Excess nutrient doesn’t cause algae growth?

[Nont]

Hi everyone,

I’m a bit confuse on this one. In another thread I want some recommendation on house plants that can quickly remove nutrients from the water and @erwin123 told me that nutrients doesn’t cause algae? This is a something I’ve never heard and I’ve been thinking about these questions for a while now:

1. Why doesn’t excess nutrients cause algae growth
2. Why do osmocote that come out of the substrate cause algae bloom?
3. Why do we need to plant heavily from the start or use the floating plants? Isn’t it too steal nutrients from algae?


Cheers

 

[arcturus]

Hi everyone,

I’m a bit confuse on this one. In another thread I want some recommendation on house plants that can quickly remove nutrients from the water and @erwin123 told me that nutrients doesn’t cause algae? This is a something I’ve never heard and I’ve been thinking about these questions for a while now:

1. Why doesn’t excess nutrients cause algae growth

Very short answer. Nutrients are a necessary condition for algae, but not a sufficient condition. You would need additional factors, often related to an incorrect balance between light, CO2 and nutrients (for example, too much light for the available nutrients). The rapid fluctuation of CO2 or nutrient levels also causes instability. If plants are growing healthy they can keep up their natural defences against algae. This is why algae often start appearing on slow growing plants or unhealthy plants and not on healthy plants.

If excess nutrients caused algae, then the only possible fertilization method would be the "lean" method, which provides plants with the minimum required amount of nutrients.

2. Why do osmocote that come out of the substrate cause algae bloom?

Mostly because of a rapid increase in the concentration of nutrients. This effect can be mitigated if there is sufficient plant mass to absorb those nutrients and ample water circulation inside the tank.

3. Why do we need to plant heavily from the start or use the floating plants? Isn’t it too steal nutrients from algae?

Plants will need a significant amount of time to adapt to a new tank. They will be weak during this phase until they start growing at a steady rate. This means that opportunistic algae can explore these weaknesses. Moreover, tanks are unstable during the first months. The more plants you have, the higher the capability of the system to remain stable and to deal with unwanted substances in the water (such as ammonia). This helps keeping algae in check. Floating plants have direct access to atmospheric CO2 (this means they do not need CO2 injection and even with CO2 injection they would have access to +10x more CO2 than submersed plants). They also receive the maximum light input from the lamps. So, they are in the best position to consume the excess nutrients in the water column and to grow fast, thereby countering algae growth.

In any case, (most) algae are plants and thrive in the same environment - they are actually much more efficient than higher plants. They will be competing with the higher plants, and they are not a sign that something is wrong... the only problem is that we often want to grow other type of plants than algae 😉

 

[dw1305]

Hi all,
edit: What @arcturus just said.

Why doesn’t excess nutrients cause algae growth

I think plenty of nutrients encourages the growth of <"all photosynthetic organisms">. If you just look at the <"Green Algae"> they have the same <"photosystems and basic physiology"> as all the plants you want to grow, and I can't see how conditions that favour the "plants you want to grow" don't also favour the plants "you don't want to grow" (the algae).

Personally I use <"slow growing plants">, <"floating plants"> and <"low nutrients"> in tanks with a <"lot of tank janitors">, and that <"keeps the algae under control">.

Other (@Roland , @Geoffrey Rea etc) will have found high tech "sweet spots" where they can grow the "plants they want".

cheers Darrel

 

[brhau]

I can't see how conditions that favour the "plants you want to grow" don't also favour the plants "you don't want to grow" (the algae).

I've been thinking the same thing. I've read a lot of posts saying that healthy plants discourage algae because the algae predate on unhealthy plants. It makes some sense, but doesn't explain to my why algae grow on nonplant surfaces or in plant-free aquariums. Are these different algae? Do unhealthy plants favor growth of algae away from the plant? Would love some references to threads that discuss this. I know EI works and that you can dose heavily and still avoid algae. But I can't reconcile the explanation. In the elephants/mice analogy, it would seem to me that adding more peanuts would favor both animals.

Thanks

 

[arcturus]

I've been thinking the same thing. I've read a lot of posts saying that healthy plants discourage algae because the algae predate on unhealthy plants. It makes some sense, but doesn't explain to my why algae grow on nonplant surfaces or in plant-free aquariums.

Plants are known to release <allelopathic substances>. These might interfere with algae growth on the surface of healthy plants (citation needed...) Can these substances reach such a concentration that will affect the whole tank? No idea. If these substances play a role, then this could justify why plant-free surfaces would be more prone to get algae. Plants with damaged tissue also be providing additional substances that either promote algae growth or just feed the algae. Again, citation needed. There are other possible factors, such as higher exposition to light or presence of minerals on the hardscape (but this fails to explain why the glass is often affected). In plant-free aquariums I think the explanation could be simpler, because we would just need the sufficient conditions for algae growth to be met since plants are out of the equation.

Do unhealthy plants favor growth of algae away from the plant?

