This week we have a special show. In Topic one we are joined by Jake Adams who discusses some topics about zooxanthellae, and then In topic 2, Jake interviews Dr. Dan Thornhill of The university of George Athens

Get the show notes here (http://www.talkingreef.com/ShowNotes/TR-Ep-41.html)

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As always,,A+++++++++++! Thanks Rob and Jake! So here is a basic question for everyone, Is there a way to visually tell if a coral contains zooxanthellae? Also, in the show you talked about coral bleaching and how it's caused by exposure to high lighting and high temps along with possible loss of water current. Is it the actual increase in temperature that causes the bleaching or is it the exposure to too much light? Once again, thanks for the show!

it can actually be either, but my understanding is that high/low temps is a very common cause for bleaching.

i will make sure Jake keeps an eye on this thread and can answer these also.

thanks again for the comments.. :D

Many thanks both - very interesting. I'v noticed corals that are bleaching or near bleaching when they are first put in the tank - then recover - so the adaptive hypothesis many explain that.

More of this advanced material would be great:)

Many thanks for all your efforts.

Welcome to TR trythechi! ;)

I'm listening to the show now- it sounds like I'll have to listen to this one about 10 times before I understand it! Thanks Jake, Dan, and Rob!!

Awesome!!! This is one of the most informative, (at least for me), podcasts. I"m really surprised at the fact that Jake was able to pack so much useful info in a 30 minutes show and still make it so the information didn't go right over our heads. Awesome!!!

As always - a great show. Hopefully in the future there will be more advanced topics like this.

I thought I was pretty well versed in this hobby until I listened to that podcast.....

Needless to say it waaaaaay over my head :) but you did warn us before it began

Unfortunately, only your intro downloaded into my itunes. Nevertheless, the show was very informative. As an experienced hobbiest, I really like the science oriented nerdy stuff. Great job!

Jake and Dan - Thanks for the time and energy invested into this terrific podcast! I finally had time to listen to it (a week late!) and I loved it!

I had a bunch of well-thought out questions (at least I thought so) while listening to the show, but I guess I'll have to listen again, because I can't remember all of them!

But, here's a try:

1. What happens to the expelled zooxanthellae from corals such as Euphyllia? Are they dead and that's why the coral is expelling them?

2. Do the zooxanthellae proliferate within the coral? Or are they proliferating while free-living and then are incorporated into the host?

3. Does anyone know what the life-span is of a single zooxanthellae?

Thanks much!:D

Hey Guys. thanks for all the praise and the comments. I will try to answer all the questions, let me know if you have any more.

Is it the actual increase in temperature that causes the bleaching or is it the exposure to too much light?
Both increasing light and increasing temperature can cause a reduction of zooxanthellae concentration. IN the context of the adaptive bleaching hypothesis, it is often stressfully high water temperatures which induce expulsion of the zoox.

I'v noticed corals that are bleaching or near bleaching when they are first put in the tank - then recover - so the adaptive hypothesis many explain that.
DOnt confuse plain old regulation of zooxanthellae density for the adaptive bleaching hypothesis. Corals and symbionts are in this dance of always trying to strike a balance between the needs of the symbiont and the host. When a coral expels all its zoox, it is basically wiping the dance floor clean and starting over. ;-)

1. What happens to the expelled zooxanthellae from corals such as Euphyllia? Are they dead and that's why the coral is expelling them?
When a coral does a normal expulsion of zooxanthellae, appearing as an elongated brownish mucous strand, these are mostly dead zoox but there are plenty of live ones also.

2. Do the zooxanthellae proliferate within the coral? Or are they proliferating while free-living and then are incorporated into the host?
The zooxanthellae population living inside the coral is made up of mostly cells which have divided within the host but free-living cells are always being incorporated into the host.

3. Does anyone know what the life-span is of a single zooxanthellae?
I want to say that it is on the order of days to a couple weeks at most. its hard to pin down age of an organism that is constantly dividing.

Is there any validity to the idea that you can "seed" zooxanthellae? I'm not sure who originally did some of the work with blending up corals to use the zooxanthellae.

If you have a coral with a certain strain of zooxanthellae and add another genus/species of coral with the same strain can they "share"? For example if coral A is transfered from another tank and is stressed and slightly bleached (with continual polyp extension) can it borrow zooxanthellae from another coral?

