[Coral-List] RE: Units for expressing ammonia concentration

Szmant, Alina szmanta at uncw.edu
Tue Jan 3 23:51:02 EST 2006


Dear Dr. Booth:
 
I promise this is my last attempt to clarify the whole unit thing but I gather there are a number of interested parties out there that are not quite clear on the various units used in discussing nutrient concentrations and how to go back and forth among them.  And, of course there is the delete key.
 
I have worked both as a physiologist and as an ecologist, and yes, unfortunately the two groups treat concentration units differently.  I was originally trained as a chemist and as an oceanographer so I sorta go back and forth among the various units without thinking about it.  Without wanting to waste too much of people's time with elemenatry stuff:
 
For those that might have forgetten their basic chemistry a gram atom [= g-at or gm-at if you are British] of an element is Avogadro's number of atoms, and a Mole [= M] of a molecule is Avogradro's number of molecules.  
 
For a molecule with a single unit of a given element (e.g. N in nitrate or ammonium) 1 g-at = 1 M  = 14 gm of ammonium or nitrate-N    BUT = 62 of gm of nitrate or 18 gm of ammonium
 
In the olden days, most marine ecologists/oceanographers used concentration units (for dissolved substances) expressed in atomic units, e.g. g-at, mg-at, ug-at of element X.  Example:  ug-at ammonium-N.  Maybe this was because much of the research was concerned with mass balances and elemental cycles and less concerned with the form of the element? As your wrote, Chuck, this would be one correct form of expressing the amount of N tied up in ammonium molecules (or ammonia depending on the pH).  Oceanographic levels are fairly low so we work with ug-at most commonly (and mg-at in sediments).  
 
But it seems that over the past few decades the trend has been to use this convention less often than that of using molecular units, not atomic units.  Maybe it's because we are better at measuring specific forms of an element or are working on how specific molecules work etc.
 
When referring to a molecule / compound that contains the element of interest, or when one is interested in the entire molecule not just one of it's elements, then we use concentration units of M, mM, uM etc.  Thus 1 ug-at ammonium-N would be expressed as 1 uM ammonium.
 
Then it gets confusing when many non-scientists or ones working with regulatory agencies (and aquaria?) get into the picture:  They generally use weight units such as mg/L or ppm.  For nutrients, people get confused as to whether the mg is of the whole ammonium or just the N in the ammonium.  EPA units refer to the N in the ammonium so it doesn't make any mass difference whether the molecules are in the form of ammonium or ammonia (same amount of N either way).  But some folks use the same unit to refer to the weight of the entire molecule (ammonium = 18 mass units but ammonia = 17 mass units), and so here the form of the molecule makes a difference in how many molecules are in 1 mg/L.  This last form of concentration expression should not be used by scientists (or in fact, anybody else!!!)  because it is so ambiguous and one would need to specify what element or molecule one is referring to with each use (which people seldom do).  Use of atomic or molecular units avoids this mess.
 
The correct choice of unit should be based on purpose of reporting the concentrations, and what was measured:  if one is doing an ecological N mass balance, one may not want to distinguish between ammonium or nitrate, or even combine their values and thus report ug-at N. However, uM DIN should not be used and is frequently.   If one is working with organic N (DON) where one has no idea what the molecular composition is of the N-containing molecules, one should use ug-at N but some folks move on to using uM or mg (of N) per L (=mg/L or ppm) when reporting this kind of concentration. But if one is a physiologist working on intracellular ammonium/ammonia concentrations, or a physiological ecologist measuring uptake rates them I would chose uM ammonium or ammonia or nitrate (i.e specify your molecule measured).   Can get confusing, I agree, if one doesn't have the concepts down pat.  
 