These plants would leach substances into the water due to cell/tissue damage. If the concentration of such substances in the tank is relevant or not is a good question. Another question is if these substances actually remain in the vicinity of the plant because of water flow/circulation.

Would love some references to threads that discuss this.

There are scientific studies on this topic. Several focus on bacterial blooms due to eutrophication. Let's let the plant experts give their input.

I know EI works and that you can dose heavily and still avoid algae. But I can't reconcile the explanation. In the elephants/mice analogy, it would seem to me that adding more peanuts would favor both animals.

I also find this to be a paradox. For example, <eutrophication processes> are linked to excess nutrients (often nitrites and/or phosphates). But there must be other triggers at play, since a given concentration of those nutrients will not automatically cause a algae or bacterial bloom. Light surely plays a major role: algae cultures are promoted using a combination of nutrients and specific light spectrum and intensity. I consider this to be a fascinating topic 🙂

 

[MichaelJ]

I've been thinking the same thing. I've read a lot of posts saying that healthy plants discourage algae because the algae predate on unhealthy plants. It makes some sense, but doesn't explain to my why algae grow on nonplant surfaces or in plant-free aquariums. Are these different algae? Do unhealthy plants favor growth of algae away from the plant? Would love some references to threads that discuss this. I know EI works and that you can dose heavily and still avoid algae. But I can't reconcile the explanation. In the elephants/mice analogy, it would seem to me that adding more peanuts would favor both animals.

Thanks

I've had a lot of near plant-less tanks over the years - mostly keeping big cichlids. The main trigger for algae always appeared to be organic waste buildup. I was not as disciplined back then with water changes as I am now, and I always got algae in one shape or another when I didn't keep up the maintenance. Weakened plants provide an excellent substrate for algae to grow but in lieu of weak plants, algae will grow on rocks/wood or the interior of the glass etc.

Cheers,
Michael

 

[jaypeecee]

I also find this to be a paradox. For example, <eutrophication processes> are linked to excess nutrients (often nitrites and/or phosphates). But there must be other triggers at play, since a given concentration of those nutrients will not automatically cause a algae or bacterial bloom. Light surely plays a major role: algae cultures are promoted using a combination of nutrients and specific light spectrum and intensity. I consider this to be a fascinating topic 🙂

Hi @arcturus

It is a very fascinating topic and that's why I started to take a deep interest, firstly in Cyanobacteria and, more recently, BBA. I have accumulated many scientific papers on both these topics and would be happy to put a list together for you. Light plays a very important part in what we're discussing, not least because of a phenomenon known as the photoreduction of iron. At which point, I must go and join my wife for coffee time!

JPC

 

[brhau]

Plants are known to release <allelopathic substances>. These might interfere with algae growth on the surface of healthy plants (citation needed...) Can these substances reach such a concentration that will affect the whole tank? No idea. If these substances play a role, then this could justify why plant-free surfaces would be more prone to get algae.

It's an interesting idea. You might expect to see plants inhibiting each other's growth in this case. The article proposes that the HDAC inhibitors are released by the roots into the soil. So they could theoretically go into the water column, especially for plants that grow roots above the substrate.

Plants with damaged tissue also be providing additional substances that either promote algae growth or just feed the algae. Again, citation needed.

Would love a citation if you come across it. Curious what these substances are.

Cheers

 

[arcturus]

It's an interesting idea. You might expect to see plants inhibiting each other's growth in this case. The article proposes that the HDAC inhibitors are released by the roots into the soil. So they could theoretically go into the water column, especially for plants that grow roots above the substrate.

The question is if the concentration of these inhibitors in the water column has any significance. In a natural environment, these substances would be often diluted in large volumes of water. So, from an evolutionary perspective, it makes more sense for a plant to have developed localized mechanisms, rather than mechanisms that require dispersion in water. But this conjecture is likely wrong...

Would love a citation if you come across it. Curious what these substances are.

Have a <look at this article>. It describes some of the metabolites, toxins, and others substances that leach out of a damaged plant. This is about terrestrial plants but the mechanisms aquatic plants should be rather similar, at least when they are in emersed form.

 

[jaypeecee]

Hi @brhau & @arcturus & Everyone

Are you all aware that Diana Walstad dedicates a whole chapter of her book* to the topic of allelopathy?

JPC

* Ecology of the Planted Aquarium

 

[arcturus]

Hi @brhau & @arcturus & Everyone

Are you all aware that Diana Walstad dedicates a whole chapter of her book* to the topic of allelopathy?

JPC

* Ecology of the Planted Aquarium

I am not sure there is consensus on that matter. Tom Barr (on barrreport.com) linked to studies <like this>.

But at least some recent articles seem to point in the same direction as Walstad.

 

[jaypeecee]

I am not sure there is consensus on that matter.

Hi @arcturus

Now, where have I heard that before?! 😉

JPC

 

[brhau]

Are you all aware that Diana Walstad dedicates a whole chapter of her book* to the topic of allelopathy?

