coral/ algae partnerships

[the guy]

in coral species which have a partnership with algae, how does the coral recieve the products of photosynthesis from the algae?

[Mokele]

The algae actually live in the stomach of the polyp, so they either excrete nutrients or are just digested.

[Moontanman]

I've been growing and propagating live coral for many years, almost 35 years. From what I've read about the process in my attempts to understand how and why coral grow the main idea is the Zooxanthellae leak their excess nutrients through their cell walls. No digestion of the Zooxanthellae actually occurs. I did a quick search to find some links to confirm this but I couldn't find any. It's been so long since I read this I can't remember the book or books i got it from.

[CharonY]

Well, physiologically it is almost impossible just to leak nutrients out of a functional cell (it would not be viable otherwise). At the very least a transporter has to be involved.

[Moontanman]

The term "leaks" could simply be a poor choice of words, excrete might be better. The algae is symbiotic with the corals. The way nutrients are transported to the coral is mutually beneficial and works both ways. The algae lives through out the flesh of the Coral, mostly at the surface of the polyps to maximize the absorption of sunlight. The bright colors of the corals is due primarily to the symbiotic algae and the reason for the pigments is to allow the algae to use sunlight outside the blue and red parts of the spectrum generally used by plants. Many of the pigments allow the use of UV light by the algae.

Edited September 2, 2009 by Moontanman

[Tonington]

The zooxanthellae resides in the gastrodermis of the coral polyps, specifically in vacuoles. The concentration is quite high, at up to one million dinoflagellates per square centimeter; though the density is dependent on coral/algal species. The actual mechanism by which the corals derive nutrition from the algae is via translocation of the photosynthetic products.

 

There is a fairly rich literature on this subject.

[the guy]

would you be able to explain that in a bit more detail?

[periphery]

translocation of photosynthate is my vote as well, as stated above there are osmotic gradient distributions so common in cell biology, vacuole or gated pathways for the nutrients to make it's way and who knows what they will find in the future. I do think that one interesting notes is that they don't store up nutrients in specialized structures like plants and roots, tubers etc. other than in tissue abundance, the relationship needs to be ongoing and consistent unless you are dealing with a highly heterotrophic species that can capture it's own food.

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Merged post follows:

Consecutive posts merged Edited November 3, 2009 by periphery
Consecutive posts merged.

[greenprogrammin]

Do Coral have a biofilm on their surface?

Are the Algae embedded in the tissue of the coral?

 

I'm sooo not familiar with coral (sorry).

 

I know some Algae can fix nitrogen and/or Carbon but I'm not sure if they are part of a biofilm or tissue that is sybiotically supportive of the coral.

 

I'm guessing the Algae is embedded and the cellular metabolites of the coral is dependant on the production of a essential product of the algae.

Another guess is the need to fix a primary metabolite.

 

Depending on that primary metabolite will probably depend on the availability and method of transfer (passive/active transport, diffusion/osmosis, etc...).

 

I hope this may help develop a better understanding on the symbiotic nature between the two.

 

Believe me...

I don't know what I'm talking about.

Ssooo Beee Careful!

hahaha

C-Ya

Edited November 7, 2009 by greenprogrammin