sure we are all on the same page, coral bleaching has nothing to do with bleach :)
You don’t have a tank full of coral skeletons that you bleach every month or two to keep bright white? Wait, aren’t we in the 80s/90s still?
 
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“Over the course of their lives, corals are able to obtain multiple different species of zooxanthellae. During a bleaching event the zooxanthellae may be expelled from the coral, and if the coral survives, its tissues can be re-populated by a different species of zooxanthellae” (Muller-Parker et al, 2015).

Wonder why they chose the 2 zooxanthellae in the product. Are the two species in the bottle just the easiest to collect and grow, or were they chosen for their versatility?
 
As far as I‘m aware, that is not well understood. Less than you would think is known about zoox/coral symbiosis, but it is a very active area of study.

This particular product claims to have 2 different strains of zoox, for what that’s worth.

We have a resident expert, I’m interested to hear his insight - @gaberosenfield ?

TLDR:
"Browning" does not indicate the coral/anemone is unhealthy, just that it isn't producing the fluorescent pigments we think are so pretty under its current environmental conditions. "Bleaching" occurs when a coral/anemone expels most/all of its "zoox" due to some stress, most famously high temperatures. Different cnidarians, even different strains of the same species, prefer different strains of "zoox", and different strains of "zoox" appear confer advantages to their host cnidarian under different conditions. Although adding more "zoox" to a tank could theoretically decrease the time it takes for a bleached cnidarian to recover, I doubt the AlgaGen PhycoPure(TM) Zooxanthellae product really helps. As already suggested by @Bruce Spiegelman & @JVU, an experiment would need to be conducted on each individual coral under given tank conditions to determine whether the AlgaGen product actually helps.

My thoughts in (very) long-form:
The term "zooxanthellae" was coined to refer to the algae that live inside cnidarian cells before we could sequence DNA. Since then, researchers have used DNA sequencing to determine there are many different types of "zooxanthellae" living both inside corals and other animals, as well as free-living types. Some of these "zoox" strains are so genetically different that the "zooxanthellae" group has been converted into a family of algae called the Symbiodinaceae (pronounced sym-by-o-din-ay-see). To get a sense of the biodiversity of "zoox", consider that the family containing Homo sapiens (us) is called the Hominidae and contains all the great apes: humans, chimps, orangutans, and gorillas. But this analogy does not do justice to the diversity of "zoox": while all the members of Hominidae had a common ancestor ~14 million years ago, the last common ancestor of Symbiodinaceae coincided with the last common ancestor of Scleractinia (modern hard corals) ~170 million years ago. In light of these discoveries scientists no longer use the term "zooxanthellae", preferring the term Symbiodinaceae for the whole group, or specific genera and species names for specific algal strains (e.g. Symbiodinium microadriaticum). See the figure I've copied from the 2018 paper by LaJeunesse et al. entitled "Systematic Revision of Symbiodiniaceae Highlights the Antiquity and Diversity of Coral Endosymbionts" published in Current Biology for an overview of the phylogeny of the Symbiodinaceae:
1586645949885.png


As you can see, there are many strains of Symbiodinaceae and at least some species from most of these genera can be symbiotic with some cnidarians. However, individual species of cnidarian have preferences based on factors we don't yet understand. For example, Exaiptasia pallida (one of the common tank pests reefers typically call "Aiptasia") cannot form a symbiosis with Effrenium voratum (clade E Symbiodinaceae), but can form symbioses with species from Symbiodinium and Breviolum (Symbiodinaceae clades A and B). Other species of cnidarian have different preferences.

Furthermore, different Symbiodinaceae species appear to confer varying levels of tolerance to their host corals for different environmental conditions. For example, Exaiptasia pallida strain CC7 was collected from the Florida Keys and found to contain a Symbiodinium species. In the lab, we bleached some clones of this anemone strain and reinfected them with a Breviolum species (despite the negative connotation of the word, we refer to the formation of a symbiosis between a Symbiodinaceae strain and a cnidarian as an "infection"). In experiments, we found that CC7 anemones harboring Symbiodinium algae were more resistant to heat-induced bleaching than genetically identical CC7 anemones harboring Breviolum algae.