With regard to the various ionic forms of  the NH4+/NH3 pair, in seawater with a pH of ca. 8 there is very little NH3.  This is not true in cells and/or in many aquaria with altered pHs.  The chemical analysis used by marine chemists based on the Solorzano (1969) method and more recent improvements, which have been adapted for autonalyzers as well as the manual method, measures both ammonium and ammonia.  One of the reagents (the alkaline citrate solution) converts any NH4 in the sample to NH3 to react to form the indophenol blue.  But in marine waters most of the molecule is in the NH4 form to begin with (<99 %).  So we generally report the cancentrations as uM NH4.  If one wanted to know how much ammonia was in a cell or solution, one would need a different method to measure the compound, such as microdiffusion or microelectrodes.
 
One last thing, for most plants, both NH4 and NO3 are equally usable, but the plants have to convert the NO3 to NH3 or NH4 before they can assimilate the N.   This is true for coral zooxs as well.  When exposed to equal concentrations of NH4 and NO3 at the same time, they take both up simultaneously at ca. the same rate (unpublished data for ca. 3-4 spp of Caribbean coral).  D'Elia has shown for corals saturation of uptake for NO3 (can't remember exact conc, but fairly high, ca. 20 uM?) but not for NH4 so there are differences in uptake dynamics. 
 
OK, back to work for me!
 
Alina Szmant
 
*******************************************************************
Dr. Alina M. Szmant
Coral Reef Research Group
UNCW-Center for Marine Science 
5600 Marvin K. Moss Ln
Wilmington NC 28409
Tel: (910)962-2362 & Fax:  (910)962-2410
Cell:  (910)200-3913
email:  szmanta at uncw.edu
Web Page:  http://people.uncw.edu/szmanta
******************************************************************

________________________________

From: coral-list-bounces at coral.aoml.noaa.gov on behalf of BOOTH, Charles E. (Biology)
Sent: Tue 1/3/2006 3:17 PM
To: coral-list at coral.aoml.noaa.gov; coral-list at coral.aoml.noaa.gov
Subject: [Coral-List] RE: Units for expressing ammonia concentration



As a physiologist whose research focuses on acid-base and ion regulation in crustaceans, I am somewhat of an outsider here (my interest in coral reefs stems from my teaching tropical biology field courses in the Bahamas and Caribbean). But, I do have a special interest in the ongoing discussion of ammonia levels in aquaria, as I study mechanisms of ammonia excretion by marine crabs, and have to maintain those crabs in closed aquaria where ammonia and nitrate levels are a concern.    Dr. Szmant's recent post attempted to clarify the units used to express ammonia concentration.  But, from my perspective, there is still the potential for considerable confusion.  She wrote:
"The mg/L refers to the weight amount of N only in the ammonium or nitrate, not to any of the other elements in the compound." 
In physiology, we use molar units (mM or uM) but we always refer to the concentration of the complete molecule (NH3) or ion (NH4+), as we are concerned with the forms of ammonia that circulate in the blood and move across the gills.  Physiologists who conduct toxicology research (at least that published in the physiology journals) also express ammonia concentrations this way, as it is the NH3 and/or NH4+ (not the N atom alone) that exerts toxic effects inside animals. 
I understand, and respect the fact, that scientists in different sub-fields of biology tend to write for one another using their preferred lingo. But, expressing ammonia concentration as, say, 20 ppm, or 1.4 mMol, NH4+ when you are really referring to concentration of ammonia nitrogen is almost guaranteed to befuddle we non-ecologists who read your or listserv threads (or published papers).  Admittedly, this is less a concern for ammonia (78-82% N) than for nitrate (only 23% N), or for that matter, phosphate (33% P), but it is still a source of potential error in interpreting stated values for ammonia.  In the older literature with which I am familiar, papers in which ammonia conc. was expressed as ammonia-N clearly stated this fact (as I recall, the 1969 Solorzano paper on a phenolhypochlorite method for measuring ammonia, published in Limnology and Oceanography, expressed ammonia conc. this way).
It is not my place to tell other scientists how to report their data, but I would urge you to keep in mind that some people reading your posts here, or your published papers, may misinterpret your nutrient values if the units are not clearly stated. Stating explitly that you are referring to ammonia-N, rather than molecular or ionic ammonia conc, is relatively simple and would eliminate any uncertainty.

