[Coral-List] NH4 Levels in Aquaria
szmanta at uncw.edu
Mon Jan 2 16:30:47 EST 2006
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) function 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
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
I have been interested in the ammonia/nitrate issue
- 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
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
> Happy New Year!
> -----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
> 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
> 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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