I don't mean to throw stones at the AlgaGen PhycoPure(TM) Zooxanthellae product, but their website does not specify what strains they use (although it is probably good they use two strains), nor does it specify how they grow and confirm the identities of their algae. Symbiodinaceae algae grow quite slowly compared with other microalgae (doubling time ~5 days under lab conditions) and are easily overgrown and/or contaminated in culture. Even under laboratory conditions, we have to genotype our strains every 6 months or so to confirm they are still what we think they are! Also the age of the algal cells dramatically impacts their ability to infect cnidarians, with newly divided cells being far more competent to form symbioses than those that haven't divided in a few weeks. As pointed out by @JVU, it's also worth remembering that healthy corals are constantly spitting out some Symbiodinaceae from their gastric cavities, and therefore I expect all established aquaria to contain populations of Symbiodinaceae algae that can theoretically reinfect bleached corals (this is one of the ways that bleached corals can recover in our tanks). Finally, many apparently bleached corals are not completely bleached; most still contain a small population of algae that can repopulate the coral over time under the right conditions. For reference, it takes weeks of treatment with photosynthesis-inhibiting drugs or months in total darkness to completely eliminate Symbiodinaceae algae from Exaiptasia pallida in the Pringle lab at Stanford.

Given all these variables, I doubt the AlgaGen product helps under most circumstances and I'd bet money it is not a panacea for bleached cnidarians in general. However, I cannot be sure of this and will change my mind as soon as I'm presented with properly controlled empirical evidence. That's the beauty of science: you can always be proven wrong!

Thanks for requesting my input @JVU and sorry I responded with an essay!
 
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TLDR:
"Browning" does not indicate the coral/anemone is unhealthy, just that it isn't producing the fluorescent pigments we think are so pretty under its current environmental conditions. "Bleaching" occurs when a coral/anemone expels most/all of its "zoox" due to some stress, most famously high temperatures. Different cnidarians, even different strains of the same species, prefer different strains of "zoox", and different strains of "zoox" appear confer advantages to their host cnidarian under different conditions. Although adding more "zoox" to a tank could theoretically decrease the time it takes for a bleached cnidarian to recover, I doubt the AlgaGen PhycoPure(TM) Zooxanthellae product really helps. As already suggested by @Bruce Spiegelman & @JVU, an experiment would need to be conducted on each individual coral under given tank conditions to determine whether the AlgaGen product actually helps.

My thoughts in (very) long-form:
The term "zooxanthellae" was coined to refer to the algae that live inside cnidarian cells before we could sequence DNA. Since then, researchers have used DNA sequencing to determine there are many different types of "zooxanthellae" living both inside corals and other animals, as well as free-living types. Some of these "zoox" strains are so genetically different that the "zooxanthellae" group has been converted into a family of algae called the Symbiodinaceae (pronounced sym-by-o-din-ay-see). To get a sense of the biodiversity of "zoox", consider that the family containing Homo sapiens (us) is called the Hominidae and contains all the great apes: humans, chimps, orangutans, and gorillas. But this analogy does not do justice to the diversity of "zoox": while all the members of Hominidae had a common ancestor ~14 million years ago, the last common ancestor of Symbiodinaceae coincided with the last common ancestor of Scleractinia (modern hard corals) ~170 million years ago. In light of these discoveries scientists no longer use the term "zooxanthellae", preferring the term Symbiodinaceae for the whole group, or specific genera and species names for specific algal strains (e.g. Symbiodinium microadriaticum). See the figure I've copied from the 2018 paper by LaJeunesse et al. entitled "Systematic Revision of Symbiodiniaceae Highlights the Antiquity and Diversity of Coral Endosymbionts" published in Current Biology for an overview of the phylogeny of the Symbiodinaceae:
View attachment 14964

As you can see, there are many strains of Symbiodinaceae and at least some species from most of these genera can be symbiotic with some cnidarians. However, individual species of cnidarian have preferences based on factors we don't yet understand. For example, Exaiptasia pallida (one of the common tank pests reefers typically call "Aiptasia") cannot form a symbiosis with Effrenium voratum (clade E Symbiodinaceae), but can form symbioses with species from Symbiodinium and Breviolum (Symbiodinaceae clades A and B). Other species of cnidarian have different preferences.

