Julian: Mn and Fe and Goniopora

[Habib (Salifert)]

This is a question for Julian regarding his Goniopora article.

If another forum section is more appropriate for it then please feel free to move it.

Hi Julian,

I hope you are doing well.

I would appreciate if you could respond to the following.

The Goniopora sp. at Waikiki, for example, is in an open system fed plankton-free well water. If food were the only issue, surely specimens maintained in heavily fed aquariums would fare better than those maintained in sparsely fed aquariums. They apparently don't.

Has it been experimentally verified that it is free of plankton both day and night?

Did you consider the presence of other potential food sources such colloidal organic matter, snow, dissolved organics and bacteria?

and partly due to what I believe is the principle problem, oxidative stress damage

If there would be oxidative stress then it seems logical to me that the Goniopora would retract all it’s polyps immediately and fully in such a stress situation.
I personally have seen this with several Goniopora when temperature did rise suddenly to something like 34 C.

The Goniopora cf. tenuidens remained closed for several days, but I noticed that the addition of a supplement I prepared that contains iron and manganese seemed to stimulate polyp expansion in the coral within hours. When I discontinued the addition, after a few days the polyps remained contracted for days. When I added the supplement again they expanded within hours and stayed expanded for a few days. When I added the supplement regularly the polyps remained expanded and developed colorful tentacles

If it would have been oxidative stress and if the Mn and or Fe allowed the Goniopora to synthesize the superoxide dismutase then I don’t understand how it could recover so fast (hours) after being prolonged in a stress situation and not just a mild stress situation but one caused by superoxide or other reactive oxygen species. Wouldn't it?

It is known that some metals such as Mn and Fe readily form complexes with organic substances. Could it be that the complexes are more readily taken up by the Goniopora?
It is also known that some metals cause a feeding response in aquatic organisms and is probably one mechanism by which e.g. mussels sense the algae (copper or zinc adsorbed on the algae surface). Could it be that by addition of Mn and or Fe caused a feeding response in the Goniopora this caused by the (temporarily) free ions or as complexes with organic matter?

If this would be true or would not be unlikely then how could you seperate the oxidative stress effect from the starvation effect?

FWIW after the temperature rise (as mentioned above) one of the Goniopora remained completely closed for many months. When it started to expand it’s polyps again after that period it had become green. Initially it was brown.
There has always been sufficient iron and manganese in that tank.

Julian, many thanks in advance.

 

[THEFishHead]

Pardon me, but I can't seem to use the bold key to distinguish my text from Habib's, thus I inserted "Q' to indicate his question and "A" my response.


Q. Has it been experimentally verified that it is free of plankton both day and night?

A. Habib, My point was that the water supply is plankton free, being water taken from a deep well as opposed to fresh raw seawater. I later clarified the fact that the aquarium itself is a reef aquarium, so it certainly does contain some planktonic life due to the presence of live rock and associated fauna. That, however is no different from any other reef tank. One difference is that this well water is rich in Iron and Manganese (also nitrate and silicate, but those were not the subject of my article).




Q. Did you consider the presence of other potential food sources such colloidal organic matter, snow, dissolved organics and bacteria?

A. I don't believe the issue is food. The well water is inorganic rich and organic poor.








Q. If there would be oxidative stress then it seems logical to me that the Goniopora would retract all it’s polyps immediately and fully in such a stress situation.

A. No- the effect has to do with light. One can see it in that the most retracted polyps are the ones most brightly illuminated. In one sense you are right... if you provide strong enough light, or light for a long enough period, the polyps will retract completely






Q. If it would have been oxidative stress and if the Mn and or Fe allowed the Goniopora to synthesize the superoxide dismutase then I don’t understand how it could recover so fast (hours) after being prolonged in a stress situation and not just a mild stress situation but one caused by superoxide or other reactive oxygen species. Wouldn't it?

A. Wow- you managed with one question to pose about three. Hum, where to begin?

1. the stress from reactive oxygen species depends on their rate of generation and what form of oxygen, and how long the exposure, and what is being stressed- the cnidarian, the dinoflagellate, or both.

2. The response to the reactive oxygen (ie retraction of polyps) can exist before there is actual damage, as a means of minimizing potential for damage. The rate or capacity of dealing with the "stressor" is managed by such physical responses in addition to the use of SOD and other enzymes. The last resort is to expel the zooxanthellae, and that happens often after damage to tissues has already occured.