Chuck Booth





        -----Original Message-----
        From: coral-list-bounces at coral.aoml.noaa.gov on behalf of coral-list-request at coral.aoml.noaa.gov
        Sent: Mon 1/2/2006 7:01 PM
        To: coral-list at coral.aoml.noaa.gov
        Cc:
        Subject: Coral-List Digest, Vol 31, Issue 3
       
       

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        Today's Topics:
       
           1. RE: NH4 Levels In Aquaria (Stephen Lowes)
           2. Conservation and Fragmentation Course (D. Wade Lehmann)
           3. RE: NH4 Levels in Aquaria (Szmant, Alina)
           4. Re: Contents of Coral-List digest... (M Kaiser)
           5. Re: RE: NH4 Levels In Aquaria (Charles Delbeek)
       
       
        ----------------------------------------------------------------------
       
        Message: 1
        Date: Mon, 2 Jan 2006 13:05:04 -0500
        From: "Stephen Lowes" <slowes at twcny.rr.com>
        Subject: [Coral-List] RE: NH4 Levels In Aquaria
        To: <coral-list at coral.aoml.noaa.gov>
        Message-ID: <200601021805.k02I5Jp5016066 at ms-smtp-03.nyroc.rr.com>
        Content-Type: text/plain;       charset="us-ascii"
       
        With reference to NH4 Levels in Aquaria (Steve Lowes)
       
        Dear Coral List:
       
        Julian makes a good point to the "potential" benefit of dosing ammonia to
        stimulate strong coral growth. I can add that I am currently experimenting
        with this in the aquaculture of Pacific scleractinian species. Following a
        guideline offered by Jorg Kokott (Coral, Vol 2 No 1, p68 2005) I am dosing a
        250 mM stock solution of ammonium chloride to a fully matured, closed, coral
        propagation system. I am only doing so to the extent that I raise the
        nitrate levels in the system from undetectable (< 0.25 ppm) to approximately
        1 ppm. Ammonia and nitrite levels remain undetectable using colorimetric
        aquarist test kits. I am also employing several mechanisms of nitrification
        including sand beds so without daily dosing the nitrate level is quickly
        reduced to undetectable. Together with herbivores I am able to control
        nuisance algae growth.
       
        I do not pretend that the above is a rigorous scientific approach but I am
        looking to try and quantify the coral growth rates across species. Since we
        are dealing with a multi-variable dynamic system it is always going to be
        difficult to get a categorical handle on quantifying the effects of a dosing
        protocol of this type. Assuming that increased growth rates could be
        demonstrated, it would be interesting to determine if this is from the
        corals use of ammonia or the oxidized products (nitrite and or nitrate).
        Only other info that I can offer to this interesting thread is reference to
        the paper - Titlyanov et. al. Effects of dissolved ammonium addition and
        host feeding with Artemia salina on photoacclimation of the hermatypic coral
        Stylophora pistillata Mar. Biol. 137: 463-472 (2000).
       
        Steve
       
       
       
       
        ------------------------------
       
        Message: 2
        Date: Mon, 2 Jan 2006 14:11:33 -0500 (EST)
        From: "D. Wade Lehmann" <dwlehman at ncsu.edu>
        Subject: [Coral-List] Conservation and Fragmentation Course
        To: coral-list at coral.aoml.noaa.gov
        Message-ID:
                <60595.24.211.190.228.1136229093.squirrel at webmail.ncsu.edu>
        Content-Type: text/plain;charset=iso-8859-1
       
       
        I thought various parties on this list might be interested in this...
       
