aquabillpers;26113 said:
Tom,
I would be willing to try filtering the water through activated charcoal and then adding more plants, but I don't know what that would prove.
If the new plants prospered, I would assume that there had been some chemical in the water that was selectively killing newly added plants. Whether that chemical was allelopathic in nature or came from another source I wouldn't be able to say.
If the new plants died, that could mean several things: that the AC didn't filter out the chemical that was causing the problem; that more of that chemical was being produced in the tank; that there was a non-chemical cause for their demise; and on and on. I don't see how AC filtering would help to answer the question in this case.
Plants of 4 different species died almost immediately in a tank that was half full of healthy crypts. Light and water column nutrients were at least adequate. The water was from a well and a wilderness stream and was being used in other aquariums with success.
Since allelopathy in terrestrial plants has been well documented, it seemed at least possible that the mass of crypts was using allelopathic warfare to protect their turf, so to speak.
The only way to prove that theory would be to find the chemical that the crypts were using. According to the Tropica article, that has been done numerous times in cases of terrestrial allelopathy. Producing a result by changing a variable in an experiment is not proof. Coincidence is not causation, right?
You need to find the agent that is producing the result in question.
Thanks for your stimulating responses!
Bill
AC would/does remove the offending chemical in question.
Then if you repeated the test and had the plant die without AC, then repeated the same test again with AC and it did not, then you'd have evidence that alleopathy is occurring and is significant.
I'd wait at least 2-4 weeks between treatments for the levels of allepoathic chemicals to build up.
If it takes longer than that, then the levels are no that significant in their impact and will be difficult to measure and see conclusively. Tanks also change over time, so repeated measurements using the same methods/protocols needs addressed.
But if after say 4-6 X cycles of this, where you see strong effects on plants with/without the AC, then you have good evidence that Allelopathy is occurring.
I am very curious why folks are so very willing to lend alleopathy such leeway and speculation, yet are so critical about other alternative reasons for poor plant growth which are more reasonable and have been shown in many studies on aquatic plant ecology.
Do not believe everything you think or want to believe.
the evidence against it occurring in aquatic systems is far far greater than for it, both in aquariums as well as in natural systems. There's no evolutionary pressure I can really think of either.
Our aquariums might be small finite boxes full of plants, but they are not natural nor anything like the large highly varied examples in the field. And that is where natural selection will take place, we put a lot of pressure on aquatic weeds/plants these days, but we really do no pick only the best plants for our tanks over time and thus it's more like agricultural ecology and crop evolution than anything inherently "natural"
without influence from man kind.........we obviously influence many things and plant growth with our aquariums. So pin pointing it is something that would need tested and tentatively accepted.......if we find evidence for it based on results, not hypothesis, speculation or the desire to believe some "nice" theory.
So we need to see that first, then argue more about why, it's potential etc.
It's like the folks that claimed excess PO4 = algae blooms, they never even bothered to test their hypothesis that they made, they told everyone about it and ran around promoting the theory.
And after I do bother to test it, I get questioned harshly often times.
Why aren't folks questioning allelopathy more harshly is my question?
I have offered up this simple test to test this hypothesis and it's been around for several years now, yet no one other than myself has appeared to have done it to date
However, there seems to be an infinite number that will fall into the "allelopathy trap" mind set.
Keep in mind that the easy road is not the best or the right road.
FYI.........I am speaking generally here, not at your line of questioning or personally etc.
Ask away there.
Regards,
Tom Barr