3. The synthesis of SOD by the cnidarian may or may not occur quickly. I do not know what an expected rate might be. All I know is that the qualitative response of addition of Mn and Fe is observable within hours. This does not necessarily mean the host cnidarian has synthesized SOD- the dinflagellates are likely also be involved in SOD formation, and their capacity to utilize these metals should be rapid. Your question reminds me that, among other things that I did not explain well this in the article, the host and its symbionts both benefit, and that while it is an area of scientific interest regarding coral bleaching, not much exists in the literature about SOD in zooxanthellae.






Q. It is known that some metals such as Mn and Fe readily form complexes with organic substances. Could it be that the complexes are more readily taken up by the Goniopora?

A. Yes and no, and I don't that this is the issue for Goniopora stokesi (remember, don't generalize the genus).

If iron and manganese availability are the issue, or if they at least help resolve the issue of oxidative stress, then it is more relevant to consider the fate of iron and manganese in aquaria, something I'm sure you know alot about. I suspect that in addition to the fact that these metals are rapidly taken up by algae and perhaps bacteria, they may also be lost from the water column due to precipitation by "kalkwasser." That is something I have not read about, but have hypothesized- It stands to reason that iron hydroxides should form and fall out of solution when kalkwasser is added. If iron is reaily available when kalkwasser is added, this may also assist the phosphate lowering capacity attributed to kalkwasser, since iron hydroxide strongly binds phosphate. Perhaps you, Randy, and Craig could confirm or dispute that idea- it's just an idea I have. By no means am I suggesting that kalkwasser harms Goniopora- don't misunderstand.








Q. It is also known that some metals cause a feeding response in aquatic organisms and is probably one mechanism by which e.g. mussels sense the algae (copper or zinc adsorbed on the algae surface). Could it be that by addition of Mn and or Fe caused a feeding response in the Goniopora this caused by the (temporarily) free ions or as complexes with organic matter?

A. Interesting idea but...nah, I don't think it plays a role in the response of the coral. The effect is something more like shade... relief from the damaging effect of the light.








Q. If this would be true or would not be unlikely then how could you seperate the oxidative stress effect from the starvation effect?

A. Very good question, and this must be taken into consideration in the experimental design! A confounding issue is that starvation is linked to the zooxanthellae as well, so it is not easy to separate them absolutely. I will have more to say on this in a follow up- be patient.










Q. FWIW after the temperature rise (as mentioned above) one of the Goniopora remained completely closed for many months. When it started to expand it’s polyps again after that period it had become green. Initially it was brown.
There has always been sufficient iron and manganese in that tank.

A. Such observations need closer examination. Protection from damaging effects of light affect both host and symbiont, and are produced in different ways by both. The color change you observed can be due to fluorescent protein(s) that react(s) to light and has a protective effect That's another long topic. Was the change related to the heat stress? The closing down certainly was, but the color change may have been a response to the light field. This coral had much to adapt to and it managed.

Heat and light work together to exacerbate oxidative stress (due to increased evolution and accumulation of reactive oxygen). SOD (in its various forms) is but one of the mechanisms that helps a coral deal with reactive oxygen species, albeit one of the most important ones. I do not propose that Mn and Fe are always the only thing needed to stop a bleaching event in general, but I do propose that the slow wasting problem affecting Goniopora stokesi is a type of bleaching event, and that Mn and Fe seem to be important for preventing this problem in its typical manifestation.

Other manifestations may include bacteria induced bleaching (though this is certainly not the common example), or other physiological or physical effects that produce bleaching (I believe your example falls in this category).

You're welcome,

Julian

P.S. Happy Holidays- I won't have a chance to reply again until after New Years.[/u]

 

[jamesw]

FYI, here are two photographs of the tank being discussed from the Waikiki Aquarium:

For more photos, please see the article:

http://www.advancedaquarist.com/issues/ ... /index.htm

I believe the goniopora being discussed is in the second photo. I hope this is of some assistance.

James Wiseman

[/url]

 

[simonh]

Is the Goniopora at Waikiki in the new display tank? If I remember correctly Bruce Carlson recently indicated at a talk in the UK that the new tank that Charles had setup was a little different from previous setups. It would not use well water and wasn't a flow through design? If so then it will be interesting to see how the coral progresses.