This is like when the teacher asks if you actually did the reading before class. 😳 I'll check it out.

But at least some recent articles seem to point in the same direction as Walstad.

I just came across that as well, in addition to <this one>. The article isn't free, but the experiments were conducted in water. Apologies if you've already linked to this above-- your two links on eutrophication aren't working in my browser.

Cheers

 

[MichaelJ]

I am not sure there is consensus on that matter. Tom Barr (on barrreport.com) linked to studies <like this>.

At least for allelopathy between plants, I agree... back in the day they always said... oh you cant plant crypts next to so and so, or this crypt next to that crypt... Never occurred to me that there were any truth to that to an extent that it mattered - and my current tanks are a total hodge-podge of countless different crypts with lots of other plant species and all are healthy.

Cheers,
Michael

 

[plantnoobdude]

At least for allelopathy between plants, I agree... back in the day they always said... oh you cant plant crypts next to so and so, or this crypt next to that crypt... Never occurred to me that there were any truth to that to an extent that it mattered - and my current tanks are a total hodge-podge of countless different crypts with lots of other plant species and all are healthy.

I don't think it matters much in tanks with regular water changes TBH. high tech tanks usually vacuum the substrate quite often and frequent water changes should minimise allelopathic chemical accumulation. if you had a low tech tank that very rarely got water changes, then it might be a different story.

 

[PARAGUAY]

Tropica say dosing their products (AFAIK they only have 2 liquid fertilisers premium and specialists) can cause algae if too much is added. EI dosing for CO2 aquariums care has to be taken as we know if everything else isn't right algae beckons. I thought in a YT Green Aqua tutorial they warned of excess nutrients causing algae. George Farmer doses double treble rec. dose Tropical Specalised but we know he's knows what to dose and when.

 

[plantnoobdude]

Tropica say dosing their products (AFAIK they only have 2 liquid fertilisers premium and specialists) can cause algae if too much is added

it's because specialised uses nh4/nh3 as N source. overdosing can sometimes cause algae. nothing to worry much about if using no3 though.

 

[erwin123]

The whole point behind Estimative Index is to dose in Excess so that plant nutrients never becomes a limiting factor. Numerous successful EI tanks show that excess nutrients do not cause/trigger algae.

The 3 things that matter most are:
(1) optimised CO2 (stable pH drop from lights on to lights off)
(2) good water flow, especially at substrate level
(3) clean tank (regular water change, vacuum substrate etc).

Worrying about dosing too much or too little, is not in the Top 3

Heres a good description of EI:

The Estimative Index Of Dosing, Or No Need For Test Kits

The Estimative Index of Dosing, or No Need for Test Kits

barrreport.com

 

[swyftfeet]

You know as crazy as I might begin to sound here, I only noticed BBA in my journal tank when the moneywort started struggling and dying.

BBA is not poisonous to wildlife it’s just ugly in our little experiments.

This might be just natures way of trying to make things habitable for other life. I’m not trying to go on some theological rant, I’m merely saying this planet has a way of trying to do things, maybe the appearance of BBA no matter whether your in AUS , UK or USA, France or Denmark. It’s always right there to start in our tanks when the chemistry/conditions are ripe for it in our water.

I’d be super happy to be able to avoid it, I’d love to know the science behind it. But the only conclusive thing about it is it will show up anywhere anytime in almost everyone’s tank except for the folks who’ve really got their recipie working. They also tend to be the same ones who are the most fastidious with tank maintenance and cleaning… It’s the only thing I’ve seen anyone say is it’s due to some unbalance: light ferts water quality etc.

Maybe the trigger is simply some part of the chemicals released when plant death occurs. Could be trimmings in established tanks or the struggle of new tanks and plant melt.

I think it’s more like a sentinel lymph node when you’ve got cancer. It’s just showing up to let you know your “soup” isn’t cooking perfectly but nature wants our life of some form to grow so it’s gonna substitute it’s pinch-hitter simplistic oxygen creator for us.

One thing we know about BBA is it’s black and it can outcompete our lovely green stuff. That means it’s meant to absorb every damn bit of visible light, every color on the spectrum and it can live in terrible water chemistry. That in itself should tell smarter people than me something, but I don’t know what it means.

Edit: I guess I just described alleopathy from a point of ignorance, as I just looked it up after typing this all out :-/

 

[erwin123]

I never had, and still don't have BBA in my low tech tank for some reason.

Most the plants in my low tech tank come from my high tech tank in the form of excess cuttings, and I'l sure that plenty of BBA spores come over. But they never grow in my low tech for some reason.

Apart from CO2, my low tech and high tech tanks are very similar. They use the same tap water, same fertiliser, same substrate. Previously I would say my water change routine was the same but for my low tech i've gotten lazy because I WFH less and only do WC for low tech every 2 weeks...

I do have GDA and a little bit of GSA in my low tech however.