        Marine Aquarists Online Courses is hosting a short course (non-credit) on
        Coral Reef Conservation that lasts for 6 weeks starting in late January.
        The course is being taught by ReefBall volunteers and covers a variety of
        topics related to real-world conservation issues.  A brief syllabus is
        below that I pulled from the website.
       
        http://aquaristcourses.org
       
        Week One: Reef Ball Module (What is a Reef Ball?)
        Week Two: Marine Eco-Systems (Replication & Restoration)
        Weeks Three & Four: Coral Propagation (Reef Balls Methodology)
        Week Five: Coral Attachment Techniques (used in the field)
        Week Six: Reef Ball Coral Team
       
       
        ------------------------------
       
        Message: 3
        Date: Mon, 2 Jan 2006 16:30:47 -0500
        From: "Szmant, Alina" <szmanta at uncw.edu>
        Subject: RE: [Coral-List] NH4 Levels in Aquaria
        To: "Tom Williams" <ctwiliams at yahoo.com>,       "Julian Sprung"
                <julian at twolittlefishies.com>,  "D'Elia, Christopher F."
                <cdelia at spadmin.usf.edu>,       "Stephen Lowes" <slowes at twcny.rr.com>,
                <coral-list at coral.aoml.noaa.gov>
        Message-ID:
                <4E15FCC7981F7A4CA5AA0DEF4B2141C9091CADF1 at UNCWMAILVS2.dcs.uncw.edu>
        Content-Type: text/plain;       charset="iso-8859-1"
       
        Hi Tom:
       
        I will try to provide replies to some of your questions below where we have some sort of evidence one way or another.  But, there are two camps of people (maybe more) involved in this dialogue, that have very different experiences with nutrients.  One is the aquarium group:  corals are often kept with fishes that are fed daily and nutrient loads from fish waste/excretion builds up in the system even with all the high tech gadgets used to remove them to levels that a second group involved in this info exchange, the coral reef scientists, would consider outrageous if measured in coral reef waters.  For example, your low level of 0.5 ppm towrads end of your message = 35 uM NH4+ which is outrageouslyhigh for natural coral reef waters  but you think it's low.  Furthre, 2 mg/L O2 would be considered almost anoxic on a coral reef where levels are not expected to drop below 4 mg/L.  Thus to advance our level of communication we must realize that aquaria (and the corals in them) funct
         ion very differently than full natural systems.
       
        My take from all this feedback from aquarists is that coral animals are much more tolerant to high levels (by coral reef standards) of ammonium and nitrate than many coral reef scientists realize.  This is no surprise to me as your might expect if you've read my papers on related subjects.
       
        One source of confsuion for some is the various units used to express nutrient concentrations.  Scientists are trained to use atomic units such as uM, mM etc.  Environmental engineers and aquarists use either mg/L or ppm.  But the concentrartion ranges of coral reef waters are in the ppb range, not ppm (i.e. 1000 times lower than the ppm levels).
       
        1 mg/L ammonium or nitrate = 1 ppm = 1000 ppb = 0.07 mM = 70 uM.   The mg/L refers to the weight amount of N only in the ammonium or nitrate, not to any of the other elements in the compound.  Reefs waters have nutrient concentrations in the ca. 0.1-0.5 uM ammonium or nitrate, with lots of higher and lower levels depending on tide, season, proximity to shore & runoff, upwelling etc.  So there is basically no comparison at all between the levels reef scientists work with when looking for contamination etc and those occuring in a very well kept aquarium with healthy corals and fishes.
       
        My replys to your specific questions follow IN CAPS each question below.
       
       
        *******************************************************************
        Dr. Alina M. Szmant
        Coral Reef Research Group
        UNCW-Center for Marine Science
        5600 Marvin K. Moss Ln
        Wilmington NC 28409
        Tel: (910)962-2362 & Fax:  (910)962-2410
        Cell:  (910)200-3913
        email:  szmanta at uncw.edu
        Web Page:  http://people.uncw.edu/szmanta
        ******************************************************************
       