 

[Eric Borneman]

Hi Habib and Julian:

A few comments:

First, on the tentacle withdrawal response. A recent paper, in addition to previous ones showing the use of tentacle expansion contration to moderate light environments (most listed in this article), suggests that retraction is photoprotective in corals that cannot use xanthophyll quenching. Its also a paper by Craig Downs - Julian, you negelected to set in the ref for the Downs et al 2002, and Craig has put out a number of bleaching papers in the past few years - dealing with both SOD and hsp's (which are a whole nother ball of wax in bleaching responses). The ref I refer to is
B.E. Brown, C.A. Downs, R.P. Dunne, S.W. Gibb. 2002. Preliminary evidence for tissue retraction as a factor in photoprotection of corals incapable of xanthophyll cycling Journal of Experimental Marine Biology and Ecology277 129– 144

The one I think you might be referring to is:

C. A. Downs, John E. Fauth, John C. Halas, Phillip Dustan, John Bemiss, and
Cheryl M. Woodley 2002. Oxidative stress and seasonal coral bleaching. Free Radical Biology & Medicine, Vol. 33, No. 4, pp. 533–543

Also see

B. E. Brown, C. A. Downs, R. P. Dunne, S. W. Gibb. 2002. Exploring the basis of thermotolerance in the reef coral Goniastrea aspera MARINE ECOLOGY PROGRESS SERIES Mar Ecol Prog Ser Vol. 242: 119–129

Dykens, J. A. and M. Shick (1982). "Oxygen production by endosymbiotic algae controls superoxide dismutase activity in their animal host." Nature 297(17 June 1982): 579-580.

Lesser MP, Shick JM. 1989. Effects of irradiance and ultraviolet radiation on photoadaptation in the zooxanthellae of Aiptasia pallida: primary production, photoinhibition, and enzymic defenses against oxygen toxicity. Mar. Biol. 102:243-255.

Lesser MP, Stochaj WR, Tapley DW, Shick JM. 1990. Bleaching in coral reef anthozoans - effects of irradiance, UV radiation and temperature on the activities of protective enzymes against active. Coral reefs. 8:225-232

Lesser MP. 1996. Elevated temperatures und Ultraviolet radiation cause oxidative stress and inhibit photosynthesis in symbiotic dinoflagellates. Limnol. Oceanogr. 41(2):271-283.

Lesser MP. 1997. Oxidative stress causes coral bleaching during exposure to elevated temperatures. Coral Reefs 16:187-192.

and this might be helpful since it deals with G. stokesi


Marine Biology


Abstract Volume 137 Issue 1 (2000) pp 1-9
Localisation of antioxidant enzymes in the cnidarians Anemonia viridis and Goniopora stokesi

J. M. Hawkridge (1), R. K. Pipe (2), B. E. Brown (1)


Abstract Antioxidant enzymes scavenge to protect cells against destructive oxyradicals. In excess, reactive radicals can have wide-reaching consequences, including lipid peroxidation, protein degradation and DNA damage, resulting in tissue damage and cell death. Recently, oxyradicals have been implicated in coral-bleaching, but only the activities of antioxidant enzymes in the host and endosymbiotic algae have been reported. To locate the potential cellular targets of excess oxyradicals in cnidarians, it is important to establish in which cell areas these enzymes are active. Using immunocytochemical techniques, the antioxidant enzymes superoxide dismutase [SOD], catalase [CAT] and glutathione peroxidase [GPX] were localised in the sea anemone Anemonia viridis (Forskal) and the coral Goniopora stokesi (Edwards & Haime). Using affinity-purified primary antibodies and transmission electron microscopy, antioxidant enzymes were found predominantly associated with granulated vesicles, accumulation bodies of endosymbiotic algae and cnida. SOD and CAT gold-labelling was localised in all forms of cnida, with SOD being particularly pronounced on the ruptured threads and shafts of b-mastigophores in A. viridis, possibly suggesting that the b-mastigophore had undergone autolysis and required SOD to prevent damage to host cells. The presence of both SOD and CAT in the accumulation body of endosymbiotic algae is consistent with the hypothesised role of these bodies in digestion and cell-ageing. CAT was also found in isolated electron-dense bodies, often near microvillous borders in G. stokesi. Similar bodies were recorded in A. viridis, but contained GPX rather than CAT. GPX was also present in symbiotic algae, where it was associated with electron-dense bodies.

 

[delbeek]

Is the Goniopora at Waikiki in the new display tank? If I remember correctly Bruce Carlson recently indicated at a talk in the UK that the new tank that Charles had setup was a little different from previous setups. It would not use well water and wasn't a flow through design? If so then it will be interesting to see how the coral progresses.

Simon: No the Goniopora is NOT in the new 5500 gallon tank which is a closed system. The Goniopora is in a new system (1200 gallon lagoon coral exhibit) that has a slow trickle of natural seawater, NOT well-water, so it will be interesting to see how it does. So far it is 15 months and all is well. I do OCCASSIONALLY (once every two months or so) run well-water in here just to give a nutrient boost.

You can see pictures of both tanks in the reefs.org General Discussion area under the topic heading "Lets see pics of your tanks" or some such thing.

Aloha!
Charles

 

[simonh]

Thanks Charles. The pictures I saw in the other thread awhile back looked stunning. Hope everything continues to go well with the Goniopora.