Furthermore, different Symbiodinaceae species appear to confer varying levels of tolerance to their host corals for different environmental conditions. For example, Exaiptasia pallida strain CC7 was collected from the Florida Keys and found to contain a Symbiodinium species. In the lab, we bleached some clones of this anemone strain and reinfected them with a Breviolum species (despite the negative connotation of the word, we refer to the formation of a symbiosis between a Symbiodinaceae strain and a cnidarian as an "infection"). In experiments, we found that CC7 anemones harboring Symbiodinium algae were more resistant to heat-induced bleaching than genetically identical CC7 anemones harboring Breviolum algae.

I don't mean to throw stones at the AlgaGen PhycoPure(TM) Zooxanthellae product, but their website does not specify what strains they use (although it is probably good they use two strains), nor does it specify how they grow and confirm the identities of their algae. Symbiodinaceae algae grow quite slowly compared with other microalgae (doubling time ~5 days under lab conditions) and are easily overgrown and/or contaminated in culture. Even under laboratory conditions, we have to genotype our strains every 6 months or so to confirm they are still what we think they are! Also the age of the algal cells dramatically impacts their ability to infect cnidarians, with newly divided cells are far more competent to form symbioses than those that haven't divided in a few weeks. As pointed out by @JVU, it's also worth remembering that healthy corals are constantly spitting out some Symbiodinaceae from their gastric cavities, and therefore I expect all established aquaria to contain populations of Symbiodinaceae algae that can theoretically reinfect bleached corals (this is one of the ways that bleached corals can recover in our tanks). Finally, many apparently bleached corals are not completely bleached; most still contain a small population of algae that can repopulate the coral over time under the right conditions. For reference, it takes weeks of treatment with photosynthesis-inhibiting drugs or months in total darkness to completely eliminate Symbiodinaceae algae from Exaiptasia pallida in the Pringle lab at Stanford.

Given all these variables, I doubt the AlgaGen product helps under most circumstances and I'd bet money it is not a panacea for bleached cnidarians in general. However, I cannot be sure of this and will change my mind as soon as I'm presented with properly controlled empirical evidence. That's the beauty of science: you can always be proven wrong!


Thanks for requesting my input @JVU and sorry I responded with an essay!
That was a lot of info, but I bet you have more. Sounds like we need a club meeting to all listen to you speak! (Please)
 
That was a lot of info, but I bet you have more. Sounds like we need a club meeting to all listen to you speak! (Please)
I'd be happy to attend/speak at a club meeting, but most of my "uncommon" knowledge within the reefing community isn't very useful/practical. I'm no better, and often worse, at keeping corals alive and thriving than you all are!
 
Love it!! Thank you very much, super informative, maybe the most informative post I’ve ever seen on the subject in any reefkeeping forum.

I agree further discussion would be fun at one of our meetings... once we can actually meet again.

In the hobby we spend a lot of time/money/worry about proper lighting, flow, feeding, nutrients, etc for our coral. But we pay almost no attention to the symbiotic algae in them that are providing most of the actual nurishment, not to mention coloration, to the corals. I’d love to learn more.
 
Thank you for taking the time to convey all that. It was a fascinating read. One of these days I'd love to see a "Consumers Report Company" of reef products. Snake Oil or Science -- and see actual lab experiments performed. Rich's talk on many well-known products that don't have a lick of science behind their claims always amuses me.
 
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