        ________________________________
       
        From: coral-list-bounces at coral.aoml.noaa.gov on behalf of Tom Williams
        Sent: Sun 1/1/2006 12:48 PM
        To: Julian Sprung; D'Elia, Christopher F.; Stephen Lowes; coral-list at coral.aoml.noaa.gov
        Subject: RE: [Coral-List] NH4 Levels in Aquaria
       
       
       
       
        To List
        I have been interested in the ammonia/nitrate issue
        because:
       
        - I don't understand how the ammonia can persist in a
        >2mg/L dissolved oxygen environment;
       
        HI LEVELS OF AMMOUNIUM INDICATE LOTS OF ORGANIC MATTER BREAKDOWN.  AMMONIUM IS WHAT BACTERIA AND FUNGI RELEASE; AFTRWARDS OTHER BACTERIA CONVERT THE AMMONIUM TO NITRATE.  IN SOME ENVIRONMENTS SOME FACTOR CAN SLOW OR INHIBIT CONVERSION OF TH NH4 TO NO3.  I HAVE BEEN TOLD HIGH LEVELS OF UV CAN DO THAT.  IN AN AQUARIUM IT MAY MEAN THAT AMMONIUM EXCRRETION AND ORGANIC REMINERALIZATION EXCEEDS THE RATES OF NITRIFICATION AND DENITRIFICATION.  ALSO, 2 MG/L O2 IS NOT VERY HIGH.
       
       
        - I don't understand how an equivalent nitrate can
        persist in a "nutrient" deficient environment
        typically ascribed to reefs;
       
        NUTIENT LEVELS WILL BE LOW EITHER IF THERE IS NO SUPPLY OR THERE ARE NO USERS.  HIGH LEVELS OF ONE NUTRIENT COULD MEAN SOME OTHER NUTRIENT OR GROWTH FACTOR (E.G. IRON) ARE MORE LIMITING TO ALGAL GROWTH THAN IS THE N SOURCE.  AND THERE USUALLY ARE NOT HIGH LEVELS OF NO3 OR NH4 ON REEFS UNLESS THERE IS NEARBY SOURCE OF POLLUTION/RUN-OFF OR UPWELLING.
       
       
        - How any coral can directly use/survive a high
        dissolved ammonia/nitrate environment;
       
        GOING BACK TO MY INTO:  WHAT IS HIGH?  THE ANSWER TO YOUR QUESTION LEADS TO ANOTHER ONE:  WHY SHOULD AMMONIUM OR NITRATE BE BAD FOR CORALS?  AT THE LEVELS OF SOMEWHAT POLLUTED COASTAL WATERS, THEY ARE NOT PHYSIOLOGICALLY HARMFUL TO CORALS (AS DEMONSTRATED BY HEALTHY CORALS IN AQUARIA AT MUCH HIGHER CONCENTRATION).  ON REEFS HIGH LEVELS OF NUTRIENT CAN DESTABILIZE COMPETITIVE INTERACTIONS (YOU CAN READ A REVIEW ON THIS IN MY ESTUARIES (2002) PAPER AVAILABLE FROM MY WEB PAGE. WHEN HIGH NUTRIENTS DO HARM CORALS IT IS GENERALLY BY DESTABILIZING THE SYMBIOSIS BETWEEN THE CORAL HOST CELLS AND THEIR ZOOXANTHELLAE.  AT ELEVATED NUTRIENT LEVELS (WHICH CORALS SUCK UP FROM SEAWATER) ZOOX CAN GROW FASTER THAN CORAL AND OVER-GROW THEIR HABITAT.  SOME CNIDARIANS WILL JUST EXPECL EXCESS ZOOXS BUT IT APPEARS CORALS ARE NOT GOOD AT THIS.
       
       
        - what mechanisms/sources the coral can use for
        gathering nitrogen for reproduction from the media vs
        from ingested food;
       
        FROM INGESTED FOOD, OBVIOUSLY; FROM MEDIA, THEY TAKE IT UP BY FACILITATED DIFFUSION OR PRESENCE OF TRANSPORTERS.  THIS ASPECT NOT WELL STUDIED.
       
