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Re: Alage, bacteria, nutrients, allelopathy
- To: <Aquatic-Plants at actwin_com>
- Subject: Re: Alage, bacteria, nutrients, allelopathy
- From: Thomas Barr <tcbiii at earthlink_net>
- Date: Fri, 25 Jan 2002 10:45:14 -0800
- In-Reply-To: <200201242048.g0OKm6c26884 at actwin_com>
- User-Agent: Microsoft-Outlook-Express-Macintosh-Edition/5.02.2022
> Now, what about in a tank where the plants are not capable of sucking
> nutrients quickly, say when the plants are not at peak health or in a new
You mean a _disturbed_ plant?
> Recently I set up a new tank and densely populated it with lots of plants
> (including several fast growing stem plant species). The tank had flourite
> (mixed in with gravel, 50/50), CO2 injection and 2.5 wpg light. No filter.
> The plants were pearling almost immediately, but all were not growing as
> fast as they were in the tank from which they were plucked. I performed
> weekly and biweekly water changes to help get things going. My water has
> good amounts of everything, although in small concentrations.
> Then I got "cocky."
> I added some macro nutrients (NO3, K) ... and... added
> a tiny amount of my Miracle Grow (MG) solution for a little PO4 (and as Tom
> reminded me, I also gave the tank a small (non toxic to fish) amount of
> ammonium, NH4+).
> One of the outcomes: green water!
Almost a guaranteed prediction especially on a new tank and on a tank
without a filter. Even later, you'll still produce GW until you get that
filter on there. You do not have to even add NH4 in many cases.
> Was it due to excess nutrients that the
> transplanted water plants were not ready to handle, was it specifically the
> phosphate or ammonium ( in combination with higher initial iron from a new
> flourite substrate), or was it going to happen anyway?
NH4 and lack of water movement. Likely forms micro patches of high NH4 from
the plant waste/rot or fish critter populations. You also see this same
pattern of algae at high fish loads even if you have a filter. Once a small
patch is inoculated, your SOL. It takes over.
Consider this: High PO4 levels have not been found to be a direct cause of
algae so you cannot blame the PO4 for the algae out break(it happens at both
a high and low PO4's).
High fish loads produce too much NH4 for the tank to handle well. Plant can
and do use it. Plant will also use the PO4. But many folks do not separate
the NO3 and NH4.
NO3 can "hang out" and plants do quite well if only supplied with this form
of N. No algae also if the NO3 are kept in a decent range.
Next one attempts to add NH3/NH4 via fish load, substrate disturbance or
inorganic or organic (urea) chemicals you'll get algae.
The pattern I've seen is GW followed by staghorn algae. GW blocks out a
number of other species of algae but not staghorn(Entromorpha sp).
Another element or source of NH4 is uprooting a large plant. The substrate
is fairly reductive and holds some NH4+ in many tanks.
If you do a water change and remove most of the detrital matter with a fine
net you can escape this.
I believe GW blooms have little to do with uptake of "excess nutrients"
except for NH4 exclusively.
> In retrospect, I
> should have avoided the extra water column nutrients until the plants
> settled in, started excreting their various allelochemicals and the tank
> with its various microorganisms matured a bit.
If you perform large water changes there will be few allelochemicals. I just
don't think allelochemicals play a large role but rather a small perhaps
side issue(A non CO2 no water change method).
Amano used carbon in the start up. No problems(this removes allelochemicals
also). Big water changes(removes them) yet no problems at all, great plant
growth , no algae.
Allelopathic chemicals are not a bad investment for a terrestrial plant but
for an aquatic it seems like a bad idea except at low easy to produce
levels. Suppose there are rains(all your hard earned chemicals are washed
away). Suppose you had grown instead and flowered instead of producing
allelopathic chemicals? Suppose your growing in Lake Erie? Or a small pond?
Seems like a risky investment to produce large amounts of these. Small low
levels would be a better strategy. It's better to put your energy into
growth and seed production, covering the surface and blocking out the light
etc. Speed is the key to many of these "weeds".
Something else must be going on besides these allelopathic chemicals.
Carbon is used in soil mixes to test for this effect in terrestrial plants.
You can also remove this allelopathic chemical from the carbon later and try
to characterize it.
Perhaps send Jamie Johnson some of that for analysis would be elucidating.
On the topic of allelopathic chemicals: a number if plants can even tell if
a clone is not part of their "area" and can produce allelopathic responses
as strong as non clonal plants responses.
As we bark up the allelopathic tree, plants also inhibit plants, not just
algae. We do not see much plant -plant inhibition in aquatic plants. I know
of only one suspicion out of some 250 plants. It fair to assume this issue
as not a factor I'd say.
> I believe that my tap water
> with chloramines is another source of NH4 (after treatment with chloramine
> remover, the bound NH4 is treated harmless, but somehow its nitrogen gets
> to be available to the plants ).
This has been speculated and I think it is a very small effect to plant
growth. If the contribution was larger, you'd get more algae blooms the
larger the water change. We do not see that pattern.
> Maybe using a filter (with old filter
> material) could have helped to remove NH4 not used quickly enough by the
> new plants. In fact, that is what I would have recommended to someone else.
Me too. I'm a water change before I do anything kind of person.
> BTW, adding the MG to my other mature tanks has never resulted in green
> water. I can get that to happen in different ways :-) One message: effects
> of liberal fertilizer usage is probably different in mature tanks with lots
> of healthy plants vs. non-mature tanks or ones with plants that are
Some tanks are more sensitive for a number of reasons. Filterless tanks are
very sensitive and as they get larger, this can be come even more difficult
to deal with. Some tanks are tetering on the brink already, not enough CO2,
bio filtration, too shallow a substrate(2" or less), highly limited and
stunted plants etc. You add NH4 to those and your sure to get problems in a
> Algae are common in new setups and must run their course. What are people's
> experience with initial blooms of suspended algae (green water)?
See above. GW makes the best study since it really does no harm to the
plants, only involves a flip of a UV to kill it and start a new run, is
suspended rather than attached allowing good mixing light etc, fast growing
and has little needs as far as nutrients once inoculated. You can have all
sorts of P and NO3 etc and still kill it. Tank looks great after.