[Coral-List] NH4 Levels in Aquaria

Sat Dec 31 12:26:42 EST 2005

Hi Julian et al.-

Len Muscatine, Ken Webb, Steve Domotor, Clay Cook, Gisele Muller-Parker and I (in various collaborative combinations) published quite a few papers on the nitrogen uptake kinetics of corals, anemones and isolated zooxanthellae. Other folks, such as Alina, who has weighed in on this discussion, have also published quite a bit on this topic. Many of these papers are cited in your comprehensive Volumes I and II with Delbeek.  Ammonia does not seem to saturate based on the Muscatine and D'Elia 1978 paper, but I am not sure if that means anything about growth since with very high N availability other things would probably be growth limiting.

There is really no good study that I aware of linking the uptake of dissolved inorganic nutrients to coral growth, and as you well know, it all depends on the coral of interest as some corals seem to be more phototrophic than others.  (Even the paper linking fish excreta to coral growth as I vaguely recall, is highly speculative about the effects of excreted N on growth.)  However, I do note that excess N addition may destabilize the symbiosis and cause the zooxanthellae to "outgrow" the host, as Ove. Hoegh-Guldberg and collaborators have shown.  I would not think that this is helpful to the coral symbiosis, so I think you are right when you say "MIGHT produce strong growth in certain species."

The concentration of 20 ppm ammonium is really very high.  I would think that in such circumstances one would want to enhance denitrification to remove excess N from the system.  (Of course, this would require coupled nitrification as well.)

I am struck by the fact that with all of the "academic" research that has been conducted, I would not be surprised if there were not some aquarist out there who may, through years of practical experimentation and observation, be able to shed light on the relationship between dissolved N uptake and coral growth.

Happy New Year to all,

Chris

________________________________

From: Julian Sprung [mailto:julian at twolittlefishies.com]
Sent: Sat 12/31/2005 10:51 AM
To: D'Elia, Christopher F.; Stephen Lowes; coral-list at coral.aoml.noaa.gov
Subject: RE: [Coral-List] NH4 Levels in Aquaria

Dear Coral List,

I have been reading the responses to Angus with interest. I have a slightly different angle to add-

I'm not sure but I believe that Angus was asking about maintaining an elevated ammonia level to promote higher than normal growth rate in a coral farm system.

In any aquarium system with a sand or gravel bed of any significant size, living rock, strong illumination, various algae, and corals, the maintenance of high levels of ammonia would be quite difficult without daily addition of ammonia or lots of food. I don't think that Angus was asking about how to lower the ammonia level in a system-- that happens automatically. On the contrary I think he was exploring raising the level artificially to boost coral growth. The concept has merit because to a limited extent it works.

Corals in the natural setting benefit from resident schools of fish that release elevated levels of ammonia directly among the coral polyps. This increases available nitrogen to a "level" in excess of the background nutrient poor seawater. One of the downsides of overfishing is that it potentially LOWERS the amount of nutrients a coral may recieve, and thus lowers growth potential. If the overfishing affects herbivores, then coral growth is slowed at the same time that algae are given an advantage.

In any case I agree with all the responders who pointed out that the proposed level from Angus seems quite high. I have not tested such high levels with corals, however. In an established aquarium with sandbed the dosing of ammonia to achieve this level would produce a spike for a limited time, followed by both nitrification and assimilation. The expected outcome would be excess algae, but with strong herbivory it MIGHT produce strong coral growth in certain species. Someone on the list probably knows of a saturation level for zooxanthellae assimilation of ammonia. That appears to be the main question-- beyond a saturation level it would seem that any additional amount of ammonia added would have no benefit.

Happy New Year!

Julian

-----Original Message-----
From: coral-list-bounces at coral.aoml.noaa.gov on behalf of D'Elia, Christopher F.
Sent: Thu 12/29/2005 10:05 AM
To: Stephen Lowes; coral-list at coral.aoml.noaa.gov
Subject: RE: [Coral-List] NH4 Levels in Aquaria

Steve, Angus, and others-

I agree - these are very high levels of ammonia (~1.4 mM), and it suggests that denitrification needs to be enhanced in the aquarium.  Note that in his book Aquarium Corals, Eric Borneman recommends that "ammonia levels should remain effectively undetectable or near zero parts per million (ppm)."  In case you are not aware of it, his book is a scientifically based treatise on maintaining corals in aquaria, but is written with a lay audience in mind.  It has superb pictures and illustrations.  I recommend it highly.

Chris D'Elia

________________________________

From: Stephen Lowes [mailto:slowes at twcny.rr.com]
Sent: Wed 12/28/2005 8:11 AM
To: coral-list at coral.aoml.noaa.gov
Subject: [Coral-List] NH4 Levels in Aquaria

 Angus:

I'm not sure where you are getting your published NH4 levels for coral
propagation. 20ppm NH4 would be very detrimental to any aquaria, fish or
invertebrate culture. I run a small coral farm and strive for undetectable
ammonia (ammonium), and nitrite levels. There is reasonable rationale for
maintaining 1-5 ppm nitrate levels for efficient coral growth but there is
little work published species by species.

Steve Lowes, Ph.D.

Angus, others.

Sorry about the following but I am not familar with the aquarium worlds.

Could you provide some of the "lot" references for ammonia NH4 being 20ppm
for coral propagation as these levels far exceed the levels accepted for
discharge of treated sewage effluent to marine waters.

Are these levels acceptable for aquaria only ?? - I believe they would
stimulate alot of alga in the tank or real water.

Dr. Tom Williams

--- Angus Macdonald <angus at ori.org.za> wrote:

> Hi,
>
>
>
> A lot has been published about optimal NH4 concentration in aquaria in
> which coral is propagated. 20 ppm seems to be about right.
> Is this in the right
> ballpark and does it become toxic to hard or soft corals at higher
> concentrations?
>
>
>
> Thanks
>
>
>
>
>
> Angus Macdonald
>
>
>
> Oceanographic Research Institute
>
> uShaka Marine World
>
> Point Road
>
> Durban
>
> (031) 328 8168
>
>
>
> _______________________________________________
> Coral-List mailing list
> Coral-List at coral.aoml.noaa.gov
>
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>

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