       
        -from a habitat/foodchain - I would assume that the
        algae could be far more stimulated by such levels opf
        ammonia or nitrate and would generate a habitat which
        would Kill the coral;
       
        YES THAT CA N AND DOES HAPPEN, ESPECIALLY WHERE HERBIVOROUS FISHES AND URCHINS ARE DEPLETED
       
        - when in Kota Kinabalu Borneo (E.Mal.)the rive runoff
        appear to have high levels of nitrate fertilizers and
        although the reef water was clear - no blooms - a
        brownish slime layer had formed over many coral heads
        near the river discharge;
       
        MAY BE THE ORGANICS IN THE DISCHARGE COMPLEXING WITH FINE SEDIMENTS AND PRECIPITATING OUT ON THE CORALS.  FYI:  ORGANIC NUTRIENT LEVELS ARE USUALLY 5-10 X HIGHER THAN THE DISSOLVED INORGANIC LEVELS BUT NOT OFTEN CONSIDERED
       
       
        - in sewage works we are required to keep the ammonia
        less than 1mg/L but with a DO of 2mg/L it is virtually
        impossible to get an ammonia of 0.5-1.0mg/L
       
        ADDRESSED ABOVE
       
        The reef fish observation may also be of conservation
        interests as the entire reef formation balance depends
        on the nitrogen assimilation of the coral/good algae
        vs the "bad algae".
       
        I am interested in the direct runoff and indirect
        leaching discharges of "treated sewage effluent" for
        irrigation on golf courses and hi-end residential
        units on recently reclaimed areas of Dubai, Sharjah,
        Ajman, and Ras Al Khaimah UAE.
       
        I am glad to participate in these discussions, as
        these are the sorts of issues which the LIST I believe
        was created to discussed (sorry about resumes  /
        employment as I am semi-retired).
       
        Dr. Tom Williams
       
        --- Julian Sprung <julian at twolittlefishies.com> wrote:
       
        > 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
        > >
        >
        http://coral.aoml.noaa.gov/mailman/listinfo/coral-list
        > >
        >
        >
        >
        >
        >
        > _______________________________________________
        > Coral-List mailing list
        > Coral-List at coral.aoml.noaa.gov
        >
        http://coral.aoml.noaa.gov/mailman/listinfo/coral-list
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        >
        http://coral.aoml.noaa.gov/mailman/listinfo/coral-list
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        ------------------------------
       
        Message: 4
        Date: Mon, 2 Jan 2006 12:27:45 -0800
        From: "M Kaiser" <wireframe at pker.org>
        Subject: [Coral-List] Re: Contents of Coral-List digest...
        To: <coral-list at coral.aoml.noaa.gov>
        Message-ID: <PLEFICIKEDHNMBGPOEPKEEAPCAAA.wireframe at pker.org>
        Content-Type: text/plain;       charset="us-ascii"
       
         1. RE: NH4 Levels in Aquaria (Tom Williams)
       
        Marine aquariums that house "reefs" are not nutrient deprived.  Quiet the
        opposite in fact, in fact it is actually a delicate balance between the
        bacteria that break down the ammonia, nitrites, and nitrates.  As such, it
        is the bacteria that break down and maintain these levels be it in a wet/dry
        system or a wet system such as a under gravel filter system.  It requires
        the constant addition of nutrients be it from light sources, or added in
        order to feed animals or whatever else maybe housed.  The same can be said
        for our oceans in that they are not deprived but have the same bacteria
        living everywhere.  Instead of protein skimmers the oceans pound the seas
        and deposit the yellow waste we would see along the beaches at high tides.
        Now when things happen on land that cause fertilizers to be added as run off
        from watersheds you have blooms as would occur in closed aquarium systems.
        It is simply that we see things happen faster in closed systems then we do
        in the open seas.
       