Think of the symbiosis between corals and zooxanthellae as an infection, not necessarily one that causes problems like a cold but one that can be either harmless or beneficial. The coral itself is like a miniature environment for zooxanthellae. Coral A and zoox a get along well and coral b and zoox b get along well. if coral B loses all of zoox b and it there is zoox a around, it will most likely incorporate whatever zoox can live in its tissues. ALthough zoox a can live in coral b and coral b can live with zoox a, neither is as happy or prolific as when they are in symbiosis with their preffered type. As far as your sharing question goes, it is likely that there is (always) a cross infection of symbiodinium but likely in such small numbers that the prefered symbiont type is still dominant. This is assuming that the environment stays the same etc.

Hey Jake - did you change your username and avatar?

hey reefbaby, I am new to the site so my avatar and sig are new as well.

I really liked this show. Actually, I really like all of the shows!

I'm a science type person (my 17 year old says I am both a nerd and a geek) and really appreciated the way the information was presented.

CarmieJo..
we are always looking for more geeks...

Geek is Sheik

hey reefbaby, I am new to the site so my avatar and sig are new as well. coralite - oh, sorry, I must have confused you with another Jake!

In that case, WELCOME to TR!!!! :-)

Jake

Based on the comment by Dr. Thornhill about 80% of the corals in certain areas harbor the same clade of Zooxanthellae, can we safely deduct that maybe all these corals really don't differ as much as far as lighting requirements and feeding goes? That maybe this whole SPS/LPS "classification" maybe is way off? Maybe looking into coral requirements based upon Genus, Sp. or whatever is not as important as maybe looking at the area where they were collected. I know I'm overgeneralizing but i hope you can understand what I'm trying to get across.

Just musing, any thoughts?

Hey gman,

There is a definite correlation between the type of clade found in a coral and the depth at which the coral occurs. Although around 80% of corals at a certain depth share a common clade type, our definition of coral types still is pretty useful for many other biological characteristics such as preffered water flow, food types, general aggression and relative growth rate. So I wouldnt quite throw the lps/sps class out the window btu you're right in your assumption that some classic "lps" have definite sps-like preferences and vice versa. Does that answer your question? can I elaborate on some part of that for you?

Jake

Actually that those answer it very well TY. Another question regarding bleached corals in our tanks... would the chances of a coral recuperating their symbiotic zoox. be higher if it was housed in a tank with corals that are known to come from the same geographic region (f.e. Fiji/ PI ), than being housed with corals from another part? Or would it be just as good?

I understand there should be 100's of other factors contributing to the possible success of this, but I would assume it would be much easier if this was the case.

Ok... another question related to zoox. How about the relationship between zoox and coral pigmentation? What role if any do clades have in determining the coloration of a coral?

I like reading dissertations and scientific papers so anything you have that could be shared I would really appreciate it.

TY Jake and Rob for an awesome topic.

suprise, suprise, I'm back here asking a question about my poor old BTA's. It's a re-occurring theme, I know... don't worry, I'm only slightly obsessive.
Jake, are you aware of any cases where BTA's have repopulated their tissues with Zooxanthelae after bleaching? Can anything be done to encourage repopulation?

So - after listening to the Goniopora podcast and the topic of bleaching, I was wondering if any scientists have ever tried to reincorporate zoos into corals that have bleached. For example, could you keep a bleached coral (one that's bleached due to loss of zoos) in a quarantine tank and "dose" it with its preferred clade of zoos? Maybe thinking a bit futuristic here, but maybe one day we'll just be able to dose our sick/bleached corals with zoos in order to "boost" them back up again.

Is that kinda like if I die from an eating disorder- just pump some food back into my system and I come back to life!?! he he

Sounds good to me Christy!!

Well....I was thinking of course BEFORE you were actually dead! :-)

When I was at IMAC last weekend, we were sitting around and one of my friends told me that if you take a black light, you can see the free zooxanthellae in the water column. Has anyone ever done this?

To the site admin,

I am very interested in this episode on Zooxanthallae, however I am not able to download this from your suggested link and even the itune podcast(it seems like it is loading forever). Would you look into the links and help me with this mp3 episode and how I can download it? Thanks.

Eric

Welcome to TR Eric!! Great to have you hear.

I just checked the links - both on the website (http://www.talkingreef.com/forums/showthread.php?t=614) and in iTunes and both are working. Have you subscribed to the feed? You can also individually download shows. Do you have broadband or dial in? I've heard that for some people that have dial in, they've had problems.

Try opening iTunes on your computer and then going to the iTunes Store - Podcasts and do a search for Talking Reef, then either subscribe to the feed or download individual shows.

Let me know if it works for you! Best luck!

thanks Christi,

Eric, please do let us know if it does not work

Hi Eric,

Welcome to TR. Did you get your show?