Why dose amino acids into our aquarium water? I assume that
being a freely suspended item within the water, the idea is that
the corals will somehow directly absorb the amino acids and be fed.
Thats the theory at least.
Being the skeptic that I am, I of course was not about to just
take a product's or another hobbyists word for it and start happily
pouring amino acids into my aquarium water.
The remainder of this page is
an excerpt from an online discussion that I had with Eric Borneman. To
view it in its entirety, please click HERE.
Prior to my
starting to read through the reference material. I thought it would be
wise to write down the questions I wanted answers for that would
pertain to the use of amino acids added directly to the water. After
writing down a few questions, it dawned on me that just one, would
pretty much cover all others. To keep it simplified for myself, knowing
what amino acids are needed is not as important to me as to how they get what they do need.
I am also aware that the question itself makes assumptions that other
related questions have been answered correctly, such as knowing what
amino acids corals actually need.
How do
corals get amino acids that they need, yet are unable to synthesize or
are unable to synthesize enough of, for their metabolic needs?
"Eight
amino acids normally considered essential for animals were made by the
five corals tested, although some of them were made only in small
quantities. These eight amino acids are valine, isoleucine, leucine,
tyrosine, phenylalanine histidine, methionine and lysine. The ability
of cnidarians to synthesize these amino acids could be yet another
indicator of a separate evolutionary history of the cnidarians from the
rest of the Metazoa. "
This
shows that corals are able to synthesize or have them synthesized for
them by bacteria, at least some of the amino acids thought to be
essential.
Okay,
so they can "make" some of their own, thats one source, How do they get
the rest of the amino acids, or those that they can not make? Same as
the original question.
"Food" is the obvious answer of course, since corals, being an animal, need
protein to grow and heal wounds, and being an animal, they get their protein by
eating other animals.
The
crux of the question then becomes many other questions, Outside of
synthesis and prey capture, do corals have a need to absorb amino acids
directly out of the water? Are they even capable of doing so? Do they
do so only when prey is scarce? Is there even enough free amino acids
floating around to make that capability something worth evolving to
have? If the answers are no, then adding amino acids directly to the
tank water would in short be nothing but polluting the tank for no good
reason.
Having gone through the
reference material, it appears that the answers are both yes and no.
Some coral species do uptake amino acids, but appear to me, to be in
extremely small amounts. While other coral species do not uptake amino
acids, and some species even "give off" amino acids. All appearing to
have one thing in common though, very small percentages. Any amino
acids added to the tank water would be pretty much useless, any benefit
of doing so, would be so small as to be unperceivable and would be just
another item that your aquarium has to clean up after.
Without risking further brain damage, I am going to fall back onto one sentence that Eric stated " Basically, food, bacteria growing on the coral and zooxanthellae are all that is needed. "
All the
hoopla about pouring in amino acids seems to be yet another result of
something that this hobby falls for all the time. And thats the old, if
a creature / or reaction, process, uses something, then providing that
something in great abundance is always some how a good thing. Theres an
old saying that has gotten old simply because of the truth it contains
" Too much of a good thing...."
Okay, but
what about soaking "food" in amino acids as a way to enrich the food? I
suspect that such soaking would only be of use if you were feeding your
corals cardboard instead of a varied sea food (meaty) diet, such
soaking could lead to additional source of water nutrients simply
because the coral is only going to take what it needs from the feed it
eats, or, it would most likely be too "rich" and could cause health
issues, just as too much protein can be unhealthy for us.
Per this discussion, I will quote Eric Borneman for a summary :
In Summary: Quote : " Chuck, You
are answering your questions very well. The material I provided leads
me to the same conclusion. Most are synthesized by the coral, plus an
added boost from recycling with zooxanthellae, strong evidence of
bacteria as food and as bacteria providing AAs as breakdown products by
growing on the surface. Now, we want "good bacteria" growing and not
pathogens invading the normal flora growing...like our gut bacteria.
And Ritchie, Rohwer, Kline, Kuntz, and Knowlton have all shown that
carbon (sugar, ethanol, gluconates, tons of corals releasing mucus in a
small water volume) causing issues with that normal flora and can lead
to disease. And, some - not all, but maybe most, but only a handful
actually tested at all) are capable of absorbing AAs directly, and they
seem to do so in most cases at low levels or ineffectively. There
aren't a ton of AAs floating in the water, but zooplankton and
phytoplankton are leaky...and this stimulates a FEEDING response. It's
not the AAs that they want, its the food.
Second, the "protocols" of water changes and skimming.
First, DFAAs will likely be used by all the single celled critters, bacteria,
etc. rapidly...those that are not capable of biosynthesis. So, of the amount
poured in the tank, corals are going to get leftovers. Then the protocols
suggest water changes because of course this is a nutrient pollutant as N in
seawater is so crazy low and most is as NH4. Then, the skimming. PROTEIN
SKIMMING. All polar AA's will be quickly removed and others likely bound in foam
aggregates.
We
anthropomorphize a lot. We call our fish and corals "him" and "her" a
lot. We are caretakers and they are like pets. So, we are easily led
into thinking and behaviors towards tanks as we would ourselves or our
dogs/cats, etc. Further, its not a simple task to find and read
everything science knows about a subject. So, as an analogy:
Originally, everyone
ate whole foods - nothing processed. Then, all the wonderful technology came
that gave us food that stayed on the shelf, preserved, dried, etc. Then the
artificial ingredients. Then, we learned that things like eggs, butter,
chocolate, coffee, etc were bad for us. Then, we learned it was a specific
component, not the food, so we eliminated fats, carbs, whatever with sugar-free,
fat-free, caffeine-free foods that were even more processed. Then we learned all
the chemicals weren't good for us, and lots of people take vitamins and AA
supplements to correct unbalanced diets. Now we are learning that the problem
was largely not the whole foods but the way they were provided. And now we see
that many of those same things we once thought were "bad" for us are actually
pretty good for us and, specifically, diverse diets of small portions with all
the varied nutrients and antioxidants eaten more frequently so as to avoid
having to take supplements unless there is something wrong. " Unquote.
References : http://www.pubmedcentral.nih.gov/picrender.fcgi?artid=1218179&blobtype=pdf
http://www.springerlink.com/content/v97tuf5whdgahhd2/
http://www.springerlink.com/content/v4j6887225n33538/
http://phage.sdsu.edu/research/pdf/Rohwer%20-%20Coral-bacteria%20in%20MEPS.pdf
http://phage.sdsu.edu/research/pdf/Knowlton%20and%20Rohwer%20-%20Holobiont%20in%20American%20Naturalist.pdf
Also,
this is interesting in that the planulae take up AAs but the adults release
it:
Revital Ben-David-Zaslow and Yehuda
Benayahu. 2000. biochemical Composition, Metabolism, and Amino Acid
Transport in Planula–Larvae of the Soft Coral Heteroxenia
fuscescens J Exp. Zool 287: 401-412
Schlichter D,
Liebezeit G. 1991. The natural release of amino acids from the symbiotic coral
Heteroxenia fuscescens(Ehrb.) as a function of photosynthesis. J Exp Mar
BiolEcol 150:83–90.