        Respectfully,
        M. Kaiser
       
       
        ------------------------------
       
        Message: 5
        Date: Mon, 02 Jan 2006 12:32:17 -1000
        From: Charles Delbeek <delbeek at waquarium.org>
        Subject: Re: [Coral-List] RE: NH4 Levels In Aquaria
        To: coral-list at coral.aoml.noaa.gov
        Message-ID: <6.1.2.0.2.20060102123206.025b0ab0 at mail.waquarium.org>
        Content-Type: text/plain; charset="us-ascii"; format=flowed
       
        We conducted a study of growth rates in three species of Acropora in our
        open systems that receive water from a saltwater well system. This system
        is described in Atkinson et al. 1995 (Coral Reefs 14:215-223). Our well has
        elevated inorganic nitrogen and phosphate levels but corals still grow
        fine. Unfortunately, we never worked up the data beyond a few graphs, and
        never completed the paper. Maybe its time to take a look at those numbers
        again and compare it to in situ growth rates! We measured buoyant weight
        and counted the number of branches over a 10 month period. Bruce Carlson
        published some work on comparing the density of Calaustrea furcata grown in
        our systems to C. furcata from the same colony in the wild and found they
        were about 50% lower.
       
        I know that ammonium nitrate has been used to enhance the growth of
        tridacnid clams e.g. Hastie et al. 1992 (Aquaculture 106) and Fitt et al.
        1993 Aquaculture 104) so why not corals too? However, it was found that
        while the clams grew faster, often the shells were thinner and more brittle
        compared to clams from unenriched water. This was most likely a case of the
        shell growth not being able to keep up with tissue growth and the same may
        apply to corals??
       
        Aloha!
       
        J. Charles Delbeek
       
       
        At 08:05 AM 1/2/2006, you wrote:
        >With reference to NH4 Levels in Aquaria (Steve Lowes)
        >
        >Dear Coral List:
        >
        >Julian makes a good point to the "potential" benefit of dosing ammonia to
        >stimulate strong coral growth. I can add that I am currently experimenting
        >with this in the aquaculture of Pacific scleractinian species. Following a
        >guideline offered by Jorg Kokott (Coral, Vol 2 No 1, p68 2005) I am dosing a
        >250 mM stock solution of ammonium chloride to a fully matured, closed, coral
        >propagation system. I am only doing so to the extent that I raise the
        >nitrate levels in the system from undetectable (< 0.25 ppm) to approximately
        >1 ppm. Ammonia and nitrite levels remain undetectable using colorimetric
        >aquarist test kits. I am also employing several mechanisms of nitrification
        >including sand beds so without daily dosing the nitrate level is quickly
        >reduced to undetectable. Together with herbivores I am able to control
        >nuisance algae growth.
        >
        >I do not pretend that the above is a rigorous scientific approach but I am
        >looking to try and quantify the coral growth rates across species. Since we
        >are dealing with a multi-variable dynamic system it is always going to be
        >difficult to get a categorical handle on quantifying the effects of a dosing
        >protocol of this type. Assuming that increased growth rates could be
        >demonstrated, it would be interesting to determine if this is from the
        >corals use of ammonia or the oxidized products (nitrite and or nitrate).
        >Only other info that I can offer to this interesting thread is reference to
        >the paper - Titlyanov et. al. Effects of dissolved ammonium addition and
        >host feeding with Artemia salina on photoacclimation of the hermatypic coral
        >Stylophora pistillata Mar. Biol. 137: 463-472 (2000).
        >
        >Steve
        >
        >
        >
        >_______________________________________________
        >Coral-List mailing list
        >Coral-List at coral.aoml.noaa.gov
        >http://coral.aoml.noaa.gov/mailman/listinfo/coral-list
       
        J. Charles Delbeek M.Sc.
        Aquarium Biologist III
        Waikiki Aquarium
        2777 Kalakaua Ave.
        Honolulu, HI, USA 96815
        www.waquarium.org
       
        808-923-9741
        808-923-1771 FAX
       
       
       
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        End of Coral-List Digest, Vol 31, Issue 3
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