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Trying to understand the mechanism of algae supression

Discussion in 'Algae Control' started by ceg4048, Mar 26, 2005.

  1. ceg4048

    ceg4048 Lifetime Charter Member
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    Mr. Barr
    I've never really understood the reasons that algae are suppressed as a result of proper dosing such as your EI method. To be quite honest, the (Sears & Conlin?) hypothesis regarding limiting PO4 seems more logical to me since it offers a mechanism, or a control variable by which the algae may be throttled. I've read enough on this site to realize that you disagree and that you do not feel there is a direct correlation between PO4 and algal blooms. This is mind bending for me because it seems that most of the ecological studies of agricultural areas equate algal blooms in downstream lakes and waterways with causal factors associated with farm fertilizers mostly containing nitrates and phosphates. I certainly don't know all the facts though so there could be other factors involved.

    From what I've gathered, the theory behind algae supression is that when all available nutrients are present in the water column the plants are able to "out-compete" the algae, but what does this really mean? Algae (spores?) and plants are present in the tank concurrently and seemingly have an equal opportunity at any point in time to compete for and to uptake at whatever individual rate each is capable of.

    Suppose for a moment that we maintain the band of optimum nutrient levels for the plants, lets say 40 ppm NO3 for example. Let's also suppose that we have plant uptake sufficient for optimum growth, let's say for arguments sake 2 ppm NO3 per day. At the end of the day there is still 38 ppm of NO3 left for the algae to "scrounge" isn't there? The following 24 hour period the plants take another 2 ppm. That still leaves at or near 36 ppm NO3. The same situation goes for all the other nutrients, whatever the plants take there should be plenty left for the scrounging algae. It seems to me an EI treated tank should have both optimum plant growth and algae. Furthermore each plant is competing with the other. There does not seem to be a concerted effort on the plants to gang up on the algae, it's a jungle, with every plant for itself. It would makes sense somehow if the metabolic rate of the plants depleted all the nutrients before the algae could uptake any but this is not the case as there are plenty of nutrients available at any time for any organism to use - which is exactly the point of EI!

    When I look at my tank I see just as much or more pearling from the beard algae as from any given plant (well, I assume it's O2 and not some other gas). This leads me to believe, without any formal training in plant physiology, that the algae are functioning in more or less the same way the plants are in terms of nutrient uptake. In my case I'm also speculating that the algae are contributors to the overall uptake rate.

    I therefore fail to see why the algae is supressed just because the plants are happy as a result a non-deficiency. I was hoping you could clarify these linger doubts for me.

    Would appreciate any insights.

    Cheers,
     
  2. bonklers

    bonklers Junior Poster

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    Re: Trying to understand the mechanism of algae supression

    Interesting discussion!

    I'm seeing my algae pearling every day as well. If you've seen my topic (bonklers algae farm), then you know I'm having lots of thread/hair algae. Either with or without EI. There has been lots of changes in the few last days though. I was able to turn all the green algae into black algae :), which I'm not sure if they are because you can fluff them right off. But enough about me for now.

    About the Sears&Conlin paper:
    If you read the January report, you can't miss the message that the algae has less nutrient demand than the SAM's. So limiting nutrients to give your plants a headstart is probably not the way to go. (to put it mildly)

    The best thing I like about EI is the different approach towards an algae free aquarium. Which is concentrating on the plants instead of on the algae. This includes less thinking about how do I get rid of algae and more thinking about what does my plant needs? You can notice this approach in the reports, I've noticed Barr has put little effort into subjects of how to supress algae. Instead he makes effort in the opposite way, like why won't limiting nutrient supress algae, knowing other types of algae inducers, knowing more about SAM (enzymes and lighting limits). So I don't really feel like the EI method is one of those where your main goal is to supress algae and I don't expect an explenation why it should work that way when it's not based on the idea in the first place. It's far more difficult to say: "hey this will suppress algae" then saying "hey this won't work", but I like the second approach better because it's a building up process instead of you're either right or wrong. FYI my last "focus on getting rid of algae method" was Redfield Ratio.

    I do have some of my own crappy/unscientific reasoning behind the why focusing on your plants will work. Notice that the algae are growing on top of your SAM's? If they were doing well then the plant won't let the algae attach to them by some sort of unknown process. And I've yet to see a tank having healthy/clean SAM's with massive thread/hair algae growing on the glass/wood/equipment.

    If you're having thread algae on you plants and you want to make them look black and easy to fluff away (no more leaves scrubbing) try to shorten your light periods (not less intensity). I've shorten mine from 12 hours to 9. Ofcourse other then it's easier to clean, this black algae (if you get them) looks just as ugly as the green ones.

    Greetings,
    Hendra
     
  3. ceg4048

    ceg4048 Lifetime Charter Member
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    Re: Trying to understand the mechanism of algae supression

    Hi Hendra,
    Yes, I agree with every thing you said; that the algae require less nutrients, that EI focuses more on plant needs etc., but the fact remains that EI is lauded herein because of it's advantage of providing for the plants as well as it's ultimate benefit of reducing algae as a result of plant health.

    A review of many posts which begin with "...I have a problem with xyz algae..." reveals that the typical response goes something like "...follow the general concepts of EI, the plants will be happy and within some time period the algae will subside..."

    I guess the origin of my confusion is that I see no logical reason for the algae to ever subside regardless of what advantage to the plants the dosing system provides. In fact, it seems to me that just the opposite should occur; as the plants do well so should the algae. Unlike some, I have no reservations whatsoever about dosing more of everything if needed. That's because I inevitably see a growth increase or better colors and so forth. There is however, some gap in my comprehension that leaves me unable to reconcile why, if algae require less nutrients to thrive, should they be unable to survive when we offer them plenty of nutrients? Surely the algae don't realize that all these nutrients aren't really for them!

    I can't shake the feeling that there is some other dynamic occurring. You are probably right about shortening the light period, but in a way, even that is illogical to me. As long as the light is on aren't the algae being "out-competed"? What physiological change occurs after 9 hours?

    I think you may be right about the unknown process which doesn't permit algae to grow on healthy plants. But then does that mean the health of the leaf/plant cannot be judged purely on the basis of growth rate? Case in point my Hygrophila corymbosa "Stricta". From diminuative plantlets having 1 inch leaves they have quadrupled in girth and sport 6 inch leaves within 3 weeks. They are probably the fastest growing weed in the tank, yet, wisps of thread algae grows at the tips and a thin layer of the mottled dark green slime (easily removed) often covers the rest of the leaf. A similar story for the H. Polysperma and H. difformis. Weekly trimmings of at least 1/2 pound of material yet, algae persists. Are the leaves/plants not healthy?

    I'll continue to follow the principles of EI because that makes sense for the plants and because it mitigates the addiction to test kits. I just wish I understood why the secondary effect should be algae decrease.

    Cheers,
     
  4. jippalbert

    jippalbert Junior Poster

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    Re: Trying to understand the mechanism of algae supression

    Hello- I am a newbie.

    I have had planted tanks for about 1 year and I just purchaed compressed c02.

    With my DIY I was able to make 90% of all my algae disappear by using the EI. I am going to say that when using proper c02, lighting and ferts the plants are able to do a major nutrient uptake more so than the spores and thus they suck Amonia right up leaving this water column thing amonia free. Hence no more algae growth.

    I would check with the experts but Craig wolfen helped me as a beginner and once i did the EI for 3 weeks It is almost all gone. I am hoping with Cc02 now I can make it all go into hiding.


    Am I close experts ?



    Jipp Jipp ?
     
  5. Tom Barr

    Tom Barr Founder
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    Re: Trying to understand the mechanism of algae supression

    Yes, if you keep good CO2, then the EI will address the remainder.

    Pruning and good conditions will remove even the worse issue in 3 weeks or less.

    I do not do that pruning and removal till I change the issue that caused the algae to bloom in the first place.
    Otherwise, you do all this work for not.
    It'll grow right back.

    Regards,
    Tom Barr
     
  6. Tom Barr

    Tom Barr Founder
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    Re: Trying to understand the mechanism of algae supression

    You assume algae are limited, they are not at the levels he suggested.
    We do not have the test kits as hobbyists to measure limitation levels of algae.

    Other main issue: they are simply not in the same niche.
    Do not assume they are.
    Read the Florida notes, read the Ref's for FL lakes.
    Float down the Ichetucknee river full of plants and high PO4.

    To some extent there are, but with high plant biomass, all you get are more weeds, not algae.

    True but if you add aquatic weeds to these water systems=> you get more weeds. This is what I do for living, kill aquatic weeds.
    We add fert run off to the delta in CA from all the ag, we get aquatic weeds.
    Then they call Tom Barr, then I come out and try to kill them without causing harm to the environment. Algae is easy to kill, it's the damn plants we have trouble with.

    Yep.

    Nope.

    Try this:
    How much PO4 does the plant need?
    Now how much PO4 does the alga need?
    Plants need about 3-10x more PO4.
    How do plan on limiting the algae in this case?

    Yep

    They need far less than the plants do.
    They exist at a tiny scale, one cell or a few vs trillions of cells(plants).
    Sheer numbers and subsequent demand alone should make this obvious.

    Turn it around, why would the plants be supressed?

    Start with a good question rather than asking why algae is there.
    Unless you like growing algae..........
    I do and use algae to determine water quality.

    Ask your self, what is the goal?

    Regards,
    Tom Barr
     
  7. Tom Barr

    Tom Barr Founder
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    Re: Trying to understand the mechanism of algae supression

    Algae cells don't generally live long, if you kill off the adults, the new spores, young cells will not have any trigger to till them to grow/bloom.

    We could argue the same thing about plants and seeds.
    Algae think it's "winter" or the dry season, so they stop, produce gametes, and go dormant.

    They have signals that tell them when to grow, namely low NO3, high NH4, varying the CO2.

     
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